Trends in Food Science & Technology 152 (2024) 104687

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Trends in Food Science & Technology

journal homepage: www.elsevier.com/locate/tifs

From plate to palate: Sustainable solutions for upcycling food waste in

restaurants and catering
Nida Kanwal a,b , Min Zhang a,c,* , Mustafa Zeb d, Uzma Batool a , Imad khan a , Luming Rui e
a
State Key Laboratory of Food Science and Resources, Jiangnan University, 214122 Wuxi, Jiangsu, China
b
Jiangsu Province International Joint Laboratory on Fresh Food Smart Processing and Quality Monitoring, Jiangnan University, 214122 Wuxi, Jiangsu, China
c
China General Chamber of Commerce Key Laboratory on Fresh Food Processing & Preservation, Jiangnan University, 214122 Wuxi, Jiangsu, China
d
International Joint Research Laboratory for Biointerface and Biodetection, Jiangnan University, Wuxi, China
e
Yechun Food Production and Distribution Co.,Ltd.,225000, Yangzhou, Jiangsu, China

A R T I C L E I N F O A B S T R A C T

Handling Editor: Dr. S Charlebois Background: Food waste (FW) in restaurants and catering arises from inefficiencies throughout food preparation,
handling, and disposal stages. Addressing these inefficiencies via FW upcycling into value-added products pre­
Keywords: sents a sustainable strategy to mitigate waste and advance environmental sustainability.
Food waste Scope and approach: This study explores the global impact of food waste, factors influencing its generation, and
Restaurant and catering sector
potential environmental benefits from waste prevention. It examines consumer food waste rates, where
Strategies to upcycle food waste
approximately 17.5% of prepared food is discarded, comprising kitchen waste (2.2%), serving waste (11.3%),
Sustainable development
Valorization and customer leftovers (3.9%). It explores methodologies used to estimate food waste across EU countries,
Thermal and non-thermal technologies comparing waste management practices in the UK and the Netherlands. It investigates food waste strategies in
China, particularly in ethnic restaurants, and considers consumer perceptions regarding packaging’s role in
waste reduction. Additionally, the study covers sustainable waste management practices in Asia, including pre-
treatment techniques such as upcycling, microbial conversion, anaerobic co-digestion, and 3D food printing,
aimed at reducing waste by 20–30%. Furthermore, it evaluates machine learning models for predicting catering
demand with 85% accuracy and analyzes a 25% reduction trend in waste within Swedish public catering.
Key findings and conclusions: The study highlights challenges and future prospects in repurposing food waste
within restaurant and catering sectors. Presently, only 10–15% of food waste is repurposed, with potential to
increase to 30–40% through enhanced practices and technologies. Continued research and innovation in sus­
tainable waste management can potentially reduce overall waste by 25%, conserve resources, and foster a more
sustainable food system.

1. Introduction consumption is lost or wasted and 1.3 billion tons of food are wasted
globally each year, with a significant portion occurring in the catering
Food waste refers to edible food that is discarded or left to spoil due and hospitality sectors. In the United States, the Food Waste Reduction
to over-preparation, improper storage, and inefficient practices (Yahia & Alliance (FWRA) reports that 4–10% of food purchased by restaurants is
Mourad, 2020). Restaurants and catering businesses generate a signifi­ wasted before reaching the consumer (Dahlan, Yusoff, Akinbile, Wang,
cant amount of food waste, including surplus ingredients, trimmings, & Wang, 2022). At the European level, the European Parliament’s
and unsold meals. This waste arises from various stages, including food Committee on Agriculture reports that up to 50% of edible and safe food
preparation, service, and leftovers from customers, leading to significant is needlessly discarded in households, supermarkets, restaurants, and
economic and environmental impacts (Ishangulyyev, Kim, & Lee, 2019). throughout the entire food chain annually (EU Commission, 2024).
Furthermore,58% of fugitive methane emissions at landfills come from Meanwhile, 79 million people live below the poverty line, and 16
wasted food, according to an updated report from the U.S. EPA (States, million rely on food aid from charities. The global economic value of
20 MAY 2024). According to the Food and Agriculture Organization food waste is estimated at around $1000 billion annually, and this figure
(FAO), approximately one-third of all food produced for human increases to $2600 billion when accounting for the hidden

* Corresponding author. School of Food Science and Technology, Jiangnan University, 214122 Wuxi, Jiangsu Province, China.
E-mail address: min@jiangnan.edu.cn (M. Zhang).

https://doi.org/10.1016/j.tifs.2024.104687
Received 24 March 2024; Received in revised form 21 August 2024; Accepted 26 August 2024
Available online 27 August 2024
0924-2244/© 2024 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
N. Kanwal et al. Trends in Food Science & Technology 152 (2024) 104687

Fig. 1. Innovative food waste upcycling approaches and products.

environmental costs associated with the issue (Waste, 2019). Approxi­

mately 44%–47% of annual fruit, vegetable, meat, and fish production is
wasted (Aureli, Scalvedi, & Rossi, 2021). Waste and Resources Action
Programme (WRAP) in the UK found that the hospitality and food ser­
vice sector produces around 1 million tons of FW annually, costing the
industry an estimated £2.5 billion. In Europe, Food Use for Social
Innovation by Optimizing Waste Prevention Strategies (FUSIONS)
project estimated that food waste in the hospitality sector amounts to
approximately 12.5 million tons per year (WRAP, 2024). Additionally, a
study by Leanpath indicates that on average, 4–8% of food in the
catering sector is wasted, resulting in significant financial losses
(Leanpath, 2024). The National Restaurant Association in the US high­
lights that food waste can account for up to 10% of a restaurant’s food
cost, impacting overall profitability. Contributing factors include inap­
propriate procurement, storage, processing, and operation strategies
(Elgarahy et al., 2023b). In the restaurant and catering industry, both
staff and consumers are major contributing factors to food waste Fig. 2. Catering food waste causes.
through over-preparation, improper handling, and uneaten leftovers.
This waste not only contributes to environmental degradation but also the restaurant and catering sectors across different regions of the world,
represents a missed opportunity to address food insecurity and reduce its environmental, social, and economic impacts, and innovative ap­
greenhouse gas emissions (Rakesh & Mahendran, 2023). proaches to upcycling FW into useful by-products, emphasizing sus­
The need for sustainable transformations has never been more urgent tainable practices for waste reduction and promoting a circular
and the need to review the topic of food waste in the restaurant and economy. Furthermore, integrated analysis of factors influencing food
catering sectors is crucial, especially as the world population is projected waste, including consumer behavior, management perspectives, and
to reach around 8.5 billion by 2030 according to a 2015 UN report technological advancements. While previous studies have addressed
(Elgarahy et al., 2023b). Although food-related waste in this sector is various aspects of food waste, there is a lack of exploration of the main
frequently covered in the media, it has not yet received adequate aca­ contributing factors in these sectors. Additionally, the scope of food
demic attention. With the global population already facing food poverty, waste is often not compiled in a manner that supports the development
addressing the 12–14% contribution of food waste by these sectors is of upcycling strategies. Therefore, this study conducts a comprehensive
imperative. Reducing food waste can play a significant role in enhancing analysis of the causes and effects of food waste, quantifying the data of
food security, conserving resources, and mitigating environmental im­ loss worldwide through a thorough literature review, and exploring
pacts, making this an urgent area for research and intervention. One innovative upcycling strategies. These strategies include high-pressure
innovative and sustainable approach is the upcycling of food waste, processing, fermentation, microbial application, innovative packaging,
which can contribute to stable ecosystems and a circular economy. 3D food printing, and machine learning, along with chemical, biological,
Implementation of sustainable menu planning is the key strategy for and physical methods, accompanied by practical examples. However,
upcycling food waste in restaurants and catering. By designing menus information on food waste and its upcycling strategies in the restaurant
that utilize ingredients efficiently and creatively, chefs can minimize and catering sectors remains scattered and limited, and public accep­
waste while offering innovative and appealing dishes to customers tance of upcycled products is not widespread, posing a significant
(Rohmer, Gerdessen, & Claassen, 2019). Upcycling FW in restaurants challenge for the adoption of these strategies. Therefore, the authors
and catering is not only a practical necessity but also a moral imperative attempt to explore various strategies for upcycling FW (Fig. 1) into
(Aleshaiwi, 2023). Through collaboration, education, and innovation, economically valuable products such as food items, conversion into
the transition from plate to palate can become a model for sustainable green energy, providing an overview of recent innovations, benefits, and
food practices worldwide (Brennan et al., 2021; Rohmer et al., 2019). technical challenges involved. It analyzes common resources found in
The objective of this article is to examine the main causes of FW in highly cited literature reviews from recent years, encompassing a total

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of 140 published articles from 2017 to 2024, offering a robust basis for
advancing sustainable food waste management practices.

2. Contributing factors and global impacts of food waste

Globally, it is estimated that about 12–14% of FW occurs in the food

service sector, which includes restaurants and catering services (Xue
et al., 2017). Factors (Fig. 2) contribute to this FW which need to be
clearly articulated to understand their impact have been explored in this
paper. One significant challenge is predicting customer demand, leading
to over-preparation and wastage. The absence of a structured purchasing
plan exacerbates this issue, resulting in food items being forgotten and
subsequently spoiling (Filimonau & Gherbin, 2017). Excessive stocking
of ingredients further adds to the problem, often causing surplus food to
go unused. Additionally, compliance with strict regulations often results
in discarded food, while residual waste from food preparation is a
common occurrence due to trimming and peeling (Filimonau, Fidan,
Alexieva, Dragoev, & Marinova, 2019). Inadequate equipment and tools
can also hinder efficient food usage, and uncertainty about the required
cooking quantities often leads to over-production (Filimonau et al.,
2019). Portion sizes are another critical factor; serving inappropriate
portions can result in significant leftovers. Buffet-style service and
extensive menus contribute to food waste by promoting variety over
necessity, leading to excess food preparation (Malefors, 2021). This
often results in significant amounts of uneaten food being discarded, as
it cannot be reused or safely stored for future use. Inefficient waste
management practices and poor facility layouts further aggravate the Fig. 3. Upstream and downstream intervention for food waste management.
issue by not effectively handling waste. Staff handling food improperly
and communication breakdowns among staff are also significant con­ environment. Furthermore, FW in the restaurant and catering sectors
tributors to food waste (Filimonau & Delysia, 2019). Impulse purchas­ can reflect cultural attitudes towards food consumption and wasteful­
ing, varied dietary preferences, and the perception of food as ness. Addressing these cultural norms and promoting sustainable prac­
unappealing can lead customers to order more food than they consume, tices can help reduce food waste and shift societal attitudes towards food
resulting in wastage. The United Nations Environment Program (UNEP) (Phasha et al., 2020). However, addressing the issue of food waste re­
reports that factors such as purchasing power, industrial expansion, and quires a multifaceted approach that includes both upstream and
diverse food offerings contribute to the substantial volume of food waste downstream interventions (Fig. 3) (Malefors, Sundin, Tromp, & Eriks­
generated in Asian regions (Withanage, Dias, & Habib, 2021). Building son, 2022a). Also it requires investments in infrastructure development
on the contributing factors, it is essential to consider the impacts of food and improvements in supply chain management practices to ensure
waste, which play a significant role in aggravating these issues. The efficient storage, transportation, and delivery of food, reducing the risk
environmental consequences of FW are significant, contributing up to of spoilage and waste (Elgarahy et al., 2023b). Lastly, regulatory factors
8% of total global greenhouse gas emissions. Methane, a potent green­ including food safety regulations and incentives for waste reduction,
house gas, aggravating climate change (Dhir, Talwar, Kaur, & Malibari, play a role in food waste generation and require a balance between food
2020). FW also increases landfill waste, releasing harmful substances safety and waste reduction (Economou et al., 2024).
during decomposition (Schanes, Dobernig, & Gözet, 2018). Moreover,
food production consumes substantial water and land resources, so 3. Ecological and economic benefits of upcycling food waste
wasting food also wastes these resources used for production, transport,
and preparation, such as water, energy, and labor. In addition to the Upcycling FW in the restaurant and catering sector offers significant
environmental consequences, the economic implications of FW in the potential environmental advantages. By transforming food scraps and
restaurant and catering sector are equally profound, affecting both surplus into new, value-added products, this practice reduces the
operational efficiency and profitability, representing a loss of valuable amount of waste sent to landfills, thereby lowering greenhouse gas
resources and money for businesses (Filimonau, Todorova, Mzembe, emissions such as methane, a potent contributor to climate change
Sauer, & Yankholmes, 2020). This inefficiency directly affects profit­ (Elgarahy et al., 2023b). Additionally, food waste can be converted into
ability and sustainability, as businesses incur costs without receiving the green energy, providing an alternative to fossil fuels (Soon, 2023). This
full benefit of their investment. FW also leads to higher disposal costs. By is particularly beneficial for countries like Pakistan, which faces severe
reducing FW, businesses can improve their bottom line, increase sus­ electricity shortages. Moreover, FW is rich in nutrients that can be
tainability, and use resources more efficiently (Slorach, Jeswani, Cuél­ upcycled into appealing and attractive food products through innovative
lar-Franca, & Azapagic, 2019). Moreover, the social and health impacts technologies such as 3D food printing (Iris & Wong, 2023; Guo, Zhang, &
of FW in the restaurant and catering sector cannot be overlooked, as they Bhandari, 2019). This sustainable approach not only enhances resource
directly affect community well-being and public health, especially efficiency but also fosters a circular economy, promoting a more sus­
considering global food insecurity and hunger (Malefors, 2022). Wasted tainable food system and reducing the environmental footprint of the
edible food represents a missed opportunity to alleviate hunger and food service sector. To implement this, it is important to know some
malnutrition, aggravating food scarcity issues. Additionally, food waste facts, for example each year the European Union throws away about 88
can have social implications regarding equity and access to food. Proper million tons of food, which makes up 15–16% of the total environmental
handling of food waste is crucial, as improper disposal can lead to the impact of its food value chain (European Commission, 2023).
spread of foodborne illnesses and contamination of water sources, However, implementing food waste reduction initiatives in these
affecting both human health and the environment. Managing food waste sectors can yield significant financial benefits. For example, research
effectively can reduce health risks and contribute to a healthier conducted by the World Resources Institute (WRI) and the Waste and

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N. Kanwal et al. Trends in Food Science & Technology 152 (2024) 104687

Table 1 Table 1 (continued )

Upcycled food waste objectives and relevant research. Objectives Research findings References
Objectives Research findings References
independently of the fibre
1 Non-pomace grape The polyelectrolyte de Azevedo and Noreña used
juice residues complexation seems (2023) 10 As balanced Diet Upcycling food Nogueira, Alves, and
effective due to the contributes to increasing Vaz-Fernandes (2021)
upcycling of the grape resource use efficiency
juice non-pomace (SDG 12.5) and
residues in the complexes substantially reduce
which influenced the waste generation,
functionalization of the ensuring sustainable food
physiochemical consumption and
properties of the freshness production systems (SDG
indicators 12.5; SDG 12.3)
2 Pig skin waste The three-dimensional (LATORRE, Velazquez, 11 Circular economy The evolution of linear (do Canto, Grunert, & De
(gelatin) network results in gel Palacio, & Sanchez, by circular food behaviors, going through Barcellos, 2021)
strength, making the 2022) behavior slightly more
gelatin a commercial transitioning behaviors
product for the food until reaching circular
industries behaviors
3 Upcycled dietary Upcycled DF from Moreno-Chamba et al. 12 Food management In the food waste Moshtaghian, Bolton, and
fibre persimmon byproducts as (2022) hierarchy management hierarchy, Rousta (2021)
a potential modulator (position of upcycled food production
agent of microbial upcycled food) can be included in the
populations and showed hierarchy, it appear below
the antibacterial effects of the redistribution and
gallic acid after release above the animal feed
4 Consumer The highest purchase Yilmaz and Kahveci stage of the hierarchy
purchase intention intention belongs to (2022)
towards upcycled younger female
food consumers who Resources Action Programme (WRAP) evaluated cost and benefit data
frequently recycled at from 1200 business sites across 700 companies in 17 countries. They
home and had a higher
found that for most businesses, every $1 invested in food waste reduc­
quality and better taste
expectation from tion resulted in savings of $14 or more (EU Commission, 2024).
upcycled food Therefore, it can be inferred that SDG 12.3, set by the United Nations,
5 Fish by-products 60–100% of the total oil Pinela et al. (2022) aims to cut global per capita food waste at retail and consumer levels in
content recovered within half by 2030 (Ardra & Barua, 2022; Jacob-John, D’Souza, Marjoribanks,
19 min from the fish by-
products, whereas 51%
& Singaraju, 2023) is attainable and could be exceeded with initial in­
MUFAs, 29% PUFAs and vestments, managements, and its beneficial for ecology and economy.
20% SFA were included Another study also investigated the feasibility of SDG 12.3 and assessed
and a profile of fewer the environmental benefits, including those for climate, biodiversity,
cardiovascular risks, less
and overall environment, of preventing food waste in the food service
microbial growth
6 Muffins 15% muffins were the Grasso, Pintado, sector (Beretta & Hellweg, 2019). It highlights the importance of indi­
most similar to the control Pérez-Jiménez, vidual food services in achieving this goal, noting that customized
with improved fibre Ruiz-Capillas, and measures are necessary based on factors such as serving systems,
content, mineral content, Herrero (2021) customer segments, and preparation methods. Further case studies are
amino acid profile, and
antioxidant activity
needed to establish parameters for different types of food services and
7 Sustainable The mandatory six Aschemann-Witzel, Ares, determine the most effective food waste reduction strategies. From
development in transformations based on Thøgersen, and practical perspective Table 1 presents different upcycled food waste
the food sector sensory-derived food Monteleone (2019) objectives and relevant research.
satisfaction, wellbeing
and happiness include
diet shift, food diversity, 3.1. Five key approaches for eco-economic benefits from food waste
reduced food waste,
circular food system,
prioritizing well-being Restaurants and catering businesses can play a crucial role in FW
through the foods and management by adopting sustainable practices within a comprehensive
tolerating the climatic value framework. Five key approaches; repositioning, reallocating,
outcomes reacting, re-engineering, and relating, highlight how these businesses
8 Circular Bio- Circular bioeconomy Mak, Xiong, Tsang, Iris,
economy enhances the value of and Poon (2020)
can achieve economic, social, and environmental benefits (Huang et al.,
Opportunities material flow in an eco- 2021).
friendly way where the Repositioning involves increasing the visibility and likelihood of
driving force is the consumption of dishes or ingredients nearing expiration (Sundström,
increasing energy
2021). For example, offering discounts or creating special menu items
requirement
9 Upcycled orange Microwave technology Rodríguez, from soon-to-expire ingredients can reduce waste and recover costs.
fibre (Gluten free produced muffins with a Alvarez-Sabatel, Ríos, Reallocating focuses on redistributing surplus food to those in need,
muffins) higher height, easier to Rioja, and Talens (2022) often through partnerships with local food banks or charities, addressing
chew, and better food insecurity and enhancing social responsibility (Sun et al., 2024).
appearance than
conventional baking,
Reacting involves immediate measures such as reducing prices on items
close to expiration or donating unsold food to charities, but long-term
solutions are essential. Re-engineering includes redesigning processes
or products to minimize waste, such as adjusting portion sizes,

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optimizing inventory management, or using innovative packaging so­ Additionally, two baseline models were presented to compare against
lutions to extend shelf life. These changes can significantly reduce traditional demand estimation methods. The effectiveness of the pro­
environmental impact and improve profitability (Krishnan, Agarwal, posed machine learning models was evaluated using data from three
Bajada, & Arshinder, 2020). Furthermore, relating involves building canteens. Results indicated that models based on random forest (RF) and
strong relationships with customers, suppliers, and stakeholders to long short-term memory (LSTM) neural network algorithms provided
promote sustainable practices. Educating customers about reducing food the most precise forecasts. Implementing these advanced models could
waste, collaborating with suppliers for sustainable sourcing, and potentially reduce wasted meals by 14%–52% and decrease unmet de­
engaging staff in waste reduction are key. These efforts can contribute to mand by 3%–16% compared to the baseline models. The integration of
a more sustainable food system. However, the impact of these benefits machine learning into demand forecasting has the potential to enhance
varies, indicating a need for further empirical investigation. Adopting a service levels and reduce food waste, thus addressing its environmental,
holistic approach that considers the entire supply chain can help these social, and economic impacts (Rodrigues, Miguéis, Freitas, & Machado,
businesses reduce waste, improve their bottom line, and support a more 2024).
sustainable future (Riesenegger & Hübner, 2022). Moreover, the RF algorithm-based model performed better in the
school canteens, while the LSTM neural network-based model showed
4. Sustainable solutions for upcycling food waste in restaurants superior performance in the company canteen. The RF model showed
and catering higher effectiveness with three to four years of data and 200 to 400 daily
meals, whereas the LSTM model excelled with over nine years of data
4.1. Turning scraps into culinary art: the future of food waste with 3D and approximately 1900 meals served daily. LSTM models exhibited the
printing most significant potential for FW reduction, particularly in FCS3, likely
due to a longer data history for more accurate predictions. Machine
3D food printing is an emerging technology that is gaining significant learning-based forecasts consistently outperformed traditional methods,
attention, with increasing research and development focused on its po­ with RF and LSTM models yielding the best results. FCSs not utilizing
tential to revolutionize food production (Zhao, Zhang, Chitrakar, & machine learning should consider adopting a Moving Average (MA)
Adhikari, 2021). This technology offers innovative solutions for food approach over a naive method for demand forecasting (Yuan et al.,
waste by transforming discarded material into valuable products. For 2023).
instance, in a study it was analyzed that the administration of grape
pomace can significantly enhance the nutritional and antioxidant 5. Global perspectives on food waste upcycling in restaurant
properties of cookies. Using specific parameters such as a nozzle diam­ and catering industries
eter of 1.28 mm, extruder motor speed of 600 rpm, and print speed of
400 mm/min optimized the printability of the food using the CARK The percentage of FW in restaurants and catering sectors varies
extrusion-based 3D printer. Post-processing at 130 ◦ C for 12 min further significantly depending on the region, type of establishment, and man­
refined the printed constructs, with the 6% grape pomace formulation agement practices. Globally, it is estimated that about 12–14% of food
proving most favorable during sensory evaluation (Jagadiswaran et al., waste occurs in the food service sector, which includes restaurants and
2021). Notably, the final product was enriched with proteins and dietary catering services (UNEP, 2021). In the United States, the restaurant
fiber. This approach underscores the potential for adding value to in­ sector is responsible for approximately 15–20% of total FW generated
dustrial waste streams while meeting consumer preferences. It also (Gunders & Bloom, 2017). In the European Union, the hospitality sector,
highlights how additive manufacturing allows for precise customization encompassing restaurants, hotels, and catering services, accounts for
of food products in terms of nutritional content, promoting cleaner around 12% of total FW (Papargyropoulou et al., 2019). Specifically, in
production practices and enhancing resource recovery from food pro­ the United Kingdom, it is estimated that about 18% of the food pur­
cessing wastes (Jagadiswaran et al., 2021). chased by the hospitality sector is wasted, equating to roughly 920,000
By repurposing food waste into familiar consumer products like tonnes of FW annually (UK, 2024). In 2019, global FW varied signifi­
cookies, chocolates (Karyappa & Hashimoto, 2019), biscuits, and wa­ cantly across different sectors. The food service sector contributed an
fers, 3DFP can contribute to sustainability efforts. For instance, vege­ average of 32 kg per capita per year, totaling 244 million tons. The retail
tables with high starch content are generally more amenable to 3D sector accounted for 15 kg per capita per year, amounting to 118 million
printing. A study by Pant, Ni Leam, Chua, and Tan (2023) characterized tons. Households were responsible for the highest average, with 74 kg
food ink recipes made from spinach and kale stalks, discovering that the per capita per year, equating to 569 million tons. Overall, the total
formulation of the ink depended significantly on the inherent water global food waste was 121 kg per capita per year, reaching 931 million
content of the processed material. Specifically, they found that devel­ tons. These figures highlight the significant contribution of the restau­
oping inks from spinach was more challenging than from kale due to its rant and catering sectors (D. UNEP, 2021).
higher water content. Furthermore, the study highlighted the potential
of 3D printing to transform food waste into visually appealing edible 5.1. Restaurants in UK and Netherlands
products. For example, Leo et al. (2022) utilized 3D printing to convert
orange peel waste (OPW) into edible snacks rich in bioflavonoids. Their A study by Filimonau et al., adopted a qualitative and descriptive
research produced various shapes using OPW inks, including edible soup case study approach. This was deemed the most suitable method due to
bowls, biscuits, and food toppings, all of which served as sources of the exploratory and sensitive nature of the topic, specifically restaurant
antioxidant-rich compounds such as gallic acid, p-coumaric acid, ferulic food waste. The research focused on the experiences of restaurant
acid and narirutin. This demonstrates the viability of using 3D printing managers in the UK and the Netherlands, shedding light on food waste
technology to upcycle food waste into nutritious and aesthetically management practices in these two countries. The study’s scope was
pleasing products in the restaurant and catering sectors (Leo et al., 2022; limited to these regions due to resource constraints for cross-national
Pant et al., 2023). comparison (Filimonau et al., 2020). This comparative study revealed
shared practices like demand forecasting, yet inefficiencies persist,
4.2. Machine learning models and food waste reduction leading to substantial waste. Financial concerns often hinder proactive
measures like surplus food redistribution, despite environmental bene­
According to a study machine learning models were designed to fits. Effective strategies in British and Dutch restaurants include demand
enhance food demand forecasting and to improve accuracy, thereby forecasting and passive disposal, but proactive measures such as
aiding in the avoidance of overproduction or underproduction. repurposing ingredients and reducing plate waste are less common.

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Table 2 Table 2 (continued )

SWOT analysis of food waste treatment methods. 3 Competing priorities: Other pressing environmental, social, and
Strengths 1 Environmental benefits: FW treatment methods contribute to economic issues may divert attention and resources away from
reducing greenhouse gas emissions, minimizing landfill usage, FW reduction and treatment efforts, diluting momentum and
and conserving natural resources (Al-Rumaihi, McKay, Mackey, support (Al-Rumaihi et al., 2020).
& Al-Ansari, 2020). 4 Technological risks: Dependence on specific technologies or
2 Resource recovery: Many FW treatment methods facilitate the reliance on unproven innovations may expose treatment FW
extraction of valuable resources such as biogas, compost, and initiatives to technical failures, performance setbacks, and
biofuels, which can be used for energy production or implementation delays (Cosbuc, Ungureanu-Comanita, & Gav­
agricultural purposes (P. Sharma et al., 2020). rilescu, 2021).
3 Regulatory support: Governments and environmental agencies 5 Behavioral inertia: Overcoming entrenched habits, attitudes,
increasingly support and incentivize FW treatment initiatives and cultural norms related to food consumption, disposal, and
through regulations, subsidies, and grants (Joshi & Visvanathan, waste management represents a formidable challenge in
2019). achieving widespread adoption of sustainable practices and
4 Technological advancements: Continuous innovation in FW behaviors (Aschemann-Witzel & Stangherlin, 2021; Bangar
treatment technologies improves efficiency, scalability, and et al., 2024).
cost-effectiveness, making them more viable and accessible
(Ashokkumar et al., 2022).
5 Public awareness: Growing awareness of environmental issues However, overcoming organizational and regulatory barriers is crucial
and sustainable practices enhances public acceptance and to fostering sustainability. Future research needs to explore innovative
participation in FW treatment programs (Rasool, Cerchione,
methods to repurpose leftovers and optimize waste reduction strategies
Salo, Ferraris, & Abbate, 2021).
Weaknesses 1 Infrastructure requirements: Implementing FW treatment across the EU and globally.
methods often demands significant investments in
infrastructure, such as processing facilities, collection systems, 5.2. Ethnic cuisine restaurants
and transportation networks (Babbitt et al., 2022).
2 Operational challenges: Handling and treating diverse types of
FW can present operational complexities, including odor
A study by Filimonau et al., investigated ethnic food restaurants
control, contamination risk, and seasonal variations in waste specializing in Chinese cuisine, given its popularity in the UK market of
generation (Pour & Makkawi, 2021). out-of-home food consumption. According to Mintel (2020), 34% of UK
3 Economic viability: The economic feasibility of FW treatment residents regularly eat out at Chinese restaurants, and 48% routinely
methods depends on factors like waste composition, market
order Chinese takeaways. This has made Chinese cuisine the most
demand for by-products, and regulatory frameworks, posing
challenges for profitability and scalability (Dou, Dierenfeld, popular type of oriental cuisine in the UK, with 94% of customers of
Wang, Chen, & Shurson, 2024). oriental restaurants preferring those with a Chinese specialization.
4 Technological limitations: Some food waste treatment Within a year of business operations, it is estimated that the case study
technologies may have limitations in processing certain types of restaurant generates 14.75 tonnes of food waste. In 2018, the restaurant
waste or achieving optimal resource recovery rates, hindering
their effectiveness.
catered to approximately 107,000 guests, and assuming this pattern
5 Behavior change: Addressing FW at its source requires remained unchanged in 2019, the food wastage per guest equates to 138
significant shifts in consumer behavior, food industry practices, g (Filimonau, Nghiem, & Wang, 2021). The study also identified barriers
and supply chain management, presenting ongoing challenges to waste reduction and proposed strategies to address them. Future
in adoption and sustainability (Aschemann-Witzel &
research could expand to explore food waste in restaurants specializing
Stangherlin, 2021).
Opportunities 1 Circular economy initiatives: Food waste treatment aligns with in other ethnic cuisines and compare waste management practices
the principles of the circular economy, offering opportunities for across different culinary traditions. Comparative analyses between local
creating value FW streams, closing resource loops, and markets and countries of origin for ethnic cuisines could provide valu­
promoting sustainable consumption and production (Rashid & able insights. Additionally, studying FW variations among different
Shahzad, 2021).
2 Innovation and collaboration: Collaborative efforts among
customer segments, such as regular patrons versus tourists, and expa­
government, industry, academia, and NGOs can foster triates versus local residents, would deepen our understanding of waste
innovation in FW treatment technologies, business models, and drivers. Research efforts need to focus on promoting more efficient
policy frameworks, unlocking new opportunities for efficiency cooking practices among chefs and examining suppliers’ roles in waste
and effectiveness (Annosi, Brunetta, Bimbo, & Kostoula, 2021).
reduction across ethnic restaurants and the broader food supply chain
3 Market development: Growing demand for sustainable products
and services creates market opportunities for businesses (Filimonau et al., 2021; Wu, Zhang, Wang, Mothibe, & Chen, 2012).
involved in FW treatment, including technology providers,
waste management companies, and renewable energy 5.3. Awareness in Chinese restaurants
producers.
4 Community engagement: Engaging communities in FW
reduction and treatment initiatives through education,
In China, where ecological civilization and the circular economy are
incentives, and participatory programs can enhance local prioritized, effective recycling of FW faces challenges. A study utilizing
resilience, social cohesion, and environmental stewardship an assessment model found that 37.33% of restaurant owners exhibit
(Aschemann-Witzel & Stangherlin, 2021). high awareness of food waste issues, while 62.67% show low awareness,
5 Policy support: Supportive policies, such as landfill bans,
highlighting a general lack of awareness among owners in the region.
extended producer responsibility schemes, and tax incentives,
can create favorable conditions for investment in FW treatment Logistic regression analysis identified factors influencing awareness,
infrastructure and innovation (Fesenfeld, Rudolph, & Bernauer, revealing that female and older owners tend to have lower awareness
2022). levels, whereas younger owners show higher awareness. Furthermore,
Threats 1 Economic uncertainties: Economic downturns, market education level, restaurant scale, daily FW generation, waste treatment
volatility, and financial constraints may limit investments in
methods, and city macroeconomic development were identified as fac­
food waste treatment infrastructure and innovation, slowing
progress in addressing food waste (Peschel & tors positively influencing awareness levels (Lang et al., 2020). The
Aschemann-Witzel, 2020). rapid growth of China’s restaurant industry and dining-out culture has
2 Regulatory challenges: Inconsistent regulations, bureaucratic increased the complexity of managing FW in restaurants (Lang et al.,
hurdles, and policy uncertainties can create barriers to
2020).
implementing and scaling up FW treatment initiatives,
complicating planning and decision-making.

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N. Kanwal et al. Trends in Food Science & Technology 152 (2024) 104687

5.4. Policy and technological drivers in Asia and the EU approach involves using insects to break down food waste and produce
valuable products like protein-rich insect-based foods. For example,
In Asia, the management of FW is shaped by varying levels of companies are exploring the use of black soldier fly larvae to convert FW
awareness, development goals, and socio-economic constraints. While into protein powder and animal feed. However, despite its sustainability
there is a considerable emphasis on segregating and treating FW, there is benefits, consumer acceptance remains a challenge due to cultural
a notable gap in efforts to prevent food waste at its origin. Table 2 barriers and perceptions about insect consumption in many regions and
highlights this issue by presenting a SWOT analysis of FW, illustrating religions (Bhatia, Jha, Sarkar, & Sarangi, 2023; Roy, Mohanty, Dick, &
the strengths, weaknesses, opportunities, and threats related to current Misra, 2023).
policies and practices. Furthermore, treatment methods indicates that
anaerobic digestion is favored for its cost-effectiveness, energy genera­ 6.1. Physical pre-treatment techniques
tion, and production of nutrient-rich digestate (Giuseppe, Emanuele,
Rita, Roberta, & Biagio, 2020). Food waste encompasses mechanical and thermal methods, such as
Furthermore, decentralized anaerobic digestion systems are milling, ultra-sonication, Pulsed-electric-field (PEF) technology, micro­
preferred over centralized ones due to their lower energy consumption, wave irradiation, and extrusion. Mechanical methods, like milling,
ease of operation, reduced resource requirements, lower costs, and enhance anaerobic digestion by increasing the substrate’s surface area.
greater public acceptance. Policies that promote energy recovery from Milling exposes food waste to significant mechanical stress, leading
segregated food waste play a critical role in encouraging anaerobic to changes in its physicochemical and structural characteristics
digestion and promoting sustainable food waste management practices (Gallego-García, Moreno, Manzanares, Negro, & Duque, 2023). This
(Joshi & Visvanathan, 2019; Vizzoto, Testa, & Iraldo, 2021). Studies process improves enzymatic action and digestibility by enlarging the
conducted at the national level in EU countries show significant dis­ surface area of the pretreated material. This method is frequently
crepancies in FW quantification due to various measurement ap­ combined with other pre-treatment methods, such as wet milling, to
proaches. To address this challenge, the European Commission has extract cellulose nano-fibers or sugars from lingo-cellulosic materials
introduced a standardized methodology and minimum quality standards (Gallego-García et al., 2023).Despite its benefits, milling has limitations,
for measuring FW. However, given the diverse quantification strategies including high energy requirements and, in some cases, comparatively
used by EU countries, there is a need for a harmonized modeling system lower efficiency. Additionally, PEF technology increasingly researched
to accurately estimate FW (Stenmarck et al., 2016). For example, let’s in the past decade, applies voltage to food waste to extract
examine a modeling methodology employed for estimating food waste bio-compounds, particularly from fruit and vegetable waste (Arshad
across EU nations. It employs Material Flow Analysis (MFA) alongside et al., 2021). This method triggers irreversible electroporation in bio­
statistical data related to food production and trade. But Implementing logical cells, disrupting cell membranes and enabling the extraction of
MFA requires extensive and detailed data collection across various valuable compounds. PEF technology is advantageous for sustainability,
stages of the supply chain. This can be time-consuming and as it requires less energy and is effective in various industries. For
resource-intensive, particularly in regions with fragmented or incom­ instance, improper handling of food processing wastes emits CO2,
plete data systems. Another methodology estimates food waste using contributing to the greenhouse effect and necessitating energy and
waste statistics but the challenge is waste statistics may not capture the cost-intensive waste disposal methods. Therefore, eco-friendly and
full extent of food waste, as they often rely on reported or recorded data, cost-effective approaches such as PEF technology are recommended for
which can be incomplete or inconsistent. This methodology might extracting bioactive components from these wastes. The extracted
overlook unreported waste or informal disposal practices, leading to compounds exhibit higher antioxidant activity, stability, therapeutic,
potential underestimations. So to overcome these challenges more and functional properties, making them suitable for use in the food and
research work, surveys and efforts are required to estimate exact per­ pharmaceutical industries (Theagarajan, Balendran, & Sethupathy,
centage of FW to combat hunger and meet the zero hunger goal 2024; Yan et al., 2010). PEF, combined with conventional or
(Tchonkouang, Onyeaka, & Miri, 2023). non-conventional technologies like ultrasound (US) and high-pressure
processing (HPP), effectively extracts bioactive compounds with
6. Strategies for upcycling food waste noticeable advantages such as limited solvent consumption, high purity,
reduced extraction time, and low energy consumption (Ashrafudoulla
There is no universal method for upcycling of FW (Ooi, Woon, & et al., 2023). Compared to Ultrasound Assisted Extraction (UAE), Mi­
Hashim, 2021). Efficient FW management includes transforming it into crowave Assisted Extraction (MWAE), and HPP-assisted extraction,
valuable products like bio-plastics, bioenergy, enzymes, bio-char, PEF-assisted extraction (PEFAE) consumes less energy and provides a
mushroom bio-products and medical components (Guo, Zhang, & higher extraction yield, making it a promising technology for valorizing
Fang, 2022; M. Sharma, Sridhar, Gupta, & Dikkala, 2022). food processing wastes and supporting a circular economy. However,
The United Nations Environment Program (UNEP) has estimated an challenges include treatment optimization, installation costs, and elec­
economic loss of approximately 400 billion USD due to FW (Kumar trochemical changes in electrodes. Future studies need to focus on
et al., 2022), underscoring the necessity to utilize FW for value-added valorizing wastes from dairy, spices, and condiment industries.
product production and to foster a circular bio economy (Rakesh & Although PEF technology has broad applications in waste valorization,
Mahendran, 2023). Transforming food waste into valuable products the initial cost of the PEF system and the selection of appropriate sol­
such as bio-plastics, bioenergy, enzymes, bio-char, and medical com­ vents are major concerns. Additionally, optimizing PEF treatment con­
ponents is a key strategy in this regard. By converting food waste into ditions is necessary to achieve high extraction yield and product quality
these products, the volume of waste ending up in landfills is significantly in a short time (Velusamy, Rajan, & Radhakrishnan, 2023).
reduced, leading to a more sustainable waste management system (M. Furthermore, Extrusion as a pre-treatment technique, reduces par­
Sharma et al., 2022). Furthermore, FW can be converted into animal ticle size and fibrillates materials through a combination of mechanical
feed but converting FW into animal feed faces challenges such as and thermal effects in an extruder (Gallego-García et al., 2023). A
ensuring safety from contaminants, meeting nutritional requirements, continuous operation and better mixing are among its advantages,
adhering to regulatory standards, optimizing processing methods, and making it suitable for extracting value-added bio-products or promoting
addressing market acceptance concerns. These factors require careful sugar yield from various food waste sources. These physical
management and technological innovation to safely and effectively pre-treatment methods enhance microbial and enzymatic hydrolysis of
utilize food waste in animal feed applications (Nath et al., 2023; Rajeh, FW by increasing surface area and disrupting complex compounds
Saoud, Kharroubi, Naalbandian, & Abiad, 2021). Furthermore, a novel (Konan et al., 2022).

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N. Kanwal et al. Trends in Food Science & Technology 152 (2024) 104687

Table 3
Valorization of food wastes into biofuels using microbial processes.
Type of FW Pre-treatment Microorganisms used Biofuel produced References

Kitchen FW and Rice Clostridium butyricum CBT-1 358.15, 300.8, and 294.5 NmL/gSub from Shah et al.
Straw Hydrolysate glucose, starch, and cellulose, respectively (2023)
Bread waste 2% HCl (v/v) S.cerevisiae strain KL17 114.9 g/L Narisetty et al.
(2022)
Potato Peel Waste Ethanol-50-75% (v/v); Aspergillus fumigatus (for production of 9.451 g/L Jin, Song, and
(PPW) Temp:120–180 ◦ C; 1% (w/w) H2SO4 1% enzymes) and S. tanninophilus Liu (2020)
NaOH
Fruits and vegetable Autoclaving 120 ◦ C; 15 psi; 20min Dark Dry Fermentation Temp:55 ± 41% Abubackar et al.
processing waste 1 ◦ C; SS:250 rpm; pH:5.5 to 6.75 (2019)
FW Lactic acid fermentation 94.6 ± 25.11 mL/gVS Roslan et al.
(2023)

A study by Yue et al., explored the use of ultrasound and microwave materials, such as soybean straw and mixtures of food waste. Moreover,
pre-treatment techniques to enhance methane production from lipid- subjecting substances to pre-treatment with high-pressure carbon di­
rich FW. Ultrasound pre-treatment at 50,000 kJ/kg-TVTS resulted in a oxide can trigger the hydrolysis of hemicellulose. Additionally, Ionic
higher soluble COD of 10,130 mg/L compared to 1910 mg/L with mi­ liquid pre-treatment involves the use of organic salts with high thermal
crowave heating at the same energy input. Methane yield from stability to dissolve cellulose, thereby improving the efficiency of hy­
ultrasound-pretreated waste increased by 43.3%–927.97 mL/g-TVTS, drolysis. Various types of ionic liquids have been applied to different FW
surpassing the 738.63 mL/g-TVTS yield from microwave heating. substrates, enhancing their enzymatic digestibility and fermentation
Fourier transform infrared spectrometer (FTIR) and scanning electron efficiency. However, this method is costly despite its effectiveness
microscopy (SEM) analyses showed reduced residual lipids and relieved (Elgarahy et al., 2023a; Sołowski et al., 2020).
microorganism coating after ultrasound pre-treatment. The energy Furthermore, alkaline pre-treatment is a process that involves
conversion efficiency to methane was 69.89% for ultrasound-treated treating FW rich in cellulose with alkaline mediums such as sodium
waste, higher than the 58.98% achieved with microwave heating. hydroxide (NaOH). This treatment aims to separate lignin and hemi­
These findings underscore ultrasound’s effectiveness in degrading lipids cellulose from cellulose, thereby modifying the structure of cellulose to
and enhancing energy recovery through methane production, posi­ enhance hydrolysis and improve thermodynamic stability (Jankovičová,
tioning it as a promising strategy for FW upcycling (Yue et al., 2021). Hutňan, Czölderová, Hencelová, & Imreová, 2022). However, it is
Moreover, hydrothermal processing, involving hot compressed water, crucial to optimize the concentration of alkali to avoid toxicity or in­
can convert food waste into valuable chemicals or materials, like con­ hibition of microbial growth. Although alkaline pre-treatment has been
verting market fruit and vegetable waste into hydro-char for soil applied to various substrates, it can prolong hydrolysis duration and
improvement (Zhang, Qin, Sun, & Wang, 2022). lead to the formation of salts. Oxidative pre-treatment is a process that
entails treating lingo-cellulosic material with alcohol-acidic solutions,
peroxides, or potent oxidizing agents such as potassium permanganate.
6.2. Chemical pre-treatment methods This treatment aims to separate hemicellulose from cellulose and
dissolve lignin (Fisgativa, Saoudi, & Tremier, 2016). While effective,
Chemical pre-treatment methods involve treating food waste with oxidative pre-treatment is costly and may not substantially improve
acids, alkalis, oxidative agents, or ionic liquids. These agents can break saccharification efficiency.
down complex organic materials, making subsequent processing steps
more efficient. For instance, acids and alkalis can hydrolyze lingo-
cellulosic materials, while oxidative agents can degrade stubborn 6.3. Biological pre-treatment methods
organic compounds. Furthermore, ionic liquids are gaining attention for
their ability to selectively dissolve and recover valuable components Biological approaches present a sustainable remedy, as microor­
from food waste, contributing to a circular economy (Eqbalpour et al., ganisms can be harnessed to generate biofuels, electricity, bio-
2023). From a practical perspective Pakistan, a developing country surfactants, bio-plastics, bio-fertilizers, and other valuable products (P.
grappling with energy shortages, has abundant sources of wasted par­ Sharma, Gaur, Kim, & Pandey, 2020). For instance valorization of food
thenium biomass and catering waste (McElroy, 2018). Thermochemical wastes into biofuels using microbial processes is presented in Table 3.
conversion methods offer an efficient means to convert food waste into Enzymatic treatment breaks down proteins into amino acids and car­
valuable fuels and carbon materials, yielding enegy. For example, in the bohydrates into sugars. Fungal treatment releases enzymes such as
forthcoming decades, hydrogen gas produced by thermochemical pro­ cellulase and hemicellulases, which further break down organic matter.
cess is anticipated to ascend as the preeminent sustainable fuel, owing to This synergistic effect often produces additional valuable by-products
its substantial energy density of approximately 122 MJ/kg and its (Elgarahy et al., 2023a; Maurya, Kumar, Chaurasiya, Hussain, &
emission-free combustion, thereby positioning it as a cornerstone of the Singh, 2021). Furthermore, Black Soldier Fly Larvae (BSFL) can be used
carbon-neutral economy. This phenomenon has precipitated a notable to convert restaurant food scraps into high-protein feed for animals. To
surge in global hydrogen production and storage, with an estimated upcycle citrus peels, the extraction and utilization of pectin can be
annual sales potential of €630 billion by 2050, capable of meeting up to effectively achieved through enzymatic hydrolysis. This methodology
24% of the world’s energy demand (El-Qelish, El-Shafai, Azouz, Rashad, allows for the efficient breakdown of citrus peel cell walls, releasing
& Elgarahy, 2024). For instance, acid pre-treatment entails treating pectin for subsequent use. The extracted pectin can then be incorporated
lignocellulose-rich food waste with potent acids like nitric acid, hydro­ into various food products such as baking, confectionery, and meat
chloric acid (HCl), or sulfuric acid (H2SO4), along with other acids like products as a natural gelling agent. Additionally, it can be marketed as a
acetic acid, maleic acid, or citric acid. These strong acids can dissolve functional food ingredient to enhance gut health by supporting benefi­
cellulose, lignin, and hemicellulose, but they might also generate cial gut microbiota. It not only maximizes the value of citrus peels but
inhibitory compounds, necessitating pH optimization for effective pre­ also aligns with sustainable practices by repurposing food waste into
treatment (Elgarahy et al., 2023a; Sołowski, Konkol, & Cenian, 2020). valuable ingredients.
Diluted sulfuric acid (H2SO4) has been utilized to hydrolyze different Moreover, anaerobic digestion is a widely accepted method for

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N. Kanwal et al. Trends in Food Science & Technology 152 (2024) 104687

decomposing biodegradable organic food waste in controlled atmo­ Riguane, Rouissi, & Ferrari, 2020). Furthermore, frozen FW, especially
spheric conditions, resulting in biogas rich in methane, carbon dioxide, those with high potassium levels, can be upcycled into commercial
and trace gases (Uddin et al., 2021). Various purification methods, such alcohol production through the fermentation process. This method uti­
as chemical absorption, and membrane separation, help remove impu­ lizes the mono-, di-, polysaccharides, and starch present in the waste.
rities, enhancing the energy value of biofuels. Furthermore, coffee waste During fermentation, microorganisms such as yeast convert these sugars
can be effectively upcycled into biofuels such as biogas and bioethanol into ethanol, a valuable commercial alcohol. The ideal conditions for
through anaerobic digestion and fermentation processes. Anaerobic ethanol fermentation occur within a pH of 4.5–5.5 and a temperature
digestion breaks down organic matter in coffee waste by microorgan­ range of 20–35 ◦ C. For example, one ton of such waste can yield
isms in the absence of oxygen, producing biogas, which can be used for approximately 100 L of ethanol, providing an efficient way to repurpose
heating, electricity, or as vehicle fuel. For example, 100 tons of coffee frozen FW into a useful product while reducing environmental impact
waste can generate approximately 4000 cubic meters of biogas, (Bangar, Chaudhary, Kajla, Balakrishnan, & Phimolsiripol, 2024; Banu,
providing a renewable energy source. Fermentation converts carbohy­ Kumar, Gunasekaran, & Kavitha, 2020).
drates in coffee waste into bioethanol using yeasts like Saccharomyces
cerevisiae, producing ethanol as a biofuel. This method can yield around 7. Food waste upcycling into valuable products
30 L of bioethanol from one ton of coffee waste, contributing signifi­
cantly to sustainable waste management and energy production. Addi­ 7.1. Packaging materials
tionally, FW rich in carbohydrates can serve as a viable substrate for
producing ethanol, hydrogen, and succinic acid, offering potential so­ A study by Gupta et al., revealed that addressing the dual challenges
lutions for greenhouse gas reduction and sustainable energy generation of plastic waste and FW in populous regions like India and China re­
(Papadaki & Mantzouridou, 2019; Song et al., 2021). quires innovative solutions. In India alone, major cities generated
approximately 26,000 tonnes of plastic waste daily in 2019–20, with
6.4. Fermentation and hydrolysis only 60% being recycled. Concurrently, these countries produced vast
amounts of food waste, with China and India accounting for 91 and 69
Organic acids, including citric acid, succinic acid, lactic acid, and million tonnes respectively in 2019. To mitigate these issues, biode­
acetic acid, can be obtained from FW and have diverse applications in gradable packaging films offer a promising avenue. By utilizing bio-
industries such as food, pharmaceuticals, and cosmetics. Through compounds such as proteins, cellulose, starch, and lipids derived from
innovative conversion methods like fermentation and enzymatic hy­ food and vegetative waste, researchers are developing films that can
drolysis, organic acids can be produced from waste materials, contrib­ replace non-biodegradable plastics. Despite challenges in mechanical
uting to a more sustainable environment (Behera, Mishra, & Mohapatra, strength and barrier properties, advancements in material science aim to
2021; Harun, Hassan, Zainol, Ibrahim, & Hashim, 2019). For example, a optimize these films for practical packaging applications, thereby
study by Papadaki et al., aimed to optimize an integrated simple process reducing environmental pollution and enhancing sustainability efforts
for citric acid production using Spanish-style green olive processing (Gupta, Toksha, & Rahaman, 2022). Furthermore, edible films made
wastewaters enriched with sugars from white grape pomace and the from milk whey proteins, pectin from citrus peels, and chitosan from
robust Aspergillus niger B60. Mild mixing of equal quantities of the shrimp shells have been shown to extend the shelf life of fresh produce
above streams governed satisfactory amount of appropriate carbon by protecting it from environmental conditions and reducing spoilage.
sources (equimolar mixture of glucose and fructose, 111.5 g/L) in the These advancements not only contribute to waste reduction but also
sugar-enriched wastewater and its neutralization. Various nutrients and enhance the overall sustainability of food service operations by utilizing
fermentation conditions were investigated and maximum citric acid food waste to create valuable packaging materials (Nunes et al., 2023).
content (85 g/L) and yield (0.56 g/g) were obtained in liquid surface
culture after minimum regulation by adding sucrose and NH4NO3 (100 7.2. Bio-pigments pyocyanin and 1-hydroxyphenazine
g/L and 1.1 g/L, respectively). Scale-up experiments (5 L-scale) verified
findings from small scale (250 mL). The chemical oxygen demand value Phenazines, such as pyocyanin and 1-hydroxyphenazine, are pig­
and phenolic content of the treated wastewater were reduced by 78% ments found in Pseudomonas aeruginosa, contributing to its blue-green
and 64%, respectively. Findings support the potential for clustering the color. These compounds play various roles, including being electro­
respective enterprises in a biorefinery plant for citric acid fermentation. chemically active and beneficial for the host. Additionally, they possess
Likewise, lactic acid can be effectively generated from restaurant and antimicrobial and anticancer properties. However, their use is restricted
bakery waste using enzymatic hydrolysis and fermentation processes, due to the high cost of carbon substrates. Utilizing carbon derived from
providing environmentally friendly alternatives to chemical methods. FW in bio refineries could help overcome this limitation (Pantelic et al.,
Additionally, advanced fermentation techniques use specific microbial 2023). Moreover, waste materials like vegetable peels, fruit scraps,
strains to ferment food waste into high-value products, such as fer­ coffee grounds, leftover food, and used cooking oil can be collected and
menting spent grain from breweries to create probiotic beverages or processed through hydrolysis, fermentation, and pyrolysis or gasifica­
flavor-enhancing ingredients (Papadaki & Mantzouridou, 2019). tion to extract carbon. This not only provides a cost-effective carbon
A study by Chouaibi et al., revealed that pumpkin peel waste, rich in source but also promotes sustainable waste management, facilitating the
starch, can be effectively converted into bioethanol. This process in­ production of valuable phenazines in biorefineries (Ganesh, Sridhar, &
volves optimizing reducing sugar concentration and bioethanol pro­ Vishali, 2022; Verma, Rao, Joshi, Choudhary, & Srivastava, 2022).
duction using artificial neural networks (ANN) and response surface
methodology (RSM). The hydrolysis process conditions are: 120 min 7.3. Super activated hydro-char for remarkable hydrogen storage
hydrolysis time, 17.5 g/L substrate loading, 7.5 U/g α-amylase, and
56.40 U/mL amyloglucosidase. For fermentation, the optimal conditions According to a study the simulated FW, including apple, bread, green
are: 45 ◦ C temperature, pH 5.06, 188.5 rpm shaking speed, and 1.95 g/L beans, cabbage, cheese, and canned chicken, underwent hydrothermal
yeast concentration. Under these conditions, the experimental reducing carbonization at 220 ◦ C and chemical activation at 800 ◦ C using various
sugar and bioethanol concentrations are 50.60 g/L and 84.36 g/L, KOH-to-hydrochar ratios (2:1, 3:1, 4:1). The resulting solid products,
respectively. The ANN model proved superior in prediction accuracy, termed super-activated hydro-chars, were examined for surface prop­
and key factors influencing production were substrate loading and erties using XRD, nitrogen adsorption isotherms at 77K, and proximate
fermentation temperature. This method highlights pumpkin peel waste and ultimate analyses. The super-activated hydro-chars exhibited sur­
as a viable source for fuel-ethanol production (Chouaibi, Daoued, face areas ranging from 2070 to 2885 m2/g and total pore volumes of

9
N. Kanwal et al. Trends in Food Science & Technology 152 (2024) 104687

0.98–1.93 cm3/g. Notably, one sample produced with a 4:1 KOH-to- 8. Case studies
hydrochar ratio demonstrated a hydrogen storage capacity of up to
6.15 wt% at 23 bar and 77 K, showcasing the potential of up-cycled FW 8.1. Food waste reduction in Swedish public catering
for effective hydrogen storage. It can be concluded that FW is a suitable
source for developing hydrogen gas adsorbents through hydrothermal An analysis of eight years of FW data from Swedish public catering
carbonization and KOH activation. Higher hydro-char-to-KOH ratios was conducted to assess progress towards the global goal of halving FW
improved material porosity, with optimal properties achieved at 4:1. by 2030. The findings indicated a 15–30% reduction, suggesting a
The hydrogen adsorption capacity surpassed the US Department of downward trend. If all canteens perform similarly, achieving the 2030
Energy’s 2020 target, highlighting food waste’s promise for hydrogen target appears feasible. However, it’s possible that these canteens
storage material development (Saha & Reza, 2021). While the study represent the best performers, which could lead to an underestimation of
demonstrates the potential of food waste-derived super-activated the actual change or current waste levels. Swedish preschools and
hydro-chars for hydrogen storage, a notable gap exists in the long-term schools generate 19,000–21,000 tons of FW annually, highlighting the
stability and reusability of these materials. Future research needs to need for waste monitoring tools, progress tracking mechanisms, and
focus on assessing the durability and performance of these hydro-chars incentives for further reduction (Malefors, Strid, & Eriksson, 2022b).
over multiple adsorption-desorption cycles to ensure their practical The study observed decreasing FW levels and trends across all sectors of
applicability in real-world hydrogen storage systems. Swedish public catering over the study period. By 2020, primary schools
reduced waste by 16%–42 g per portion, preschools by 26%–53 g, sec­
7.4. Polyunsaturated fatty acids (PUFA) production ondary schools by 20%–66 g, and elderly care homes by 43%–56 g.
Primary school data had the highest representativeness, impacting the
An adaptive evolution process involving two factors significantly overall results. Scaling up, FW reduction in the sector from 2016 to 2020
increased biomass and PUFA production in wild-type P. tricornutum ranged from 15% to 30%, depending on the portion factor used. In 2020,
under high-glucose conditions, resulting in the creation of an evolved Swedish school catering generated 19,000 to 23,000 tons of FW.
strain, ALE-Pt1. This strain efficiently utilized food waste hydrolysate as Achieving a 50% reduction is feasible with current trends and by helping
an affordable carbon source during cultivation under mixotrophic con­ underperforming canteens improve. Understanding the causes of food
ditions, leading to improved biomass yield and PUFA production (Wang waste is a key, and canteens need tools for waste reduction and progress
et al., 2022). Furthermore, a study conducted using upcycling food tracking. Verification of data through random samples could improve
waste valorization methods revealed the potential of single-cell protein accuracy, and legal procedures may ensure data provision from estab­
technology to address global protein shortages, highlighting its inde­ lishments not addressing the issue (Malefors, Strid, & Eriksson, 2022b).
pendence from climate, soil characteristics, and available land (Hülsen,
Hsieh, Lu, Tait, & Batstone, 2018). 8.2. Food waste from Air-line catering

7.5. Transforming food waste into medical product components The airline industry’s food provisioning practices often lead to un­
sustainable consumption and FW (You, Bhamra, & Lilley, 2020). In
A study by Carolo et al., created a marine collagen scaffold by 2018, airlines worldwide disposed of approximately 6.1 million tons of
combining 2 g/L of collagen with 0.01% TritonX-100, which was then cabin waste, with approximately 20–30% of this total, around 2.1
placed into rubber silicon molds, frozen overnight, and subsequently million tons, comprising unused food and beverages. According to the
lyophilized overnight. To test the scaffold, researchers inflicted a wound International Air Transport Association, managing this 5.7 million tons
on the dorsal column of adult male rats and applied the scaffold to the of cabin waste incurred costs totaling approximately US$927 million for
wound area. When compared to a commercially available dermal the aviation sector (Elwakeel, Elgarahy, Alghamdi, & El-Qelish, 2023). A
regeneration product, the marine collagen scaffold demonstrated com­ study focusing on Halal food production identified and analyzed FW
parable biocompatibility, promoted angiogenesis, and facilitated the hotspots in a flight catering. The research aimed to assist organizations
deposition of mature collagen (Carolo et al., 2023). Rajbimashhadi in developing FW management policies for sustainable growth. Vege­
et al., emphasized the methods for extracting collagen from fish indus­ table waste accounted for 40–50% of the total FW generated during
trial wastes and its applications in tissue engineering and wound healing operations. Efforts to reduce FW in airline catering should prioritize the
(Moffat, Ye, & Jin, 2022). Furthermore, food waste-derived materials reduction of seafood waste, as this can lead to significant cost savings.
have been investigated for fabricating nanoparticles for drug delivery. This can be achieved through menu and recipe design, as well as
For example, Dai et al., extracted alkali lignin from corn cob using hy­ engaging with customers to understand their preferences and con­
drothermal treatment to create nanoparticles with an organic solvent sumption patterns better. By aligning food offerings with customer
solution. These nanoparticles were then combined with resveratrol and preferences and optimizing portion sizes, airlines can reduce over­
magnetite to form a nano-drug carrier. The resulting materials demon­ production and minimize waste (Halizahari, Mohamad, Anis, & Wan,
strated good stability, biocompatibility, and a relatively high drug 2021). Future research in this area could explore the key factors driving
loading capacity of over 20% by weight. Additionally, they effectively waste generation in airline catering businesses, including clients, sup­
inhibited tumor growth and improved survival rates in experimental pliers, and staff. Understanding these factors can help develop more
animals (Dai, Liu, Hu, Zou, & Si, 2017). In another study, researchers targeted waste reduction strategies. For example, identifying specific
integrated citrus pectin into a copper-based metal–organic framework menu items that are consistently wasted can help tailor menu designs to
with folic acid. The resulting fibers exhibited antibacterial activity, minimize waste. Similarly, understanding how suppliers’ practices
biocompatibility, and good tensile strength (Kiadeh et al., 2021). impact waste generation can help airlines work with their suppliers to
Research in these areas is crucial as it offers innovative solutions for implement more sustainable practices. Engaging with staff to raise
waste valorization, turning food industry by-products into valuable awareness about the importance of reducing FW and providing them
medical and pharmaceutical materials. These advancements not only with the tools and training to minimize waste can also be effective
promote sustainability by reducing waste but also provide new avenues strategies. By involving all stakeholders in the food provisioning pro­
for developing biocompatible and efficient therapeutic options. cess, airlines can create a culture of sustainability that extends
Continued exploration and optimization in this field can significantly throughout their operations. The airline industry faces significant
enhance the effectiveness and applicability of biomedical products, challenges in managing FW, but there are opportunities for improve­
contributing to improved health outcomes and environmental ment. One example of successful FW reduction in the airline industry is
conservation. the initiative undertaken by “Delta Air Lines”. Delta implemented a

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N. Kanwal et al. Trends in Food Science & Technology 152 (2024) 104687

Fig. 4. The power of upcycling: Current success and future potential.

comprehensive FW management program that included measures such hotspots, and detecting anomalies that could affect FW generation. This
as menu planning based on customer preferences, optimizing portion information can help guide FW reduction strategies and the develop­
sizes, and donating surplus food to local charities. Additionally, Delta ment of best practices (Jayasekara et al., 2024).
partnered with composting and recycling facilities to ensure that un­
avoidable food waste was repurposed sustainably (report, 2024). As a
8.4. Successful initiatives of food waste reduction
result of these efforts, Delta significantly reduced its FW, demonstrating
that strategic waste reduction and upcycling methodologies can lead to
The current success rate and potential of upcycling FW is given in
both environmental benefits and cost savings. Therefore, by focusing on
Fig. 4. Furthermore, in a study by Beretta et al., 13 cases of initiatives
preventing and reducing waste at the source, airlines can minimize their
aimed at reducing FW were analyzed. Avoidable FW amounts to 108 g
environmental impact and achieve cost savings. Future research in this
per meal, which was 13% of the food purchased, resulting in 238 g of
area needs further exploration of innovative strategies for reducing food
CO2-equivalent emissions per meal. Reduction rates observed in the
waste in airline catering, taking into account the unique challenges and
case studies ranged from 32% in the education sector to 62% in the
opportunities of the industry.
business sector. On average, a 38% decrease in FW correlated with a
41% decrease in climate impacts and a 30% decrease in biodiversity
8.3. Quick-service restaurants (QSRs) on a university campus impacts. In a more extensive reduction plan, food services made use of
50% of non-marketable vegetables that would otherwise be discarded,
A study validated a tool for quantifying pre-consumer food waste in leading to a 70% reduction in food waste (Beretta & Hellweg, 2019).
QSRs and used statistical process control to map the waste generation
process. The study also investigated FW categories and factors, such as 9. Challenges
menu practices, that influence waste production. Food waste audits
were carried out in two Australian university campus food outlets, each Implementing upcycling practices in restaurants presents several
for duration of two weeks, using direct weighing. Observations and notable challenges. Staff training is a major hurdle, with 60% of
menu practices were documented and compared with reports from restaurant managers reporting difficulties in effectively training staff to
owner-managers. Waste quantities were analyzed using statistical pro­ handle upcycled ingredients, leading to potential food safety issues.
cess control. Both outlets had an average daily pre-consumer food waste Supply chain adjustments also pose significant problems; 50% of res­
of around 25 kg, with 60% being inedible waste, totaling about 5.5–6.1 taurants struggle with sourcing consistent upcycled materials, indicating
kg per full-time-equivalent employee (FTE) per day. Coffee grounds issues with logistics and cost management. Maintaining food quality
were the largest contributor to total waste. Both outlets were compliant further complicates efforts, as 30% of restaurants must alter their menus
with Australian best practices (Jayasekara, McGrath, Kravchuk, Zhou, & or cooking processes, with 25% of customers expressing dissatisfaction
Morris, 2024). The study concluded that the method for separating and with upcycled dishes. Consumer acceptance remains a complex chal­
quantifying pre-consumer food waste was feasible for the QSRs under lenge due to cultural barriers and perceptions about insect consumption,
investigation. By employing statistical process control, the study was which hinder methods like using black soldier fly larvae. In British and
able to distinguish between common and special causes of variation, Dutch restaurants, while effective strategies like demand forecasting and
providing valuable insights for food waste reduction initiatives passive disposal are utilized, proactive measures such as ingredient
(Jayasekara et al., 2024). But the study’s brief audit period (9–10 days) repurposing and reducing plate waste are less common due to organi­
restricted the identification of patterns. Extended audits could uncover zational and regulatory barriers. Additionally, consumer perceptions of
trends, assisting in FW management. Further research involving QSRs is food packaging impact waste reduction efforts, highlighting a research
necessary to comprehend FW generation and enhance processes. Iden­ gap on packaging’s role in waste mitigation. Emerging technologies
tifying coffee grounds as a significant waste stream could inform tar­ introduce further issues, including high installation costs and electro­
geted reduction strategies. The tool and methodology are valuable for chemical challenges with PEF, uncertainty about the stability and
evaluating the stability of FW production processes, identifying reusability of food waste-derived super-activated hydro-chars, and

11
N. Kanwal et al. Trends in Food Science & Technology 152 (2024) 104687

Table 4 economic barriers to widespread adoption is crucial for this

Summarized challenges for Food waste management and their potential advancement.
solutions. Case studies, such as Delta Air Lines’ comprehensive food waste
Challenges Potential solutions References management program, demonstrate the potential for significant waste
Lack of Consumer Implement educational campaigns Di Talia, Simeone,
reduction. Future research needs to apply these findings to other sectors,
Awareness and labels to raise awareness. and Scarpato (2019) like quick-service restaurants, to develop targeted waste reduction
Logistical Use technology to optimize Jagtap et al. (2020) strategies. Identifying and addressing key waste streams in various
Challenges collection routes and schedules. sectors can lead to more effective and tailored waste management
Regulatory Implement robust tracking and George, Harsh, Ray,
practices. Finally, collaboration with industry stakeholders and the
Compliance documentation systems. and Babu (2019)
Storage Limitations Invest in compacting or Shiekh (2020) integration of advanced technologies will be key to enhancing the
dehydrating systems to reduce effectiveness of waste management strategies. Fostering partnerships
volume. between researchers, industry practitioners, and policymakers can drive
Cost Constraints Collaborate with food banks or Iacovidou, innovation and facilitate the implementation of sustainable solutions.
local governments for cost-sharing. Hahladakis, and
Purnell (2021)
Ultimately, advancing food waste upcycling requires a combination of
Supply Chain Establish partnerships and Iacovidou et al. critical evaluations of current methods, exploration of new technologies,
Fragmentation networks to streamline processes. (2021) and an understanding of consumer behavior. By addressing these areas,
Technological Develop open-source or affordable Bangar et al. (2024) the field can move towards more sustainable and practical solutions for
Barriers technologies.
managing food waste.
Staff Training Provide regular training and Al-Kandari,
incentives for staff. Al-abdeen, and Sidhu
(2019) Data availability
Perception of Implement quality control Al-Kandari et al.
Quality measures and communicate (2019) Data will be made available on request.
benefits to customers.
Waste Sorting Provide clear guidelines and tools Jamali and Misman
for sorting. (2021) Acknowledgements

We acknowledge the financial support from National Key R&D

variable performance of machine learning models for catering demand Program of China (No. 2022YFD2100601), the Fundamental Research
prediction. The scalability of microbial processes and ensuring consis­ Funds for the Central Universities (JUSRP202416005), Jiangsu Province
tent quality in 3D food printing of upcycled waste also presents critical Key Laboratory Project of Advanced Food Manufacturing Equipment
challenges. However, Table 4 presents these issues and their potential and Technology (No. FMZ202003), National First-class Discipline Pro­
solutions. Addressing these issues requires targeted solutions, such as gram of Food Science and Technology (No. JUFSTR20180205), all of
comprehensive training programs, robust supply chain partnerships, which enabled us to carry out this study.
quality control measures, clearer regulatory guidelines, and consumer
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