Section Biotechnology for Sustainable Solutions.

Bioengineering

EDIBLE BIOPOLYMER PACKAGING, ZERO-WASTE

ALTERNATIVES FOR PRESERVATION AND CONSUMING
POWDERED BEVERAGES

Lecturer Dr. Roxana Gheorghita

Assoc. Prof. Dr. Roxana Filip
Lecturer Dr. Irina Besliu
Stefan cel Mare University of Suceava, Romania

ABSTRACT
Refinement of consumer preferences made the food industry to develop new products,
with improved characteristics, with openness to monocomponent products.
Unfortunately, the preference for this type of products leads to high costs, especially
due to the packaging used. International policies, and especially European ones, are
looking for solutions to eliminate the hazardous waste for the environment. The present
study discusses the development of a biopolymeric material intended for the packaging
of powdered drinks, solubilized and consumed together with them. Based on a patent-
pending composition of sodium alginate, agar, glycerol and water, the newly developed
material has very good physical, mechanical and solubility properties, comparable to
those of conventional packaging, often multilayered, difficult to sort and almost
impossible to recycle. According to laboratory tests, the material dissolves completely
in water at a temperature of 80 degrees. For the sensory analysis, 80 students from the
food industry program constituted a group of panelists who tested soluble coffee with
and without solubilized edible packaging. According to the results obtained after the
application of two questionnaires, the panelists are open to consuming such materials
and scored the attributes of the new product with good to very good scores. The results
indicated the possibility of using biopolymer-based material for soluble coffee
packaging. For the safety of the consumer and the increase of the product's shelf life, it
is recommended that it be delivered in a secondary packaging, based on cardboard, in
order to continue the initiative to respect the environment.
Keywords: food; environment; alginate; agar; innovation

INTRODUCTION
Current research regarding the use of biopolymers as films and coatings in the food
industry has been ongoing for a long time, and the results have been a game changer for
the industry. Although initially used as substances with the role of texturing,
preservation, stabilization, etc., biopolymers, due to their properties, have become more
and more used for other purposes. For example, the development of smart packaging or
coatings, antimicrobial or antioxidant, with additions of substances that can improve or
potentiate various characteristics (flavours, colours, biological properties). All these,
among other very good properties, have made them great candidates for food packaging,
with comparable characteristics and sometimes superior to conventional synthetic ones
[1]. Biopolymers are extensively used due to their characteristics such as regenerability,
sustainability, compostability, edibility, lack of allergens, toxicity, but also properties

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such as: i) mechanical - high tensile strength and elongation at break; ii) physical -
different thicknesses, from nanometres to meters, colours, pleasant textures, which can
be improved due to the ability of the matrix to retain various compounds, different
aromas, good optical properties (transmittance, opacity, UV barrier), optimized
retraction ratio; iii) chemical - due to the structure of the matrix, they allow the
development of new chemical bonds with other molecules and the modification of the
initial structure; iv) biological - by adding active substances they can receive new
characteristics, such as antioxidant, antimicrobial, regenerator or accelerator, intelligent
sensors etc; v) thermal stability; vi) barrier – can control the exchange of gases, aroma,
moisture, or water vapor with other environments [2].
Food packaging is one of the most important steps in ensuring the safety and the
acceptance of the final product. In addition to the ability to ensure preservation and
maintain the characteristics of the product, a material used for packaging must be
economical in terms of manufacturing costs, comply with the regulations and those
related to waste disposal [3]. Many times, due to these factors, the final price of the
products is higher, an unfavourable aspect for the industry. The studies carried out on
consumers and their preferences have highlighted the fact that, often, they choose the
product depending on the packaging [4]. Therefore, packaging has become not only a
way to provide a safer product for consumption, but a real marketing strategy.
Polysaccharides and proteins are among the most used biopolymers for the development
of packaging for the food industry. Using a packaging based on biopolymers, accepted
for consumption in quantum statis doses, a series of problems are eliminated, such as
those related to product safety, the costs of raw materials and processing, those related
to the elimination of waste because they are completely biodegradable, compostable and
edible, generating zero waste.
The aim of the current study was to develop a material based on biopolymers, used for
packaging soluble drinks, coffee and cappuccino, and consumed together with them.
Unfortunately, the disposable packages used for coffee or other types of soluble drinks
are difficult to sort and almost impossible to recycle, due to the multilayer component
(usually they contain 2 or 3 layers of different materials, of which at least one is
metallic or polyethylene base, glued and coloured with synthetic substances) [5]. Thus,
our packaging, entirely obtained from biopolymers, completely solubilized together
with the contained product, aligns with the EU directives on reduce, reuse and recycle
packaging and eliminates the problems generated by the waste resulting from the use of
conventional packaging, so harmful to the environment [6].

MATERIALS AND METHODS

For this study, polysaccharides such as alginate and agar were used to obtain a
completely soluble packaging in water at temperatures above 70°C. Once obtained, the
material was tested in order to establish the physical-chemical and mechanical
characteristics. Thus, the microstructure, thickness, retraction ratio, color, transmittance,
opacity, water activity index, microbiological and solubility tests were performed. For
consumers’ testing, it was used for packaging single servings of instant coffee and
cappuccino. In order to evaluate the acceptability and preferences of the consumers,
they were distributed and tested by 80 students from Stefan cel Mare Suceava
University (age 20-24 years old, 42% - 21 years old).

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After testing, they filled in two questionnaires regarding their habits about the
consumption of coffee and other soluble drinks, as well as the openness to a bio-edible
packaging. The second questionnaire, filled in after consumption presented the scores
obtained by the tested and control samples, following characteristics such as
appearance, smell, colour, taste, aroma, smoothness and palatability. For the second
questionnaire, the scores were assigned as follows: 1 – very bad, 2 – bad, 3 – no
changes, regardless, 4 – good and 5 – very good.
Biopolymeric packaging development - The was obtained through casting method.
Thus, for a 30 x 60 cm material, 2 g of sodium alginate, 1 g of agar, 1 g glycerol, and
150 ml water were used. This composition has been tested in our previous research
studies [7] and it is included in a patent proposal registered at the State Office for
Inventions and Trademarks. The film-forming solution was stirred at 450 rpm and 90°C
± 1.5°C for 20 minutes. After that, the solution was poured in a silicone plate and
maintained until complete dry (approx. 40 hours at 25°C ± 2°C).
Physico-chemical evaluation - After development, the film was tested in order to
evaluate the physico-chemical properties. For microstructure and roughness, the
MAHRSURF CWM 100 confocal microscope was used. The images were processed
and analysed using Mountain Map 7.4 software. The thickness (t) was measured with
0.001 accuracy digital Yato micrometer (Shanghai, China) and expressed as average
after at least 10 readings in different areas of material. The retraction ratio (RR), an
important parameter for industrial production, was calculated as average between
solution thickness and film thickness. The colour was evaluated using the Chroma
Meter CR400 (Konika Minolta) colorimeter and CIE Lab method, taking into account
parameters such as a*, b* and luminosity (L*). The result represents the average of min
10 reads in different areas of material. Transmittance (T) and opacity (O) were read
spectrophotometrically (Epoch, BIOTEK Instruments, Winooski, VT, USA). 1 cm x 3
cm samples were used and an empty cuvette was used as standard. The transmittance
was read at 600 nm. The opacity of the material was calculated as absorbance/thickness,
after the absorbance at 660 nm was read. Water activity index (wa) was expressed by
average at least 10 readings of the material (23°C ± 1.5°C). Thus, an AquaLab 4TE
equipment (Meter Group, München, Germany) was used. The determination it is
important in order to establish the type of products that can be packaged in this material,
but for microbial safety as well. A water activity index below 0.6 prevents the
development of microorganisms. Therefore, in industry, reducing the water activity
index is a method of preserving food products and avoiding microbiological
contamination. Sometimes, when the water activity index values are reduced,
microbiological tests are no longer carried out, being considered unnecessary.
Mechanical tests - The tensile strength (TS) and elongation (E) were determined using
ESM Mark 10 texturometer with 5 KN cell and grips for thin films and foils attached.
As reference, the Standard Test Method for Tensile Properties of Thin Plastic Sheeting
ASTM D882 was used. Samples of 1 cm x 10 cm were used. The travel speed was set at
10 mm/min and the working temperature was 24°C ± 2°C.
Microbiological evaluation - Plates with specific culture medium (Nissui
Pharmaceutical, Tokyo, Japan) were used to evaluate the incidence of the
Staphylococcus aures (X-SA), Escherichia coli (EC), Listeria monocytogenes (LM),
yeasts and molds (YM) or total count (TC). 1 g of biopolymeric material was solubilized

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in 9 ml of saline solution after homogenization at 500 rpm. 1 ml from this solution was
poured onto the plate with medium and maintained at 37 °C ± 2 °C for 48-72 hours,
according to the suppliers’ recommendations. The results were expressed as CFU/ml.
Solubility tests - Because the material is intended to be consume with the soluble
coffee, this test is very important for the future features of the product. Thus, moisture
content (MC) and water solubility (WS) were performed. For MC evaluation, 3 cm x 3
cm sample was weighed, dried in a hot oven (110° C) for 24 hours and weighted again.
For WS evaluation, 3cm x 3 cm sample was weighed, immersed in a container with 50
mL water and maintained for 8 hours. After that, the water excess was eliminated with
filter paper and the film was let to dry at 110°C for 24 hours. After this time, the sample
was weighed.
For consumers perception, soluble coffee was packed in edible material and prepared
according to the manufacturer: one coffee bag was solubilized in 80°C water and stirred
for 30 seconds. After that, the panellists received the control sample (No.1) and tested
sample (No.2). After testing, they filled in questionnaires regarding their habits about
the consumption of coffee and other soluble drinks, as well as the openness to a bio-
edible packaging.
Statistical analysis was performed with Minitab statistical software trial version.

RESULTS AND DISCUSSION

Material testing results regarding physico-chemical and mechanical properties are
presented in Table 1.
Table 1. The main properties of biopolymeric material
Physical and mechanical evaluation
T, µm RR, % Roughness, µm TS, MPa E, %
58.12 ± 0.84 42.45 ± 0.71 14.57 ± 0.54 26.82 ± 0.66 71.49 ± 0.24
Optical evaluation
Color T, % O,
L* a* b* A/mm2
89.17 ± 0.33 -5.21 ± 0.33 18.46 ± 0.33 81.74 ± 0.25 3.82 ± 0.01
Solubility evaluation
MC, % WS, % aw
11.24 ± 0.03 62.67 ± 0.71 0.381 ± 0.15

The thickness is an important feature for the material, mainly due to the fact that it will
be dissolved and consumed once with product. In this case, it is recommended that
thickness to present lower values to not interfere too much with the food. Even if the
thickness of the material is very low, we must state that mechanical properties are very
good and problems related to the disintegration of the packaging are unlikely to occur.
The amount of sodium alginate is strongly correlated with thickness, tensile strength
and elongation. Li et al. demonstrated that films with 2% sodium alginate into
composition presented higher thickness (97.8 µm) and better mechanical properties:
elongation 7.67% and strength 67.21MPa, compared with those with 0.5% sodium
alginate (thickness 53.7, elongation 6.15 and resistance 46.48 MPa) [8]. Furthermore,
the addition of water and glycerol as plasticizers increased the free volume from the
matrix and decreased the intermolecular forces. According to other research, glycerol is

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suitable for polysaccharides – based materials development because possess the same
solubility properties and lead to stronger and more elastic materials when it was used as
plasticizer in sodium-alginate based films, compared with sorbitol, which was stiffer
[9]. The roughness of material is a good one, taking into account that, according to the
microstructure from Figure 1, the film does not present pores or fissures into structure.
The same results were observed by Arzate-Vasquez et al. when compared the alginate -
based films with alginate-chitosan-based films. According to their research, sodium
alginate is a good biopolymer to develop smooth and uniform material [10].
The colour of the material is highly influenced by the mass of biopolymers into
composition. The temperature represents another factor that may influence the final
colour of the material. Thus, Soazo et al. demonstrated that a higher temperature for
sodium-alginate film drying favoured the development of a yellow ochre colour and
more brittle material [11]. In our case, the colour does not represent a problem due to
the fact that is very similar with coffee powder colour and it is much lighter than that of
instant coffee. The higher transmittance of the packaging is important because the
consumer can observe the contain, but may be a negative point regarding the UV light
transmission. In this case, it is recommended that biopolymeric coffee bags to be sold in
a secondary packaging, made of cardboard, similar to teas. Studies regarding consumer
perception demonstrated that a product with transparent packaging material will be
choose over another one, with full covered content [12].

a) b)

Fig. 1. Microstructure (a) and microtopography (b) of biopolymeric material

According to microbiological assessment, the product is safe to consume. No pathogens

were identified on the material surface and waster activity index is very low and
prevents the development and proliferation of microorganisms. In several cases, the wa
is the main responsible factor for food stability [13]. In our case, the water activity
index is 0.381, a much lower value than 0.6, the reference standard for microbial
development and proliferation. The min wa necessary for the growth of the most known
bacteria is 0.87 (0.75 for halophile ones). Even the Staphylococcus aureus, adapted to
environment with low values of wa cannot survive at values lower than 0.85 [14].
Consumer perception results
One of the main inclusion criteria of panellists was to be coffee drinkers. More than
60% of them drink 1-2 coffees per day, more than 15% used to drink 3-4 coffee per day,
and 5% - more than 4. The rest of the people involved in our study drink one coffee less
than 1-2 times/day. Most of the panellists that used to drink one coffee per day are
women (40%); men preferred to drink more than 3-4 coffees/day.
Almost 60% from students drink coffee for pleasure, 12% as a habit, and 28% for both

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reasons. Most of the them started to drink coffee at 17-19 years old (48 %); 12% at 14
years old, 34% at 15 or 16 years old, and 18% at 20 or 21.
In the present study, the most of the panellists liked the beverage with edible material
solubilized and will choose this type of product over the conventional one. The young
male panellists are more open to consuming edible materials together with the food
product. According to results, the most of the panellists preferred edible and
biodegradable packaging material (43.8%), followed by those that preferred glass
(33.8%) or cardboard (15%); 6.2% preferred plastic packaging material. According to
Babaremu et al., the consumers are not aware by the plastic harmful effect. In their
study, eight in ten people are convinced that plastic packaging remains the best option
for long-term materials and considered that bioplastic is not so convenient and practical
[15]. A better acceptance of edible packaging material was reported by Taylo et al. For
example, in their study that evaluated the consumer attitude, acceptability and purchase
intent, the panellists positively reacted and considered that edible packaging material for
powdered lemonade is a great alternative to synthetic ones. Furthermore, their liking
scores were almost 7.48, where 1- extremely dislike and 9 – extremely like [16].
The complete solubilization of biopolymeric packaging into food product is more
accepted by consumers than the edible layer separately. Studies demonstrated that
consumers prefer an edible packaging material that is integrated into principal food
product and are more likely to consume the product for its features than the
environmental benefits [17]. In the present study, the students are aware by the benefits
of replacing plastic-based materials with those based on completely natural composition
and the most response that eating a biopolymeric material does not endanger their
health. Another aspect is that young generation is more open to consuming such
products, unlike older people who are usually more conservative and hardly respond to
innovations in the food industry.
The panellists involved in this study preferred to consume coffee with sweeteners. Thus,
sugar is overwhelmingly the most preferred sweetener, with 45 out of 62 respondents
(72.58%) indicating it as their choice. Honey is the second most preferred, chosen by 4
respondents (6.45%). Brown sugar is chosen by 6 respondents (3.23% + 6.45%).
Several other sweeteners like agave syrup (1.61% for each variation), milk (1.61%),
sugar/sweetener (1.61%), and other sweeteners (3.23%) have been chosen by a small
number of respondents. Most preferred additives in coffee beverages are natural
sweeteners: 8 respondents (13.33%), chocolate: 7 respondents (11.67% when
combined), flavours: 8 respondents (10.00% for "flavours", and additional responses for
related terms), vanilla: 5 respondents (8.33%), and sweeteners: 6 respondents (10.00%).
As recommendations, they mentioned the focus on popular additives, respectively to
emphasize natural sweeteners, chocolate, and various flavours in product development
and marketing and to highlight the inclusion of vanilla and sweeteners as secondary
options. Furthermore, they considered that the market should consider diverse
preferences and to offer a variety of product lines that include fewer common additives
to cater to niche markets.
The results obtained after product testing are mentioned in Table 2. Both tested products
have similar high ratings for appearance, with Product 1 slightly higher. The variation in
ratings is also similar. Product 2 is slightly preferred over Product 1 in terms of smell.
The variation in ratings is similar for both products. Product 1 is rated higher for colour.

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The ratings' variability is similar for both products. Product 1 is slightly preferred for
taste, though both products have similar ratings with some variability. Product 1 is
slightly preferred in terms of flavour. There is a bit more variability in Product 2's
ratings. Product 2 is slightly preferred in terms of unctuosity, though the difference is
minimal and both products have similar variability. Both products have nearly identical
ratings for palatability, indicating no clear preference.

Table 2. The average of the scores obtained after the test

Attribute Product 1 – Product 2 – P-Value
soluble coffee coffee with edible packaging
Appearance 4.225 ± 0.927 4.162 ± 0.980 0.684
Smell 3.988 ± 0.907 4.108 ± 0.869 0.401
Colors 4.275 ± 0.841 4.000 ± 0.827 0.043
Taste 3.713 ± 0.970 3.568 ± 1.111 0.392
Flavour 3.800 ± 0.920 3.662 ± 1.101 0.403
Uonctuozity 3.675 ± 0.938 3.743 ± 0.922 0.650
Palatability 3.588 ± 0.964 3.581 ± 0.951 0.967
The results are expressed as mean and standard deviation

The small differences in means suggest that both products are quite similar in most
attributes. The attribute that most differentiates the two products from the consumer's
perspective is the colour.
For appearance, since the p-value (0.684) is much greater than the common significance
level of 0.05, we fail to reject the null hypothesis. This means there is no statistically
significant evidence to suggest a difference in the mean ratings between Product 1 and
Product 2 for the attribute tested. The observed difference in mean ratings between the
two products is likely due to random variation rather than a true difference in preference
or perception.

CONCLUSION
The current study aimed to develop a new packaging material for soluble coffee
products, packaged in disposable packaging, often obtained from conventional,
synthetic, petroleum-based materials. Developed from sodium alginate, agar, glycerol
and water, based on a composition already submitted for patenting, the material
possesses good physical, mechanical and, above all, solubility properties. Tested on a
group of 80 panellists, the drink that contained both powdered coffee and the solubilized
packaging received good and very good reviews, comparable to those of the classic
drink, without the possibility of discovering the product during testing.

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