International Symposium for Green Solutions (ISGS 2022)

ICATSD2F.322

THE ROLE OF CITRUS FIBER ON THE TEXTURE OF GLUTEN-FREE,

SUGAR-FREE, AND BUTTER-FREE BISCUITS FROM LABLAB BEAN,
PUMPKIN, AND BANANA

NGUYEN THI MINH NGUYET*; PHAN NHU PHUONG, NGUYEN THI TUYET TRINH, NGUYEN
PHUONG BAO NGOC
Institute of Biotechnology and Food Technology, Industrial University of Ho Chi Minh City, Vietnam
*nguyenthiminhnguyet@iuh.edu.vn

Abstract. In the trend of sustainable food system development, the implementation of a healthy diet
through the use of whole foods, local foods, and plant-based foods to prepare food at the restaurant is being
cared for. The objective of the study was to investigate the role of citrus fiber in the structure of biscuits
made from peas, whole pumpkin, and porcelain banana puree to develop a line of butter, sugar, and gluten-
free biscuits. Mixture formulas (MF) including pea flour: pumpkin powder: porcelain banana puree are
1:1:1, 2:1:1, and 3:1:1, respectively (by mass % MF). Citri-Fi 100 (100% Citrus Fibre) was investigated at
levels 0 and 0.25 (mass % MF) respectively. The water content is additionally calculated to ensure that the
dough samples have the same moisture content of 35 - 36%. Structural properties of 6 cake recipes, in
which the cake control sample was the sample without the addition of Citri-Fi 100, were recorded.
Determine the cake structure by measuring the penetration force on the Brookfield CT3 4500 structure
measuring device, the color of the cake is determined by the Minotab CS-10 colourimeter. The results show
that Citri-Fi 100 plays an important role in creating the structure for butter-free, sugar-free, gluten-free
biscuits from beans, pumpkin, and bananas. The cake recipe with a mixing ratio of 2:1:1 and 0.25% Citrus
Fibre shows that the cake has the right structural properties. It is noteworthy that the color ∆E of the 3
recipes with 0.25% citrus fiber added did not have any significant difference compared with the color of
the control cake (premium biscuits Coffee Joy - Indonesia has the values as follows: L* = 50.52; a* = 9.27;
b* = 26.9). The finding of this work could be applied to the development of biscuits for consumers who are
on a diet or have gluten intolerance syndromes.

Keywords. free-sugar biscuit, free-gluten biscuit, free-butter biscuit, lablab bean, pumpkin, banana.

1. INTRODUCTION
Biscuits are the most commonly consumed bakery goods in India and other parts of the world because of
their convenience, affordable price, good nutritional quality, availability in different tastes, and longer shelf
life [1]. Ingredients of biscuits include flour, fat, and sugar to form cookie dough [2].
Gluten-free biscuits are gluten-free biscuit – products specifically for people with gluten allergies. Celiac
disease, also known as gluten intolerance, is most common in infants through toddlers due to their immature
immune and digestive systems [3].
Today, the incidence of Celiac disease, gluten allergy, and cardiovascular diseases is increasing. According
to current and future consumption trends globally, consumers reduce their consumption of animal products
(including eggs) and increase their consumption of plant-based foods towards an ideal meal, with 85%
plants and 15% animals.
Citrus fiber is the insoluble and/ or soluble fiber component of citrus fruits such as oranges, lemons, and
grapefruits [4]. In recent years, citrus fiber has received more and more attention from researchers due to
its significant effects on the human body, such as stress relief, improved skin tone, digestive ailments, heart
health, and cancer prevention. Citrus fiber is gaining popularity as a natural speciality food ingredient,
commonly used as an emulsifier and water binding agent in various food products such as baked goods.
Many manufacturers adopt citrus fiber as an egg or oil substitute, providing a more natural and functional

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emulsion [5]. Citrus fiber can form gels from the natural pectin content in fruit preparations with the
required Brix and pH [6].
In the confectionery industry, the primary sugar used is sucrose. Sugar is an essential ingredient in bakery
products. As well as imparting a sweet taste, they also affect the fermentability, appearance, taste, color,
structure, and texture of the finished products. There are many choices of sweeteners available, and the type
chosen depends on the degree of sweetness required for its function in the flour or dough, and the desired
shape or texture of the baked product [7]. As sugar consumption increased in the last decades of the 20th
century, researchers began to examine whether a diet high in sugar, especially refined sugar, is harmful to
human health. Consuming too much sugar has been linked to obesity, diabetes, cardiovascular disease,
dementia, and tooth decay. Many studies have attempted to clarify those effects, but with mixed results,
mainly because it is difficult to find populations to use as controls that consume little or no sugar. In 2015,
the World Health Organization recommended that adults and children reduced their free sugar intake to less
than 10% and encouraged them to reduce it to less than 5% of their total energy intake [8]. Studies show a
potential link between sugar consumption and health problems, including obesity and tooth decay.
Excessive use of sugar has been linked to type 2 diabetes, obesity, increased heart disease, and faster growth
of cancer cells [9].
Butter is a dairy product made by whipping fresh or fermented milk or cream. Butter is used to spread bread
as a condiment and cook, such as sauces, frying, and baking. Butter is made up of butterfat surrounded by
little water and milk proteins. Butter contains mainly saturated fat and is a significant source of cholesterol.
So eating many avocados can lead to several health risks, especially heart disease [10].
An unhealthy diet rich in calories and saturated fat, physical inactivity is a serious health threat. The
relationship between diet and health problems is not a new notion. People are paying more attention to their
calorie intake through their daily fat and carbohydrate intake. To limit the prevalence of diabetes and
coronary heart diseases, the food technology industry has been focusing on producing low-fat/low-calorie,
high-fiber foods in response to public interest [11].
Lablab bean seeds (Lablab purpureus) are an annual or sometimes short-term perennial legume. It is a
herbaceous plant that grows twisted, creeping, crawling, or upright, which can grow to a length of 3 - 6m.
It has a deep taproot and strong hairy or crescent-shaped stems. Lablab leaves are alternate leaves and have
a trifoliolate effect. The leaflets are rhomboid, 7.5 - 15cm long x 8-14cm wide, pointed at the apex. The
upper surface is smooth, while the underside has short hairs. Lablab seeds (beans) are oval, compressed
laterally with a conspicuous linear hilum. Lablab beans vary in color, depending on the variety or cultivar,
typically white to dark brown, and some black. Wild varieties and some cultivated varieties tend to have
spotted seeds [12].
Lablab beans contain about 26% of the dry matter in protein, but it varies widely between seedlings or
between varieties (23 to 28%). The lysine content of lablab beans is relatively high (6.3% protein) and
similar to soybean but lower in methionine and cystine. The starch content of lablab is relatively high (45%),
while the fiber content is low (crude fiber less than 10% dry matter) [12].
Pumpkin is a nutrient-rich fruit of the genus Cucurbita, family Cucurbitaceae. This is a common name for
plants of the following species: Cucurbita pepo, Cucurbita mixta, Cucurbita maxima, and Cucurbita
moschata. Pumpkin contains a lot of fiber, vitamins A, C, and E, bioactive compounds, b-carotene, and
other valuable vitamins (B6, K, thiamine, and riboflavin), as well as minerals (K, P, Mg, Fe, and Se) [13].
Pumpkin is a rich source of natural provitamin A. In addition to a fairly high ratio of fiber and iron, pumpkin
also provides vitamin C, folic acid, magnesium, potassium, and protein [13]. In particular, pumpkin meat
is a rich source of vitamin A, which plays an important role in bone growth and reproduction; vitamin A is
also involved in protein biosynthesis, immune system regulation, and protecting the skin. The pumpkin also
contains a substance necessary for the development of the brain, which is glutamic acid, which plays an
important role in healthy nerves, enhancing metabolic reactions in nerve cells and the brain. Therefore,
pumpkin is considered a portion of brain food, a treatment for neurasthenia, and food for children with
mental retardation.
Porcelain bananas (Pisang Awak) are one of the most widely consumed fruits globally because they bring
great nutritional value to human health. Today, bananas are grown mainly in Southeast Asia and rank among
the world's important food crops [14]. Porcelain banana is also known as Siamese banana because the king
of Siam gave tribute to our country in the past. With the shape of two slender and petite ends, the middle

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part is more significant, and the shell has three edges and a long stalk. When ripe, it is yellow, and the flesh
is white and sweet. They are grown mainly in the southern provinces of our country because they are
suitable for hot and sunny climates.
Bananas are grown in at least 107 countries. The banana tree has a false stem up to 6 – 7.6m, growing from
an underground stem. Banana leaves are twisted and can be 2.7m long and 60cm wide. The banana tree is
the largest herbaceous species [15]. Banana flowers are usually hermaphroditic, the flower heads usually
produce a separate, non-reproductive male flower, also known as a banana flower, but sometimes it can
create additional flowers. Bananas come out into hanging baskets, each layer (bundle) has up to 20 fruits,
and each stem has 3 - 20 bunches. The bags are generally called a stem, weighing 30 - 50kg. An average
fruit weighs 125g, of which about 75% is water, and 25% is dry matter. Each fruit has a tough rind around
soft edible flesh. The peel and meat are both edible fresh or processed.
Porcelain bananas contain many nutritional components such as fiber, vitamins, starch, protein, and
minerals such as magnesium, sodium, calcium, zinc, iron, potassium, and phosphate ... Therefore, they are
used for processing many dishes such as banana ice cream, banana soup, fried bananas, grilled bananas,
boiled bananas ... Not only can the porcelain bananas be cooked, but when the green fruit is still alive, it
can be used in salads and side dishes. In addition, porcelain bananas also contain 2 compounds, Serotonin
and Norepinephrine (NE), which improve mental, and psychological comfort, especially against depression
[16].
Bananas are a healthy food, as they contain several essential nutrients and provide benefits for digestion,
heart health, and weight loss. Besides, bananas are also a very convenient snack. A 2017 meta-analysis
study published by the Prilozi Division of Medical Sciences suggested that unripe green bananas confer
several health benefits. They can help control gastrointestinal problems such as diarrhea and ulcers and
lower cholesterol and blood pressure [17]. In addition, some studies have also suggested that the herbal
substances in green bananas can provide treatment for HIV patients.
To use plant food sources with many health benefits and contribute to the sustainable development of
Vietnam's food system, this study is conducted with the following specific research contents: 1)
Determination of the physical properties of the material; 2) Investigation of structural properties of gluten-
free, butter-free, sugar-free biscuits; 3) Determine the color of biscuits.

2. MATERIALS AND METHODS

2.1. Materials
Beans are purchased at Duc Trong farmers market, Lam Dong, Da Lat.
Porcelain bananas and pumpkins were purchased at BigC Go Vap supermarket. Bananas used are ripe
bananas, banana peels appear in many dark spots, and dark yellow to take advantage of overripe banana
products, which are not sold out at markets and supermarkets. The pumpkin used is a round, undamaged
squash to utilize both the skin and the flesh.
Citrus Fiber CF 100M40 (abbreviated CF) is a product made in the US by Asia Shine Light Company.
Address: 353C Nguyen Trong Tuyen, Ward 1, Tan Binh District, City. HCM.
Dried salt is a product of Thanh Phat Salt Production-DV-Production Co., Ltd. Address: 638/5 National
Highway 1A, Binh Hung Hoa B Ward, Binh Tan District, City. HCM.
Vietcoco Organic Coconut Oil is produced at Luong Quoi Coconut Processing Co., Ltd. Address: Lot A36-
A37, An Hiep Industrial Park, Thuan Dien hamlet, An Hiep commune, Chau Thanh district, Ben Tre
province.
Aquafina purified water is a product of Thien An drinking water distribution company.

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 The 2nd International Conference on Advanced Technology & Sustainable Development (ICATSD 2022)

Figure 1. Images of ingredients forlablab bean, pumpkin, and banana (from left to right)

Getting lablab seed flour, pumpkin, and banana puree

Pumpkin flour was obtained according to the modified Abdelbaki (1980) procedure [18]: Pumpkin →
Handling → Sliced (1.6mm) → Drying at 50 oC, for 24 hours → Finely ground → Sift through a sieve
(300µm) → Pumpkin flour. Pumpkin flour is stored in an airtight container and kept at room temperature.
The banana puree was obtained according to the procedure of Abdelbaki (1980) modified [18]: Ripe Banana
→ Peeled → Chopped → Puree → Banana puree.
Lablab seed flour was collected according to the modified Awolu (2017) process [19]: Lablab beans →
Classify → Soaking 7 - 8 hours → Cooking at 100 C for 30 minutes → Harvesting beans → Drying at
500C for 24 hours → Finely ground → Sift through a sieve (300µm) → Lablab seed flour. The collected
lablab seed flour was stored in an airtight container at room temperature to serve throughout the study.

Figure 2. Images of the powder obtained from pure bananas, lablab beans, and pumpkins (from left to right)
2.2. The formula for mixing powder and sample preparation
Proceed to mix the flour with the ratios of lablab seed flour: banana puree: pumpkin flour at different levels,
varying the water content addition with the dough mass moisture target in the formulas (CT) CT1, CT2,
and CT3 reached 35.69 ± 1%. Due to the investigation of the role of Citrus Fiber CF 100M40, in this study,
the mixing formula of the control samples did not use CF to compare (see Table 1).
Preparation of dough and baking: The dough, after shaping by rolling and receiving molds according to the
thickness of 2mm and diameter of 42mm, rests for 30 minutes and is baked. Set the oven temperature to
90oC ± 5oC; after reaching the set temperature, put the cake in the oven for 25 minutes, take it out to cool
and turn the cake over, and brush with coconut oil on both sides to prevent the cake from drying and burning,
continue put the cake in the oven for another 25 minutes.

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Table 1. Mixture formula of dough in different survey treatments

Dough mixing ratio (lablab seed flour: banana puree: pumpkin flour, %wt)
Ingredients 1:1:1 2:1:1 3:1:1
ĐC 1 CT1 ĐC 2 CT2 ĐC 3 CT3
Lablab seed flour 33.33 33.33 50 50 60 60
Banana puree 33.33 33.33 25 25 20 20
Pumpkin flour 33.33 33.33 25 25 20 20
Salt 0.2 0.2 0.2 0.2 0.2 0.2
Coconut oil 13.36 13.36 13.36 13.36 13.36 13.36
CF - 0.25 - 0.25 - 0.25
Water 2.97 2.97 8.38 8.38 11.63 11.63

Note: Salt, coconut oil, and CF were calculated as % of the total powder

Lablab seed flour, pumpkin flour

Mixing 1 Salt

Mixing 2 Banana puree, coconut

oil

Water, citrus fiber Doughing (10 minutes)

Resting (30 minutes)

Laminating and shaping

Baking at 90°C for 50 minutes

Cooling and packing

Biscuits products

Figure 3. Process for making biscuits Gluten-free and Whole plant-based

The dough after resting for 1 hour was taken for SEM imaging to check the association of ingredients in
the mixtures with and without CF.

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 The 2nd International Conference on Advanced Technology & Sustainable Development (ICATSD 2022)

Factors affecting the quality of biscuits

Sugar content: Low sugar the gluten network is well developed due to its elasticity, so the cake shrinks, and
the cake structure will be very firm. The sugar increases the dough; when shaping the dough, it melts,
leading to an increase in the diameter of the cake and a decrease in the thickness of the cake after baking;
it will be hard and have a burnt sugar smell [20].
Fat ratio: Fat makes the cake structure porous because the fat in the dough will create a thin film that covers
and lubricates the dough particles, thereby keeping the amount of air in the dough smooth and uniform. But
when the amount of fat increases, the percentage of gluten formed is less, so the bread's rise is reduced [20].
Water content: Water content also determines the sponginess of the cake. When the amount of water added
is low, the percentage of gluten produced is insufficient, and starch is not enough water to swell, the cake
will be dry and cracked. When the amount of water added is high, the cake will be soft [21].
Citrus Fiber content: The addition of CF to the dough increases the moisture content and reduces the breadth
and thickness of the cake [22].
Types of raw dough: Different types of dough will have different leavening agents, and the resulting cake
also has a different structure [23].
Kneading method, kneading time: For each type of biscuits, there must be a suitable kneading method and
time; if kneading for too long, the gluten frame will be broken, and the cake structure will be complicated.
2.3 Structure determination method
According to the method of Agrahar-Murugkar et al. (2015) with correction [24]. After baking, the cake
was taken out to cool in a desiccator for 3 days to measure the structural properties of the finished cake.
Measure the cake's structure on Brookfield CT3 4500 device, using TA39 Cylinder measuring head 2mm
in diameter, 20mm in height. The cake has a flower shape of 42mm in diameter and 2mm in thickness. Test
probe speed is 1mm/s, pre-test speed is 2mm/s, post-test speed is 5mm/s with initial pressure 2N and
compression 1 time, sample touch length 4mm.

Figure 4. Illustrating images a) depiction of probe operation; b) graph of the penetration force of the probe

The sample is placed in the measuring position; when we press the measuring probe to run down and touch
the sample, the device will automatically measure the sample height and calculate the penetration force
based on this height, and the probe speed is converted to speed test and sample penetration. After reaching
the target deform, the transducer returns to the original position.
2.4 Method of determining cake color
According to the method of Sapers et al. (1987) with correction [24]. The CS-10 colourimeter determined
the color indices of the cake, with the control sample being the premium Coffee Joy biscuits (according to
the information on the cake packaging made in Indonesia, imported, and packaged. Packaged in Vietnam
and distributed by Sun Resources Food Co., Ltd., 8th Floor, No. 9 Dinh Tien Hoang, District 1, HCMC).
The target color of the control cake sample has the following values: L* = 50.52; a* = 9.27; b* = 26.9.
Measure 5 different positions on the surface of the cake to compare the color difference (expressed in ∆E
value) of the survey cakes compared to the color of the control cake. Each sample was repeated 3 times.
The values ∆L*, ∆a*, ∆b*, and ∆E were recognized.

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2.5 Determination of nutritional components of powdered raw materials

2.5.1 Humidity
The moisture content of starting materials: Determined by drying method to constant weight according to
Vietnamese standards (TCVN 9706: 2013, ISO 711: 1985) with correction.
Principle of method: Samples, after pretreatment, ground to powder, rapidly weigh the resulting mash into
a dried petri dish and pre-weigh, together with a lid, to the nearest 0.2 mg. Place the test sample in an oven
under reduced pressure, at 105°C, until the constant mass is obtained.
(𝑚 −𝑚 )
Determined by the formula: Humidity (%) = 1𝑚 2 x 100
1
m1: mass (g) of the test piece before drying; m2: mass (g) of the test piece after drying.
2.5.2 Determination of total protein
Protein content was determined by the Kjeldahl method according to AOAC 950.48. Principle of the
method: The test portion is decomposed with sulfuric acid in the presence of a catalyst. The reaction product
is neutralized with alkali, then distilled. The liberated ammonia is collected into the boric acid solution and
then titrated with the sulfuric acid solution.
The formula determined the total nitrogen content as % by mass of the sample:
(𝑉 −𝑉 )𝑥0.0014
Total Nitrogen Content (%) = 1 2𝑚 × 100
V1: The volume of 0.1N NaOH solution consumed in the blank titration (ml);
V2: Volume of 0.1N NaOH solution consumed in a titration of the test sample, in ml;
m: Mass of the test piece (g);
0.0014: The number of grams of nitrogen corresponds to 1ml of 0.1N NaOH solution.
Crude Protein Content: Protein (%) = % Total Nitrogen Content × 6.25.
2.5.3 Determination of total fat content
The hydrolysis-Extraction method determined fat content according to AOAC 996.06 carried out to total
fat collection. Treat 1g of sample with 6ml of 5M HCl solution in a stoppered test tube. Shake the mixture
vigorously for 10 seconds and heat in a hot water bath (800C, 60 minutes). Shake the test tube every 10
minutes. After hydrolysis, cool the test tube with water. Add 7ml of diethyl ether and shake the test tube
for 10 min. Centrifuge at 5000 - 6000 rpm for 5 - 10 minutes, collect the above phase into a clean test tube
(weigh the test tube before converting the solvent phase). Add 7ml of diethyl ether and repeat the extraction
two more times. Evaporate the solvent with N2 gas or in a fume hood. Reweigh the test tube and determine
the fat content using the formula:
𝑚
Lipid mass m = m2 – m1; Lipid content (%) = 𝑚 x 100
0
With m0: the mass (g) of the original sample, m1, and m2: the mass (g) of the test tube, respectively, before
transferring the solvent to the test tube and after taking it out of the fume hood.
2.6 Data acquisition and processing methods
Each experiment was arranged in a randomized design with 3 replications, and the data are presented as
Mean ± SD. Analysis of variance ANOVA and treatment of differences between treatments by LSD (Least
Significant Difference) test at the significance level α = 0.05 using Statgraphics Centurion XV.I software.
Graphing using Microsoft Excel 2016 software.

3. RESULTS AND DISCUSSION

3.1 Nutritional composition of the raw materials
Carry out the determination of the main nutritional components of the raw materials according to the
methods described in Section 2.5; the results obtained are shown in Table 2.

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Table 2. Nutritional composition of the raw materials

Ingredients (% wt.) Lablab seed flour Pumpkin flour Banana puree

Humidity 5.65 ± 0.316 8.333 ± 0.272 66.093 ± 2.284
Lipid 6.999 ± 0.014 13.06 ± 0.411 3.427 ± 0.055
Protein 27.393 ± 2.668 12.242 ± 1.746 5.244 ± 1.750

Mean ± SD representation value of 3 replicates.

The results show that bean flour has a very high protein content. The obtained pumpkin powder has a fairly
high total protein and lipid content. Analytical data show that the obtained flours have a much higher
nutritional value than wheat flour. It is worth noting that Pure banana has a very high moisture content, so
it is important to pay attention to the additional water content when kneading the dough. Besides, the banana
puree is quite sweet, dissolved solids content (Brix) 27.97 ± 0.25, pH = 4.65 ± 0.08.
3.2 Microscopic properties of dough

Figure 5. Structure of dough samples by SEM at the size of 100 µm

A- Dough with 1:1:1 ratio - without CF and 0.25% CF (from left to right)
B- Dough with 2:1:1 ratio - without CF and 0.25% CF (from left to right)
C- Dough with 3:1:1 ratio - without CF and 0.25% CF (from left to right)

The images above indicate that the presence of citrus fiber modifies the rheological properties of the dough.
The acidity and electrical charge of the pectin components in citrus fiber may be a contributing factor in
the formation of the apparent viscosity or gelling properties [25]. Hemicellulose also makes up a significant
portion of citrus fiber (about 10.06%). Although the chemical composition is different from that of pectin,
hemicellulose may also contribute to the viscosity and water-holding capacity of citrus fibers.
Hemicellulose has a high apparent viscosity when it is hydrated and has a high water holding capacity due
to its branched, amorphous, and non-crystalline structure [6]. In general, Citrus fiber exhibits outstanding
rheological properties such as stabilizing viscosity, increasing water retention and swelling capacity, and
fat absorption [26]. Therefore, it is often used as an emulsifier to improve the texture or nutritional
properties of foods [27]. The presence of a highly water-absorbent substance caused structure strengthening
in the range of small deformations, while large deformations allowed easier flow. Thus, the rheological

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properties of the dough were improved, allowing it to be more susceptible to technological processing,
including mixing, transport, and molding [28].
3.3 The color parameters of biscuits
The color parameters of the cake samples are shown in Table 3. The ∆L* value represents the difference in
brightness of the cake samples compared with the control sample. Cake with a ratio of 3:1:1 showed light
color closer to the control sample -2.22a ± 0.376. The other samples had a darker color than the control
sample, and the highest was the 1:1:1 ratio of -8.757a ± 0.741. This indicates that the presence of pumpkin
flour and banana puree reduces the brightness of the cake.

Table 3. Average values of color parameters of surveyed cake recipes

Flour mixing ratio ∆L* ∆a* ∆b* ∆E

1:1:1 – 0.25% a
-8.467 ± 0.874 b
3.317 ± 1.196 b
4.34 ± 1.043 10.173a ± 0.603
2:1:1 – 0.25% -8.26a ± 0.311 3.663b ± 0.23 3.097b ± 0.814 9.62a ± 0.341
3:1:1 – 0.25% -8.4a ± 0.434 2.73b ± 0.416 4.687c ± 0.104 9.833a ± 0.222
1:1:1 – 0% -8.757a ± 0.741 2.273b ± 0.83 6.033c ± 0.625 11.08a ± 0.044
2:1:1 – 0% -3.543a ± 0.482 1.46b ± 0.148 12.483c ± 0.204 13.067b ± 0.222
3:1:1 – 0% -2.22a ± 0.376 0.547b ± 0.215 14.073c ± 0.839 14.263b ± 0.773
(Means± SD with different superscripts in the same row are significantly different at P < 0.05 by LSD)
The ∆a* value represents the difference in the red color of the cake sample compared with the control
sample. The red intensity of the cake is highest at the ratio of 2:1:1, higher than the control sample 3.663b
± 0.23.
The color difference is not high because the primary color of the cake is not inclined to red. The red intensity
gradually decreased, and at the ratio of 3:1:1, this difference was only 0.547b ± 0.215, compared with the
control sample, there was not much difference. This shows that reducing the ratio of pumpkin flour and
banana puree to increasing the percentage of lablab seed flour will not cause a red difference between the
study sample and the control sample. The ∆b* value represents the yellow color of the cake sample
compared to the control sample. In the 1:1:1 ratio, the yellow intensity is lower than that of the standard
sample, while in the two ratios of 2:1:1 and 3:1:1, the yellow color is higher than the control sample (4.340b
± 1.043 versus 14.073c ± 0.839). This shows that the percentage of lablab sea flour determines the intensity
of the yellow color of the cake. In the samples with the same flour ratio of 1:1:1 but different in the CF
ratio, there was no color difference, so it can be concluded that CF does not affect the color of the cake at
this ratio. It is noteworthy that the difference in color ∆E of the 3 formulations with 0.25% CF addition was
not significantly different. This result also proves that CF does not produce a color difference even when
the ratio of the ingredients of lablab sea flour: banana puree: pumpkin flour is changed. However, when
banana puree and pumpkin flour content was reduced (2:1:1 and 3:1:1, respectively) and CF was not used,
the color difference became significant. Especially at the 3:1:1 ratio, the color difference between the cakes
with and without the addition of CF was also significantly different. This difference can be explained by
the fact that banana puree and pumpkin flour are high in sugar and can also interact with each other and
with CF to affect the color of the cake. During baking, the reducing sugars in bananas react with amino
acids, causing the Maillard reaction to darken the color of biscuits [29].
3.4 Physical properties of biscuits
The moisture content (see Table 4) of all cake samples (2.98 – 3.89%) met the requirements of the moisture
standard of biscuits according to TCVN 5909:1995 (not more than 4%).

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Table 4. Physical properties of cakes in different mixing recipes

Flour mixing ratio Humidity Width (mm) Thickness (mm) Spread ratio W/T Hardness (N)
1:1:1 – 0.25% 3.89b ± 0.066 41.613a ± 0.435 1.803bc ± 0.067 23.098cd ± 0.925 14.423a ± 2.296
2:1:1 – 0.25% 3.743a ± 0,047 41.267a ± 0.645 1.733b ± 0.08 23.849d ± 1.377 25.39b ± 1.127
3:1:1 – 0.25% 3.72b ± 0.066 41.05a ± 0.344 1.983de ± 0.023 20.698ab ± 0.101 22.32b ± 2.003
1:1:1 – 0% 3.223b ± 0.023 41.667a ± 0.2 1.62a ± 0.061 25.745e ± 1.011 12.217a ± 1.061
2:1:1 – 0% 2.987a ± 0.091 41.553a ± 0.331 1.903cd ± 0.071 21.856bc ± 0.977 21.847b ± 0.131
3:1:1 – 0% 2.977a ± 0.091 41.023a ± 0.254 2.03e ± 0.035 20.213a ± 0.4 23.753b ± 3.981
(Means± SD with different superscripts in the same row are significantly different at P < 0.05 by LSD)
Proportional recipes increase the amount of lablab seed flour and decrease banana puree with decreasing
moisture content. In the recipes that mix lablab seed flour, pumpkin flour, and banana puree without CF
added, the 1:1:1 ratio has the highest moisture content, then the 2:1:1 ratio, and finally the 3:1:1 ratio. This
is explained by the fact that banana puree has a higher moisture content than the other two ingredients. At
the same time, the high sugar content significantly affects the cake's ability to retain moisture; the higher
the percentage of lablab seed flour, the harder the cake structure.
In 3 recipes mixed with CF, its ability to retain moisture increases the moisture content of the cake. With
the same amount of CF when combined with a high banana ratio, the 1:1:1 cake samples had a high moisture
content when compared with the moisture content of the cake at the ratio of 3:1:1 (3.89b ± 0.066% vs with
2.977a ± 0.091%) corresponding to the percentage of lablab seed flour accounting for 60% reduced to 20%
banana puree.
The agricultural flours used in this study contain biopolymers such as protein concentrates, and
carbohydrates, ... and they will interact complexly with each other. The obtained results showed that the
gluten-free varieties with the higher the banana puree content, the more porous the cake, and vice versa, the
higher the lablab flour, the higher the hardness.
According to the data in Table 4, the moisture content of the formulations added with CF was higher than
that of the formulations without CF because of the nature of these ingredients, which is less able to hold
water. At the same time, CF can hold water and oil [4] should improve the cake's texture, taste, and stability.
In the ratios 1:1:1, 2:1:1, and 3:1:1, there is a gradual decrease in moisture content and an increase in the
hardness, which shows the influence of the flour ratio in the cake recipe. The 1:1:1 pattern with a higher
banana ratio results in a softer cake structure, the 3:1:1 pattern with a higher the lablab flour ratio makes
the cake structure spongier and stiffer, which results in the penetration force of the cake of the 3:1:1 ratio
being higher than the 1:1:1 ratio. In contrast, the structure of the 2:1:1 cake is reported to be stable. Overall,
it can be concluded that the ratio of banana puree and the addition of CF are the two main determinants of
the change in cake moisture content, resulting in a difference in the hardness of the cake.
The results showed that, although the cake product did not meet the requirements of the control product on
the market, the 2:1:1 cake sample obtained the results closest to the desired result, meeting the criteria:
medium hardness, about 2mm thin, characteristic dark color, fine texture. The CF by-product has a high
water absorption capacity, leading to the bakery products supplemented with CF having a higher moisture
content than the control cake products (0% CF). The physical values of biscuits were also affected in the
presence of CF preparations, the diameter and thickness of biscuits tended to decrease with increasing CF
content added to biscuits [22]. In the Vietnamese market, there are no biscuits that combine lablab seed
flour, pumpkin flour, and banana puree, creating an expectation of a new vegan nutritional product suitable
for dieters.

4. CONCLUSION
The results showed that the cake recipe with a mixing ratio of 2:1:1 and 0.25% Citrus Fiber had the most
suitable structural properties. The following research direction is a survey on consumer acceptance of
gluten-free, sugar-free, and butter-free biscuit products. Currently, there are no similar studies on using
these ingredients to replace flour for biscuits. The use of locally available ingredients actively contributes

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 International Symposium for Green Solutions (ISGS 2022)

to building a sustainable food system. This is a breakthrough, opening a new turning point for the bakery
industry with high nutritional value to serve the needs of consumers who are on a diet, cardiovascular
disease, diabetes, and especially is for patients with gluten sensitivity (Celiac disease), moreover, Whole
Food Plant-Based is becoming a healthy food trend in the future.

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