The acceptability, expiration, and fibre level of gluten - free mung bean biscuits

Gluten - free mung bean biscuits have been made of mung bean flour, tapioca flour, corn starch, and egg whites. This research aimed to determine the differences amongst varied mung bean biscuit compositions and their influence on the acceptability, the measured expiration period, and the content of water and fibre. This research was conducted through a random group experiment design. Different compositions of ingredients were used, i.e., 60% mung bean flour, 15.0 - 22.5% tapioca flour, 17.5 - 25% corn starch and 7% - 10% egg whites. The packaging was made of plastics with a permeability of 0.0265 g/ m 2 .day.mmHg was used. The packed biscuits were put into a jar. In the analysing process, the food acceptability was measured using a hedonic test. A further data analysis using ANOVA followed by a Duncan test was conducted to justify the acceptability of the prepared biscuits with different ingredient compositions. The expiration of the food was tested using an ASLT method. The content of water and fibre was determined using an oven method and a gravimetric analysis. This study showed that the biscuits ’ acceptability was in the range of 6.6 – 7.1 (out of 9) or the favourable scale. All the prepared biscuits showed no significant difference in the physical appearance, with slight golden yellow (p = 0.008) and the overall quality (p = 0.039). The expiration period of the gluten - free biscuits with the F5 code (20% tapioca, 20% corn starch and 7% egg whites) was 8.66 months. The water content of all prepared biscuits was very low, in the range of 0.7 - 2.36%, while the fibre content was very high in the range of 18.6 – 23.6 g.


Introduction
A biscuit is a product that is principally made of flour, sugar, and fat.Biscuits are often consumed with tea, coffee, and other snacks.They are consumed by all age groups of consumers and are practical to bring during travels (Mehta et al., 2012;Warinporn and Savage, 2018).Biscuits are consumed by most people (Vijayalakshmi et al., 2019) as well as most favoured by kids after milk (Fathonah et al., 2014).Biscuits are nutritious food packed hygienically.They are sold at a competitive price, volume, and taste.The main ingredient of biscuits is wheat flour, a high energy composition with low quality.
The market of biscuits and cakes move to the healthy food market due to the increase in health incidents, media reports of human health, the increase in the awareness of physical and body lifestyle, and the increase in the cost of health services (Santos et al., 2015;Trivedi and Soni, 2016).To improve the quality of biscuits, the manufacturer includes vegetable and animal protein.The rising inclusion of protein in biscuits runs in the same way with the inclusion of soybean and cassava flour (Akubor et al., 2003), wheat (Nagi et al., 2012), spirulina powder (Singh et al., 2015), sorghum (Adiamo et al., 2017), purple rice and green clams (Warinporn and Savage, 2018), green tea powder (Phongnariscorn et al., 2018), and mung beans flour (Fathonah and Muvida, 2015;Fathonah et al., 2019).Previous studies regarding consumer behaviour showed that the respondents were willing to eat a healthier biscuit.People appreciated the advantage of biscuit consumption made of wheat flour (Trivedi and Soni, 2016).That caused interest and created the market for gluten-free biscuits as a part of the healthy food industry (Cureton and Fasano, 2009;Houben et al., 2012;Foschia et al., 2016).
Previous studies also showed that mung bean biscuits contained 35% of butter with 453 kcal of energy, FULL PAPER 11.3% of protein, and 13.1% fibre.This kind of biscuit showed a high favourability (Fathonah and Sari, 2015).The best composition of the mung bean biscuits was made of 60% mung beans, 20% wheat flour, and 20% corn starch and roasted in a 17-minute heating time (Fathonah et al., 2018).This composition comprised 454 kcal (7.95%) of energy, 19.75 mg of iron, and 1.94% of fibre (Setyaningsih et al., 2019).The nutrition of mung bean is useful with protein content in health improvement (Du et al., 2017), pro-anthocyanins for the antioxidant (Chai et al., 2018), and angiotensin renin for blood tension control (Yi-Shen et al., 2018).
Mung bean is a vegetarian food with the richest nutrition in the world (Mannay and Shadeksharasway, 2005).The high level of protein and iron is better consumed by toddlers, pregnant women, breastfeeding mothers, and anaemia survivors.In previous research, mung bean biscuits have been distributed to toddlers in an Early Childhood Education Centre in Gunung Pati, Semarang, Indonesia for a month, along with nutritional education to the parents (Fathonah et al., 2019).A better understanding and improvement of kids' and their family health has been observed.
A further study regarding the replacement of wheat flour with tapioca was necessary to obtain the best quality ingredient composition.Wheat flour contains gluten which is not good for celiac survivors.Their intolerance to gluten could promote dermatitis herpetiformis, gluten ataxia, allergy, and sensitivity (Padalino et al., 2016;Wolf et al., 2018;Chakrabarti et al., 2019).A psychological effect may occur to the survivors, such as exhaustion and anxiety (Churruca et al., 2017).Some examples of gluten-free products are biscuits made of spinach, wheat seeds, buckwheat, and peanuts (Schonlechner et al., 2006), rice muffins (Matos et al., 2014), and cookies made of rice and buckwheat (Sakac et al., 2016).The replacement of wheat flour with gluten -free ingredients was reported earlier in the product of gluten-free cereal, like corn and rice (Lasa et al., 2017).
The information on product expiration is essential for producers, consumers, distributors, and sellers.Consumers are entitled to the right to know the safety level of the products.They also have the right to know the composition of the taste, the ingredients for the looks, and the nutrition in the product.For producers, expiration is the concept of product marketing.This concept is economically important in product distribution.It is also important to the packaging of the product.For sellers and distributors, this information is extremely important to handle the stocks of food.Expiration reflects the nutrition, function, sensory profile, and safety of the food (Zielinski et al., 2012).The most significant changes to food could occur in the processing, storage, and handling of lipid oxidation and microbiological decomposition.These processes reduce the quality of food and eventually lead to health dangers for consumers (Laguerre et al., 2007).
Previous studies regarding biscuits' expiration period were done using various methods.The research was conducted on ten types of biscuits (five types of each local and foreign originating product) in Bangladesh kept at a temperature of 30°C and 60% RH.The result showed that the humidity of food and the water content increased over time for all samples, while the sensory value of the biscuits decreased (Chowdhury et al., 2012).The use of metalized polyester polyethylene (MET-APE) -based packaging for cookies can store biscuits for four months at room temperature (Jan et al., 2017).This research indicated that biscuits' expiration varied from 3 to 17.4 months.
Biscuits containing 3% of water showed a longer endurance of storability (Lean, 2006).To measure the expiration period, accelerated shelf-life testing was conducted with the approach of critical water level (Bell and Lazuda, 2000).The expiration period of biscuits or other food products was able to support the wider market.Food quality represents the properties and attributes of food.These specifications are measured using three qualifications, i.e., sensory, suitability, and healthiness (Leitzmann, 1993).In this paper, the quality of biscuits has been measured only from the acceptability, expiration, and content of water and coarse fibre.This study aimed to investigate the effect of the composition of mung bean biscuits on consumer acceptability, to measure the expiration period of the biscuits with the optimum ingredient composition, and to determine the content of water and fibre in the prepared biscuits.

Subject of the research
The subject of this research was gluten-free biscuits with different ingredient compositions of tapioca, corn starch, and egg whites.In detail, the compositions varied in the range of 15-22.5% tapioca, 2.5% corn starch, and 7-10% egg white.The biscuits were packaged in two types of packaging, i.e., small (containing 2 biscuits) and plastic box packaging, as shown in Figure 1.

Biscuit production
This research used a random group experiment model with a three-times repetition.The composition of the ingredients used in preparing the gluten-free biscuits FULL PAPER was formulated as listed in Table 1.
The process of biscuit production follows the following steps.The granulated sugar was mixed with egg whites for 5 mins.This process continued until homogenous and was prolonged for 4 mins.The mung bean flour, wheat flour, corn starch, and baking powder were added to the egg white mixture and eventually mixed in 3 mins.The butter was added to the biscuit mould.The dough was moulded on a baking sheet for 17 min under the upper limit temperature of 150°C and lower limit temperature of 130°C.The biscuits were cooled down to room temperature for 15 mins and packed using plastics with a permeability of 0.0265 g/ m 2 .days.mmHg or using a plastic box (Figure 1).

Biscuit acceptability
The acceptability of the biscuits was tested by eighty panellists.They provided scores to the biscuits using a hedonic test on the favourability scale of 1-9.A score of 1 indicated an extremely unfavourable criterion while that of 9 designated an extremely favourable criterion, as shown in Table 2 (Meilgaard et al., 2007).The aspects considered in the analysis were colour, textures, sweetness, aroma, and acceptability.The panellists were required to neutralize the taste of biscuits using water after tasting each biscuit.

Analysis of nutrition
The measurement of the expiration period was done by the ASLT method.The water and fibre contents of the biscuits were measured using the oven method and gravimetric analysis, respectively (AOAC, 2010).The water content was calculated using equation ( 1) (Bell and Lazuda, 2000).
From the sensory test, biscuit 5 showed the best quality.The water content and isothermal water sorption of biscuit 5 were used to determine the expiration period.The critical water content was determined by storing the biscuits at 30°C in an open door without any plastic package (RH of 75 -80%).The curve of isothermal sorption of air (ISA) was used to determine the correlation between water content and room RH.The test effectively predicted the water level of an ingredient composition under different environments.The curve of ISA was made by keeping the product in a desiccator containing saturated salts (MgCl 2 , K 2 CO 3 , NaBr, NaCl, KCl, KNO 3 ) with different RH.There will be a water balance content (Me) after some time.Consequentially, a curve was made to relate RH and salt with the product's water content.The expiration of biscuits was measured using the date of the experiment to Equation (1), with t is the estimated expiration time (days), Me is water balance content (g H 2 O/g solid), Mo is initial water content (g H 2 O/g solid), Mc is critical water content (g H 2 O/g solid), k/x is water vapour constants of permeability (g/ m 2 .days.mmHg),A is an area of the package sample (m 2 ), Ws is the weight of the dry product (g solid), Po is saturated vapour pressure (mmHg), b is the slope of isothermal sorption curve.The expiration unit used was months with the assumption that one month was 30 days.

Data analysis
To analyse the influence of the ingredient compositions on the sensory quality and the favourability of the biscuits, factorial analysis was used.Duncan test was used to examine the difference between the acceptability of the biscuits with different compositions of ingredients (Minium et al., 1993).

Results
An insignificant difference in the appearance of the biscuits with different ingredient compositions was observed as shown in Figure 2. A slight difference in the darker yellow colour was observed for F2, F4, and F6 biscuits.Meanwhile, F1, F3, and F5 biscuits were darker than F7 and F8 biscuits.The biscuits' acceptability ranged from 6.5 -7.4 (Table 3) with favourable to very favourable categories.Meanwhile, the overall categories were in very favourable category.Overall, the most favourable biscuits were F3 biscuits.
The ANOVA analysis showed a significant difference between the acceptability of the gluten-free biscuits, as shown in Figure 3(a).The highlights of the difference were in the golden colour with p value of 0.008 and the overall acceptability with p value of 0.038.In detail, the colour difference could be grouped as follows: F1, F5, and F7 biscuits were different in colour from F4, F6, and F8 biscuits.They also showed different colours from F2 and F3 biscuits.There was a tendency that the higher amount of egg whites used (in F2, F6, F8 biscuits) resulted in better acceptability than the lower amount of egg white usage (in F1, F5, F7 biscuits).An exception was observed in the colour of F3 and F4 biscuits which used 17.5% tapioca and 22.5% corn starch.Generally, the acceptability of biscuits was in the range of favourable and very favourable categories.This study showed that the overall acceptability of F1, F4, F5, F6, F7, and F8 biscuits was different from that of F2 and F3 biscuits.
Table 4 shows that the water content of the eight biscuits was very low, in the range of 0.70 -2.30%.The higher composition of tapioca was reflected in formula 6, while the lower use of corn starch is depicted in formulas 7 and 8 (Figure 3(b)).The use of egg whites did not affect the content of water and fibre.Overall, the content of fibre in the eight biscuits was very high, in the range of 18.6-23.6g.The high level of fibre affected the texture of the biscuits.The biscuits became dry and difficult to swallow.The use of higher tapioca and lower corn starch increased the content of the fibre in the biscuits.In contrast, the content of the fibre decreased with the lower use of tapioca.Moreover, the content of total energy and protein of the F5 biscuits were 402 kcal and 9.6 g, respectively.

Discussion
Low-gluten mung bean biscuits (20% wheat flour) and gluten-free biscuits (20% tapioca) were acceptable for consumers (Fathonah et al., 2019).The replacement of wheat with tapioca worked perfectly on the biscuit production resulting in the eight biscuits with different compositions with the acceptability of 6.9 -7.2 (out of 9) or in a good category for all indicators.The biscuits showed a good level of crispness as the main aspect of the biscuits' acceptance.The best composition of the biscuits based on the acceptability test was the F5 biscuits with 20% tapioca, 20% corn starch, and 10% egg whites.
Other studies of gluten-free biscuits showed varied acceptability levels.Gluten-free biscuits made of red rice flour (70%), corn starch (10%), potato flour (10%), and soybean flour (10%) showed the best acceptability level in the sensory level (Schober et al., 2003).Rao et al. (2016) reported that sorghum flour resulted in a cake with a lower solidity and higher consumer acceptance.Mancebo et al. (2016) have developed rice-containing cookies with a higher spread factor and lower solidity.Biscuits with a composition of 50% soybean and 50% cassava showed the highest acceptability for all sensory indicators.Soybean biscuits with more than 50% soybean content showed lower acceptability (Akuabor and Ukwuru, 2004).Miranda et al. (2014) found that gluten-free snacks with the composition of red rice (70%), spinach flour (20%), and pear skin powder (10%) showed the best sensory in comparison with other commercial snacks.That snack also showed a low level of fat and high content of fibre and protein.Another study showed that nutritious products made of various flours (yeast, jowar, soybean, oats, corn starch, nuts) were accepted by all age groups of consumers (Mehta, et al., 2012).The acceptance of gluten-free biscuits with different flours resulted in 50% for taro flour, 25% for tapioca, 15% for sorghum flour, and 10% for cassava flour (Giri and Sajeev, 2020).
The different compositions of the biscuit production resulted in different colours of the biscuits.The difference was caused by the different types of flour and different amounts of egg whites added.These flours contain different levels of carbohydrates.In this case, tapioca contains 80.0 g of carbs while corn starch has 85 g of carbohydrates (Directorate General of Public Health, 2018).The higher the level of corn starch (carbohydrate) and egg white (amino acid), the darker the colour of the products.Zanoni et al. (1995) reported that the development of brown colour in a biscuit crust was due to the reaction of caramelization.Caramelization is the degradation of sugar at a temperature above 150°C (Zanoni et al., 1995;Hadiyanto et al., 2007).This reaction known as the Maillard reaction involves the chemical conformation of the protein, amino acid, and reduced sugar to complex carbohydrates (Chung et al., 2012).
The use of nuts, including mung beans has many advantages, such as containing complex carbohydrates and high levels of fibre, low levels of fat, noncholesterol, high vitamin and mineral, and low level of sodium (Drummond and Brefere, 2004).Mung bean flour was selected to be the main composition of biscuits in this study due to its high level of protein (Stauffer, 1992).Mung bean contains vegetal protein, which is a good fat source for the human body in dissolving the vitamin and antioxidant/phytochemicals for human health (Hegazy and Ibrahim, 2009;Serrem et al., 2011;Domero et al., 2013).The phytochemicals in mung beans help to prevent cancer and ulcer as well as reduce cholesterol levels.The high fibre prevents a significant increase in blood sugar after fasting (Michele, 2013).The consumption of beans increased energy consumption by 250 kcal without significantly raising the bodyweight of the consumers (King et al., 2008).
The expiration period of the gluten-free biscuits in this study was 8.66 months.This result was higher than other studies.In the previous study, a biscuit of bran (20%) has 3 months expiration period with a low level of microbes under HDPE and lamination (Nagi et al., 2012).A study in Bangladesh showed that five local and five foreign biscuit brands were stored well for 3 months at 30 o C and 60% RH.All these samples were distributable.Only one local biscuit was not tradeable.These biscuits showed a lower sensory level over time (Chowdhury et al., 2012).The addition of vitamin E in cookies resulted in high acceptability and storability for 4 months (Kaur et al., 2015).A sensory level is an identification to signify the expiration period of glutenfree cookies with an aldehyde (Sakac et al., 2016).In this case, an unpleasant smell of food is the product of secondary lipid formation from the oxidation of biscuits.The compounds formed from that reaction could be 2heptenal, 2-octenal, 2-nonenal, and 2,4-decadienal (Laguerre et al., 2007), nonanal and 2-nonenal (Pasqualone et al., 2015).
In this research, the biscuits were kept in a plastic container.Plastic is a durable, low, and cheap composition that is easily printed on all products (Nasrollahi et al., 2020).The use of BOPP biaxial oriented polypropylene/casting polypropylene (BOPP_40/CPP_50 and polyethylene/ethylene vinyl alcohol/polypropylene (PE/EVOH/PP_50) could prolong the storage time of the gluten-free biscuits to 90 days on darks and lights without any change in the FULL PAPER physicochemical properties and sensory elements of the biscuits (Duta et al., 2019).
The storability was supported by the low level of water.All compositions of the biscuits in this study showed a water content in the range of 0.70 -2.30%, while the water content of some commercial biscuits was in the range of 1.7-5.0%(Passos et al., 2013).The water content of the biscuits in this study was also lower than that of a biscuit mixed with pear porridge (Obeta et al., 2020).The lower content of water made the biscuits more durable to eat with a longer expiration period, allowing the scale-up to a bigger manufacturing process.
The fibre content of the biscuits in this study was in the range of 18.6-23.6g.In this case, the required fibre for an adult human is 38 g for 55 g of biscuits (Sizer and Whitney, 2020).This fibre content can contribute 31.0 -39% of daily fibre needs.Referring to the data, previous studies showed various fibre contents of the products.Mung bean biscuits with wheat flour contained fibre of 4.50-4.90%(Yusuf et al., 2015).15% of spinach flour in biscuit ingredients could result in biscuits with 2.87 g of fibre (Galla et al., 2017).A biscuit of corn starch (15-30 % PBF (rice and peeled black bean pre-gelatinized flour)) contained 2.03-2.07g fibre (Bassinello et al., 2011).Biscuits of wheat flour with pear porridge contained 0.47-0.84%fibre (Obeta et al., 2020).There was different level of calories, macronutrients, fibre, sodium, salts, and cholesterols in 206 gluten-free products and 289 glutinous products (Miranda et al., 2014).The biscuits made of wheat flour and mocaf increased the composition of cyanogen and coarse flour (Harijono et al., 2017).In the end, mung bean represented the fraction of fibre food with lignin, cellulose, and hemicellulose (Mannay and Shadeksharasway, 2005).A high level of fibre is appropriate for people who require food with high fibre content.Fibre is insoluble in water.Therefore, it smooths the defecation process of the human body and prevents obstipation, haemorrhoid, and diverticulosis.Fibre could decrease the level of fat and cholesterol in the blood.Thereby, it reduces the chance of sickness, coronary heart disease, and dyslipidaemia.A study found that the increasing level of fibre intake decreased the blood pressure of hypertension survivors.The intervention should be done in 8 weeks to decrease blood level maximally (Whelton et al., 2005).Fibre helps to reduce the risk of type 2 diabetes (Montonen et al., 2003), and the cholesterol total and low-density lipoprotein (Brown et al., 1999).A diabetes survivor should provide a dietary fibre of 25-50 g/day (15-25 g/1000 kcal) (Anderson et al., 2004).Rich fibre food is positively related to the reduction of chronic diseases (Ng et al., 2017).The acceptability of biscuits with the addition of fibre and combination with commercial biscuits did not show a significant difference in consumers' interest (Santos et al., 2015).
Apart from the fibre, the biscuits produced in this study were high in protein (9.0-10.7 g) and energy (390-420 kcal).A distinctive energy and protein content was observed in the F5 biscuits which contained 402 kcal of energy, and 9 g of protein.Gluten-free multigrain biscuits (jowar, soybean, oats, corn starch, peanuts) contained a high content of nutrition (protein, vitamin A, calcium, and fibre).These products were highly recommended for all age groups of consumers.Biscuits are recommendable to celiac survivors, breastfeeding women, and malnutrition survivors (Mehta et al., 2012).

Conclusion
The acceptability of gluten-free mung bean biscuits was in a very favourable category with high energy and protein content.The moisture content of the biscuits was very low and has met the standard due to a long expiration period (8.66 months), with a very high crude fibre content.These biscuits were highly recommended for consumption by all age groups, especially celiac survivors, breastfeeding women, and malnutrition survivors.

Figure
Figure 2. Eight Gluten-free mung bean biscuits

Figure 3 .
Figure 3. (a) The graph of colour and overall acceptability difference to each gluten-free mung beans biscuits formula, (b) The content of water and fibre of the biscuits (a) (b)

Table 9 .
Expiration on different storing method