Effects of Jasmine Rice Flour, Glutinous Rice Flour, and Potato Flour on Gluten-Free Coffee Biscuit Quality

ABSTRACT This study investigated the effects of jasmine rice flour, glutinous rice flour, and potato flour on the physical, sensory properties and consumer acceptance of biscuits. The biscuits were made using varying ratios of jasmine rice flour: glutinous rice flour: potato flour. The mixture design was used for 10 treatments. Increasing the ratio of glutinous rice flour while keeping the ratio of jasmine rice flour constant increased the biscuit hardness, crispness, lightness (L*), appearance, aroma, flavor, and overall acceptance by >70%. However, it tended to decrease the biscuits’ redness (a*) and yellowness (b*). The higher acceptance score of appearance and color was found in the ratios of 66.7:16.7:16.7 and 50:50:0. The higher acceptance score of hardness and crispiness was found in the ratios of 16.7:66.7:16.7 and 50:50:0. The ratios of 16.7:6.7:16.7, 16.7:16.7:66.7, 50:50:0 and 33.3:33.3:33.3 received high overall acceptance scores.


Introduction
Biscuits are baked products and are also known as cookies.Biscuits typically have a hard flakiness to them, and they are flat and unleavened.The term biscuit is used in European countries, while the term cookie is used in the USA (Mian, Masood, Faqir, & Haq, 2009).Basically, biscuits can be classified as either soft dough or hard dough like other types of short breads, however biscuits do not require dough fermentation (Manley, 1998;Nwosu, 2013).Biscuits are popular ready-to-eat bakery products that are widely accepted and eaten by populations around the world (Boobier, Baker, & Davies, 2006;Okpala & Okoli, 2013).Biscuits have low moisture content (below 5%) so they are free from microbial spoilage and have a long shelf life (Adebowale, Adegoke, Sanni, Adegunwa, & Fetuga, 2012).Biscuits are high in carbohydrates, fat and calories, and low in fiber, vitamins, and minerals (Angelica, Merly, Juan, & Pedro, 2017).The fundamental ingredients of biscuits are soft wheat flour, sugar, fat, and water (Manley, 1998).In addition, they are mixed with other ingredients including baking powder, milk, emulsifier, and egg.used in the food industry, especially in Europe, because of its unique properties with low gelatinization temperature and high paste consistency (Hielko & Do, 2009;Kerr, 1950;Mason, 2009).Due to its film properties, paste penetration depth, and adhesive power, potato starch has also been applied to textile production.Due to the high level of phosphate in potato starch, it has larger granule size and greater susceptibility to gelatinization (Bergthaller, 2004).Potato starch differs from other cereal starches in that it consists of long amylopectin chains, which form hydrated and ordered B-type crystallites, and phosphate esters (Eric & Andreas, 2016).Even though potato starch contains a very low level of phosphorus of approximately 0.01-0.6%(w/w).It contains significant amounts of monophosphate esters covalently bound to starch.The distribution of the phosphate monoesters on the C2, C3, and C6 hydroxyls of the glucose units in potato starch has been reported to be 1, 38, and 61%, respectively (Kasemsuwan & Jane, 1995;Lim, Kasemsuwan, & Jane, 1994).These ester bonds have an effect on starch gelatinization and pasting changes (Galliard & Bowler, 1987).
The gluten-free flour and starch that is fortified can improve a desirable attribute in these kinds of biscuits.Hardness and flakiness can be attained by adding gluten-free starch mixture to the dough.Therefore, this research aims to study the effect of jasmine rice starch, glutinous rice starch, and potato starch on the physical, sensory characteristics, and consumer acceptance of biscuits.

Flour preparation
Jasmine and glutinous rice was steeped in water for 5 hours and then wet-milled.Rice slurry was centrifuged to get rice cake that was then dried at 45°C until the moisture content reached 10-12%.Dried rice cakes were ground and sieved through a 120 mesh sieve.
Fresh potatoes are the raw materials of potato flour.They were peeled and sliced into thin slices and steam blanched for five minutes.The blanched potatoes were dried in a hot air oven at 45°C until the moisture content reached 10-12%.The slices were milled and passed through the 120 mesh sieve.

Biscuit preparation
In this study, biscuits were prepared by combining 15% whipping cream, 12% butter, and 10% sugar in a large mixing bowl.This blend was then beaten at a medium-high speed until creamy, light, and fluffy.Next, 10% coffee peel (cascara) and 1.5% coffee flavor extracts were added and well combined.After that, 50% all-purposed wheat flour, 1.4% yeast, and 0.1% salt were mixed with the liquid ingredients until perfect dough formed.The dough was rested in the refrigerator for 20 minutes and then kneaded until its thickness was 3 mm.It was then rested in the refrigerator for another 20 minutes.The biscuit dough was cut into 3 cm diameter circular shapes and baked at 180°C for 20 minutes.

Application for biscuits from jasmine rice flour, glutinous rice flour, and potato flour
The mixture design was used for 10 different treatments in which jasmine rice flour, glutinous rice flour, and potato flour were substituted for wheat flour, where X 1 represents jasmine rice flour, X 2 represents glutinous rice flour, and X 3 represents potato flour, as shown in Figure 1.

Physical properties of biscuit product
Biscuit hardness and crispiness were determined by texture analyzer (TA.XT Express, Stable Micro System, UK).A cylindrical probe with a diameter of 5 cm was used and dipped 5 mm into a sample at a speed of 1 mm/s.The test speeds were separated into pretest speed at 1.0 mm/s, test-speed at 3.0 mm/s, and posttest speed at 10.0 mm/s.The distance was 10 mm and a five-kilogram load cell was used.An average value of 10 replicates was reported.

Sensory evaluation
Sensory evaluation was carried out by 10 panelists comprising trained students from Srinakharinwirot University, who performed descriptive analysis of sensory attributes.
An intensive 30 h of descriptive sensory panel training, using a barrage of samples and sensory techniques through scaling (with a 15-point intensity scale) was conducted.The panelists discussed definitions and evaluation methods.Finally, sensory attributes and their respective reference intensities were established.The panel also discussed the anchoring references for each attribute.Many baked products samples from markets were reviewed.The definitions and the testing method of all descriptive terms were as follows: Odor was the degree of odor clearly noticeable on the biscuit surface.Flavor was the degree of flavor in the mouth between chewing the biscuit.Hardness described the degree of difficulty swallowing one sample of biscuit.Crispiness was the ability of a cross-sectional structure of the sample to be forced or compressed.The test samples were randomly presented to each assessor.Three pieces of each sample in a white dish coded with 3-digit random number were presented in monadic servings to each consumer.

Consumer acceptance
Consumer acceptance was tested using a 9-point hedonic scale.The following values were given: 1 = the most disliked, 2 = disliked a lot, 3 = disliked a little, 4 = neither liked nor disliked, 5 = fairly liked, 6 = liked a lot and 7 = liked the most.All 100 consumers were untrained panelists.The samples were served at room temperature (25 ± 1°C) and the evaluation was conducted under normal lighting conditions.The consumer cleansed their palates between samples with drinking water.

Biscuit proximate analysis
Nutrient content of the accepted incorporated biscuit sample was determined.The nutritional values including crude protein, fat, and ash content of the biscuits were determined by AOAC (1990).Carbohydrate was expressed as the difference from moisture, protein, fat, and ash.

Statistical analysis
Each treatment was repeated three times.SPSS software was used to determine the differences between treatment means using the Duncan Multiple Range Test.The treatment means were considered significantly different at p ≤ .05unless otherwise stated.

Physical properties of biscuit products
The physical characteristics and colors of the biscuits with jasmine rice flour, glutinous rice flour, and potato flour are shown in Table 2 and Table 3 and  Figure 2. It is important to note that the biscuits were not able to be produced using the ratio of jasmine rice flour, glutinous rice flour, and   potato flour at 0:0:100.The biscuits with the ratio of jasmine rice flour, glutinous flour, and potato flour at 0:100:0, respectively, produced the highest crispiness and lightness (L*) and at 100:0:0 provided the highest redness (a*) and yellowness (b*) of biscuits.The ratio of 0:100:0 and 50:50:0 gave the highest hardness.With the ratio of potato flour kept constant, biscuits with a higher ratio of jasmine rice flour had significantly lower crispiness and hardness (p ≤ .05),whereas the lightness (L*), redness (a*) and yellowness (b*) increased.With the ratio of glutinous rice flour kept constant, increasing the ratio of jasmine rice flour provided significantly higher crispiness, hhardness,and redness (a*) (p ≤ .05).With the ratio of jasmine rice flour kept constant, increasing potato flour significantly decreased crispiness, hardness, and lightness (L*), but significantly increased the redness (a*) and yellowness (b*) (p ≤ .05).

Sensory evaluation
Figure 3 shows the sensory properties of biscuit with jasmine rice flour, glutinous rice flour, and potato flour.Increasing jasmine rice flour with the ratio of potato flour kept constant significantly increased the biscuits' aroma (Figure 3a) and decreased hardness (Figure 3c) and crispness (Figure 3d) (p ≤ .05).Increasing glutinous rice flour with the ratio of jasmine rice flour kept constant significantly increased the aroma, flavor (Figure 3b), hardness, and crispness of biscuits (p ≤ .05).Increasing potato flour with the ratio of glutinous rice flour kept constant significantly decreased the biscuit's aroma (p ≤ .05),but the flavor, hardness, and crispness were not significantly different (p > .05).

Consumer acceptance
Figure 4 shows consumer acceptance based on the biscuits' appearance, color, aroma, flavor, hardness, crispness, and overall acceptance.The ratio of jasmine rice flour, glutinous rice flour and potato flour at 66.7:16.7:16.7 and 50:50:0 were shown to have the highest positive rating on the biscuits' appearance and color.The ratio of 100:0:0, 0:50:50 and 50:50:0 achieved the minimum rating on the biscuits' aroma and flavor, while hardness and crispness of the biscuits were rated highest at 16.7:66.7:16.7 and 50:50:0.In addition, overall acceptance achieved the highest positive score at the ratio of 33.3:33.3:33.3,50:50:0 and 16.7:16.7:66.7.When the ratio of jasmine rice flour was kept constant, increasing the ratio of potato flour significantly decreased consumer acceptance on the biscuits' appearance, aroma, flavor, hardness, crispness, and overall acceptance (p ≤ .05).When the ratio of glutinous rice flour was kept constant, increasing the ratio of jasmine rice flour significantly increased color, aroma, crispness, and overall acceptance (p ≤ .05).When the ratio of potato flour was kept constant, increasing the ratio of jasmine rice flour increased appearance and color, but decreased hardness, crispness, and overall acceptance (p ≤ .05).

Flour proximate composition
The jasmine rice flour revealed that they contained proximate composition similar to the research of Kraithong, Lee, and Rawdkuen (2018) 2016) which reported the chemical composition of potato starch is 93.4% starch, 14.6% moisture, 20.9-54.2%amylose, 0.08% protein, 0-0.19% lipid, and 0.33% ash Studies have found that potato flour contains fewer lipids than cereal flour.

Physical properties of biscuit products
This study found that increasing jasmine rice flour and decreasing potato flour, while keeping the ratio of glutinous rice flour constant, increased biscuit hardness.The result is consistent with Ergin and Herken (2012) who reported that the hardness of biscuits is positively correlated with rice flour, while increased proportions of potato flour result in softer biscuits.This is due to the high water-holding capacity of potato flour (Johry et al., 2016).Therefore, biscuits made from the ratio of jasmine rice flour, glutinous rice flour, and potato flour at 0:0:100 was not able to form biscuit dough in this study.
A high amylose flour provides firmness, hardness, and crispness to products (Kraithong et al., 2018;Mohamed, Hamid, & Hamid, 1998).However, recent studies have found that starch granule sizes can affect the hardness, which increases when smaller sized starch granules are used (Ai, Jin, Kelly, & Ng, 2017;Rao et al., 2016;Zhang, Yang, Ji, & Ma, 2014).This is consistent with studies that have found that rice flour with 100-200 μm particle size provided less hardness and specific volume of products (Chusak, Henry, Chantarasinlapin, Techasukthavorn, & Adisakwattana, 2018).The average granular size of non-waxy rice starch, waxy rice starch, and potato starch were around 2.4-5.4 μm, 4.9-5.7 μm, and 15-100 μm, respectively (Qi, Tester, Snape, & Ansell, 2003;Sodhi & Singh, 2003;Horstmann, Lynch, & Arendt, 2017).Jasmine rice flour has an average particle size of 140 ± 0.58 μm (Thiranusornkij, Thamnarathip, Chandrachai, Kuakpetoon, & Adisakwattana, 2018).This can explain why increasing the ratio of potato flour and decreasing glutinous rice flour while holding the ratio of jasmine rice flour constant, result in a decrease in the hardness of biscuits.Another study that might explain this result showed that amylopectin has a high branch molecular structure, which might prevent the loss of water from its structure meaning that starch containing higher amounts of amylopectin could exhibit lesser solubility (Somto, 2004).Small granules have higher viscosity, swelling power, and water absorption (Landillon, Cassan, Morel, & Cuq, 2007;Ye, Wang, Wang, Zhou, & Liu, 2016).Due to a high specific surface area, more free water droplets are required to coat small granules than large ones and free water droplets are more likely to evaporate during baking (Sahlstrom, Brathen, Lea, & Autio, 1998).Ye et al. (2016) and Otegbayo, Oguniyan, and Akinwumi (2013) demonstrated that small particle size produced smoothness, fineness, cohesiveness, stickiness, and an oily feeling in the mouth, while larger particle size increased hardness, fracturability, and porosity of products.This is in agreement with Toyama, Miura, and Taneya (1997) & Chen, Schols, and Voragan (2003), who reported that noodles made of potato starch were firmer and more flexible.Starch granule size plays an important role in determining noodle quality.The larger the granular size the lower the resulting quality of the noodle (Chen et al., 2003).This phenomenon acts as a membrane that preserved more gases and water vapor within the structure, resulting in increased rigidity to the total mass.
Generally, the color of all baked products is caused by the Maillard reaction, the process of starch dextrinization and caramelization (Chung, Cho, & Lim, 2014;Valenzuela, Quilaqueo, Lagos, Estay, & Pedreschi, 2018).It can be accelerated by higher temperatures used during the process and also by lower water content of products (Kawai, Hando, Thuwanpanichayanan, & Hagura, 2016;Sharma & Gujral, 2013).The addition of potato flour decreases the moisture content of the final products, which then decreases the lightness (L*), but increases redness (a*) (Bolarinwa, Lim, & Muhammad, 2019).According to Berry (2012), starch is a natural hydrocolloid, which is a hydrophilic molecule: thus, it has greater cohesiveness toward water and keeps moisture in cookies.L* values for the samples were also affected by granular size of starch.The products become lighter as small granular starch was used in the process (Ai et al., 2017;Rao et al., 2016;Zhang et al., 2014).Interestingly, increasing the ratio of jasmine rice flour increased redness (a*).This might be due to the instability of pure 2-Acetyl-1-pyrroline (2AP), a volatile aromatic compound in jasmine rice flour, which turns red through degradation at room temperature (Fang & Cadwallader, 2014).

Sensory evaluation
Protein and fiber content of flour affects moisture retention that definitely influences the hardness of the final products (Batista et al., 2016).This is because high protein starch requires more water for the cookie dough (Nugraheni, Sutopo, Purwanti, & Handayani, 2019).This is in agreement with Batista et al. (2016), who reported that the hardness of biscuits decreases as rice flour is reduced because of lower water retention.Studies have found that wheat flour produces cookies with greater hardness because wheat flour contains the highest amount of protein among the flours used in the formulas (Nugraheni et al., 2019).Generally, rice flour has 15.04% protein, 16.04% fat, and 65.72% moisture.Glutinous rice flour contains 15.59% protein, 16.37% fat, and 65.17% moisture, while potato flour is composed of 0.08% protein, 0-0.19% lipid, and 14.6% moisture (Horstmann et al., 2016;Pereira, Hu, Xing, Zhang, & Zhou, 2020;Schirmer et al., 2013).Apart from the composition and granular size of starch, gelatinization and the formation of starch films also have a role in determining the texture of products.The gelatinization of normal rice, waxy rice, and potato starch measures in the range of 71.1-87.6°C, 59.08-72.09°C, and 58.2-73.8°C, respectively (Qin et al., 2016).Starch gelatinization has been found to be a significant factor in gluten-free formulation (Abdel-Aal, 2009;Horstmann et al., 2017).This is in agreement with Hoseney, Lineback, and Seib (1978), who found that starch was not gelatinized during cookie baking in general.However, there is some possibility of starch gelatinization in cookies with low sugar.A few gelatinized portions of waxy corn starch granules form a continuous phase, which causes expansion and hardened cookies texture (Hoseney et al., 1978).Resistant starch can influence the hardness of products as well.Studies have reported that fiber in waxy rice starch (RD6) and jasmine rice starch (KDML 105) are 0.40%, 0.56%, respectively, and that potato starch consists of 79.3% resistant starch (Moongngarm, 2013).The higher fiber content provides higher water-binding capacity that results in lower hardness values according to Mert, Sahin, and Sumnu (2015), who found that the hardness of samples, which had higher water content was significantly lower.This is consistent with Kaur et al. (2019), who found that increasing flaxseed decreased the hardness and fracturability of the cookies.Since flaxseed is high in fiber and protein content, the extensibility of dough is decreased by adding it into the mix (Kaur et al., 2019).
The sensory evaluation for quality assessment in developed food products is directly influenced by the level and type of ingredients used (Akoja & Coker, 2018;Almoraie, 2019;Sanmartin et al., 2020).More than 200 volatile aroma compounds have been detected in rice.2-Acetyl-1-pyrroline (2AP) is the most significant compound abundantly maintained in cooked aromatic rice (Jinakot & Jirapakkul, 2019;Paule & Powers, 1989).Potatoes are rich in phenolic compounds, such as phenolic acids, flavonols, and anthocyanins (Deuber, Guignard, Hoffmann, & Evers, 2012), and total phenolic contents have been found to be higher in potatoes than in carrots, onions, or tomatoes (Chun et al., 2005).The presence of phytochemical compounds affects sensory profiles, including the taste, color, and texture of processed foods (Akyol, Riciputi, Capanoglu, Caboni, & Verardo, 2016).The addition of potato flour conduced to a lower score being given by consumers for biscuit color (Johry et al., 2016).The darker color of the biscuits might be due to caramelization, dextrinization of starch or Maillard reaction stimulated by low water content of products (Kawai et al., 2016;Sharma & Gujral, 2013;Sudha, Vetrimani, & Leelavathi, 2007).Waxy rice flour exhibits a greater water absorption index (WAI) than normal rice flour due to higher amylopectin content in waxy rice flour, resulting more water penetration through crystalline areas (Kraithong & Rawdkuen, 2019).In this way, decreasing waxy rice flour would lower water content of products and consequently the biscuits would become darker.

Consumer acceptance
The study of increasing potato flour found that it provided biscuits with darker color and that the final products had the distinctive flavor and odor of potato flour, which were not acceptable to the panelists.A ratio of approximately 20-25% of potato flour incorporated into biscuits resulted in the highest score in terms of flavor, texture, and overall acceptance (Seevaratnam, Banumathi, Premalatha, Sundaram, & Arumugan, 2012).This is consistent with Khaliduzzaman, Shams, and Islam (2010); likewise, Misra and Kulshrestha (2003) found a reduction in the acceptability of biscuits with the addition of high levels of potato flour.

Biscuit proximate analysis
The nutritional content of the biscuits made from the ratio of jasmine rice flour, glutinous rice flour, and potato flour at 16.7:66.7:16.7 were similar to those found by Seevaratnam et al. (2012) and Khaliduzzaman et al. (2010).

Conclusion
Higher crispiness and lightness of biscuits was found in biscuits made from a ratio of jasmine rice flour, glutinous rice flour, and potato flour at 0:100:0.The maximum hardness was found in biscuits made from the ratios of 0:100:0 and 50:50:0.The high acceptance score of hardness and crispiness was found in biscuits made from the ratios of 16.7:66.7:16.7 and 50:50:0.Therefore, the biscuits made from the ratios of 16.7:66.7:16.7, 16.7:16.7:66.7, 50:50:0, and 33.3:33.3:33.3provided the highest positive overall acceptance scores.With the desirable characteristics, gluten-free starch can be considered as an alternative for food producers to produce gluten-free products.Possible future research would be to continue studying gluten-free starch in different products.The trend in this research can be applied for the desirable characteristics of other food product.

Figure 1 .
Figure 1.Physical characteristics of biscuits with different ratio of jasmine rice flour, glutinous rice flour and potato flour.

Figure 2 .
Figure 2. Characteristics of biscuits with different ratio of jasmine rice flour, glutinous rice flour and potato flour.

Table 1 .
Proximate analysis of jasmine flour, glutinous flour, and potato flour.

Table 2 .
Physical properties of biscuit product.
Note: The different superscript letters within the same column mean statistical significant difference (P < 0.05).

Table 3 .
Color of biscuit product.
Note: The different superscript letters within the same column mean statistical significant difference (P < 0.05).