Effect of Yeast Fermented Brown Rice Flour Substitution on Nutritional, Rheological and Textural Properties of Steamed Brown Rice Bread

The consumer demand is increasing for composite flour based bakery products like biscuits. The incorporation of brown rice flour can be justified in composite flour based biscuits as it has beneficial nutraceutical properties and its gluten-free nature can play important role in preventing celiac problem. The physicochemical and functional properties of brown rice and wheat flour were studied and biscuits were prepared with the incorporation of brown rice flour in 0, 5, 10, 15 and 20 % with the wheat flour to assess the quality and acceptability of the biscuits. The water absorption capacity of brown rice flour was lower than that of wheat flour (p?0.05), whereas oil absorption and foaming capacity of brown rice flour were significantly higher than that of wheat flour (p ?0.05). The brown rice flour had higher least gelation concentration (30.66%) as compared with wheat flour (20.33%). As the concentration of brown rice flour was increased, spread ratio of biscuits decreased. The biscuits containing 5, 10 and 15% brown rice flour indicated that addition of increasing level of brown rice flour had higher ash, fat, moisture and crude fiber contents, while protein and total carbohydrate contents found lower in the biscuits. Statistical analysis of biscuits containing various amount of brown rice flour (0, 5, 10, 15 and 20% brown rice flour) showed that control biscuits (0% brown rice flour) secured the highest score for color, flavor, texture and overall acceptability, which is followed by biscuits containing 10, 5,15 and 20% brown rice flour. DOI: http://dx.doi.org/10.3329/agric.v10i2.13135 The Agriculturists 2012; 10(2) 20-28

There is a great demand for plant-based yogurt alternatives (YAs) due to societal prevalence of milk sensitivities and allergies as well as some consumers abstaining from animal-derived products. Producing YAs from rice flour has considerable potential because (1) rice is not a major food allergen, (2) using rice flour is more economical compared to plant milks, the main ingredient in commercially available YAs, and (3) there are no rice-based yogurt alternatives in today’s marketplace. The overall goals of this study were to develop probiotic YAs from brown and white rice flours, and to evaluate their storage stability, probiotic’s survival in simulated gastrointestinal conditions, and sensory quality. Brown (FB) and white rice (FW) flours obtained from a high-protein rice cultivar (Oryza sativa L.) called Frontière were fermented with Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, and L. rhamnosus LGG (a probiotic) to produce FB and FW YAs, respectively. The YAs were stored at 4 °C and evaluated during 28 days for physicochemical properties, separate lactic acid bacterial (LAB) counts, and probiotic survival in simulated gastrointestinal conditions. Cow’s milk yogurt (MY) and YAs made from commercially available brown and white rice flours (CMB and CMW) served as controls. A consumer study was also conducted to compare FB and FW YAs to a commercially available oat-based YA. Consumers (n = 90) rated the YAs using 9-point hedonic and just-about-right (JAR) scales. All treatments maintained at least 8 log CFU/g for each LAB during storage. Samples’ pH dropped significantly from 4.58 to 3.62 during storage. There was no significant difference in probiotic survivability within treatments for simulated gastric studies. However, YAs prepared from white rice flours retained significantly more probiotic counts (>7 log CFU/g) than YAs prepared from brown rice flours (

As fermentation could reduce the negative effects of bran on final cereal products, the utilization of whole-cereal flour is recommended, such as brown rice flour as a functional food ingredient. Therefore, this study aimed to investigate the effect of fermented brown rice flour on white rice flour, white rice batter and its steamed bread qualities. Brown rice batter was fermented using commercial baker’s yeast (Eagle brand) according to the optimum conditions for moderate acidity (pH 5.5) to obtain fermented brown rice flour (FBRF). The FBRF was added to white rice flour at 0%, 10%, 20%, 30%, 40% and 50% levels to prepare steamed rice bread. Based on the sensory evaluation test, steamed rice bread containing 40% FBRF had the highest overall acceptability score. Thus, pasting properties of the composite rice flour, rheological properties of its batter, volume and texture properties of its steamed bread were determined. The results showed that peak viscosity of the rice flour containing 40% FBRF was significantly increased, whereas its breakdown, final viscosity and setback significantly decreased. Viscous, elastic and complex moduli of the batter having 40% FBRF were also significantly reduced. However, volume, specific volume, chewiness, resilience and cohesiveness of its steamed bread were significantly increased, while hardness and springiness significantly reduced in comparison to the control. These results established the effectiveness of yeast fermentation in reducing the detrimental effects of bran on the sensory properties of steamed white rice bread and encourage the usage of brown rice flour to enhance the quality of rice products.

Breads were prepared with various combinations of maize, brown rice and wheat flours in the basic formulation of bread. The baking properties and chemical composition of bread were evaluated and analysed, respectively. The bread volume decreased, where as bread weight and moisture content increased with the increasing level of maize and brown rice flour. The crumb and crust colour of breads were improved with addition of 8% maize and 8% brown rice flour in bread formulation. The protein content and other nutrients of breads were increased by addition of maize and brown rice flours. The effects of various levels of yeast, sugar, fat, improver and salt on the quality of breads prepared with maize and brown rice flour were evaluated. Bread quality in respects of bread volume and crumb texture were improved by using 2.5% yeast, 5% sugar, 5% fat and 0.6% improver. The analysis of bread containing added 8% maize and 8% brown rice flours showed protein 9.76%, fat 4.10%, ash 2.10%, crude fibre 5.16%, sugar 2.26% and total carbohydrates 46.91%. Bread having 8% maize and 8% brown rice flour had most acceptable flavour, texture, colour and overall acceptability when compared with other bread with maize and brown rice flour. DOI: http://dx.doi.org/10.3329/jbau.v9i2.11044 J. Bangladesh Agril. Univ. 9(2): 297–304, 2011

Whole grain brown rice, being a rich source of fiber and other bioactive compounds like polyphenols is effective in reducing the risk of chronic diseases including cardiovascular diseases, hypercholesterolemia and Type II diabetes. The study was aimed to evaluate the effect of gamma irradiation on the physicochemical, functional and antioxidant properties of whole grain brown rice flour. The brown rice flour was conditioned to two different moisture contents of 10% and 12% and treated with gamma irradiation doses of 0 kGy (native or control), 2.5 kGy and 5 kGy. Moisture, protein, fat, ash and carbohydrate content of native flour was found as 10 g/100 g, 6.54 g/100 g, 1.54 g/100 g, 1.0 g/100 g, and 81.48 g/100 g, respectively. The hunter color 'L', 'a', and 'b' values of the native brown rice flour sample were found as 81.95, -0.97 and 17.36, respectively and were non-significantly (p ≥ 0.05) affected by gamma irradiation. Apparent amylose content was observed to decrease significantly (p ≤ 0.05) from 29.97 to 20.30 g/100 g with the increase in gamma irradiation dose and moisture content. The pasting properties such as peak viscosity, trough viscosity and final viscosity of all the flour samples decreased significantly (p ≤ 0.05) with the increase in irradiation dose. The functional properties such as water and oil absorption and emulsion capacities were increased while emulsion stability and foaming stability decreased upon irradiation. Irradiation led to an overall increase in the antioxidant activity of rice flours. In general, FTIR spectra revealed a decrease in the absorption intensities of the functional groups. Therefore, it can be concluded that gamma irradiation can be used as a tool to modify the physicochemical properties of rice flours as well as to improve their antioxidant properties.

Sri Lankan traditional and improved rice varieties were processed into brown and polished rice flours. Samples were analyzed for AM, protein, lipid, total phenolic content, and antioxidant activity. Gelatinization and retrogradation properties were observed in the Rapid Visco Analyzer (RVA) and DSC. The AM content of the samples was high to intermediate (20 to 26%) except for one which was low (17%). Brown rice flour (BRF) samples had lower swelling power, lower RVA viscoamylograph profile, lower gel hardness, lower gelatinization enthalpy but higher gelatinization peak temperature and lower melting enthalpies of its retrograded AP relative to its corresponding polished rice flour (PRF) samples. The BRF showed a lower decrease in peak viscosity in the RVA viscoamylograph as compared to its PRF when treated with α‐amylase indicating inhibition potential. The traditional rice varieties had 68 to 86% higher total phenolic content (TPC) and 86 to 90% antioxidant activity in the BRF samples as compared to the improved varieties. A study on the antioxidant profile of the brown rice of the traditional rice varieties is being undertaken to explore their value as functional foods.

Malted grains subjected to extrusion technology could have better quality indices than non-malted grains. The effects of malting and extrusion on the functional and physical qualities of foods extruded from malted brown rice and pigeon pea flour blends were investigated. Malted pigeon pea and brown rice flours were processed into blends, extruded under various conditions of feed moisture levels (15-20), feed compositions (8-30%), and barrel temperatures (100-130 °C), and analyzed using Response Surface Methodology with a Box-Behnken design. The impacts of malting and extrusion were assessed on the following functional qualities: bulk density, rheology, swelling capacity, water absorption capacity, and solubility. The physical quality assessment included a 2-D photographic representation of the extrudates, a microscopic assessment of their internal structure, expansion index, color parameters (L*, a*, b*), and alterations in the color index. Increased feed moisture, malted pigeon pea, and decreased barrel temperature resulted in a higher bulk density (0.72 to 0.84 g/cm3) of the extrudates. There was a decrease in water absorption capacity (6.82-4.49%) with an increase in barrel temperature above 100 °C. All the samples showed a decrease in viscosity with increasing shear rate. At low barrel temperatures, feed compositions, and feed moistures, extrusion led to increases in the expansion index (3.5 to 12.94) and the color lightness (66.83-81.71) of the extrudates. Samples with a higher proportion of malted brown rice showed a higher expansion index, lower bulk density, and lighter color of the extrudates.

The influence of reducing and oxidizing buckwheat sourdoughs on the rheological, protein, and bread properties of buckwheat and brown rice flour was investigated. Batters and breads prepared with chemically acidified doughs, fresh pre-doughs, and fresh pre-doughs containing glutathione (3 mM) were used as controls. No significant differences were observed after the addition of reducing and oxidizing sourdoughs in all trials. Proteolysis was observed after proofing time in buckwheat and brown rice batters, respectively. Acidified doughs increased the elasticity and the gelatinization temperature of buckwheat batters. No notable microstructure changes were detected in brown rice batters. The extension of fermentation time in sourdough caused a slight decrease in bread volumes in all trials. Sourdoughs increased the bread volume and decreased the crumb hardness of buckwheat breads. In trials with brown rice flour, the addition of sourdough did not show relevant volume differences as compared to the controls, except big voids in sourdough bread crumb. Linear correlations between hardness, volume, and cells’ density were observed. However, no clear correlations among rheological parameters and bread characteristics could be detected. These results indicated that the applied strains were responsible for the leavening capacity of the yeast during the proofing time and for crumb structure in trials with buckwheat and brown rice flour. Applied sourdoughs were able to change the molecular, and bread properties of buckwheat and brown rice bread.

Rice bran is rich in vitamin E, dietary fiber, mineral and fat. In this study, puffed rice ball was made from brown or milled rice flour by using twin-screw extruder. Two feed moisture (15 and 20%) and two screw speed (200 and 250 rpm) were set, and the physicochemical properties and content of α-,β-, γ-, and δ-tocopherols were determined. The data showed that extrudates made from brown rice had a high a and b value in color, expansion ratio, water solubility index, but low in L value, bulk density and water absorption index than that made from milled rice flour. Extrudates made from brown rice flour had the higher content of α- and γ- tocopherols (4.8 and 5.7 μg/g). Regarding the effects of feed moisture and screw speed of extruder, the data showed that 15% feed moisture in flour and 250 rpm screw speed yielded to a high expansion ratio, high water solubility index, and low bulk density in the final products.

The aim of this study was to improve the quality of brown rice tofu to produce it with a superior-quality. When the brown rice flour was heat treated with water, the water absorption rate of flour decreased using brown rice flour with a particle size range of < 212 μm when compared with that of brown rice flour with a particle size range of < 475 μm. The cohesiveness and gumminess of brown rice tofu made from brown rice flour with a particle size range of < 212 μm were fairly high in comparison with those of brown rice tofu made from brown rice flour with a particle size range of < 475 μm. In addition, the adhesiveness and cohesiveness of brown rice tofu remarkably decreased when heating and kneading times of brown rice flour dough were extended. By textural and sensory analyses, it became clear that the use of brown rice flour with a particle size range of < 212 μm and the extension of gelatinization time and heating and kneading times of the dough were important factors for preparation of high-quality brown rice tofu. Therefore, the results indicated that it could produce acceptable high-quality brown rice tofu having smooth and new palate feeling while suppressing adhesiveness and stickiness peculiar to rice flours.

Background: Germinated brown rice (GBR) flour recently gained popularity due to its nutritional and health-promoting benefits and is being used as a functional ingredient in formulation of various food products, replacing rice flour. GBR is prepared by soaking brown rice (BR), more specifically, the embryo of brown rice in water to promote grain activation under controlled conditions. Methods: Present study was aimed to develop the GBR flours of MTU 1010 and KNM 118 at various germination hours (0, 12, 24, 36, 48 and 72 hours) and to study the effect of germination on the physical and functional properties of BR and GBR flours. Result: Our findings revealed that germination showed significant variations in l*, a*, b* and DE* of BR flours of both varieties. Germination significantly decreased the bulk density, tapped density, oil absorption capacity, water activity. Germination also considerably improved the water absorption capacity at 24 hours of germination and foaming capacity of MTU 1010 and KNM 118 GBR flours. BR flour had the least gelation concentration (LGC) of 8% and 6% which increased to 12% and 10% after 24 h germination in MTU 1010 and KNM 118 GBR flours, respectively.

The physicochemical properties, swelling power, solubility, and digestibility of flour from four rice varieties (black, brown, white, and waxy rice flour) were analyzed. The results showed that the black and brown rice had high‐amylose percentage (21.8% and 20.5%), a relatively low percentage of starch content (68.1% and 79.1%), and lower swelling power (6.6% and 7.6%) and solubility (13.5% and 15.7%), respectively. Waxy rice flour attributed to lower gelatinization temperatures and higher enthalpy values. Meanwhile, the brown, black, and white rice showed higher gelatinization temperature and lower enthalpy value. The black and brown rice flour exhibited lower pasting and viscosity values as compared to waxy rice flour. The results showed that all rice flour had an A‐type X‐ray diffraction pattern, and after cooking all rice flour showed V‐type polymorphs except waxy rice flour. Brown and black rice flour after cooking have lower digestion rate than white rice and waxy rice flour, probably due to its lower expansion and solubility rates, and higher gelatinization temperature.

Consuming gluten, a protein present in barley, wheat, and rye, can cause celiac disease, a chronic autoimmune condition that affects the small intestine and is activated in genetically susceptible individuals. The current study was designed to develop an optimal gluten-free alternative to shawarma bread with improved nutritional content and better sensory properties. For that purpose, five different types of bread were prepared: one control (T0) and four experimental treatments (T1, T2, T3, and T4). Various ingredients, including chickpea flour, rice flour, pearl millet, guar gum, potato starch, brown rice flour, and sweet potato starch, were used to analyze which bread performed best in terms of nutritional content and overall acceptability. Nutritional analysis revealed significant variations in protein, moisture, fat, fiber, and ash content across the different formulations. Among the treatments, T3, which included chickpea, brown rice, and millet flour, emerged as the most nutrient-dense, demonstrating the highest value of protein 25.82 %, fat 4.83 %, Ca 81.63, Fe 4.59, Mg 32.06, Zn 1.80, K 164.42, Na 260.7 in mg/100g as compared to control and other treatments. Water activity analysis further supported these findings, showing that T3 had lower water activity of 0.87 as compared to control bread 0.90, suggesting improved stability and a longer shelf life. Despite these advantages, sensory evaluation revealed that the control (T0) bread was the most preferred having score of 8.58 among participants for its taste and texture. T3 got a minimum score for overall acceptability 7.61, T4 (7.92), T2 (27.82) ,T1 (8.05). This preference is likely due to the control bread closely resembling the traditional shawarma bread that consumers are familiar with. While the experimental treatments offered a superior nutritional profile, their sensory attributes did not match the familiarity and appeal of the control bread. These findings highlight the potential of gluten-free shawarma bread as a nutritious alternative but also emphasize the challenge of achieving optimal consumer acceptance without compromising taste and texture. It was concluded that further research is needed to improve (by addition of natural bread improvers) the sensory profile of all gluten-free shawarma breads, specifically T3, which one was the best among all in terms of its nutritional contents. Keywords: Celiac, shawarma, bread, treatments, taste, texture, nutritional content, intolerance, sensory evaluation

Brown rice has been reported to be more nutritious after germination. Germinated brown rice flours (GBRFs) from different steeping conditions (in distilled water [DI, pH 6.8] or in a buffer solution [pH 3] for either 24 or 48 h at 35 degrees C) were evaluated in this study. GBRF obtained from brown rice steeped at pH 3 for 48 h contained the highest amount of free gamma aminobutyric acid (GABA; 67 mg/100 g flour). The composite flour (wheat-GBRF) at a ratio of 70 : 30 exhibited significantly lower peak viscosity (PV) (56.99 - 132.45 RVU) with higher alpha-amylase activity (SN = 696 - 1826) compared with those of wheat flour (control) (PV = 136.46 RVU and SN = 1976). Bread formulations, containing 30% GBRF, had lower loaf volume and greater hardness (P < 0.05) than the wheat bread. However, the hardness of bread containing 30% GBRF (except at pH 6.8 and 24 h) was significantly lower than that of bread containing 30% nongerminated brown rice flour (BRF). Acceptability scores for aroma, taste, and flavor of breads prepared with or without GBRFs (30% substitution) were not significantly different, with the mean score ranging from 6.1 (like slightly) to 7 (like moderately). Among the bread formulations containing GBRF, the one with GBRF prepared after 24 h steeping at pH 3 had a slightly higher (though not significant) overall liking score (6.8). This study demonstrated that it is feasible to substitute wheat flour with up to 30% GBRF in bread formulation without negatively affecting sensory acceptance. Practical Application: Our previous study revealed that flours from germinated brown rice have better nutritional properties, particularly gamma-aminobutyric acid (GABA), than the nongerminated one. This study demonstrated feasibility of incorporating up to 30% germinated brown rice flour in a wheat bread formulation without negatively affecting sensory acceptance. In the current United States market, this type of bread may be sold as frozen bread which would have a longer shelf life. Further study is thus needed.

Parboiling stage and drying method affect the physicochemical properties and in vitro digestibility of starch-based rice flour.