Germination Conditions Affect Selected Quality of Composite Wheat‐Germinated Brown Rice Flour and Bread Formulations

Abstract

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.

Influence of germination time of brown rice in relation to flour and gluten free bread quality

“…Chroma values associated with the purity of color were higher than the ones obtained with commercial gluten free breads, which revealed its higher purity of color related to major intensity of the yellow component. In fact, Charoenthaikij et al (2010a) reported an increase of yellowness of bread with the addition of germinated brown rice flour to wheat flour. Hence, the increase of the chroma value could be due to the increase of reducing sugar during germination.…”

“…As the germination time increased the hardness of the crumb decreased, the degradation of starch during germination could cause a decrease of crumb hardness, probably due to the formation of thinner cell walls that led to softer crumbs. Also, Charoenthaikij et al (2010a) found that a partial substitution with germinated brown rice flour reduces hardness of wheat bread compared to brown rice flour.…”

“…The benefits of these bioactive compounds include regulation of blood pressure and heart rate, alleviation of pain and anxiety, inhibition of cancer cell proliferation, and protection for oxidative stress (Oh and Oh 2004). Despite their nutritional benefits, germinated brown rice flour, pregerminated brown rice flour and germinated glutinous brown rice flour have been only used for partial substitution (10-30 %) of wheat flour in breadmaking (Charoenthaikij et al 2010a(Charoenthaikij et al , b, 2012Watanabe et al 2004). This practice produces changes in the rheological properties of the batter, modifying dough handling, besides an improvement of crumb texture, increase of gas production during fermentation and retard bread staling (Charoenthaikij et al 2010b;Watanabe et al 2004).…”

“…Germinated brown rice flour (GBRF) and germinated glutinous brown rice flour have been used as functional food ingredients in breadmaking (Charoenthaikij et al 2010a(Charoenthaikij et al , b, 2012Watanabe et al 2004), due to its high content in bioactive compounds such as γ-aminobutiric acid and antioxidants such as phenolic compounds, γ-oryzanol and vitamin E (Cáceres et al 2014). The benefits of these bioactive compounds include regulation of blood pressure and heart rate, alleviation of pain and anxiety, inhibition of cancer cell proliferation, and protection for oxidative stress (Oh and Oh 2004).…”

Cereals for developing gluten-free products and analytical tools for gluten detection

“…Making blends of cereal and pseudocereal flours such as buckwheat flour may give to gluten-free breads with enhanced contents of total phenolic compounds, rutin and quercetin contents and antioxidant activity (Sakac et al, 2011). Pregerminated brown rice is another alternative bread ingredient because it is more nutritious after germination with increased free gamma amino butyric acid (Charoenthaikij et al, 2010;.…”