Physicochemical Properties of Roasted Soybean Flour Bioconverted by Solid-State Fermentation Using Bacillus subtilis and Lactobacillus plantarum

Abstract

To produce novel cheese-like fermented soybean, the solid-state fermentation of roasted soybean flour (RSF) was performed using 1.0% inoculum Bacillus subtilis HA and Lactobacillus plantarum, with the initial 60% substrate moisture for 10 hr at 42°C, resulting in pH 6.5, 0.82% acidity, 3.5% mucilage, 14.3 unit/g protease activity, 7.6 unit/g fibrinolytic activity, 216 mg% tyrosine content and 1.7×1010 CFU/g of viable cell counts. After the second lactic acid fermentation with 10∼30% skim milk powder, the fermented RSF resulted in an increase in acidity with 1.64∼1.99%, tyrosine content with 246∼308 mg% and protease activity in the range of 5.2∼17.5 unit/g and 0.966 water activity. Viable cell counts as probiotics indicated 1.6×108 CFU/g of B. subtilis and 7.3×1010 CFU/g of L. plantarum. The firmness of the first fermented RSF with 2,491 g·ømm−1 greatly decreased to 1,533 g·ømm−1 in the second fermented RSF, although firmness was slightly increased by adding a higher content of skim milk. The consistency of the second fermented RSF also decreased greatly from 55,640 to 3,264∼3,998 in the presence of 10∼30% skim milk. The effective hydrolysis of soy protein and skim milk protein in the fermented RSF was confirmed. Thus, the second fermented RSF with a sour taste and flavor showed similar textural properties to commercial soft cheese.

Optimized Production of GABA and γ-PGA in a Turmeric and Roasted Soybean Mixture Co-fermented by <i>Bacillus subtilis</i> and <i>Lactobacillus plantarum</i>

“…Tyrosine was generated by the proteolytic enzymes produced by B. subtilis HA with highly viable cells, and was an indicator of peptide generation (Park et al, 2012).…”

“…The presence of tyrosine indicates the effective hydrolysis of the soy protein, with the resulting generation of peptides (Park et al, 2012 subtilis HA, as a result of the increased acidity.…”

“…Fermented soybean products have been reported to have antihypertensive (Shin et al, 2001), antioxidant (Wang et al, 2008, fibrinolytic (Kim et al, 2006) and anticancer (Zhao et al, 2013) activities. However, the strong smell and taste of these fermented products is a barrier for their generalized consumption (Park et al, 2012). Therefore, improving the organoleptic qualities of fermented soy products is desirable.…”

“…In LAB, GABA acts as a defense against acidic environments and as an alternative energy source (Kook et al, 2010a). Fermentation with B. subtilis generates mucilage containing γ-polyglutamic acid (γ-PGA) and fructan, which give the sticky consistency to natto (Nagai et al, 1994;Park et al, 2012). γ-PGA is a biodegradable, water soluble and edible biopolymer, which can be composed of either the L or D isomer of glutamic acid or both.…”

Characteristics of Bacillus subtilis HNMY-13 and HNMY-15 strains in aflatoxin B1 degradation and Astragalus bio-transformation

“…It also exhibited antimicrobial activity and high resistance to the simulated gut environment. In addition, B. subtilis ferments roasted soybean, wheat bran, fruit waste via solid state fermentation (SSF) for production of the novel fermented soybean, haloduracin and citric acid (Park et al, 2012;Danesh et al, 2013;Kumar et al, 2003). Astragalus was used as supplementary forage supplement for livestock and poultry industry in China, because it contains polysaccharides, saponins, flavonoids, anthraquinones, alkaloids, amino acid, β-sitosterol and metallic elements (Ibrahim et al, 2013;Sun et al, 2013;Li et al, 2009).…”