• Food Science and Biotechnology
• /
• v.15 no.2
• /
• pp.168-172
• /
• 2006

Soy sauce was fermented at $20^{\circ}C$ for 100 days in onggi containers (ethnic Korean earthenware) which had been fabricated using three different glazing treatments: unglazed, glazed only on the outside, and glazed on both surfaces. The changes in microstructure and permeability characteristics of onggi containers were examined after fermentation of soy sauce. The effect of repeated use of onggi containers on the fermentation was analyzed by the contact between an aqueous model solution and the onggi containers used once for soy sauce fermentation. The levels of reducing sugar and free amino acids produced from the dissolved starch and protein, respectively, in the solution were compared between the new and reused onggi containers. The moisture permeance and gas permeabilities of the onggi jars were progressively reduced with continuing use for soy sauce fermentation, probably due to clogging of micropores by solid materials. After having been used once for fermentation, the microbial cells and/or enzymes immobilized on the surface or in the micropores of the onggi containers seemed to contribute to accelerating the hydrolytic reactions of starch and protein.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.301-301
• /
• 2022

Dairy products are important diet source for human because of their balanced essential nutrients along with various vitamins and minerals. However, lactose in milk can result in diarrhea to some consumers with lactose intolerance. Soy milk has no lactose and is suitable as a substitute for diary milk in accordance with recent trend of replacing animal food with vegetable food. However, polysaccharides in soy milks are difficult for humans to digest, leading to flatulence. These polysaccharides can be decomposed into monosaccharides by lactic acid bacteria, and fermentation can improve food quality. Because mungbean has higher carbohydrate content than soybean, mung milk can be easily fermented than soy milk, resulting in vege yogurt with higher contents of lactic acid. In this study, fermentation characteristics of vege yogurt were analyzed with different ratio of soy milk and mung milk (0%, 25%, 50%, 75%, 100% and 0%+sucrose) and different fermentation time (0, 8, and 16 hours). In general, pH decreased as fermentation time increased. Overall, pH significantly decreased when the mung milk content in yogurt increased. All samples showed higher titratable acidity after fermentation and soy yogurt (mungbean 0%, 16 hours) with sucrose showed the highest value (6.825%). As fermentation time increase, viscosity increased. In 8 and 16 hours, mung milk yogurt (mungbean 100%) showed the lowest viscosity while soy milk yogurt (soybean 100%) with no sucrose showed the highest viscosity after 16 hours of fermentation. The contents of crude protein, crude fat and ash were measured for nutritional analysis. Soy milk (mungbean 0%, 0 hours) had the values of crude protein 2.9g, crude fat 1.8g, and ash 0.3g, and mung milk (mungbean 100%, 0 hours), showed the values of crude protein 1.7g, crude fat 0g, and ash 0.3g. To analyze the effect of the differences in the contents of nutrition between soy milk and mung milk on fermentation, the changes in sugar contents, and antioxidant capacity will be conducted depending on fermentation time. Our results will provide the information in researching plant beverages.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.32 no.3
• /
• pp.388-392
• /
• 2003

This study was conducted to examine the effect of soy flour on tapioca non- steamed fermentation. A whole soy flour was higher than roasting soy flour in alcohol content. Alcohol content was increased up to 2% of soy flour, and decreased after adding 3% soy flour. The pH and total acidity were showed no significant differences by adding soy flour, roasted soy flour, water and enzyme. The optimum conditions for alcohol production were 2% (w/w) of soy flour,0.5% (w/w) of enzyme and 250% (v/w) of water at 96 hr. Addition of soy flour increased yield of alcohol.

• The Korean Journal of Food And Nutrition
• /
• v.19 no.4
• /
• pp.460-465
• /
• 2006

This study was conducted to investigate the isoflavone contents including daidzein and genistein in soy sauces made with whole grain soybean Meju(WGSM), comparing with defatted Meju(DM) du.ins fermentation. Total isoflavone contents in 2 soy sauces made with DM, Control and product A, increased with period of fermentation and were 15 and 4.3 times higher after 180 days of fermentation than on the day before fermentation respectively. Meanwhile, 2 soy sauces made with WGSM, product B and C, had the highest amounts with $20.53{\mu}g/g\;and\;19.52{\mu}g/g$ of isoflavones on the day before fermentation respectively, and then decreased with fermentation time. High amounts of isoflavones were detected in 20 days of fermentation of soy sauce which made with WGSM and wheat Meju(product D). Daidzein was the largest amounts in isoflavone contents, regardless of total or free isoflavone types. The level of daidzein increased with fermentation time in 2 soy sauces made with DM, Control and product A, whereas 2 soy sauces made with WGSM, product B and C decreased with fermentation time, instead of increasing of genistein contents.

• Journal of Microbiology and Biotechnology
• /
• v.25 no.4
• /
• pp.469-478
• /
• 2015

In spite of the reported probiotic effects, Bifidobacterium bifidum BGN4 (BGN4) showed no βglucosidase activity and failed to biotransform isoflavone glucosides into the more bioactive aglycones during soy milk fermentation. To develop an isoflavone-biotransforming BGN4, we constructed the recombinant B. bifidum BGN4 strain (B919G) by cloning the structural β-glucosidase gene from B. lactis AD011 (AD011) using the expression vector with the constitutively active promoter 919 from BGN4. As a result, B919G highly expressed β-glucosidase and showed higher β-glucosidase activity and heat stability than the source strain of the β-glucosidase gene, AD011. The biotransformation of daidzin and genistin compounds using the crude enzyme extract from B919G was completed within 4 h, and the bioconversion of daidzin and genistin in soy milk during fermentation with B919G also occurred within 6 h, which was much faster and higher than with AD011. The incorporation of this β-glucosidase-producing Bifidobacterium strain in soy milk could lead to the production of fermented soy milk with an elevated amount of bioavailable forms of isoflavones as well as to the indigenous probiotic effects of the Bifidobacterium strain.

• Korean Journal of Food Science and Technology
• /
• v.24 no.5
• /
• pp.477-481
• /
• 1992

As a series of fundamental research projects to produce doenjang (Korean fermented soy paste) of better quality, two kinds of doenjang were manufactured from a traditional meju (Korean soy bean koji) and the mixed with Aspergillus oryzae and Bacillus natto, and histological changes in the cell structures of soy bean of the two were reported doenjang samples were observed and compared during the entire period of fermentation processes. Cell walls of the soy bean were ruptured by pressure and heat during the pressure cooking process and some of them were observed to have the ghost-like shapes. Remarkable differences in the plasmolysis of the cytoplasms were observed between the seed coat and the inner part of soy bean. Small vacuoles resulting from the fusion of the glycoprotein globules by protease and from the hydrolysis of the starch granules by amylase were also observed. Penetration of microorganisms was transferred from the seed coat to the inside of soy bean as the fermentation proceeded. Slimy substances were observed on the seed coat and the parenchyma cells of soy bean fermented with the mixed with Aspergillus oryzae and Bacillus natto. Cell walls of soy bean became difficult to stain and they showed unusual, polygonal shapes as the fermentation proceeded. Samples fermented with the mixed with Aspergillus oryzae and Bacillus natto showed more remarkable tendencies than traditional meju.

• Food Science and Biotechnology
• /
• v.15 no.5
• /
• pp.704-709
• /
• 2006

The mucilage production and tyrosine content in soy milk cake (SMC) fermented by Bacillus firmus NA-1, Bacillus subtilis GT-D, and B. subtilis KU-A was improved by fortification with 10% defatted soybean flour. The fibrinolytic activity and consistency of the SMC were drastically increased by solid-state fermentation for 1 day. However, the consistency of the fermented SMC gradually decreased during fermentation for 3 days. Furthermore, the tyrosine content of the freeze-dried powder of SMC fermented by three Bacillus sp. was 9 times higher than that of unfermented SMC. The soybean proteins, including the 7S and 11S subunits, were partially digested during alkaline fermentation, producing lower molecular-weight peptides. The fibrinolytic enzyme produced in SMC fermented by B. firmus NA-l and B. subtilis KU-A exhibited higher thermal stability than that of B. subtilis GT-D fermentation. The powder obtained from B. subtilis GT-D fermentation had an ${\alpha}$-amylase activity and lower consistency compared to those of B. firmus NA-1 and B. subtilis KU-A. In addition, this powder contained 6.3% moisture content, 27% crude protein content and 9 units of fibrinolytic activity and proteolytic activity.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.45 no.5
• /
• pp.702-710
• /
• 2016

The bioactivity of soy grits cheonggukjang was enhanced by fermentation using three ${\beta}$-glucosidase-producing Bacillus subtilis strains (HJ 18-9, HJ 25-8, and HJ 18-9+HJ 25-8) for 48 h at $37^{\circ}C$. The results indicate that protease, cellulase, and a-amylase activities significantly increased (P<0.05) with increasing fermentation time. In addition, the amino-type nitrogen content of B. subtilis-fermented soy grits cheonggukjang increased to 91.0~168.0 mg% after 48 h of fermentation. Among the isoflavones in soy grits cheonggukjang, contents of ${\beta}$-glucosides or acetyl-glucosides were reduced while aglycone content increased upon fermentation. In particular, soy grits cheonggukjang fermented with B. subtilis HJ18-9 and HJ25-8 showed the largest increases in aglycone content compared to complex treatment. These results provide useful information for development starter (single and complex) as well as for production of high quality fermented soybean food.

• Journal of the East Asian Society of Dietary Life
• /
• v.18 no.6
• /
• pp.981-988
• /
• 2008

This study was conducted to develop functional black soy sauce with (S2) and without (S3) an outer skin and then compare these products to a control soy sauce (S1). In addition, the effects of different fermentation periods on the pH, buffering power, titratable acidity, total acidity, salt content, and browning and Lab value were evaluated. Furthermore, the antioxidative activities of the black soy sauce were compared to those of the control soy sauce based on the total phenolic compounds and free radical scavenging activity, including the 1,1-diphenyl-2-picryl-hydrazil (DPPH) scavenging activity and the thiobarbituric acid value (TBA value). The pH and buffering power of S2 were lower than of S1 and S3, while the titratable acidity and total acidity were higher. The salt content of all samples decreased after 60 days of fermentation, after which it increased slightly for up to 180 days. Additionally, the browning intensity of all samples increased as the fermentation periods increased, with the browning intensity at 420 nm of S1 being the highest followed by S3 and S2. After 150 days of fermentation, the L value of S1 was higher than that of S2 and S3, but the while a value of S2 was higher than those of S1 and S3 and was increased as the fermentation periods. Moreover, the b value of S1 was the highest at the end of the fermentation period, followed by the b values of S3 and S2. The amount of total phenolics in S1 was greatest, followed by S2 and S1. Conversely, the DPPH radical scavenging activity of S2 was the highest, followed by S3 and S1. Finally, the TBA value increased rapidly from day 30 to day 180 of the fermentation period, and the TBA value of S2 was lower than those of S1 and S3.

• Applied Biological Chemistry
• /
• v.46 no.3
• /
• pp.220-224
• /
• 2003

Soy sauce added shiitake mushroom (Lentinus edodes) at a concentration of 0, 5 or 10% (w/w) was prepared and its quality characteristics were analyzed during the fermentation for 6 months. The contents of total nitrogen (TN) and amino type nitrogen (AN) increased with similar pattern during the fermentation period regardless of the added amount of mushroom. The pH values of soy sauce decreased significantly with increasing fermentation periods, while soy sauce added shiitake mushroom showed lower value. However, shiitake mushroom in soy sauce did not affect electron donating ability. The contents of total amino acid and total essential amino acid in the soy sauce containing 5% mushroom were 31.74 mg/100 ml and 19.01 mg/100 ml after 6 months of fermentation period, respectively.