This study aimed to investigate the changes in nutritional components of six domestically bred soybean cultivars before and after fermentation with Rhizopus oligosporus. Analysis of five vitamins and minerals showed that levels of vitamin B2, vitamin B3, phosphorus, and calcium increased in all cultivars following fermentation, with notable variations among the cultivars. Specifically, the vitamin B2 content in Daepung and Daewonkong increase significantly, by 6.8-fold and 6.7-fold, respectively, compared to pre-fermentation levels. Additionally, Danbaekkong exhibited the highest calcium content after fermentation, at 3.90 mg/g. Before fermentation, soybean oligosaccharides contained 3.4 to 9.0 times more stachyose than raffinose; however, these levels decreased by over 80% across all cultivars after fermentation with Rhizopus oligosporus. The total dietary fiber content rose from 9.28%~11.32% before fermentation to 12.57%~14.86% afterward, though no significant differences were observed among the cultivars. This study confirms that fermentation with Rhizopus oligosporus enhances the nutritional value of domestically bred soybeans, particularly regarding vitamin B2, vitamin B3, calcium, phosphorus, oligosaccharides, and total dietary fiber.

This study investigated the nutritional characteristics of before and after fermentation of domestic soybean (Glycine max L.) by Rhizopus oligosporus. The soybean storage proteins, β-conglycinin (11S globulin) and glycinin (7S globulin), were the most abundant in Seonyu (SY) and Danbaegkong (DBK), with concentrations of 253.4 mg/g and 193.0 mg/g, respectively. For 11S/7S related to sulfur-containing amino acid, DBK had a value of 0.95, making it the most excellent nutritionally among all the cultivars. The free amino acid content significantly increased from 0.04~10.45 mg/g before fermentation to 1.37~16.95 mg/g after fermentation, and the essential amino acid composition increased, confirming an improvement in protein quality after fermentation. Phytic acid, known as a nutritional inhibitor of soybeans, decreased from 1.66~2.13 g/100 g before fermentation to 0.90~1.58 g/100 g after fermentation, suggesting that mineral absorption inhibition was alleviated. In addition, the trypsin inhibitor content is suppressed by 76.20% to 81.25% after fermentation, which is expected to improve protein utilization in the body. This study confirmed some properties of fermented products by Rhizopus oligosporus using domestic soybeans, and these results are presented to serve as the basic data for establishing new uses of Korean soybean cultivars.

In vitro digestibility and protein digestibility corrected amino acid scores (PDCAAS) were investigated to verify the availability of protein in various Rhizopus oligosporus fermented products of domestic soybean (Glycine max L.) cultivars. Danbaegkong (DBK), Daepung (DP), Daewonkong (DWK), Saedanbaek (SDB), Seonyu (SY), and Cheongja4ho (CJ4) were used as raw samples, which were fermented using commercially available Rhizopus oligosporus for 48 h. All cultivars showed increased crude protein content after fermentation. The crude protein content of DBK and SDB was significantly higher than that of the other samples (55.12% in DBK and 54.22% in SDB) (p<0.001). CJ4 had the highest alanine content of 28.88 mg/g (p<0.001), and no significant difference in cysteine content was detected among the cultivars. In most of the fermented samples, the in vitro digestibility was 0.9 or higher, indicating high protein in the fermented samples. However, it is considered that restrictions on digestion are low. In DWK, the amino acid content and PDCAAS, which together indicate protein quality, were 0.917 and 0.855, respectively, confirming that it was the best cultivar to provide the raw material for fermentation. In conclusion Rhizopus oligosporus fermented soybean products can be considered a prospective source of protein with high utility value.

Rhizopus japonicus ATCC22959로부터 미생물성 chitosan을 생산하기 위한 최적 조건을 조사하였다. 탄소원으로써 starch와 glucose(1:1)를 3.0%, 질소원으로써 yeast extract를 3.0%, 무기염류로써 ZnSO_4를 0.02% 첨가하고 pH를 5.0으로 맞춘 배지에 Rhizopus japonicus ATCC22959의 포자를 접종한 후 30℃에서 96시간 배양하는 것이었다. Chitosan생산을 위한 기본 배지와 최적 배지에 각각 1.25×10 exp (5)개의 포자를 접종하여 배양한 후 chitosan의 생산성을 비교한 결과는 각각 0.08g/200ml와 0.51g/200ml로 약 6.4배정도 수율이 증가하였다.

전통메주의 과다건조로 인한 품질저하 및 유해 곰팡이 오염으로 인한 위생적 문제를 개선하기 위하여 백국균(Roligosporus)을 종국 제조에 이용하여 "캡슐형 메주"를 착안하고 그 품질특성을 조사하였다. R oligosporus을 0.5, 1, 2% (w/w) 비율로 첨가하여 캡슐형 메주와 종국을 넣지 않고 성형한 대조구 I,II형을 10~15에서 3일간의 자연 건조하였다. 27일간 실외에서 발효한 대조구 I형이라 하고, 대조구 II형과 캡슐