본 연구에서는 유산균에 의한 검은콩의 최적 발효조건을 확립하고 발효된 검은콩의 품질특성을 평가하였다. 가정에서 제조된 배추김치로부터 분리한 Lactobacillus plantarum SU22는 병원성 세균에 대해 강한 항균 활성을 보였고 생체 아민과 발암성 효소인 β-glucuronidase를 생성하지 않았기 때문에 검은콩 발효의 스타터로 선정되었다. 검은콩은 5 kgf/cm2, 150oC로 조절된 팽화기에서 10분 동안 팽화 처리한 것과 처리하지 않은 것으로 각각 10- 30% 혼합액을 만들고 L. plantarum SU22를 1%(v/v) 접종하여 37oC로 48시간 동안 진탕 배양하면서 유산균의 생육 특성을 비교하였다. 유산균의 생균수는 L. plantarum SU22 로 발효된 팽화 검은콩(20%) 배양액에서 9 Log CFU/mL 이상이었다. 20% 팽화 검은콩 배양액을 alcalase로 가수분 해한 후 L. plantarum SU22로 발효하는 것이 최적 조건인 것으로 밝혀졌으며 유산균의 생균수가 10.30 Log CFU/ mL까지 증가하였다. 최적 조건에서 총 폴리페놀 함량(94.02 mg GAE/g)과 DPPH 라디칼 소거능(92.50%)이 비 발효 대조군(87.74 mg GAE/g, 83.14%)에 비해 현저하게 증가하였다(P<0.05). 결론적으로 검은콩을 팽화한 후 alcalase 처리와 L. plantarum SU22를 병행하여 발효할 때 바이오제닉 아민이 없는 검은콩 발효액을 효과적으로 제조할 수 있으며, 총 폴리페놀과 DPPH 라디칼 소거능을 유의적으로 증가시킬 수 있다는 것을 알 수 있었다.

The purpose of this study was to demonstrate the neuroprotective effect of heat-treated fermented black beans. The production of fermented black beans was optimized using Lactiplantibacillus plantarum SMF470 and L. plantarum SMF796 strains isolated from kimchi as starters. Compared to heat-treated black bean extract, heat-treated fermented black beans showed significantly higher DPPH and ABTS radical scavenging activities, as well as higher total polyphenol content (p <0.05). The neuroprotective effect through the gut-brain axis was evaluated using conditioned medium (CM) obtained by culturing heat-treated fermented black beans in intestinal cells (HT-29). The CMs of heat-treated fermented black beans from SMF470 and SMF796 showed a high protective effect on SH-SY5Y human neuroblastoma cells induced by oxidative stress from H2O2. Additionally, the CMs of heat-treated fermented black beans were found to protect SH-SY5Y cells from toxicity induced by MPP+. SMF470-CM and SMF796-CM significantly increased the expression of brain-derived neurotrophic factor (BDNF) in SH-SY5Y cells treated with MPP+, while lowering the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) (p <0.05). Furthermore, SMF470-CM and SMF796-CM lowered the apoptosis-related Bax/Bcl-2 ratio. The results of this study suggest that heat-treated fermented black beans can be utilized as potential health functional materials for the prevention and improvement of degenerative brain diseases.

This study aimed to optimize the fermentation condition of black bean using probiotic lactic acid bacteria (LAB) and to evaluate characteristics and antioxidant activity of LAB fermented and heat-treated black bean. Two LAB strains were selected by analysis of acid resistance, bile resistance, antimicrobial activity, and antioxidant activity, and identified as Lactiplantibacillus plantarum CH9 and Lactiplantibacillus plantarum SU18 by 16S rRNA sequencing. Both strains showed similar or higher acid resistance, bile resistance and antimicrobial activity, compared to Lacticaseibacillus rhamnosus GG, a commercial probiotic strain. The heat-killed cells of CH9 and SU18 strains showed significantly (p<0.05) higher DPPH and ABTS radical scavenging activities than live cells. Fermentation of black bean (30%) treated with Alcalase using the two selected strains was found to be optimal condition, increasing viable cell count of LAB up to 10.8 Log CFU/g. During the fermentation, the titratable acidity of Alcalase-treated black bean was notably increased with concomitant decrease in the pH. LAB fermentation significantly (p<0.05) increased antioxidant activity based on DPPH and ABTS radical scavenging activities as well as total phenol content. In addition, total phenol content and antioxidant activity were significantly (p<0.05) enhanced by heat processing (121C, 15 min) of the fermented products. These findings are expected to be useful for the development of various LAB-fermented foods containing heat-killed probiotics.