• Journal of Life Science
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• v.27 no.8
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• pp.909-918
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• 2017

Ice plant (Mesembryanthemum crystallinum L.) was fermented in brine in the form of mulkimchi (IPMB), and its contents of organic acid and cyclitols and biological activities were compared with those before fermentation. The pH of the IPMB continuously decreased until the sixth day of fermentation. The lactic acid yield was greatest on the fourth day. D-pinitol in ice plant mulkimchi solids (IPMS) decreased during fermentation. However, myo-inositol and D-chiro-inositol increased. The radical scavenging activities of ABTS and DPPH, in addition to the activity of FRAP, of the IPMS extract were generally higher after fermentation, with the activities highest on the fifth ($79.09{\pm}0.69%$), fourth ($87.55{\pm}1.21%$), and sixth ($78.72{\pm}0.99%$) days of fermentation, respectively, when treated with 1 mg/ml of the extract. As shown by a lipid/MA assay, antioxidant activity was generally higher after fermentation. The viability of BNL CL.2 cells damaged by t-BHP, $H_2O_2$, and ethanol was $14.19{\pm}0.98$, $13.80{\pm}2.25$, and $25.89{\pm}2.90%$, respectively. When treated with $200{\mu}g/ml$ of IPMS extract, the cell viability was $57.06{\pm}4.52%$ on the first day, and $66.06{\pm}1.36%$ on the fourth day, and $50.07{\pm}04.85%$ on the sixth day of fermentation. Hepatocyte protective effects did not increase significantly after fermentation. ${\alpha}-glucosidase$ inhibitory activity was quite high, with a range of $83.52{\pm}2.69$ to $92.79{\pm}2.16%$, and the activity increased gradually in all the groups over the fermentation period. There was no clear correlation between ${\alpha}-amylase$ inhibitory activity and fermentation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.2
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• pp.243-249
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• 2014

Cheonggukjang was manufactured using three different kinds of soybeans, after which changes in the content of phytoalexins such as trans-resveratrol (3,5,4'-trihydroxy-trans-stilbene) were measured. Along with phytoalexins, changes in the content of functional oligosaccharides such as stachyose and raffinose were also measured, and the corresponding antioxidant activities were studied. The content of trans-resveratrol was found to be higher in fermented beans than in raw beans. Generally, the content was higher as the fermentation period increased. After 48 hours of fermentation, the contents of trans-resveratrol were $50.06{\pm}0.82$, $39.04{\pm}0.49$, and $34.00{\pm}0.54{\mu}g/g$ (Nulchan, Daewon, and Taekwang), respectively, which is 4 times higher than the contents of raw beans. The contents of stachyose were $10.84{\pm}0.42{\sim}13.05{\pm}0.13mg/g$ in raw beans, $11.37{\pm}0.03{\sim}12.05{\pm}0.52mg/g$ immediately after boiling, and $0.16{\pm}0.01{\sim}0.33{\pm}0.02mg/g$ after 12 hours of fermentation, which is a 97% decrease from those of raw beans. After 24 hours of fermentation, no amount of stachyose was detected. The contents of raffinose were the lowest in raw beans at $2.66{\pm}0.09{\sim}3.54{\pm}0.05mg/g$, but they increased 3~4 times between boiling and 24 hours of fermentation to $10.61{\pm}0.16{\sim}12.66{\pm}0.17mg/g$. However, raffinose content tended to decrease to $8.28{\pm}0.17{\sim}11.83{\pm}0.44mg/g$ after 48 hours of fermentation. From FRAP, DPPH, and ABTS assays, antioxidant activities according to fermentation period of Cheonggukjang were rather low in boiled soybeans compare to raw soybeans. However, the activities were higher as the fermentation period increased. The antioxidant activity of trans-resveratrol showed an $RC_{50}$ value of $4.71{\pm}0.36{\sim}8.46{\pm}0.05{\mu}g/mL$ from the DPPH, ABTS, and FRAP assays. This could be partly due to the significant increase in trans-resveratrol according to fermentation periods. However, changes in functional oligosaccharides (stachyose and raffinose) during fermentation appear to not be related to the antioxidant effects of Cheonggukjang.