Nuruk contributes to the unique characteristics of Korean alcoholic beverages. In this study, the effects of nuruk extracts (NE) on anti-oxidant characters, melanogenesis, and anti-photoaging activity were investigated. NEs were obtained from the 70% ethanol extracts of six types of nuruk, which have been used in brewing of fermented alcohol beverages in Korea. First, various antioxidant characteristics were identified in terms of 2,2'-azino-bis(3-ethylbenzthiozoline-6-sulphonic acid) (ABTS) radical scavenging activity, superoxide dismutase (SOD) expression, and inhibition of xanthine oxidase activity. NE#4 exhibited potent ABTS radical scavenging activity (IC50 = 19.51 µg/mL). Compared with NE#4, relatively lower levels of activity were observed for NE#3 and NE#6, with IC50 values of 90.99 and 76.88 µg/mL, respectively. According to results of western blot analysis for determination of SOD expression in H2O2-treated HepG2 cells, NE#5 and NE#6 induced a dramatic increase in the expression ratio of SOD, compared to the group treated with H2O2 only. Activity of xanthine oxidase, which converts xanthine into uric acid, generating superoxide ions, was inhibited by NE#4 and NE#6 in a dose-dependent manner. NE#4 induced significant inhibition of mushroom tyrosinase activity. A reduction in cellular melanin contents of 80% was observed in B16F1 melanocytes treated with NE#5 and NE#6; these effects were similar to those of arbutin at 100 µM. In addition, gelatin zymography and reverse transcription-PCR analysis were performed for assessment of anti-photoaging activity of Nuruk. Treatment with NE#6 resulted in dramatically inhibited activities of matrix metalloproteinase (MMP)-2/-9, suppressed expression of MMP-1, and increased expression of type-1 procollagen. Results of gelatin zymography for NE#4 and NE#5 were similar, to a slightly lesser degree. These results suggest the potential of NE#4 and NE#6 as natural ingredients for use in functional foods and cosmetics.

Flavor patterns of sweet potato spirits (SPS) made from - manufactured by sweet potato showed an increasing tendency for aging from 64 to 128 weeks. When the SPS was blended with spirits made from - manufactured by rice in a 7:3 ratio, showing an increase for aging from 16 to 60 weeks, using a gas chromatography-mass spectrometry with solid-phase microextration. The main compounds showing increasing tendency of the SPS and blended spirits (BS) were iso-amyl alcohol, n-propanol. Especially, ethyl caprylate, and ethyl acetate increased in SPS. The results were cross-checked by an electronic nose. For the results of SPS in the flavor pattern, a decrease was noted by main ion fragments. For the BS, a decrease was noted. These cross-checked results were useful for controlling quality of aging spirits, especially SPS. Based on these results, it was considered that further experiments are needed to identify key compounds for accurate correlation analysis.

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