Analysis of the flavor of aged spirits made from sweet potato and rice by gas chromatography-mass spectrometry.

Flavor patterns of sweet potato spirits (SPS) made from sul-deot manufactured by sweet potato showed an increasing tendency for aging from 64 to 128 weeks. When the SPS was blended with spirits made from sul-deot 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.

Diversity analysis of Saccharomyces cerevisiae isolated from natural sources by multilocus sequence typing (MLST).

We used multilocus sequence typing (MLST) to analyze the diversity of natural isolates of Saccharomyces cerevisiae, the most important microorganism in alcoholic fermentation. Six loci, ADP1, RPN2, GLN4, ACC1, MET4, and NUP116, in S. cerevisiae genome were selected as MLST markers. To investigate genetic diversity within S. cerevisiae, 42 S. cerevisiae isolated from natural sources in Korea as well as six S. cerevisiae obtained from Genbank and four industrial S. cerevisiae were examined using MLST. Twenty-six polymorphic sites were found in the six loci. Among them, ACC1 had the most genetic variation with eight polymorphic sites. MLST differentiated the 52 strains into three clades. Alcohol fermentation results revealed that S. cerevisiae in Clade III produced less alcohol than those in Clades I and II. These results suggested that MLST is a powerful tool to differentiate S. cerevisiae and can potentially be used to select S. cerevisiae suitable for industrial use.

Restoration of Traditional Korean Nuruk and Analysis of the Brewing Characteristics.

In this study, a total of 58 different kinds of nuruk (a traditional Korean fermentation starter) were prepared, including 46 kinds of restored nuruk from ancient documents. Each nuruk was evaluated by analysis of its saccharification power, and the enzyme activities of glucoamylase, α-amylase, ß-amylase, protease, and ß-glucanase. The range of saccharification power (sp) of the restored nuruk ranged between 85 and 565 sp. The diastatic enzymes, α-amylase, ß-amylase, and glucoamylase, were significantly correlated to the saccharification power value; conversely, ß-glucanase and protease did not have a correlative relationship with saccarification power. In addition, their brewing properties on chemical and organoleptic aspects of traditional alcoholic beverage production were compared. Each raw and supplementary material contained in nuruk showed its own unique characteristics on Korean alcoholic beverage brewing. For the first time, in this study, the traditional Korean nuruk types mentioned in ancient documents were restored using modernized production methods, and also characterized based on their brewing properties. Our results could be utilized as a basis for further study of traditional alcoholic beverages and their valuable microorganisms.

Anti-Thrombosis Activity of Sinapic Acid Isolated from the Lees of Bokbunja Wine.

From the lees of bokbunja wine (LBW) made from Rubus coreanus Miquel, we have identified six compounds (1: trans-4-hydroxycinnamic acid; 2: trans-4-hydroxy-3-methoxycinnamic acid; 3: 3,4-dihydroxycinnamic acid; 4: 4-hydroxy-3-methoxybenzoic acid; 5: 3,5-dimethoxy-4- hydroxybenzoic acid; and 6: 3,5-dimethoxy-4-hydroxycinnamic acid (sinapic acid)) through silica gel chromatography and UHPLC-MS. The compounds 1-6 showed strong anticoagulation and platelet aggregation inhibitory activities without hemolytic effect against human red blood cells. To date, this is the first report of the in vitro anti-thrombosis activity of sinapic acid. Our results suggest that different cinnamic and benzoic acid derivatives are closely linked to the anti-thrombosis activity of LBW, and sinapic acid could be developed as a promising anti-thrombosis agent.

Inhibitory effects of ethanol extracts from nuruk on oxidative stress, melanogenesis, and photo-aging.

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 (IC(50) = 19.51 µg/mL). Compared with NE#4, relatively lower levels of activity were observed for NE#3 and NE#6, with IC(50) values of 90.99 and 76.88 µg/mL, respectively. According to results of western blot analysis for determination of SOD expression in H(2)O(2)-treated HepG2 cells, NE#5 and NE#6 induced a dramatic increase in the expression ratio of SOD, compared to the group treated with H(2)O(2) 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.