Chung Eun Hwang

Enhancement of Total Phenolic and Isoflavone-aglycone Contents and Antioxidant Activities during Cheonggukjang Fermentation of Brown Soybeans by the Potential Probiotic Bacillus subtilis CSY191

Changes in β-glycosidase activity, total phenolic and isoflavone contents, and antioxidant activities during the fermentation of brown soybeans (Galmi) fermented food cheonggukjang by the potential probiotic Bacillus subtilis CSY191 were investigated. The total phenolic and isoflavone-glycoside and -aglycone contents as well as ABTS radical scavenging activity and FRAP assays of extracts increased, but malonylglycoside content decreased after a steaming process. It was found that fermentation enhanced the total phenolic and isoflavone-aglycone and -malonylglycoside contents, corresponding to antioxidant activities increased, but isoflavone-glycoside content decreased. The highest levels of daidzein, glycitein, and gensitein were present at concentrations of 156.5 μg/g, 10.2 μg/g, and 2.5 μg/g after 48 h of fermentation. In addition, ABTS radical scavenging activity and FRAP assay increased significantly during fermentation. We suggest that the high antioxidant activity of cheonggukjang of brown soybeans might be related to the markedly higher levels of total phenolic content and isoflavone-aglycones achieved during fermentation.

Potential Probiotic Lactobacillus plantarum P1201 to Produce Soy-yogurt with Enhanced Antioxidant Activity

In this study, we evaluated changes in physicochemical properties, total phenol and isoflavone contents, and antioxidant activity during soymilk fermentation by a potential probiotic Lactobacillus plantarum P1201. The P1201 strain showed survival rates of 58.14% and 62.22% after 4 h exposure to acid and artificial gastric acid conditions (pH 2.5), respectively. The optimal conditions for soy-yogurt fermentation by L. plantarum were determined to be as follows: temperature of 35oC, seed volume of 5.0%, and sucrose content of 10.0%. The total phenol and isoflavone contents and antioxidant activity were higher in soy-powder milk (SPM) yogurt than soymilk yogurt. In particular, the highest levels of isoflavone-aglycones, such as daidzein, glycitein, and genistein (91.50, 12.34, and 61.39 μg/g, respectively), were observed after 48 h of SPM fermentation. Thus, these results suggest that the soy-yogurt extract could be used as a potential source of natural antioxidants in food. Kewwords: probiotic, Lactobacillus plantarum P1201, soy-yogurt, antioxidant, isoflavone

Chemometric Approach to Fatty Acid Profiles in Soybean Cultivars by Principal Component Analysis (PCA)

The purpose of this study was to investigate the fatty acid profiles in 18 soybean cultivars grown in Korea. A total of eleven fatty acids were identified in the sample set, which was comprised of myristic (C14:0), palmitic (C16:0), palmitoleic (C16:1, ω7), stearic (C18:0), oleic (C18:1, ω9), linoleic (C18:2, ω6), linolenic (C18:3, ω3), arachidic (C20:0), gondoic (C20:1, ω9), behenic (C22:0), and lignoceric (C24:0) acids by gas-liquid chromatography with flame ionization detector (GC-FID). Based on their color, yellow-, black-, brown-, and green-colored cultivars were denoted. Correlation coefficients (r) between the nine major fatty acids identified (two trace fatty acids, myristic and palmitoleic, were not included in the study) were generated and revealed an inverse association between oleic and linoleic acids (r=−0.94, p<0.05), while stearic acid was positively correlated to arachidic acid (r=0.72, p<0.05). Principal component analysis (PCA) of the fatty acid data yielded four significant principal components (PCs; i.e., eigenvalues>1), which together account for 81.49% of the total variance in the data set; with PC1 contributing 28.16% of the total. Eigen analysis of the correlation matrix loadings of the four significant PCs revealed that PC1 was mainly contributed to by oleic, linoleic, and gondoic acids, PC2 by stearic, linolenic and arachidic acids, PC3 by behenic and lignoceric acids, and PC4 by palmitic acid. The score plots generated between PC1-PC2 and PC3-PC4 segregated soybean cultivars based on fatty acid composition.

Effects of roasting on the phytochemical contents and antioxidant activities of Korean soybean (Glycine max L. Merrill) cultivars

Antioxidant activities of roasted soybeans from Daewon, Daepung, Neulchan, and Taekwang cultivars were evaluated using DPPH and ABTS radical scavenging activities and FRAP assays. Roasted soybeans exhibited significantly (p<0.05) higher antioxidant activities than unroasted soybeans. Daepung soybeans roasted at 200°C for 15 min exhibited higher antioxidant activities than other cultivars and soybeans roasted under other conditions. Contents of antioxidant compounds, including isoflavone aglycones, glycosides, and phenolic acids, increased after roasting, whereas the content of isoflavone malonlyglycosides was decreased in the roasted soybeans. Moreover, total phenolic and flavonoid contents and isoflavone aglycone, glycoside, and phenolic acid contents were increased, leading to a general increase in antioxidant activities due to roasting.

Comparison of Isoflavone Contents and Antioxidant Effect in Cheonggukjang with Black Soybean Cultivars by Bacillus subtilis CSY191

BACKGROUND: Soybeans are the rich sources of isoflavones. To date, the changes of isoflavone contents in various black soybeans cheonggukjang during fermentation by Bacillus subtilis CSY191 has not been investigated.METHODS AND RESULTS: This study investigated the changes of total phenolic and isoflavone contents and antioxidant effects during cheonggukjang fermentation made with four black soybean (BS) cultivars including Cheongja, Cheongja#3, Geomjeong#5, and Ilpumgeomjeong with a potential probiotic Bacillus subtilis CSY191. The total phenolic contents, isoflavone-malonylglycoside and -aglycone contents, and antioxidant activity were increased in cheonggukjang at 48 h fermentation, while the content of isoflavone-glycosides was decreased during cheonggukjang fermentation. In particular, the Cheongja#3 soybean fermented at 37℃ for 48 h displayed the highest antioxidant activities, compared to those of the other BS cultivars tested. Also, the highest levels of total phenolic, daidzein, glycitein, and genistein were present at concentrations of 17.28 mg/g, 283.7 g/g, 39.9 g/g, and 13.2 g/g at the end of Cheongja#3 soybean fermentation.CONCLUSION: The results from this study suggested that the enhanced antioxidant activity of cheonggukjang of BS might be related to increased levels of total phenolic, isoflavon-aglycone, and malonyl-glycoside contents achieved during fermentation. Furthermore, fermented Cheongja#3 soybean showed the highest levels of enhanced antioxidant activities than the other BS cultivars.

Fermented soy-powder milk with Lactobacillus plantarum P1201 protects against high-fat diet-induced obesity

Summary Fermented soy-powder milk (FSPM) with Lactobacillus plantarum P1201 contains more conjugated linoleic acid (CLA) and isoflavone aglycones compared with unfermented soy-powder milk (UFSPM). In this study, the antiobesity effect of FSPM was investigated in a high-fat diet (HFD)-induced obesity model. Results showed that FSPM reduced the weight of body, body weight gain, liver and mesenteric white adipose tissue by 10.7%, 17.7%, 32.8% and 24.1%, respectively, compared with the HFD group. Meanwhile, FSPM suppressed the HFD-induced increase of serum parameters such as total and low-density lipoprotein, cholesterol, alanine transaminase, glucose and c-peptide. To investigate how FSPM ameliorated obesity, several lipid metabolism and inflammation-related genes in liver were analysed. FSPM significantly ameliorated HFD-induced hepatic steatosis by down-regulating peroxisome proliferator-activated receptor gamma, lipoprotein lipase, fatty acid synthase, acetyl CoA carboxylase, adipocyte fatty acid-binding protein, tumour necrosis factor alpha and interleukin 1 beta. Our results showed FSPM can protect against HFD-induced obesity.

Comparisons of nutritional constituents in soybeans during solid state fermentation times and screening for their glucosidase enzymes and antioxidant properties

This research was the first to demonstrate the variations of nutritional constituents, glucosidase properties and antioxidant activities in soybeans during different solid state fermentation times (germination → 5 periods for 12 days) with Tricholoma matsutake. Total isoflavones were significantly reduced (2661.54 → 1559.04 μg/g) with the increase of aglycone contents (107.61 → 1285.66 μg/g, 12 times) for fermentation, whereas amino acid and fatty acid slightly increased. Among them, daidzein (43.2 → 43.6 → 421.9 → 721.4 → 634.0 μg/g), genistein (52.7 → 24.4 → 339.5 → 546.6 → 512.8 μg/g) and glutamic acid (0.3 → 1.7 → 3.9 → 6.6 → 16.1 mg/g) markedly increased between germinated and fermented soybeans. Total phenolic contents and antioxidant abilities also considerably increased, especially, ABTS displayed the predominant scavenging capacities (33.1 → 94.8%) at 200 μg/ml, followed by DPPH (11.9 → 87.0%) and hydroxyl (11.2 → 49.2%) radicals. Interestingly, α-glucosidase inhibition (11.8 → 84.9%) and β-glucosidase (3.1 → 40.3 unit/g) exhibited the highest activities after 9 days. Our results implied that fermented soybeans may be contributed to enhance the soybean value in nutrition and biological effect aspects to development of new functional foods.