• Korean Journal of Food Science and Technology
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• v.54 no.2
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• pp.115-125
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• 2022

Flavonoids are bioactive plant metabolites that have a range of beneficial effects on human health. Quercetin 4'-glycoside (Q4'G), quercetin 3,4'-diglycoside (Q3,4'G), and quercetin aglycone (QA) are the main flavonoids found in onions. QA, in particular, is likely to have a greater biological effect than glycosides. To develop an onion extract with high quercetin content, the optimal extraction conditions for red onion powder containing the outer layer of the onion were determined. The effects of acid treatment on the concentration of quercetin glycosides and QA were evaluated. The flavonoids of red onion powder were optimally extracted under 60-70% ethanol at 70℃ for 2 h. The deglycosylation of Q3,4'G and an increase in Q4'G content occurred within 6 h of 0.2% acetic acid treatment. The QA content and deglycosylation of Q4'G eventually peaked at 24 h. In addition, QA content and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity were highly correlated, with a correlation coefficient of 0.90.

• Food Science and Preservation
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• v.16 no.4
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• pp.472-481
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• 2009

Response surface methodology (RSM) is frequently used for optimization studies. In the present work, RSM was used to determine the antimicrobial activitiesof grapefruit seed extract (GFSE) and a lactic acid mixture (LA) against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Salmonella typhimurium, Pseudomonas fluorescens, and Vibrio parahaemolyticus. A central composite design was used to investigate the effects of independent variables on dependent parameters. One set of antimicrobial preparations included mixtures of 1% (w/w) GFSE and 10% (w/w) LA, in which the relative proportions of component antimicrobials varied between 0 and 100%. In further experiments, the relative proportions were between 20% and 100%. Antimicrobial effects against various microorganisms were mathematically encoded for analysis. The codes are given in parentheses after the bacterial names, and were S. aureus ($Y_1$), B. cereus ($Y_2$), E. coli ($Y_3$), S. typhimurium ($Y_4$), P. fluorescens ($Y_5$), and V. parahaemolyticus ($Y_6$). The optimum antimicrobial activity of the 1% (w/w) GFSE:10% (w/w) LA mixture against each microorganism was obtained by superimposing contour plots ofantimicrobial activities on measures of response obtained under various conditions. The optimum rangesfor maximum antimicrobial activity of a mixture with a ratio of 1:10 (by weight) GFSE and LA were 35.73:64.27 and 56.58:43.42 (v/v), and the optimum mixture ratio was 51.70-100%. Under the tested conditions (a ratio of 1% [w/w] GFSE to 10% [w/w] LA of 40:60, and a concentration of 1% [w/w] GFSE and 10% [w/w] LA, 70% of the highest value tested), and within optimum antimicrobial activity ranges, the antimicrobial activities of the 1% (w/w) GFSE:10% (w/w) LA mixture against S. aureus ($Y_1$), B. cereus ($Y_2$), E. coli ($Y_3$), S. typhimurium ($Y_4$), P. fluorescens ($Y_5$), and V. parahaemolyticus ($Y_6$) were 24.55, 25.22, 20.20, 22.49, 23.89, and 28.04 mm, respectively. The predicted values at optimum conditions were similar to experimental values.

• Korean Journal of Microbiology
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• v.47 no.2
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• pp.151-157
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• 2011

This study was to examine the quality characteristics and biological activities of the yogurt containing dual fermentation MFCY (Monascus-Fermented Chinese Yam) powder. Six different contents (0, 0.1, 0.3, 0.5, 1.0, and 2.0%, w/v) of MFCY powder were added to raw milk and 5% skim milk followed by fermentation with lactic acid bacteria at $37^{\circ}C$ for 12 h, and then the biological activities of the samples were investigated. Biological activities of the prepared yogurt were evaluated for acid production (pH, titratable acidity), number of viable cells, total polyphenol contents, DPPH radical scavenging activity, reducing power, angiotensin converting enzyme inhibitory effects and GABA contents. In this study, the results show that after fermentation in raw milk and 5% skim milk added with MFCY powder. The yogurt can produced pH, titratable acidity, number of viable cells, total polyphenol contents, DPPH radical scavenging activity and reducing power at 4.12-4.25 (pH), 0.94-0.97% (TA), $7.50{\times}10^9-1.14{\times}10^{10}$ CFU/ml, 161.4-329.9 (TP, mg/L), 54-94% (DPPH), and 1.13-1.53 (R.P), respectively. In addition, the showed ACE inhibitory activity and GABA contents was 67.1-87.7% and 304.6-685.4 (mg/L).

• Journal of Life Science
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• v.20 no.9
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• pp.1345-1352
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• 2010

We investigated the effect of brown-rice vinegar (BRV) ingestion after strenuous Wingate tests on energy substrates during a 2 hr recovery period. For this, seven healthy male adolescents were chosen as subjects. They performed 3 Wingate tests to induce fatigue, after which they ingested brown-rice vinegar (BRV) drink and/or water as a control (CON) after 15 min of the test. Blood was obtained pre-exercise and 30 min, 60 min, and 120 min post-exercise, and blood glucose, lactate, free fatty acids, ammonia, and cortisol were analyzed. After 120 min of recovery period, the 4th Wingate test was conducted to calculate the power recovery ratio of the 3rd and 4th trials. Breathing frequency, oxygen saturation, and heart rate did not show significant changes. Blood glucose level was lower in CON than BRV after 120 min of recovery, and blood lactate and ammonia levels were lower in BRV at 60 and 120 min. The higher free fatty acids were found at 60 and 120 min in BRV. In addition, Wingate power recovery ratio of peak power and peak power/body weight was significantly higher in BRV compared to CON. These results suggested that BRV ingestion after strenuous exercise facilitates fatigue recovery. Therefore, BRV might be effectively used as an ergogenic aid for events in which competitors compete two or more times a day.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.3
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• pp.211-215
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• 1983

The changes of microflora during fermentation of low salted sardine were observed. The viable cell count in the low salt fermented sardine with $8\%\;or\;10\%$ salt showed lower than that of control ($20\%$ salt) during the fermentation period and it was considered that the microbial growth was controlled by adding ethanol, sorbitol and lactic acid. Among 48 strains isolated, 7 genus of bacteria and 1 genus of yeast were identified during the fermentation of sardine. The changes of microflora also occurred during fermentation depending on the salt levels in the product. Brevibacterium, Pseudomonas, Flavobacterium and Baciilus were detected at early stage of fermentation and they disappeared after 50 days fermentation from the product with $20\%$ salt and Halobacterium, Micrococcus, Pediococcus and Torulopsis were isolated, whereas Brevibacterium, Micrococcus and Pediococcus were isolated from the product with $8\%\;or\;10\%$ salt.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.337-344
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• 1996

Gel-type yogurt was prepared from egg white powder (EWP), casein and glucose. The effects of EWP on acid production and growth of Lactobacillus were studied. The effect of EWP on sensory properties and volatile aroma compounds were also studied. Acid production by Lactobacillus in EWP (1-3%, W/V) was significantly lower than that by Lactobacillus in milk (control). However, the increase of EWP content from 1 to 3% increased acid production significantly, Number of viable cells of L. acidophilus at 24 hrs in milk and EWP containing samples (1-3%) was $3.1{\times}10^4/ml\;and\8.3{\times}10^7-3.6{\times}10^2/ml.$ respectively Sample containing lower amount of EWP generally showed lower number of viable cells. Sensory property of EWP samples (1-3%) was showed lower than that of milk yogurt (reference). However, sensory property of samples containing EWP 2% or 3% was significantly better than that of sample containing EWP 1%. Though the composition of volatile aroma compounds was slightly different from sample to sample, gas chromatographic analysis detected acetone, ethanol, diacetyl and acetoin in samples fermented by L. acidophilus.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.660-664
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• 1998

Death of non-growing microorganisms in saline was studied to observe the inhibitory effect of NaCl in foods on the viability of microorganisms. When Leuconostoc mesenteroides LA10, Staphylococcus aureus B31 and Escherichia coli B34 were incubated in McIlvaine buffer with 0, 10, 20, 30% NaCl at $30^{\circ}C$, they survived best at pH 6, 5, 7, respectively. The survival of 5 lactic acid bacteria, 9 other bacteria and 2 yeasts was tested at pH 5, 6, 7 with 10% NaCl. Gram-positive bacteria survived in saline better than Gram-negative bacteria, and lactic acid bacteria and S. aureus survived better than other bacteria. The number of survivors decreased as concentrations of NaCl increased and as pH moved to acidic or alkaline side from the above-mentioned. When L. mesenteroides LA10 was incubated in saline with those materials which are known to protect microorganisms from the killing effect of NaCl, protective effect was not observed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.3
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• pp.311-316
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• 2005

Fermentation properties and in vitro anticancer effect of young radish (YR) kimchi and young radish watery (YRW) kimchi were investigated during fermentation at 5℃. The fermentation of YR kimchi during 2-3 weeks led to the decrease of pH down to pH 4.3, increased acidity, and the highest Leuconostoc sp. counts. YR kimchi showed the acidity of 1.04-1.27% at the pH 4.3, when the kimchi was ripened properly. The fermentation of YRW kimchi during 9 days led to the decrease of pH down to pH 4.3 and the acidity of 0.20%. Inhibitory effects of the juices of YR, YR kimchi, and YRW kimchi on the growth of AGS human gastric adenocarcinoma cells in MTT assay were increased with the added concentration. The juice of YR kimchi had a higher inhibitory effect on the growth of AGS human gastric adenocarcinoma cells than that of YRW kimchi at same concentration. The juice of YR kimchi showed similar inhibitory effects on the growth of AGS human gastric and HT-29 human colon adenocarcinoma cells in MTT assay to baechu kimchi, which the inhibition rates are more than 50%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.8
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• pp.1245-1252
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• 2003

A starter formulation was developed to substitute a baker's yeast with natural starter when manufacturing bread products. To develop an active starlet, starter was formulated varying with types of wheat flours, level of water contents and various nutrients. Activities of starter were investigated in terms of viable counts of microbes and change of pH and total titratible acidity Domestic wheat flours contain 100 times more number of lactic acid bacteria than yeast regardless of types of wheat flours. The more protein contents in wheat flours, the more stable microbes in starter. This was considered to be the result of buffering effect of wheat proteins. The optimum level of protein content to ensure the activity of starter was more than 12.0%. Optimum level of water content in active starter was 110% based on strong flour. The more water or the less water had the tendency of decreasing viable counts of microbes. Addition of salt and sucrose had increased the activity of starters. However oligosaccharides did not affect the activity of starter. The optimum concentrations of salt and sucrose were 1.0% and 5.0% respectively. Bread with the starter was higher scored than breads with yeast in terms of all the quality and sensory characteristics except their volumes. In conclusion, a starter formulated with strong flour 100%, water 110%, salt 1% and sucrose 5% was considered to have high potential as a substitute of yeast in making natural bread.

• Food Science and Preservation
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• v.14 no.5
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• pp.538-544
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• 2007

This study was conducted to evaluate the antioxidant (ABTS, DPPH radical scavenging and reducing power), nitric oxide (NO)) production and anticancer activities against human cancer cells (HeLa HepG2, HT-29 and MCF-7) for methanol extracts of Glycine Semen Germinatum (Daedoowhangkeun in Korean) fermented with germinated black soybean and some bacteria. Antioxidant activities were increased by increasing the concentration of the extract at dose-dependent manner, Their activities of black soybean were higher than those of yellow soybean. Non fermented sample was slightly higher than Glycine Semen Germinatum fermented with Bacillus subtilis and lactic acid bacteria. In 1 mg/mL of the extract NO production levels were $0.374\;{\mu}M$ for yellow soybean, $0.368\;{\mu}M$ for black soybean, and $0.367\;{\mu}M$ and $0.358\;{\mu}M$ for Glycine Semen Germinatum fermented with B. subtilis and lactic acid bacteria, respectively. Methanol extract of Glycine Semen Germinatum fermented with mixture broth of lactic acid bacteria was shown to be the highest activity for anticancer activities against human cancer cells tested and their activities were exhibited in the order of HeLa > HT-29 > HepG2 > MCF-7 cell.