In this study, the quality characteristics of kombucha according to the mixing ratio of green tea extract and yuzu juice during fermentation were compared. The pH of the kombucha decreased as the amount of yuzu juice increased. The titratable acidity increased in a juice-concentration dependent manner during fermentation. The reducing sugar content was 1.68% in kombucha made with a mixture of 70% green tea extract and 30% yuzu juice on the 20 th day of fermentation, showing the lowest reducing sugar content. The alcohol content did not change until the 10 th day of fermentation and increased slightly thereafter. The number of lactic acid bacteria and the quantity of yeast were the highest in the samples of kombucha made with a mixture of 70% green tea extract and 30% yuzu juice. The total polyphenol content was 40.79 mg TAE/mL in the kombucha made with this combination and this also showed the highest total flavonoid content of 37.15 mg QE/mL. In addition, the sensory evaluation results showed the highest preference in all the measured parameters for kombucha made with a mixture of 70% green tea extract and 30% yuzu juice. Key words：kombucha, yuzu, green tea, mixed fermentation, quality characteristics

A simple technology to manufacture 'Nuruk' with pigmented rice and 'Yakju' with improved quality and functionality was developed. Yakju (designated WY and PY, respectively) was prepared with white rice flour Nuruk (WN) and pigmented rice flour Nuruk (PN), and their qualities were compared. The enzyme activities of Nuruk revealed that PN had higher β-amylase activity (1,186.67 Saccharogenic acitivty, SP/g) and higher protease activity (378.90 tyrosine mg/min) than WN. During 11 days of fermentation, the pH of PY was steady in the range of 4.77-4.58, whereas the pH (4.82) of WY decreased to 3.90 on day 3 of fermentation and then increased to similar pH of PY until the fermentation was completed. The titratable acidities of PY and WY increased to 0.40-0.48%. The ethanol content of PY and WY increased to 13.43% ad 13.23%, respectively, on day 5, after then PY showed higher ethanol content than WY until day 11 of fermentation. The organic acid content of PY (1,225.87 mg%) was higher than that of WY (1,021.69 mg%). The antioxidant activities of PY were twice as high as those of WY, and the total polyphenolics and total flavonoid contents of PY were also higher (35.96 mg% and 19.01 mg%, respectively) than those of WY (16.29 mg% and 6.36 mg%, respectively). Sensory scores on color, flavor and taste, and overall preference were higher in PY than in WY.

In this study, pigmented rice flour 'Nuruk' was prepared using various fungal strains to improve the quality of Korean traditional 'Kochujang', and the quality characteristics during the aging of 'Kochujang' made with the 'Nuruk' were confirmed. The pH of 'Nuruk' was highest using Aspergillus oryzae pigmented rice flour 'Nuruk' (N2) at 5.83, and the highest acidity was Aspergillus niger pigmented rice flour 'Nuruk' (N3) at 2.69. The crude ash content was 1.10-1.14% from the 'Nuruk' made with pigmented rice flour, which was higher than the 0.42% from 'Nuruk' made with white rice flour. The pH of 'Kochujang' decreased gradually from 0 to 90 days as aging progressed. The titratable acidity was 2.76-3.71%, which increased with increasing aging period. During the aging of 'Kochujang', the water content increased by 2-3%. The reducing sugar content decreased from 0.33 to 3.25% after 60 days of aging and increased to 3.85 to 4.94% at the end of aging. Regarding the color values, the 'Kochujang' made with white rice flour 'Nuruk' showed higher overall L, a, and b values than the 'Kochujang' made with pigmented rice flour 'Nuruk'. A sensory evaluation of six kinds of 'Kochujang' revealed the 'Kochujang' made with N2 'Nuruk' to have the highest preference in all evaluation items.

In this study, natural materials with antibacterial activity against the Streptococcus mutans KCCM 40105 strain were selected, and the most efficient extraction conditions were observed. The active substance was stable under various treatment conditions. Of the 10 food materials groups, only Prunus mume fruit showed antibacterial activity against S. mutans strains. The antimicrobial activity by the various extraction solvents was 18.66 mm (clear zone diameter) in the ethanol extract and 20.18 mm in the water extract. Measurements of the antibacterial activity according to the mixing ratio of the two solvents revealed the 30% ethanol extract to have the highest activity (20.49 mm). Measurements of the minimum inhibitory concentration (MIC) showed activity at a concentration of 3.0 mg/mL. The stability to heat was observed, but the extract was not active at pH 6.0 or higher. The antimicrobial activity of the 30% ethanol extract of P. mume treated with enzymes was the same with both 10 ppm and 100 ppm of the nine enzymes. On the other hand, the activity tended to decrease slightly at 1,000 ppm. The activity of the catazyme enzyme and hydrogen peroxide treatment decreased at the treatment concentration of 100 ppm.

This study aimed to improve the physiological activity and processing properties of ginseng sprouts. We first determined the effect of extraction and fermentation conditions on the antioxidant activity of ginseng sprouts. The optimal extraction conditions were 2 h at 80°C, with water as a solvent. The fermentation strains used were Lactobacillus delbrueckii subsp. bulgaricus KCTC 3635 and Enterococcus faecalis KCTC 3206. We then analyzed the changes in the reducing sugar and alcohol content. In fermented samples, the reducing sugar content was lower and the alcohol content was higher than those in control sample. The cell counts of lactic acid bacteria were higher in the fermented samples than those in the control sample. Fermented samples contained more ginsenoside than the extract samples, and ginsenoside was not detected in the control sample. The total polyphenol and total flavonoid contents were relatively high in the fermented samples, particularly in the sample fermented by E. faecalis. Finally, sensory evaluation revealed that the Yakju prepared using ginseng sprouts fermented by lactic acid bacteria was preferable to other drinks control and ginseng sprouts extracted sample. Overall, it was confirme that the addition of fermented ginseng improved the physiological activity and palatability of yakju, there by improving the quality of yakju.