This study examined the optimal temperature and time conditions to maintain high quality Dongchimi during the fermentation and storage period. Dongchimi was fermented at low (5oC), medium (10 and 15oC), and high (20oC) temperatures until the acidity reached 0.2, 0.3, and 0.4%. respectively. From the consumer’s preference test enrolling five consumers, Dongchimi fermented at 15oC until an acidity of 0.3% (for approximately six days) was evaluated to be the optimal status because of its high score of overall acceptance, taste, and odor of consumers. To determine the optimal storage temperature of fermentation, Dongchimi was stored at three different temperatures (−1, 2, 5oC) for four weeks after fermenting at 15oC for six days. During the storage period, most of the physicochemical properties (pH, acidity, reducing sugar content, and organic acid) and microbiological properties changed significantly in the 2 and 5oC groups, resulting in a significant change in descriptive sensory analysis of Dongchimi. These results indicate that fermentation at 15oC and storage at −1oC for Dongchimi enables it to maintain the best quality for a long time.
In this study, the physicochemical and microbiological properties of market-available skate (Raja kenojei) kimchi were evaluated in comparison to long-term fermented Baechu kimchi. The comparative results for the skate (Raja kenojei) and Baechu kimchi products are as follows: salt concentrations = 3.40% and 3.95%, respectively; pH and acidity values = 4.01 and 3.90, and 0.65% and 0.82%, respectively; redox potential Eh values = 119.82 mV and 123.08 mV respectively; reducing sugars levels = 15.51 mg% and 13.23mg%, respectively; ascorbic acid levels = 24.21mg% and 22.18mg%, respectively; color L-values = 46.86 and 44.54, a-values = 15.46 and 12.28, and b-values = 29.94 and 28.36, respectively; hardness properties = 11.36 kgf and 10.23 kgf, respectively; hot water soluble pectin (HWSP) contents and sodium hexametaphosphate soluble pectin (NaSP) contents = 15.23% and 17.35%, and 32.51% and 29.64%, respectively; hydrochloric acid soluble pectin (HClSP) contents = 55.1% and 53.2%, respectively; total viable cell counts = 4.78×108 and 1.35×108, respectively; lactic acid bacteria counts = 5.18×105 and 1.32×105, respectively; and yeast levels = 8.52×105 and 5.23×105, respectively.
To develop the low-temperature and long-term fermented kimchi, kimchi was prepared according to the recipe of a specific ratio of major and minor ingredients and adjusted its salinity to 3.7%. Prepared kimchi fermented at 15±1℃ for 24 hours and transferred and fermented in a refrigerator only used to make low-temperature and long-term fermented kimchi at -1±1℃ for 30 weeks. During 30 weeks of fermentation the changes in physicochemical and microbiological properties of low-temperature and long-term fermented kimchi were studied. The initial pH of 6.47 decrease gradually and dropped to pH 4.0 after 14 weeks of fermentation, and then it maintained at same level. Acidity increased to 0.49% on 2 weeks of fermentation and kept at 0.47 ~0.50% during 2 to 30 weeks fermentation. Salinity was slightly increased at early stage and started to decrease on 4 weeks of fermentation, and then it did not change. The change of reducing sugar content was closely related to the trend of pH change with a very high correlation coefficient(r =0.912). Lactic acid, citric acid, malic acid, succinic acid and acetic acid were major organic acids contained in low-temperature and long-term fermented kimchi. Vitamin C content decreased at initial stage of fermentation and then slightly increased up to the maximum of 22.3 mg% on 8weeks of fermentation. In color measurement, L value continued to increase during the fermentation and reached at the highest of 55.45 on 22 weeks of fermentation, and a and b values of 3.62 and 4.54 also increased to 31.26 and 37.32 on 30 weeks of fermentation, respectively. Total microbial count increased slowly from beginning and was the highest on 4 weeks of fermentation, and then began to decrease slowly. Count of Lactobacillus spp. was highest after 6weeks, but count of Lactobacillus spp. was highest on 2 weeks of fermentation, and then both showed a slow decrease. Yeast count wasn't increased until 4 weeks of fermentation and then increased rapidly to get the highest on 10 weeks of fermentation.
재래식 메주의 산업화의 공정관리를 위한 기초자료를 제시하기 위해 강원도 원주를 비롯한 전국 17개 지역에서 구입한 재래식 메주의 수분 등의 이화학적 성분, -amylase 등의 효소분석 및 생균수 등의 미생물 분석을 하였다. 전국에서 구입한 메주의 형태는 사각형의 벽돌 모양이 8개 지역, 9개지역은 둥근 모양을 띄고 있었다. 재래식 메주의 수분은 강원도 정선 메주가 최저 9.83%(w/w)인 반면 전북 정읍메주가 약 3.7배 많은 36.24%(w