김치의 조직감에서 cutting force는 제조당일 8.4kgf로 가장 큰 값을 나타낸 후 1일후 40%의 감소가 일어난 후 그 후 서서히 감소하다가 14주째에 급격한 증가를 보인 후 다시 감소하였다. 이러한 절단력은 질긴 정도와 씹힘성을 나타내 주고 있는 바 compression force 시험에서도 gumminess와 chewiness가 각각 제조 1일 후 급속히 감소하였다가 14주에 다시 증가하고 있는 것으로 나타났다. 텍스쳐 인자들 간의 상관관계는 씹힘성과 질김성이 r= 0.879로 다른 인자들보다도 가장 높은 정의 상관관계를 나타냈으며 씹힘성과 경도(r=0.570), 씹힘성과 응집성(r=0.591), 씹힘성과 탄성(r=0.513), 질김성과 경도 (r=0.503)도 정의 상관관계를 보여 주었다. 김치의 관능평가에서 외관, 짠맛, 경도는 제조당일 김치가 가장 높은 평가를 받았고 전체적인 기호도는 14주 동안 발효된 김치가 가장 높은 평가를 받았으며 18주 발효된 김치의 경우 탄산미와 신맛에 대해 높은 평가를 나타냈다. 관능검사를 통한 taste간의 상관관계는 신맛과 off-flavor(r=0.805), 신맛과 탄산미(r=0.813)는 매우 정적인 상관관계를 보였으며, 탄산미와 off-flavor(r=0.661), 짠맛과 단단함(r=0.530)은 정적인 상관관계를 보였다(p〈0.001). Taste와 조직감에 대한 상관관계는 짠맛과 단단함이 r=0.559로 정의 상관관계를 보였고, off-flavor와 단단함(r=-0.657), 탄산미와 단단함(r=-0.540), 신맛과 단단함(r=-0.651)은 역의 상관관계를 나타내었다. 조직감간의 상관관계는 아삭아삭한 정도와 뻣뻣한 정도(r=0.522)가 정의 상관관계를 나타내었다. 결론적으로 3.7% 염도의 김치를 제조하여 15±1℃에서 24시간 동안 예비 숙성시키고 -1±1℃의 김치전용냉장고에서 30주 동안 숙성시키면서 묵은 김치의 텍스쳐와 관능적 특성을 실험한 결과 묵은 김치제조를 위한 최적 발효기간은 18주인 것으로 사료되었다.

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.

This study presented the change of quality characteristics of Doenjang with various salt concentrations (4, 8, 15, and 20%) during 12 months. The pHs of Doenjang during fermentation were gradually increased for 12 months, whereas the pHs of Doenjang with 4 and 8% salt increased rapidly. Titratable acidity of Doenjang with 4 and 8% salt was high at initial time, while Doenjang with 15 and 20% salt was high at the 9 and 12 months. The amino-type nitrogen content of Doenjang with 4 and 8% salt was increased and α-amylase activity of all Doenjang was decreased during whole fermentation period. The protease activity of Doenjang with 4 and 8% salt was higher than Doenjang with 15 and 20% salt until 7 months. Total aerobic bacteria number 8.0~9.1 log CFU/g for 12 months, which was steady during fermentation period. Doenjang with 8% salt showed the highest score in umami taste whereas the lowest score in bitterness, astringency, and sourness tastes between 5 and 12 months. In conclusion, Doenjang with 8% salt was a suitable concentration for low-salt fermented foods.