Abstract
To investigate the effects of storage and pasteurization temperature on the quality of kiwi juice $(13.5^{\circ}Brix)$, the Kiwi juice was pasteurized at 65, 75 and $85^{\circ}C$ for 15 sec. The microbial, physicochemical measurements and sensory evaluations were conducted at the same condition during storage at 4 and $25^{\circ}C$ for 30 days. Most of the vegetative bacteria cells in kiwi juice were destroyed by heat treatment over $65^{\circ}C$, and they did not actively grow in kiwi juice after pasteurization. The D values of bacteria in kiwi juice by tubular type of heating exchange were 4.17, 1.47 and 0.81 sec at 65, 75 and $85^{\circ}C$, respectively. The growth of microorganisms during storage were not detected in the most samples. The amounts of vitamin C decreased as the pasteurization-storage-temperature and storage time increased. While reducing sugar increased as the pasteurization-storage temperature-storage time increased, it decreased rapidly after 20 days of storage. Hunter's color values L, a and b of stored kiwi juice were decreased at all storage conditions, browning reaction rate increased as the pasteurization-storage-temperature was decreased.
본 실험은 다양한 온도에서 살균 및 저장함에 따라 참다래 쥬스의 품질에 미치는 영향을 알아보기 위하여 참다래 쥬스$(13.5^{\circ}Brix)$를 65, 75 및 $85^{\circ}C$에서 각각 15초간 살균한 뒤 4, $25^{\circ}C$의 incubator에서 30일간 저장하며, 미생물, 이화학적 특성을 조사한 결과, 대부분의 참다래 쥬스 내 세균은 $65^{\circ}C$의 가열에서 파괴되었고 저장기간 중 모든 시료에 대하여 세균 증식은 나타나지 않았다. Tubular type가열 살균기에서 살균한 참다래 쥬스 중 세균에 대한 D value는 $65^{\circ}C$에서 4.17초, $75^{\circ}C$에서 1.47초, $85^{\circ}C$에서는 0.81초로 감소하였다. Vitamin C함량의 변화는 살균온도와 저장온도 및 저장기간이 증가할수록 감소되었으며, 환원당 함량은 모든 살균조건에서 저장 20일째 최대값을 보인 후, 급격히 감소하는 경향을 나타내었다. 색도의 경우에는 모든 살균 및 저장조건에서 L, a 및 b값은 저장기간에 따라 감소하는 경향을 나타내었으며, 갈색도 변화는 저장기간이 길어질수록 지속적인 감소현상을 나타내었다.
