Abstract
Effects of storage temperature and time on microorganism count and juice quality regarding freshly-squeezed, non-pasteurized Satsuma mandarin juice, were studied. Freshly-squeezed juice was stored at 10°C for 2 weeks and at 0 and 5°C for 4 weeks in glass and PET bottle containers. The following results were observed ; (1) The viable cell count of the freshly-squeezed juice stored at 0°C remained unchanged, but tended to increase in juice stored at 5 and 10°C. On the other hand, mold and yeast count gradually increased even at 0°C storage. Freshly-squeezed juice stored at 10°C spoiled more rapidly and diacetyl concentration of juice increased with the increase of microorganism count. (2) Approximate shelf life of freshly-squeezed juice was considered as 2 to 3 days at 10°C, about 1 week at 5°C and 2 to 3 weeks at 0°C. (3) The content of soluble solid, total sugar, reducing sugar, acidity, vitamin C and hesperidin of freshly-squeezed juice showed almost no change during storage at 0, 5 and 10°C. However, as microbiological spoilage of freshly-squeezed juice developed, the content of soluble solid, total sugar and reducing sugar decreased. (4) Most of the activities of pectinesterase and peroxidase in freshly-squeezed juice continued to remain during storage at 0 and 5°C for 4 weeks.
