金柑全果系果汁之混濁穩定性

Turbidity Stability of Comminuted Kumquat (Fortunella margarita Swingle) Juice

金柑果汁為混濁系果汁，混濁的外觀是其重要品質之一，本研究針對不同之加工處理對金柑混濁果汁混濁穩定性之影響加以探討。鮮榨金柑果汁及熱處理之金柑果汁500mL分別以6000、8000、10000 rpm的轉速各均質1、2、3、4min。均質處理對鮮榨之果汁之黏度有降低之效果；然而對熱殺菌後之果汁則有增加黏度之效果。兩種果膠分解酵素Pectinex Ultra SPL和Citrozym CloudyL，以0.05%、0.1%於室溫下處理60min後立即殺菌置低溫（2℃）貯藏，兩者皆能大幅降低果汁黏度，且在低溫貯藏期間均能維持穩定之果汁混濁度。不同酵素處理間之差異性不大。果汁含量分別為25%、50%、75%與100%之果汁黏度隨稀釋度增加而減小，果汁之混濁度與混濁沈降率亦隨稀釋度增加而變大。CMC和果膠各以0.3%添加對稀釋金柑果汁的混濁度及混濁沈降之改善效果最大。於低溫貯藏期間均能維持混濁穩定。 Turbidity Stability of comminuted kumquat juice during processing and storage was investigated. Homogenization decreased the viscosity of juice without heat treatment; however, the viscosity of heat treated juice was increased after homogenization. Pectinases, Pectinex Ultra SPL and Citrozym Cloudy-L, not only were very useful on decrease the viscosity of comminuted kumquat juice but also maintained a stable turbidity of juice during cold storage. Dilution of juice resulted in both decrease of viscosity and turbidity. Addition of thickening agents (CMC and pectin) were successful on increase the viscosity and turbidity of 25% comminuted kumquat juice during cold storage.