以逆滲透方法濃縮香茄汁之研究

Abstract

天然番茄汁與果膠酵素處理過之天然番茄汁（5.0ºBrix）以HR-95逆滲透薄膜在50℃、40bar直接濃縮雖可分別濃縮至13.0ºBrix與15.5ºBrix，但是會造成嚴重的薄膜阻塞（fouling）現象，因而縮短薄膜的使用壽命“若將天然番茄汁先以13200xg離心處理，再將離心所得之果清以HR-95或HR-98薄膜，25℃或50℃，40bar或50bar進行逆滲透濃縮，果清可濃縮至18.8ºBrix，水溶性固形物回收率達到98.5％以上。將離心果肉回添至濃縮果清後所得之濃縮番茄汁之濃度為14.8ºBrix。此法可大幅度降低薄膜阻塞的現象，透流速率亦相對提高，此外，操作後薄膜清洗效率較高，薄膜的使用壽命亦較長。 就操作效率與可溶性固形物之回收率比較，HR-95與HR-98之薄膜表現差異不大。濃縮操作溫度愈高，透流速率愈大，溶質較易透過薄膜而流失。40bar與50har的操作壓力對透流率影響差別不大。逆滲透濃縮番茄汁經還原成天然番茄汁後，黏稠度均會下降，其中以離心果清濃縮法之濃縮番茄汁所還原之果汁黏稠度下降幅度最小，果汁所測之色澤，a值與a/b值，及番茄紅素（lycopene）均較其他樣品高，且相當接近天然番茄汁的色澤。 Tomato juice and depectinzed tomato juice (5º Brix ) were able to concentrated to 13.0 ºBrix and 15.5ºBrix, respectively, by reverse osmosis (RO) using HR-95 membranes, at 50℃ and 40bar, however, severe fouling were also observed. If tomato juices were centrifuged at 13200xg first, the serums can be concentrated up to 18.8ºBrix using either HR-95 or HR-98 membranes, at 25℃ or 50℃, and 40bar or 50 bar. Average recoveries of 98.5% of soluble solids can be obtained in the RO concentrations of tomato serum. The viscosity, a value, a/b ratio, and lycopene content were only slightly lower than the fresh tomato juice.