殺菁條件對棠梨果汁品質的影響

Effect of Blanching Conditions on the Quality of Tang-Li (Pyrus pyrifolia var. Culta) Juice

本試驗是以不同殺菁溫度及時間，探討棠梨果汁最適當的加工條件，結果顯示棠梨清洗後，以75℃加熱20分鐘進行殺菁處理，可以降低可溶性單寧含量，有效除去苦澀味，且破壞多酚氧化酶的活性，防止果汁褐化，並產生良好的風味。經官能品評配合色差計讀值分析，也是以75℃，20分鐘殺菁處理的果汁被接受性最好。棠梨的有機酸含量高達2.44%，主要為檸檬酸及蘋果酸，次為酒石酸，抗壞血酸；經殺菁處理後的棠梨果汁，除蘋果酸的含量差異不顯著外，總酸、檸檬酸、酒石酸含量均顯著降低。

This study was conducted to determine the optimal blanching conditions for getting the best quality of Tang-Li juice. Blanching at 75℃ for 20 minutes resulted in lowering soluble tannin content and deastringency of juice. Quality of juice could be improved by inactivating polyphenol oxidase activity through blanching. Combining organoleptic evaluation with color difference meter readings indicated that the best acceptabity of color and flavor of Tang-Li juice wan in the condition of blanching at 75℃ for 20 minutes. The organic acid content of Tang-Li juice was up to 2.44%. Four kinds of organic acid i.e. citric acid, malic acid, tartaric acid and ascorbic acid were found in Tang-Li juice. There wan no significant changes in content of malic acid, however, the contents of total acidity, citric acid and tartaric acid were significantly decrased by blanching.