臺灣葡萄果汁加工問題之探討（一）：果膠分解酶之選用對榨汁率及果汁品質之影響

Investigation on the Preparation and Clarification of Grape Fruit Juice in Taiwan 1. Effect of Pectinesterase Application on the Extraction and Quality of Fruit Juice

本試驗以臺灣產之康歌葡萄為主要榨汁原料，榨汁前分凍藏及未凍藏二種，葡萄均先破碎加溫，選用三種果膠分解酶處理，結果以Ultrazyme的效果最佳，用量為100ppm時間一小時，可顯著提高榨汁率、自流汁率及較紅的果州等品質。經冷凍貯藏之葡萄原料，經解凍及如上述之榨汁試驗，結果發現較未凍結者所得之自流汁率為高，二者之自流汁率各為74.8%比69.1%，榨汁總收率各為81.0%比72.1%。此可能是被凍結之葡萄細胞被擠破，果汁較易流出，於是其可溶性固形物與自流汁率也較高，且有利於果膠分解酶之分解作用。

Concord grape produced in Taiwan was used for preparation and clarification of fruit juice in this experiment. All grapes were harvested from Nan-Oau, I-Lan district and directly delivered to Laboratory. One part of grapes was frozen at-20℃ and the other part was directly used for juice extraction. Both fresh and frozen samples were individually crushed and heated to temperature at 70℃, then cooled down to temperature at 55℃. Three kinds of pectinesterase as pectin hydrolytic enzymes were individually applied to the grape must. More juice yield from the free run and pressed methods, and the more brilliant red color of juice was obtained in the treatment by adding 100 ppm of Ultra-zyme for one hour. Yield of free run juice and toatl fruit juice from the frozen and unfrozen grape samples are 74.8% to 69.1% and 81.0% to 72.1% respectively as indicated in this experiment. The higher soluble solid content and the more free run juice yield obtained in the frozen and thawed sample that may be caused from the more broken cells of the fruits after freezing and thawing procedures, and more available conditions for pectin hydrolytic enzyme reaction.