Influence of Pectinesterase Inhibitor from Jelly Fig (Ficus awkeotsang Makino) Achenes on Pectinesterases and Cloud Loss of Fruit Juices

摘要

Citrus and jelly fig achene pectinesterase (PE) (1 U/mL) activity was remarkably inhibited by PE inhibitor (PEI) (2 mg/mL) from jelly fig (Ficus awkeotsang Makino) achenes, in the absence or presence of 0- to 500-mM salts or 0 to 30% of sugars. Changes in temperature (20 to 40℃) apparently decreased the activity of citrus PE in PE-PEI reaction mixture. Enzyme-activity curves for jelly fig PE alone and for that in combination with PEI were parallel. Activity of crude PEs (1 U/mL) from tomato, apple, asparagus, and guava was reduced remarkably. Cloud loss of fresh tomato juice, apple juice, and papaya juice was greatly inhibited by PEI (1 mg/ mL) during 12-wk storage.