บทคัดย่องานวิจัย

หมวดหมู่ : ฐานข้อมูลงานวิจัย

Relationship of endopolygalacturonase activity to fruit softening in a freestone peach.

Orr, G.; Brady, C.;

Postharvest Biology and Technology Year: 1993 Vol: 3 Issue: 2 Pages: 121-130 Ref: 17 ref.

1993

บทคัดย่อ

Relationship of endopolygalacturonase activity to fruit softening in a freestone peach.

A polygalacturonase protein was purified from ripe freestone peaches (cv. Flavorcrest). The purified polypeptide had a MW of 44 000, as assessed by denaturing gel electrophoresis, was bound by the lectin Concanavalin A, and was displaced from a chromatofocussing column at pH 5.5-5.6. The enzyme was shown to be endo-acting by relating changes in substrate viscosity to the release of reducing end-groups and is described as an endopolygalacturonase [poly(1,4- alpha -galacturonide) glycanohydrolase] (endoPG). EndoPG activity in individual fruits throughout ripening was assessed after separating endoPG from exopolygalacturonase by column chromatography. EndoPG activity was not apparent in very firm, mature fruits. As fruits began to soften (7-10 kgf), endoPG activity ranged from 0.3 to 0.9 nmol min-1 g-1. In softer fruits (2-7 kgf), activity was in the range 0.3 to 4.1 nmol min-1 g-1, but it increased sharply to 7.1 to 9.3 nmol min-1 g-1 in very soft fruits with the "melting soft" character. The patt

ern of accumulation of endoPG activity in peach fruits differed from that observed in tomato fruits. However, in both of these fruits evidence is accumulating that endoPG and textural changes are not closely linked.