ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Pectin esterase, polygalacturonase and gel formation in peach pectin fractions.

Zhou HongWei; Ben-Arie, R.; Lurie, S.;

Phytochemistry Year: 2000 Vol: 55 Issue: 3 Pages: 191-195 Ref: 16 ref.

2000

บทคัดย่อ

Peaches (Prunus persica cv. Hermoza) were stored at 0 deg C in regular air (RA) or in controlled atmosphere (CA 10% CO2, 3% O2) for 4 weeks and then ripened for 4 days at 20 deg C. Woolliness developed in RA-stored fruits while the CA-stored fruits ripened normally. In the woolly fruits, symptoms of the disorder were greater in the inner mesocarp than in the outer. Polygalacturonase (PG) and pectin esterase (PE) activities differed in the outer and inner mesocarp of the affected fruits. PG activity was low and PE activity was high in the inner mesocarp of the woolly fruits during ripening relative to the outer mesocarp, while in the healthy fruits, activities were similar in both areas. Cell wall fractions of water-soluble, CDTA-soluble and carbonate-soluble pectins were prepared from freshly harvested peaches and incubated with PE and PG from ripe peaches at different ratios. Only the CDTA-soluble fraction formed a gel with peach enzymes, and the rate of gelation increased with increasing amoun

ts of PE relative to PG. Both water-soluble and CDTA-soluble pectin fractions formed gels with commercial PE (extracted from orange peel). The PE extracted from peaches was stable when stored at 0 deg C for 9 days, while PG activity was stable only for 1 day. We suggest that PE, acting on pectins in the cell wall in vivo may cause gel formation and that the CDTA-soluble polymers have the capacity to bind apoplastic water and create the dry appearance observed in woolly fruits.