Effects of High O2 Pretreatment and Gibberellic Acid on Sensorial Quality and Storability of Table Grapes

Abstract

Kyoho grapes ( Vitis vinifera X V. labrusca) were stored under three different treatments at 0°C in 95% relative humidity for 60 days. Grapes in the first treatment were stored in to air (control), in the second treatment the grapes were stored in 80% O2 for 15 days and then transferred into air for 45 days, and in the third treatment the grapes were sprayed with 100ppm of gibberellic acid (GA)3 containing 100ppm of Tween 20 and then kept in air. Compared with the air control, high oxygen pretreatment (HOP) and GA3 maintained higher fruit detachment force and membrane integrity, markedly reduced berry drop, rachis browning and decay and delayed the decrease of soluble solids content (SSC) and vitamin C. In addition, HOP and GA3 retarded the conversion of protopectin to water-soluble pectin and improved berry firmness. HOP resulted in a significantly firmer berry, less berry drop, and more soluble solids content, total acidity and protopectin than those treated with GA3, but did not markedly reduce rachis browning and membrane integrity loss. There were no significant differences in fruit detachment force and water-soluble pectin levels between HOP and GA3. In conclusion, high O2 pretreatment and GA3application retained effectively the quality of harvested grapes.