Changing in TSS, TA and Sugar Contents and Sucrose Synthase Activity in Ethephon-Treated ‘Pattavia’ Pineapple Fruit

Abstract

Exogenous ethylene increases endogenous ethylene which plays a crucial role on ripening in climacteric fruits. Although pineapple is a non-climacteric fruit, ethylene released from ethephon is effectively used to hasten the harvesting period. Effects from the use of a high concentration of ethephon on eating quality, fruit size and the reduction in harvesting period have been reported. In this paper, the effect of a low concentration of ethephon on pineapple fruit quality and sucrose synthase (SuSy) activity was investigated. Field experiment was arranged in split plot design. In the main plot, two levels of ethephon concentrations, i.e. 0 and 500 mg/l, were used by spraying at 110 days after forcing (DAF) fruits. The sub plot was harvesting time, i.e. 5 times of one-week intervals from 124 to 152 DAF. We found that the total soluble solid (TSS) was significantly increased in most of harvesting-treated fruits while the titratable acid (TA) was significantly increased at 131 DAF of harvesting-treated fruits. Only at 131 DAF harvesting time, the glucose content and SuSy activity of ethephon-treated fruits were significantly reduced and return to the control level afterward. However, ethephon had no effect on the fructose and sucrose contents at all harvesting times. In conclusion, fruit quality with shortening of harvesting time could be improved by applying 500 mg/l ethephon at 110 DAF since TSS content which is one of the parameter predicting eating quality of pineapple was increased without decreasing fruit quality.