STUDY ON THE EFFECTS OF LONGAN FRUIT DIPPING IN CHLORINE DIOXIDE ON PERICARP BROWNING AND QUALITY DURING COLD STORAGE

Abstract

Pericarp browning is the main factor to reduce the storage life and marketability of longan fruit. In the present study evaluated chlorine dioxide (ClO2) dipping on reducing pericarp browning. Fresh longan fruit was dipped in 1%, 1.25% and 1.5% ClO2 for 5 min and stored at 5±2 oC, 85±5% RH for 42 days, investigated every 7 days. Evaluation by browning index (BI) as pericarp browning, outer pericarp color by a chromameter expressed as L*and b* value and hue angle, disease incidence, ClO2 residue and sensory acceptance was determined. The result showed that dipping in 1%, 1.25% and 1.5% ClO2 could reduce pericarp browning (lower BI, higher L* and b* value and hue angle). However, they showed no significant differences with commercial SO2 fumigation but they were significant differences with untreated fruit. ClO2 treatments could reduce disease incidence and low ClO2 residue in flesh. The sensory acceptance such as outer pericarp color, flesh and flavor treated with 1.5% ClO2 had shown great potential. The results suggested that 1.5% ClO2 dipping could reduce pericarp browning of longan fruit as same as the commercial SO2 fumigation.