Changes in Longan and Rambutan During Postharvest Storage

Abstract

Compositional changes of longan [ Euphoria longan (Lour.) Stend] and rambutan ( Nephelium lappaceum L.) collected in two seasons were measured during storage at two temperatures. Seasonal variation reflected both preharvest conditions and maturity at harvest. Total sugars and titratable acidity of longan aril showed little change after harvest at 4° and 22°C. Sucrose of rambutan aril increased from 51 mg·g −1 to 76 mg·g −1 when fruit were stored at 12°, and no change occurred when stored at 22°. Titratable acidity, 20.8 meq·g −1 at harvest in rambutan aril, first declined and then increased at both storage regimes. Succinic acid was found in rambutan aril only at harvest and declined rapidly to an undetectable level. No malic acid was detected in rambutan. A high level of citric acid (≈175 meq·g 1 ) was maintained during storage. The organic acids in longan aril were succinic, malic, and citric acids, present in a ratio of 10:5:1. Ascorbic acid content declined in aril tissue of both longan and rambutan during storage. Total phenols showed little change in either fruit during storage. Except for the changes noted, there were only minor compositional changes in longan fruit stored for 35 days at 4° and rambutan stored for 20 days at 12°.