PHYSICO-CHEMICAL QUALITY CHARACTERISTICS OF LEMONGRASS AS AFFECTED BY MATURITY STAGE AT HARVEST, PACKAGING MATERIALS AND STORAGE DURATIONS

This study was conducted to determine the effects of different maturity stages, packaging materials and storage durations on physico-chemical quality characteristics of lemongrass. Lemongrass was planted at the Universiti Agricultural Park, Universiti Putra Malaysia, Serdang, Selangor using a randomized complete block design with four replications. Harvesting was done at 5.5, 6.5, and 7.5 months after planting. The physico-chemical characteristics of the lemongrass evaluated firmness, chlorophyll, anthocyanin, ascorbic acid, and total phenolic contents. Measurements were made at 0, 5, 10 and 15 days after storage (10°C, 68% RH). Results indicated that there were no interaction effects between the treatments on firmness and ascorbic acid contents. Firmness increased as maturity stage advances from 5.5 to 7.5 months after planting, but decreased as storage duration was increased. Ascorbic acid content decreased with increase in maturity stages and storage duration. During storage, data obtained show that firmness and ascorbic acid content were not affected by the use of the clear and black polyethylene (PE) packaging materials (bag). Chlorophyll content of lemongrass harvested at 5.5, 6.5 and 7.5 months after planting tends to decrease during storage. In contrast, the anthocyanin content increased when the storage duration was increased, but it was lower in lemongrass pseudostems that were packed in black PE bag than those packed in clear PE bag. There was a significant interaction effect between maturity stage at harvest and storage duration of lemongrass on total phenolic content of lemongrass pseudostems. By the end of the storage duration, lemongrass harvested at 7.5 months after planting contained the highest total phenolic content compared to those harvested at 5.5 and 6.5 months after planting. Thus, lemongrass should be harvested between 6.5 to 7.5 months after planting to obtain optimum postharvest quality characteristics.