Effect of Propionic Acid and Bee–Carnauba Wax on Purple Passion Fruit Quality and Stability During Ambient Storage
Nguyen Thu Huyen *
National Institute of Medicinal Materials, Vietnam.
Nguyen Minh Duc
Thuyloi University, Hanoi, Vietnam.
*Author to whom correspondence should be addressed.
Abstract
This study aimed to determine the effects of different concentrations of propionic acid combined with mixed wax (beeswax and carnauba wax; MW) on the quality and storage life of postharvest purple passion fruit under ambient conditions (25 ± 2 °C and 70%–80% relative humidity). After washing and air-drying, the fruits were dipped for 1 min in propionic acid solutions at concentrations of 0.15%, 0.25%, or 0.35% (v/v), or in 0.2% carbendazim, and were then manually coated with 2.5% MW. After drying, the fruits were stored under the stated ambient conditions for 18 days. Untreated and uncoated fruits served as controls. The assessed parameters included the isolation and identification of microorganisms, total microorganism counts, fruit decay, weight loss, total soluble solids (TSS), total sugars, titratable acidity, and ascorbic acid content, measured at 3-day intervals. Two microorganisms, Fusarium moniliforme var. subglutinans and Fusarium oxysporum Schlecht., were identified. Treatment with 0.25% propionic acid followed by MW coating reduced total microorganism counts, fruit decay, and weight loss during 18 days of storage. This treatment also maintained TSS, total sugars, titratable acidity, and ascorbic acid content throughout the storage period.
Keywords: Purple passion fruit, propionic, bees and carnauba wax, chemical quality, total microorganism