Integrated ethylene scavenging and Generally Recognized as Safe (GRAS) antifungal active packaging extend shelf life of jamun (Syzygium cumini) under ambient storage

Jamun (Syzygium cumini L.) is a climacteric, highly perishable fruit grown in the tropics; its shelf life rarely exceeds 24-48 hrs under ambient conditions due to rapid softening, drying and fungal spoilage. This study evaluated the combined effect of potassium permanganate (KMnO4), an ethylene scavenger, and the GRAS antifungal agent potassium metabisulfite (KMS), dispensed via silica gel-based active sachets, on jamun shelf life. A nine-treatment, single-factor CRD combined three KMnO4 levels (0, 60, 120 mg) with three KMS levels (0, 500, 1000 mg) per 500 g fruit pack (T1-T9; N = 27) under non-refrigerated storage. Apart from the control (T1), where 91.67% of fruits spoiled, the 120 mg KMnO4 + 1000 mg KMS treatment (T9) limited spoilage to just 7.33%, while retaining firmness at 1.55 kg cm⁻², TSS at 13.35 °Brix, ascorbic acid at 18.21 mg 100 g⁻¹, and total phenolics at 238.03 mg 100 g⁻¹ on day 6. The joint effect of ethylene breakdown by KMnO4 and steady SO2 release from KMS is hypothesized to have created a favourable package microenvironment that slowed ripening, restricted weight loss, and inhibited fungal growth. This low-cost active-packaging approach can more than double jamun's shelf life at ambient temperature, offering a practical solution for short-value-chain markets lacking cold-chain infrastructure.