Combined effects of natural substances and modified atmosphere packaging on reducing enzymatic browning and postharvest decay of longan fruit

An integrated control strategy on preventing pericarp browning (BI) and decay incidence (DI) of longan fruit was investigated to replace sulphur dioxide (SO₂) fumigation. Fruit was treated with 5% ascorbic acid (AA), citric acid (CA), oxalic acid (OA), thymol (TH) and 2% chitosan (CH) for 5 min; sealed under modified atmosphere packaging (MAP) using high permeable film; and stored at 5 °C. Fruit treated with distilled water and sealed under MAP condition (MAPC) and air condition (AIRC) was used as controls. Combined effects of chemical treatments and MAP maintained quality of longan for 56 and 49 days in CH and TH, respectively, as compared to 28 days in MAPC and 21 days in AIRC. AA, CA and OA prevented BI, restrained enzyme activities and maintained high phenols. AA, CA and OA were most potent BI inhibitors; however, DI was the limitation of these treatments, while CH and TH effectively inhibited DI.