Optimization of melatonin treatments using response surface methodology (RSM) to waste control, increase quality and shelf-life of mulberry fruit in the postharvest stage

The present study investigates the effect of coating white mulberry fruit using different concentrations of melatonin (0, 200 and 400 μM) and storing them at the temperature of 1ºC for 0, 6 and 12 days. Using response surface methodology (RSM), this piece of research set out to measure the optimized interaction effect of melatonin (MT) concentration and storage time on product quality characteristics, including weight loss (WL), total soluble solids (TSS), browning index (BI), ascorbic acid concentration (AsA) and pH. The results showed that the response surface regression model with a coefficient of determination (R 2 ) higher than 0.98 was successful in predicting the responses (P<0.05). The findings showed that by increasing storage time, the quality indicators of mulberry fruit decreased. However, the application of MT treatment was able to slow down this downward trend well and thus improve and maintain fruit quality during storage. Using the optimization model, the present study determined the optimal concentration of 400 μM of MT as the selected treatment to maintain the quality of white mulberry fruit for up to 10 days after harvest. Melatonin has a high potential to increase the shelf life and improve the nutritional value of white mulberry in the post-harvest stage.