Microwaves as sustainable approach for artificial ripening of date fruit cv. Khupra to reduce fruit waste

Abstract

Date fruit ripening depends upon various factors, including climate, environment, soil type, air and humidity. Due to these factors, some cultivars of date fruit are unable to ripen on the trees and deteriorates. Thus a significant quantity of date fruit is wasted every year, which impose significant concerns on food security. Therefore, this study investigated the effect of microwave pre-treatment for ripening of dates. For this purpose, date fruits cv. Khupra at the Khalal stage were pretreated at different microwave power level (30, 50 and 80 W) and time (30, 40 and 50 s) combinations for the improved microstructural and compositional characteristics. Afterwards, the treated samples were stored at relative humidity (50 %) and temperature (50 °C). The data indicated that microwave pretreated dates retained better quality in comparison to sun dried samples. The microwave treated fruits exhibited TSS contents up to 60.3 ± 0.09 °Brix, a whiteness index of up to 15.4, and an antioxidant capacity of up to 78 ± 0.04 %. Texture profile analysis also revealed that the sundried fruits have more hardness of 724 ± 0.01 (g-force) compared to microwave pretreated samples which was supported by the Scanning electron microscopy analysis. Moreover, FTIR spectra readings indicated the presence of various dietary fiber components such as cellulose, lignin, hemicellulose, fructose, glucose, arabinose, glactomannans, pectins, and organic acids retained in microwave pretreated dates. In short, Microwave pretreatment can potentially replace the conventional sun drying method for production of superior quality ripened dates.