Antioxidant and antibacterial activities of date palm fruit (Phoenix dactylifera L.) in response to postharvest application with natural elicitors

Date palm cultivar 'Khesab' is one of the most popular cultivars in the United Arab Emirates, and it is often consumed at rutab stage of maturity (half soft fruit). However, after harvesting, the fruit begins to lose firmness, color, flavor, and overall quality characteristics, lowering its market value. To overcome this, the postharvest loss should have to be reduced. Various strategies have been used in the past, however, still, it is a big challenge, especially in the case of a fruit such as date. Therefore, the Objective of this study was to investigate the effect of postharvest dip application of a natural elicitor chitosan alone (Ch) 1% and in combination with vanillin (Van) 1%, orange essential oil (EO) 0.2% and salicylic acid (SA) 2 mM on the quality parameters, storage life, bioactive compound content, antioxidant activities during cold storage (2°C) for 2 months. The minimum fruit weight loss (%) was observed in Ch+Van+EO treated fruit as compared to the other treatments. Similarly, fruit treated with Ch+Van+EO were least firm followed by Ch+Van, Ch, and Ch+SA in descending order. Total soluble solids were found highest in Ch treated fruit followed by Ch+Van+EO, Ch+Van, Ch+SA in comparison to control. Ch+Van treated fruit showed minimum bacterial growth, and Ch+SA suppressed the fungal growth on fruit after 2 weeks of cold storage. Similarly, Ch+Van and Ch+Van+EO treated fruit showed improved total phenolics (TPC), tannins (TTC), flavonoids (TFC), and antioxidants activities. The natural combinations Ch+Van and Ch+SA used in the present study were found promising in improving the storage life and quality of 'Khesab' date fruit during cold storage.