Abstract:

Edible coating formulations have been applied to many food produce to increase their shelf-life. The objective of this research was to study the effect of edible nanoemulsions based on sodium alginate at 2% (w/w) (Alg2%) and carnauba wax at 1% (w/w) (Cwax1%) enriched with citral (1 and 2% (w/w)) and lemongrass oil (1.25 and 2.5% (w/w)) to preserve the quality of ‘Galia’ melon for 1 month at refrigerated storage (5±1°C, RH 90±2%) and ensuing shelf-life (3 days). Control consisted of uncoated fruit. Measurements of color CIE (L*, a*, b*), firmness, soluble solids content (SSC), electrolytic leakage, microbial growth and visual evaluation of rot and physiological disorders were done. Melons coated with Cwax1% alone or with citral 1% maintained higher hue values than controls. During storage, firmness decreased less in fruits covered with Cwax1% but after shelf-life only fruit coated with Cwax1% + lemongrass 1.25% kept higher firmness. Melons coated with Cwax1% + lemongras 1.25% showed the lowest SSC value after storage, reaching similar values to control fruit after shelf-life. Just after storage, only fruit coated with Alg 2% + lemongrass presented higher electrolytic leakage than control. Mesophilic bacteria and yeasts and molds population decreased more in fruit coated with the nanoemulsions containing higher essential oils concentration. Fruit covered with Cwax showed the highest percentage of fruit without visible symptoms of rot and slightly less chilling when containing essential oils. Edible nano-coatings based on Cwax enriched with citral 1% and lemongrass 1.25% seems to slow ripening and reduce rot and chilling injury.