Edible coatings for strawberry based on extracellular compounds of Humphreya coffeata

Abstract

Edible coatings (EC) are a biodegradable alternative for food preservation. In this work EC based on extracellular compounds of Humphreya coffeata and pectin (PHC) were elaborated and characterized through testing on strawberries. Two PHC types were obtained (PHC1, which settled, and PHC2, which floated during the first separation). The conservation period of the strawberry and the phenol content and antioxidant activity in strawberries with the EC were determined. Four EC were prepared (EC1, EC2, EC3, and EC4), in which EC1 did not contain any PHC, EC2 contained PHC1, EC3 contained PHC2, and EC4 contained both PHCs. Three EC types (EC2, EC3, and EC4) delayed the decay of strawberries approximately 90% at 20 °C during the first 10 days of evaluation, and at 4 °C the effect was between 75 and 90% after 25 days of experimentation. However, EC3 and EC4, both of which contained PHC2, presented the best results. The content of total phenols (approximately 55 mg (gallic acid equivalent (GAE)/mL) and the free radical scavenging activity were 35% with ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 75% with DPPH (2,2-diphenyl-1-picrylhydrazyl) in strawberries with EC. Thus, EC are an alternative for preserving strawberries without losing their antioxidant capacity.