Coating with chitosan-based edible films for mechanical/biological protection of strawberries

The present work reports the development of chitosan-based films for application as protective layer for natural foods such as fruits and vegetables. Chitosan is a biopolymer known for its antibacterial and antifungal properties that when combined with its biocompatibility and biodegradability can be widely applied in areas such as cosmetic, pharmaceutical and food industry. In this work, thin films based on chitosan were obtained by the drop-casting method using glycerol to enhance elasticity and hydrophobic character. Such properties are desirable to form a protective layer that is not highly soluble in water. The results showed that the bactericidal character of chitosan against gram-positive and gram-negative bacteria remains after plasticization. Strawberries coated with chitosan/glycerol 30% films (Chi/30%Gly) showed resistance against gray fungus attack and an insignificant alteration in their flavor, appearance, aroma and texture. In other words, the chitosan film protected the strawberry from fungi attack, showing its great potential as edible coating for fruits and vegetables.