The Effect of Variations in Fresh-Cut Apple Composition on the Performance of Polyvinyl Chloride Active Films

Abstract

Enzymatic browning is one of the limiting factors in extending the shelf-life of food products. Since the chemical composition can differ depending on fruit species and variety, browning prevention treatments may not always present the same efficacy. The goal of this study was to verify if differences between two fresh-cut apple varieties, Granny Smith (GS) and Red Delicious (RD), would affect the performance of polyvinyl chloride (PVC) active films for avoiding browning. Three active components were individually introduced in PVC films, i.e., citric acid, ascorbic acid, and tocopherol. Kinetics studies confirmed that browning behavior was affected by the apple variety. In the case of refrigerated RD apples, all films were able reduce browning, in the following order: ascorbic acid > citric acid > tocopherol. For GS samples, on the other hand, none of the active films was able to avoid browning. Oxidation test results showed that significant protective action occurred for the following phenolics, regardless of apple variety: chlorogenic acid, catechin, epicatechin, and gallic acid. In RD apples, there was protective effect also for procyanidin B2 and ethyl gallate, and in GS samples for ferulic, caffeic, and protocatechuic acids. The browning kinetic rates demonstrated the effectiveness of the produced films, despite the distinct browning behavior of the two varieties. The ascorbic acid–laden films presented an overall better performance in comparison to the other active films in controlling the enzymatic browning of apples.