Conservation of red guava 'Pedro Sato' using chitosan and gelatin-based coatings produced by the layer-by-layer technique

Abstract

The nutrients present in fruits are associated with health benefits, which is why fruit consumption has increased globally. However, global statistics show that fruits together with vegetables constitute the largest part of post-harvest food losses. This is because fruits such as guava are highly perishable and therefore degradation occurs quickly. This study aimed to assess the conservation of 'Pedro Sato' red guavas using chitosan and gelatin coatings produced by the layer-by-layer technique. The fruits were immersed in the following treatments: [1] control; [2] chitosan; [3] gelatin, and [4] chitosan and glycerol under gelatin. After drying, the guavas were stored for eight days at 21 ± 0.3 °C and 77 ± 6 % RH. Chemical characterization of coatings, weight loss, color, firmness, soluble solids, titratable acidity, ascorbic solid, chlorophylls, lycopene, total phenolic, antioxidant activity, lipid oxidation, catalase and peroxidase were analyzed in the fruits. Guava coating with gelatin/chitosan by the layer-by-layer technique delayed ripening, protected against diseases, reduced in loss of weight loss and lipid oxidation, maintained color and firmness, and enhanced catalase enzyme activity. The coating increased guava conservation for at least eight days, indicating the good potential of this coating technique association.