Coatings Based on Gelatin and Chitosan in the Conservation of Papaya (Carica papaya L.) Minimally Processed

Minimally processed fruits undergo changes that require careful monitoring. This study aimed to assess the effectiveness of edible coatings based on chitosan and gelatin using various application techniques for minimally processed papayas. The treatments included: control (distilled water), 1% chitosan, 4% gelatin, 1% chitosan + 4% gelatin (blend), and 1% chitosan with a 4% gelatin undercoat (layer-by-layer). The coatings’ infrared spectroscopies (FTIR) were analyzed, and the fruits’ fresh mass, firmness, pulp color (L*, a*, b*, and hue angle), pH, titratable acidity, soluble solids, ascorbic acid, phenolic compounds, lycopene, β-carotene, total sugars, and catalase activity were measured. The results revealed that gelatin and the layer-by-layer treatment positively influenced the preservation of minimally processed papaya. These coatings effectively reduced fresh mass loss while maintaining firmness and the characteristic orange color of the mesocarp. Furthermore, the treated samples consistently exhibited low soluble solids content during the storage period, with minimal variations in acidity, thereby influencing the maturation process. Gelatin coatings demonstrated low polyphenol content, while the layer-by-layer treatment showed no significant changes in vitamin C levels. Lycopene and β-carotene levels remained stable throughout the storage period, with a slight increase observed in total sugars. Consequently, the application of gelatin polymers and the undercoat treatment (LBL) represents a viable alternative for extending the shelf life of minimally processed papayas for at least eight days.