MULTICOMPONENT BIOPOLYMER EDIBLE COATINGS EXTEND THE POSTHARVEST QUALITY OF BANANAS (Musa spp.): EFFECTS ON MASS LOSS, SOLUBLE SOLIDS AND COLOR

Postharvest losses of climacteric fruits such as bananas are driven by high respiration and transpiration rates, which accelerate ripening, moisture loss, and senescence. Edible coatings based on polysaccharides can form semipermeable barriers that modulate gas exchange and water migration. However, the relative effectiveness of single biopolymers and their combinations remains unclear. This study evaluated pectin-, starch-, and chitosan-based coatings, applied individually and in binary and ternary combinations, on the postharvest quality of green bananas during 14 days of storage. Film-forming solutions were prepared with each biopolymer at 1% (w/v) and glycerol at 20% (w/w, based on biopolymer mass) as a plasticizer. Chitosan was solubilized in 1% (v/v) acetic acid. Individual coatings of pectin (P), starch (S), and chitosan (C), binary coatings (PS, PC, and SC), and a ternary coating (PSC) were applied by immersion. Uncoated fruits were used as controls. Mass loss, pH, total soluble solids (°Brix), and instrumental color parameters (CIELAB: L*, a*, b*, C*, and h*) were monitored. The lowest mass losses were observed for PS (28.1%), SC (30.1%), and PSC (30.4%), all below the control (31.7%), whereas the individual coatings showed higher losses: P (47.1%), C (45.5%), and S (40.6%). Total soluble solids increased during ripening. The control reached 12.6 °Brix, while P and S reached 14.0 °Brix. In contrast, SC and PSC remained at 12.0 and 12.1 °Brix, respectively. The pH remained stable in coated fruits, at approximately 5.0, compared with 4.5 in the control. Combined coatings, particularly PSC, PC, and SC, maintained higher luminosity and reduced changes in a* and b*, indicating better preservation of surface brightness and yellow coloration. These results suggest that biopolymer combinations formed denser and more cohesive barriers than individual coatings, reducing water loss and slowing changes associated with sugar accumulation and pigment degradation. Overall, binary and ternary coatings, particularly PS, SC, and PSC, showed greater potential than individual-biopolymer coatings and the uncoated control for preserving banana quality and extending postharvest shelf-life.

Enter the project / scholarship number (FAPESP, CAPES, CNPq, etc):  88887.981628/2024-00 The authors would like to thank the Foundation for the Improvement of Higher Education Personnel (Fundação Coordenação de Aperfeiçoamento de Pessoal de Nível Superior -CAPES).