Enhancing litchi shelf life with gluten-based nanocomposite films: A comparative study of montmorillonite and starch nanocrystals reinforced with chitosan

This study investigates the efficacy of gluten films incorporated with montmorillonite (MMT) and starch nanocrystals (SNCs), further enriched with chitosan, in preserving the quality of litchis over a 20 -day storage period at 4 degrees C. The addition of MMT/SNCs along with chitosan boosts the tensile strength (52.44 to 57.00 MPa) and surface uniformity of the films while also decreasing water vapour transmission rates (0.77 to 0.68 pound 10 - 3 g/m 2 /h). Notably, litchis wrapped in these nanocomposite films demonstrate superior shelf stability compared to untreated litchis, which undergo considerable deterioration. Among the film variants, SNCs/chitosan films (GSL2) outperform MMT/chitosan (GML2) due to their superior barrier properties. By the 20th day of storage, litchis packaged in GSL2 films display reduced antioxidant enzyme activity (polyphenol oxidase: 3.18 to 8.08 unit/min/g fruit weight; peroxidase: 0.94 to 5.29 unit/min/g fruit weight) and higher retention of bioactive compounds, including anthocyanin (9.15 to 9.90 mg/100 g), phenolics (347.7 to 362.07 mg/100 g), and ascorbic acid (28.21 to 29.09 mg/100 g) in litchi pericarps during last intervals. Similarly, less alteration was observed in the firmness (8.47 % and 7.36 %) and weight loss (24.04 % and 19.86 %) of the litchis packaged in GML2 and GSL2, respectively as compared to unpackaged litchis. Notably, litchi pericarp exhibits negligible functional group changes when packed in GML2 and GSL2 films until the 15th day of storage. In summary, GML2 and GSL2 films effectively maintain acceptable litchi quality for three weeks.