Development and characterization of an edible chitosan/zein-cinnamaldehyde nano-cellulose composite film and its effects on mango quality during storage

A new chitosan/zein-cinnamaldehyde (CHI/zein-CMA) nano composite film was developed, which possessed remarkable features favorable for mango preservation, including retardation of yellowing, respiration rate, weight and vitamin C loss and malondialdehyde (MDA) accumulation during storage of mango at 25 °C. The formula of chitosan/zein nano composite film was optimized through single factor experiments and orthogonal experiment with fuzzy comprehensive assessment. The results showed that the optimal formula is chitosan 35.0 g/L, zein 3.0 g/L, nano-cellulose 25.0 g/L, acetic acid 0.26 mol/L. Besides, cinnamaldehyde was incorporated into CHI/zein composite film and 3.0 g/L was chosen as the favorable concentration. The crack-free film surface observed under scanning electron microscopy (SEM) suggested that the incorporation of CMA contributed to a more flexible and dense film structure, and the significant increase in β-sheets (from 17.06% to 27.00%) accompanied with the decrease in α-helix (from 55.5% to 44.41%) further confirmed the strong cross-linking of CMA with CHI/zein matrix. The results showed that the accumulation of H2O2 to desired level and storage adjusting of antioxidant enzymes activity (SOD) might be related to the excellent storage quality of mango coated with CHI/zein-CMA, suggesting that stress response was beneficial to the preservation of mango.