Active edible coating from chitosan incorporating green tea extract as an antioxidant and antifungal on fresh walnut kernel

The effects of coatings made from chitosan (Chi) incorporating green tea extract (GTE) on lipid oxidation, fungal growth, and sensory properties of walnut kernels were studied. The Chi powder and GTE obtained from green tea were combined to obtain the final concentrations of Chi-GTE: 5-0, 5-5, 5-10,10-0,10-5 and 10-10 g L-1 in an aqueous coating solution. Effective inhibition of lipid oxidation and fungal growth during storage of walnut kernels (18 weeks) was possible using the Chi10 coating combined with GTE. Different proportions of GTE had no significant effect (p < 0.05) on lipid oxidation. Fungal growth was not detected during the storage period with Chi10 and all different proportions of GTE, Throughout the storage duration, coatings without GTE showed no significant (p < 0.05) effect on sensory properties; however Chi10-GTE10, was significantly (p < 0.05) unacceptable by panelist. The results suggested that Chi10-GTE5 could prolong the shelf life of walnut kernels. (C) 2015 Elsevier B.V. All rights reserved.