The Effect of Chitosan Edible Coating and Shelf Life on Physicochemical and Sensory Characteristics of Roostertail Grape

Chitosan is one of the natural preservers and an active coating that due to nontoxic nature, antioxidant activity, antimicrobial, and film producing properties, biocompatibility and biodegradability has been considered as one of the natural additives. This material singly or in combination and along with the other biological materials such as extracts and or essence of different herbs is used as a nanocomposite. In this study, the effect of chitosan coating was assessed on the sensory, tissue and physical changes of roostertail grape. 1 and 1.5% solutions of chitosan with median molecular weight were prepared in 1% acetic acid wherein glycerol and Tween 80 were used as the softeners and an emulsifier.After the selection of different treatments, the samples were suspended in the considered chitosan solution for 3 minutes and after extrusion of excess dripping were introduced in the disposable containers and were experimented on 1, 5 and 12 days. For tissue analysis the texture analyzer having a cylindrical steel probe TA39 with a 2mm diameter and 20mm width and for acidity measurement the pH meter was used. The results showed that the acidity rate in 1.5% chitosan had a significant reduction in comparison to 1% chitosan treatment. The results of sensory changes viz. juiciness, crack and rupture, spoilage, color change, smell in the 1 and 1.5 % chitosan treatment at different time periods were more desirable in relation to the control. The results of conducted experiments exhibited that chitosan can be considered as a biological preserver that is able to increase the shelf-life of different fruits viz. grapes besides the qualitative changes of the fruit with increased preservation time does not get exposed to significant changes.