Optimization of edible coating composition using combined design on the shelf-life and qualitative properties of fig fruits

In this research, the effect of composite edible coatings, composed of alginate (in the concentration range 0- 2.5 % w/v), aloe vera gel (0- 1 % w/v) and zedo gum (0.5- 4 % w/v) with constant values of ascorbic acid and citric acid as anti-browning agents (each at a concentration 1 % w/v), calcium chloride as crosslinking agent (2 % w/v) and glycerol as plasticizer (8 % w/v) on quality indices of semi humid fig fruits was investigated during 4 months of storage. To study the influence of three mixture factor and a continuous factor (storage time), on physicochemical parameters such as moisture content, total soluble solids, the parameters of color, texture, antioxidant activity and total phenol, polyphenol oxidase activitiy and sensory tests, a combined design was used. Regarding maximum storage time and quality attributies, optimal composition of edible coatings obtained as follows: 2.188 % w/v alginate, 0 % w/v Aloe vera and 1.812 % w/v zedo gum. Optimal composition for storage time in the range of 90-120 days determined as follows: 0 % w/v alginate, 1 % w/v Aloe vera and 3 % w/v zedo gum. Generally, the optimization of edible coating revealed the ability of aloe vera gel and zedo gum to preservation quality characteristics of semi humid fig fruits.