Formulation optimization of methylcellulose coating and Zataria multiflora Bioss extract to improvement the shelf life of table grape

In this paper¡ the simultaneous effect of coating with methylcellulose and Zataria multiflora Boiss extract on the quality of grapes has been studied. The methylcellulose was used in 0.1¡ 0.3¡ and 0.5 g and Zataria multiflora Boiss extract was used in 0¡ 125¡ and 250 µL. Glycerol was used in preparing coatings with the percentage of 25¡ 45¡ and 65 in proportion to the amount of methylcellulose used as plasticizer. After preparation of the different treatments with the aforementioned densities¡ the coating of grapes was started with the dipping method. Treatments were done in 6± 1 degrees centigrade and 70% relative humidity. The grapes were examined every 5 days for 21 days. The examinations included the evaluation of weight loss percentage¡ TSS¡ TA¡ Hardness¡ color¡ and appearance. After statistical analysis of the findings by response surface methodology (RSM)¡ a decrease in weight loss of the fruit was seen. Fruit firmness and color has not changed during this period. The coating formulations in this study had low effect on TSS and no effect on TA. The results for optimized quantities of coating formulation to achieve the best responses¡ 0.1 g methylcellulose¡ 499.99 microliters extract and 0.1 ml glycerol¡ respectively. From the results¡ it was concluded that the use of this edible coating leads to increased grape shelf life.