Effect of some edible coating films on grapes quality properties during storage

Abstract

Flame seedless grapes (Vitis vinifera) were coated with four type of edible films , the first with 1% chitosan ( T1), the second 2% calcium chloride ( T2 ), the third 1% chitosan, 2% calcium chloride ( T3 ), and the last mixture of 1% chitosan, 2% calcium chloride, 0.2 citric acid, 0.1% ascorbic acids ( T4 ). The samples treated with the edible stored at room temperature (28 ºC ±3) for 12 days or at cool temperature (4 ºC ±1) for 90 days. Shelf-life qualitative weight loss, total soluble solids (Tss), firmness, titratable acidity, sensory evaluation and microbiological analysis were tested. Significant reduction in weight loss was detected in treated samples compared to control untreated ( T0 ). The treatment T2 was better, the weight loss was 4.6% after 12 day of storage either treatments T4 , T3 , T1when compared to control ( T0 ) was 7.8 % after 4 day of storage. Also, at the cooling temperature treatment T2 was less in weight loss it was 4.4% after 90 days compared to control that was 4.7% after 15 days of storage. the better sensory acceptance and acidity retention were detected for the treated samples along the storage period. However, total soluble solids (TSS) varied from ( 20.1 to 25.23% ) at room temperature and ( 20.2 to 21.83%) at cooling temperature. Fruit firmness were increased where the treatment ( T2 ) was 225 (gm/cm2) compared to the treatment ( T1 ) that was 208 (gm/cm2) at the room temperature (28ºC ±3). The treatment ( T2 ) was 209 (gm/cm2)as for the treatment ( T1) was 199 (gm/cm2) in the cooling temperature. Also microbiological analysis increases with storage time. Total plate count , Psychrophilic bacterial count and molds and yeasts count .Calcium chloride coating ( T2 ) showed best results comparing to those obtained for Chitosan treatments ( T1 ). Coating grapes with chitosan ( T1 ) or calcium chloride ( T2 ) displayed greater external adequacy than untreated ones.