EFFECT OF EDIBLE PROTEIN-WAX COATING ON STORAGE QUALITY OF TABLE GRAPES (VITIS VINIFERA L.)

The table grapes (Vitis vinifera) arc highly valued dessert fruits, but their attractiveness can get worse if they arc not properly protected while being distributed and sold. Presently, researches have been carried out to find new methods for increasing the life-shelf of fruits and maintaining their high quality while they are on the market. Edible coatings could be a potential solution to that problem. The objective of this study was to determine the possibilities of using protein-wax coating to protect the quality of grapes. Grape fruits were coated while they were three times immersed in an aqueous solution containing: 10 % of pea protein isolate, 5 % of sorbitol (plasticizer), and 2 % of candelilla wax. The coated and uncoated (control) grapes were stored at 20 degrees C, under 40 % relative air humidity, during a period of 11 days. The study showed that, comparing to the uncoated grapes, the coated grapes stored for 11 days had a statistically significant higher content of ascorbic acid and reducing sugars, and lower weight losses, which caused the freshness of the fruits to be kept longer. The coating did not cause any changes in the titration acidity and pH of the grapes. The additional benefit of coating was an attractive sheen of the fruit surface.