Paper Title
Use of Sodium Metabisulfate to Improve Storability of two Georgian Grapes Cultivars “Rkatsiteli” and “Tbilisuri”

Abstract
Grapes are one of the most unstable crops in terms of storage, which is related to its botanical-morphological structure. The aim of our work was to study effect of sodium metabisulfite (SMB) on the most popular Georgina grapevine cultivars “Rkatsiteli” and “Tbilisuri” during Storage. p7 7 kg packed grapes into carton boxes were treated with tree concentration (15g; 25g; 35g) of SMB under cold storage at 0-10C, humidity 90-95% for 120 days to improve storability of grapes varieties: Control-7kg- no treated grape. Monitoring of weight loss, dry matter concentration (DMC) sugars and acidity were conducted at the beginning of storage, in the middle (60 days) and at the end of storage (120days). Sugar were measured by Bertrand’s method, dry mass using refractometer, 0.1 N NaOH was used to titrate acidity (g/100ml) to a phenolphthalein end point or, alternatively, to a pH of 8.2. 25g SMB treatments provided the best result to compare others, with weight loss of 6.7% in cultivar “Tbilisuri,” and 8.3% in cultivar “Rkatsiteli,”while weight reduction in control reached 9.8% at the end of storage. The effect of 15g and 25g SMB was the same on changing the amount of sugars both in the “Tbilisuri” -0/7% (20.8%-20.1%) as in the “Rkatsiteli” -1.2% (20.3%-19.1%). Significant reductions were observed in acidity at the end of storage using all concentration of SMB. Decrease of acidity was the equally in both grapevine cultivars-2.2% („Tbilisuri“ -5.6%-3.4%; „Rkatsiteli“ - 4, 8%-2,6 %)however it is fully suitable with the amount of sugar, flavor and pulp consistency. Experimental research allows us to conclude that for long-term storage most effective is to use 25 g SMB tablets per 7 kg of grapes. In addition, no grain loss was observed compared to the other variants, which is one of the most important point in the long-term storage of grapes. Keywords - Grapevine, Cultivars, Storage, Sodium Metabisulfite