Ermolina G. The Influence of the Freezing and Defrostation Processes on the Maintenance of the Fruit Quality of Table Grape Varieties

The tendency of the fruit of table grape varieties to change its commercial quality during freezing and defrostation has been established and scientifically substantiated based on the interrelationship of the tasting evaluation and the physico-chemical and microbiological indices. Recommendations concerning the effective and differentiated use of the fruit of grape varieties depending on their biological peculiarities have been provided as arising from the histological studies, the changes of the physical characteristics of the fruit and the freezing methods: the fruit of cvs Yubilei Zhuravlia, Moldova and Odesskii Suvenir should be frozen in the air medium at -35oC and subsequently stored at -20± 2 oC for seven months, the fruit of cv Italy - for more than three months, and the fruit of cvs Ajgezard, Kantemirovskii and Kutuzovskii should be frozen in the aqueous medium (20% sugar syrup) at -24oC and subsequently stored at -20o ± 2oC for seven months. The changing pattern and the intensity of changes with refer to the commercial quality of the fruit of grape table varieties have been established by investigating the interrelationship of the tasting evaluation and the physico-chemical indices of the fruit. A system of the quality criterion parameters (liability to berry splitting, water loss and evaluation of the taste) has been suggested. The parameters are simple in use, without the need for any special skills of the personnel, and have enabled the development of a rapid method to evaluate table grape varieties for storage suitability. The experiment data obtained has become part of the process message for the production of frozen grapes. The process has been implemented under industrial conditions at the Yalta refrigeration enterprise in 2006-2007, the economical effectiveness after seven months of storage being 1598 hrn/per-1729 hrn/per.