Influence of Osmotic Treatment in the Drying of Sultanina Grapes (Vitis vinifera L.)

N. PENOV1, V. ROYTCHEV2 and Ch. CHRISTOV1
1 University of Food Technologies, BG - 4000 Plovdiv, Bulgaria
2 Agricultural University, BG - 4000 Plovdiv, Bulgaria

Abstract

PENOV, N., V. ROYTCHEV and Ch. CHRISTOV, 2009. Influence of osmotic treatment in the drying of Sultanina grapes (Vitis vinifera L.). Bulg. J. Agric. Sci., 15: 386-392

The possibility for convection drying of grapes from the seedless cultivar Sultanina by applying a preliminary osmotic treatment, and the process kinetics has been investigated. By means of a complete factorial experiment of the type 22 regression models of the velocity coefficient of sugar solution concentration gradient in the osmotic treatment and a velocity coefficient model for the drying process in convection drying of the treated grapes have been derived. The influence of sugar solution concentration and its temperature on the kinetics of the studied processes has been determined. A taste evaluation of the different variants has been carried out. The dendrogram showing taste evaluation ranks for dried raisins is divided into two major clusters. Appropriate parameters for grapes treatment have been suggested.

Key words: osmotic treatment of grapes, seedless vine cultivar Sultanina, concentration and temperature of sugar solution, kinetics

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