Comparison of Important Quality Characteristics of Some Fungal Disease Resistance/Tolerance Grapes Dried with Energy-Saving Heat Pump Dryer

Abstract

Raisins have been widely consumed for many years all around the world, and different grape cultivars and drying techniques are used in their production. Recently, mechanical drying systems have been used to overcome any undesirable effects that arise from sun-drying with grape cultivars that require fewer pesticides to minimize the risk of residues. Both seeded and seedless cultivars were preferred for drying in the past; however, seedless grape cultivars have been increasingly preferred for drying purposes in addition to their use as table grapes. For the first time, an alternative processing method (using an energy-saving heat pump dryer) and important quality characteristics (total phenolics, antioxidant activity, brix, colour analyses and sensory evaluation) of disease resistant/tolerant grape cultivars of different species that can be grown in humid regions were investigated in this study. First, the fresh fruits of nine different grape (Vitis spp.) cultivars grown in a humid ecology were analysed, and then so too were the important phytochemical and quality characteristics of raisins dried with an energy-saving heat pump dryer. The water activity of the raisins ranged from 0.71 (Özer Beyazı) to 0.42 (Kay Gray). The total phenolic contents of Muscat Bleu (65.96), Philipp (64.88) and Campbell Early (64.53 g GAE/100 g db) berries were the highest (p p p p p < 0.05). The results indicated that the raisins of the seedless Rhea and Kishmish Vatkana cultivars can be appreciated more than those of the other cultivars, both in terms of their bioactive content and sensory scores, and the raisins of these cultivars, which can be grown in humid regions, hold a great deal of potential for grape growers.

Keywords

• phenolics
• grapes
• <i>Vitis</i>
• antioxidant activity
• sensory analyses