The Characteristics of Fruits Morphology, Chemical Composition and Colour Changes in Must During Maceration of Three Grapevine Cultivars

The study compares morphology of clusters and fruits, the chemical composition and changes of pulp in the process of maceration of grape cultivars ‘Mavrud’, ‘Pinot Noir’ and ‘Merlot’. The cultivar ‘Mavrud’ had biggest clusters and fruits. Its fruits were less firm but had the highest acidity while the fruits of the ‘Pinot Noir’ had the highest content of soluble solids and dry matter and the greatest firmness but the lowest acidity and content of nitrites and nitrates. The fruits of the ‘Merlot’ cultivar had the highest content of L-ascorbic acid, nitrites and nitrates. The pulp colour was largely affected by the maceration temperature. During a warm maceration, the process of pulp darkening accelerated and the red colour saturation increased, whereas cold maceration resulted in the blue colour saturation.