Articles
CHEMICAL ANALYSIS OF MUST FROM DROPPING AND NON-DROPPING, GRAFTED AND SELF-ROOTED GRAPEVINES CV DOLCETTO
The disorder causes dropping of immature berries, lowering thus the production, and affects quality of non-dropped berries, reducing the soluble solids accumulation.
Non-dropping plants were obtained by
radiation treatment and planted in Vicoforte (CN), a location where cv Dolcetto is traditionally grown although early dropping occurs every year.In 1992, berry samples were collected at ripening from vineyards located in Vicoforte, from dropping and non-dropping plants self-rooted and grafted on Kober 5BB; the must was analyzed for organic acids, sugars, N, P, K, Ca, Mg, and Na content.
Analysis of sugars and organic acids was performed by capillary gaschromatography after derivatization of the samples by BSTFA + TMCS (99:1), while cations were analyzed by atomic absorption spectrophotometry.
The dropping plants showed the lowest sugar content that was around 157 g/l, while titratable acidity was about 7 g/l expressed as tartaric acid, about 1 g/l higher than in non-dropping ones.
The nitrogen and magnesium level was lower in dropping Dolcetto, while Ca was higher.
Self-rooted grapevines showed higher sugar accumulation and lower malate content, indicating earlier ripening than grafted ones.
Dropping habit resulted in lower sugar content and in incomplete ripening that influences wine quality.