The study objective was to determine the effect of topping cut of winter squash (Cucurbita moscata) plants on the biological value of the fruit. The experiment included two cultivars; the Italian cultivar ‘Waltham’ and Bulgarian ‘Muscatna’. Moreover, biological value of fruit depending on the order of their growth on the plant (1, 2 and 3 fruit) has been compared. In fresh fruit, dry weight and content of: L-ascorbic acid, chlorophyll pigments (a, b and total chlorophyll), total carotenoids, total polyphenols, and antioxidative activity expressed as percentage of DPPH radical reduction and total acidity have been determined. Among the studied winter squash cultivars, the fruit of the ‘Waltham’ cultivar was characterized by higher biological value compared to the cultivar ‘Muscatna’.
The performed plant cutting procedure behind the third formed fruit had a significant effect on the increase of biological value of yield. Fruit appearing at the earliest date on plants were characterized by higher dry weight and higher total carotenoid, chlorophyll a and total chlorophyll content. Fruit forming as second on plants contained more chlorophyll b, total polyphenols and had higher DPPH activity, while fruit appearing as third contained significantly higher L-ascorbic acid and had higher total acidity.