Nutritional and sensorial characteristics of zucchini (Cucurbita pepo L.) as affected by freezing and the culinary treatment

Abstract

The objective of this study was to analyse the effect of freezing and different culinary treatments (stir-fried and steamed) on the nutritional composition, bioactive compounds and the sensorial characteristics of zucchini. The zucchini was stir-fried for 8 minutes at 250ºC and steamed for 13 minutes at 100ºC. The freezing of raw zucchini does not significantly affect its nutritional compounds. The stir-frying process provoked important moisture loss; this being higher is zucchini that were previously frozen. The content of ash, proteins and fats, significantly increased in stir-fried zucchini. There was an important decrease in antioxidant activity and phenolic compounds when the zucchini was frozen. The antioxidant activity was much greater in the stir-fried produce in comparison to steamed and raw. Freezing the raw zucchini provoked a significant loss in its adhesiveness qualities and hardness. A lower hardness and adhesiveness was also observed in frozen zucchini after steamed and stir-fried, with these changes not being observed in freezing. The sensorial characteristics of previously frozen zucchini were valued less by the consumer as well as those that were steamed and stir-fried. The culinary treatment had less influence its sensorial values, only better valuations were observed in fresh steamed zucchini than the stir-fried.