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

The objective of this study was to analyze the effect of freezing and different culinary treatments (stir-fried and steamed) on the nutritional composition, bioactive compounds, and sensorial characteristics of zucchini. The zucchini was stir-fried for 8 min at 250oC and steamed for 13 min at 100oC. The freezing of raw zucchini did not significantly affect its nutritional compounds. The stir-frying process provoked important moisture loss; this being higher when zucchini was 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 were also observed in frozen zucchini after steamed and stir-fried, these changes were 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 affected the sensorial values less and only better were observed in fresh steamed zucchini than the stir-fried.