Résumé:
This study aims to evaluate the total polyphenol content and antioxidant activity of four species of vegetables: potato, carrot, cabbage and spinach, and to highlight the impact of storage time at ambient temperature and duration of storage, combined with two cooking modes: one in the steam and the other in the water, on the total polyphenol content and antioxidant activity of vegetables.
The determination of the moisture content of the four vegetable species revealed high levels in the freshest samples and / or after cooking.
The extraction of total polyphenols was carried out using a polar solvent, and quantification was based on the Folin Ciocalteu reaction, the total polyphenol content was 26.17±0.44 mg EAG/100g for potato, 13.80±0.48 mg EAG/100g for carrot, 86.10±0.44 mg EAG/100g for cabbage and 28.30±0.58 mg EAG/100g for spinach. The antioxidant test was performed by the DPPH method, the percentage of the antioxidant activity of vegetables was 18.55±1.30% for potato, 13.33±1.03% for carrots, 39.27±0.98% for cabbage and 21.54 ± 0.97% for spinach.
The main results show that the storage has a positive impact in the case of carrots and a negative impact in the case of cabbage, spinach and potatoes. The heat treatment appears to have a positive impact on the total polyphenols content in the case of cooking by steam and a negative impact in the case of cooking in boiling water for carrot, cabbage and spinach. However, it has a positive impact in both cooking modes for potato. Concerning the antioxidant activity, the heat treatment appears to have a positive impact in the case of cooking by steam and a negative impact in the case of cooking in boiling water for cabbage and spinach. However, it has a positive impact in both modes of cooking of potato and a negative impact in the two cooking
modes of carrot.
