Influence of Treatment and Cooking Time on the Antioxidant Capacity of Different Vegetables Used in Atlantic and Mediterranean Diets

Resumo

Evidence from epidemiological studies has strongly suggested that diets rich in fruits and vegetables play a vital role in disease prevention. The aim of this study was to determine total phenolic content (TPC) and reducing power (RP) for nine vegetables that are normally consumed in Atlantic and Mediterranean diets. In this study vegetables were analyzed when fresh, and then again after heat processes (cooking in boiling water and steam) were applied for different lengths of time. The vegetable showing highest total phenolic content was the Brussels sprout; while zucchini had the lowest content. Green beans presented the highest reducing power, while peppers and cauliflower presented the lowest values. Heat treatment significantly reduced the concentration of total phenolic content and reducing power in all of tested vegetables; however, steam cooking resulted in lower losses. The loss of the total phenolic content and reducing power were higher when heat processes were applied for longer amounts of time. From a nutritional standpoint, it is advisable to use the least aggressive method (steaming) for as short a time as possible