Antioxidant activity of minimally processed (in modified atmospheres), dehydrated and ready-to-eat vegetables

Abstract

The antioxidant activity of vegetables subjected to minimal processing (in MAP, and intended for cooking or for use in salads), dehydrated condiments and ready-to-eat vegetables such as soups and purees, was assessed by reference to their ability to scavenge lipoperoxyl and hydroxyl radicals and Trolox-equivalent antioxidant capacity. In the case, the MAP vegetables the measurements were repeated during eight days of storage in a domestic refrigerator and after cooking (boiling, microwaving, pressure cooking, griddling, frying and baking). MAP vegetables had a good or very good antioxidant capacity, and showed no significant loss of antioxidant activity or scavenging capacity compared with fresh vegetables. The cooking treatments that keep the antioxidant activity of MAP vegetables are microwaving, sautéing and baking. The most aggressive method of cooking were steaming, boiling and frying. The dehydrated condiments (tablets) showed higher antioxidant activity than the ready-to-eat soup. The enrichment of stews and casseroles, with dehydrated vegetable tablets, and the consumption of soup or vegetable purees represent an increased antioxidant intake in our diet. Also ‘‘ready-to-eat” vegetable soups show antioxidant activity after they have been submitted to heat treatment to increase their shelf-life. They can be recommended as alternatives in our non-stop ‘‘life style”.