Effect of home cooking on the antioxidant capacity of vegetables: Relationship with Maillard reaction indicators

Vegetables are health-promoting foods due to their content on a wide range of phytochemicals, being involved in antioxidant protection. However, such bioactivity can be modified during cooking and also along the digestion-fermentation process. Thus, the aim of the paper is to establish a relation among the type of processing (raw, boiled, steamed, grilled, roasted, and fried), time of processing (raw, usual time and well-done), antioxidant capacity and the development of the Maillard reaction (measured though the analysis of furosine and HMF) of 23 widely consumed vegetables. Antioxidant capacity was measured with three methods (TEAC(ABTS), TEAC(FRAP), TEAC(OH)) after submitting vegetables to an in vitro digestion followed by and in vitro fermentation process. Furosine and HMF were useful indicators to control both cooking time and heat intensity of common vegetables, being correlated with antioxidant capacity. Those samples cooked with aggressive techniques (frying, grilling or breading) showed the higher antioxidant values.