Moreover, fruits and vegetables are good sources of natural antioxidants for the human diet, containing many different antioxidant components which provide protection against harmful free radicals and have been strongly
associated with reduced risk of chronic diseases. These antioxidants include carotenoids, vitamins, flavonoids, other phenolic compounds, dietary glutathione and endogenous metabolites [82]. It is common that many vegetables are cooked by boiling and microwave process before use or industrial process (blanching, canning, ster- ilization or freezing). These cooking processes or industrial processes would certainly bring about a number of changes in physical characteristics and chemical composition of vegetables [138] affecting the content, composition, anti- oxidant activity and bioavailability of antioxidants.