Natural antioxidants from residual sources

The growing interest in the substitution of synthetic food antioxidants by natural ones has fostered research on vegetable sources and the screening o f raw materials for identifying new antioxidants. Oxidation reactions are n ot an exclusive concern for the food industry, and antioxidants are widely needed to prevent deterioration of other oxidisable goods, such as cosmetic s, pharmaceuticals and plastics. Polyphenols are the major plant compounds with antioxidant activity, although they are not the only ones, In addition , other biological properties such as anticarcinogenicity, antimutagenicity , antiallergenicity and antiaging activity have been reported for natural a nd synthetic antioxidants. Special attention is focussed on their extractio n from inexpensive or residual sources from agricultural industries. The ai m of this review, after presenting general aspects about natural antioxidan ts, is to focus on the extraction of antioxidant compounds (mainly polyphen ols) from agricultural and industrial wastes, as well as to summarize avail able data on the factors affecting their antioxidant activity and stability , and, in some cases, the reported major active compounds identified. (C) 2 001 Elsevier Science Ltd. All rights reserved.