Proteins and Peptides as Antioxidants

Abstract

In recent years, the role of protein in the diet has been acknowledged worldwide. Dietary proteins become a source of physiologically active components, which have a positive impact on the body’s function after gastrointestinal digestion. Bioactive peptides are inactive in the sequences of their parent protein, but can be produced by one of three methods such as chemical hydrolysis, enzymatic hydrolysis, and microbial fermentation of food proteins (Lahl and Braun, 1994). However, especially in the food and pharmaceutical industries the enzymatic hydrolysis method is preferred in order to avoid the residual toxic chemicals in the products. The physicochemical conditions of the reaction media such as temperature and pH of the protein solution must then be adjusted in order to optimize the activity of the enzyme used. Proteolytic enzymes from microbes, plants, and animals can be used for the hydrolysis process of proteins to develop bioactive peptides (Simpson, 1998). Bioactive peptides usually contain 3-20 amino acid residues, and their activities are based on their amino acid composition and sequenceCONTENTS4.1 Introduction .................................................................................................. 97 4.2 Antioxidant Food Proteins and Peptides ................................................. 984.2.1 Animal-Derived Antioxidative Proteins and Peptides ..............99 4.2.2 Plant-Derived Antioxidative Proteins and Peptides ................. 100 4.2.3 Marine-Derived Antioxidative Peptides .................................... 1004.3 Methods for Evaluation of Antioxidant Activity .................................. 102 4.3.1 Reaction Mechanisms of Antioxidants ....................................... 102 4.3.2 Characteristics of Candidate Antioxidant Activity Methods .. 1034.4 Peptide Fractions with Stronger Antioxidants by Autofocusing ........ 105 4.5 Conclusion .................................................................................................. 106 References ............................................................................................................. 109(Pihlanto-Leppala, 2001). Furthermore, some of these bioactive peptides may have greater potential for human health promotion and disease risk reduction (Shahidi and Zhong, 2008). Thus, the possible role of food-derived bioactive peptides in reducing the risk of cardiovascular disease has been well demonstrated (Erdmann, Cheung, and Schroder, 2008).