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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Functional Foods Research » Research » Publications at this Location » Publication #348613

Research Project: Improving Quality, Stability, and Functionality of Oils and Bioactive Lipids

Location: Functional Foods Research

Title: Factors affecting antioxidant activity of amino acids for frying

item Hwang, Hong-Sik
item Moser, Jill
item GADGIL, MAYURESH - Bradley University
item Liu, Sean

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/15/2018
Publication Date: 7/18/2018
Citation: Hwang, H., Moser, J.K., Gadgil, M., Liu, S.X. 2018. Factors affecting antioxidant activity of amino acids for frying [abstract]. Institute of Food Technologists.

Interpretive Summary:

Technical Abstract: Synthetic antioxidants such as TBHQ and BHT are very effective antioxidants for frying and they have been widely used in the food industry and local restaurants. However, due to the concern about potential toxicity of these antioxidants and consumer preference for cleaner labels, natural antioxidant systems have been the focus for the development of new antioxidant systems for foods. Recently, our research group found that amino acids were very strong natural antioxidants for frying. For example, amino acids including arginine, cysteine, lysine, methionine, and tryptophan at the concentration of 5.5 mM showed much stronger antioxidant activity than 200 ppm (1.1 mM) TBHQ during heating at 180 °C. In this study, a variety of factors affecting the antioxidant activity of amino acids were investigated for the practical application of these natural antioxidants. First, we examined the effect of alkyl chain length on the activity by comparing antioxidant activities of alanine (C3), 2-aminobutyric acid (C4), norleucine (C6), 2-aminocaprylic acid (C8), and 2-aminohexadecanoic acid (C8). The result showed that 2-aminobutyric acid (C4) was the strongest antioxidant. This result indicates that the longer alkyl chain, which may give better solubility in oil, does not necessarily give better activity. We also examined the effect of the amino group in an amino acid by comparing the antioxidant activities of 3-(dimethylamino)propionic acid with that of beta-alanine. Converting the amino group to the dimethylamino group slightly improved the antioxidant activity. This result indicates that the well-known reaction between the amino group and oxidation products is not the only reason for the antioxidant activity of amino acids since the dimethylamino group cannot react with oxidation products. Effects of tocopherol levels in frying oil containing an amino acid and antioxidant activities of dipeptides and protein hydrolysates will also be discussed.