Study on Antioxidant Activity of Amino Acids at Frying Temperatures and Their Interaction with Rosemary Extract, Green Tea Extract, and Ascorbic Acid

Abstract

Some amino acids have strong antioxidant activity in frying oil. This study aimed to obtain further information including antioxidant activity at different concentrations and interactions with rosemary extract, green tea extract, and ascorbic acid. Antioxidant activity of arginine, cysteine, lysine, methionine, and tryptophan was examined by increasing the concentration in soybean oil (SBO) at 180°C within the concentration range of 0 to 15 mM. These amino acids showed increased activity with increasing concentration without showing prooxidant activity at the given concentration range. Addition of 15 mM methionine did not inhibit the prooxidant activity of α-tocopherol at high concentrations in SBO while it significantly increased the activity at each concentration of α-tocopherol. Methionine showed an additive effect with a commercial rosemary extract while lysine had an antagonistic interaction in SBO at the total concentration of 5.5 mM. Mixtures of green tea extract and methionine did not show better activity than methionine alone in SBO and stripped SBO. (-)-Epigallocatechin gallate, the major active component in green tea, showed a synergistic effect with methionine in stripped SBO but there was no significant interaction effect in SBO. Although ascorbic acid had a synergistic effect with methionine in stripped SBO, it showed a significant antagonistic effect in SBO. Methionine had strong antioxidant activity in six other vegetable oils showing a moderate correlation (R 2 = 0.45 to 0.52) with the ratio of unsaturated fatty acids to saturated fatty acids indicating the effectiveness may be related to the fatty acid composition of oil.Practical Application: Some amino acid such as methionine and lysine showed stronger antioxidant activity than the leading commercial natural antioxidant, rosemary extract. These amino acids showed great potential as a natural antioxidant in frying. The price of food-grade L-methionine is generally lower than rosemary extract and green tea extract. This paper provides information on the concentration effect and interactions with currently used antioxidants such as tocopherols, rosemary extract, green tea extract, and ascorbic acid.

Metabolomics Combined with Transcriptomics Analysis Revealed the Amino Acids, Phenolic Acids, and Flavonol Derivatives Biosynthesis Network in Developing Rosa roxburghii Fruit

“…Glutamic acid and histidine decreased the generation of the hydroxyl radicals [ 52 ]. Hwang et al demonstrated a strong antioxidant activity of methionine and lysine [ 53 ]. The results of Tian et al showed that the electronic and hydrogen-bonding properties of the amino acids in the tripeptide sequences, and the steric properties of the amino acid residues at the C- and N-termini, play a major role in the antioxidant activities of the tripeptides.…”

Effect of Rosemary (Rosmarinus officinalis L.) Supplementation on Probiotic Yoghurt: Physicochemical Properties, Microbial Content, and Sensory Attributes

“…The rosemary samples extracted at 60 • C were prepared as per the method of Hwang et al [23]. Each of the defatted samples (200 mg) were weighed into a glass ampoule and 5 mL of 6N HCl was added.…”

Multivariate Analysis of Amino Acids and Health Beneficial Properties of Cantaloupe Varieties Grown in Six Locations in the United States

“…Amino acids have also been shown to produce a synergistic effect with tocopherol which improves antioxidant activity [ 76 ]. Synergistic effects of methionine with epigallocatechin gallate (EGCG) and ascorbic acid have also been reported [ 77 ]. GABA can act as signaling molecules and exhibits reactive oxygen species (ROS) scavenging activity [ 78 ].…”