Effect of the pH on the lipid oxidation and polyphenols of soybean oil-in-water emulsion with added peppermint (Mentha piperita) extract in the presence and absence of iron

• Published in: Food science and biotechnology Vol. 27; no. 5; pp. 1285 - 1292
• Main Authors: Kim, Jihee, Choe, Eunok
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 01.10.2018; Springer Nature B.V; 한국식품과학회
• Subjects: bottles; buffers; Caffeic acid; Catechin; Chelation; Chemistry; Chemistry and Materials Science; Citric acid; Deceleration; Emulsions; ferrous sulfate; Food irradiation; Food Science; free radical scavengers; Iron; Iron sulfates; Lipid peroxidation; Lipids; luteolin; Mentha piperita; Mentha piperita nothosubsp. piperita; Nutrition; Oils & fats; Oxidation; Peppermint; pH effects; Polyphenols; Rosmarinic acid; Scavenging; Soybean oil; Soybeans; 식품과학; Emulsion lipid; pH; Polyphenol; Iron; Peppermint extract
• ISSN: 1226-7708; 2092-6456; 2092-6456
• DOI: 10.1007/s10068-018-0324-2

This study evaluated the pH effect on the lipid oxidation and polyphenols of the emulsions consisting of soybean oil, citric acid buffer (pH 2.6, 4.0, or 6.0), and peppermint ( Mentha piperita ) extract (400 mg/kg), with/without FeSO 4 . The emulsions in tightly-sealed bottles were placed at 25 °C in the dark, and lipid oxidation and polyphenol contents and composition were determined. The lipid oxidation was high in the emulsions at pH 4.0 in the absence of iron, however, iron addition made them more stable than the emulsions at pH 2.6 or 6.0. Total polyphenols were remained at the lowest content during oxidation in the emulsions at pH 4.0, and iron reduced and decelerated polyphenol degradation. The results strongly suggest that polyphenols contributed to decreased lipid oxidation of the emulsion via radical scavenging and iron-chelation, and rosmarinic acid along with catechin, caffeic acid, and luteolin were key polyphenols as radical scavengers in the extract.