Extraction Technology Can Impose Influences on Peanut Oil Functional Quality: A Study to Investigate the Lipid Metabolism by Sprague-Dawley Rat Model.

Abstract

In this study, peanut oil was prepared by cold pressing (temperature under 60 °C), hot pressing (temperature above 105 °C), and enzyme-assisted aqueous extraction technology. Influences of an extraction technology on the oil fatty acid composition and the content of minor bioactive compounds, including tocopherols, polyphenols, and squalene, were investigated in detail. High-fat-diet Sprague-Dawley (SD) rat model was then established to probe the impact of cold-pressed peanut oil (CPO), hot-pressed peanut oil (HPO), and enzyme-assisted aqueous-extracted peanut oil (EAO) on lipid metabolism outcomes, to explore influences of different extraction technologies on lipid functional quality. Results showed that oleic acid was the predominate fatty acid in the EAO (52.57 ± 0.11%), which was also significantly higher (P < 0.05) than CPO and HPO. The HPO showed higher total tocopherol and polyphenol contents (206.84 ± 6.93 mg/kg and 47.87 ± 6.50 mg GA/kg, respectively) than CPO and EAO (P < 0.05). However, the squalene content in CPO was 475.47 ± 12.75 mg/kg, which was the highest among the three oils (P < 0.05). The animal experiment results revealed that EAO could be more prone to induce lipid accumulation in the liver, which may likely to cause nonalcoholic fatty liver disease. However, the serum lipid profiles indicated that the CPO was more beneficial than the EAO and HPO in lowering the serum low-density lipoprotein cholesterol, alanine aminotransferase, and aspartate aminotransferase contents, and increasing the high-density lipoprotein cholesterol content. All of our efforts indicated that an extraction technology can affect the peanut oil lipid fatty acid composition, the bioactive compounds content, and, correspondingly, the lipid metabolism in SD rats.