Optimization of supercritical fluid extraction of polyphenols from oats (Avena sativa L.) and their antioxidant activities
2018
Escobedo-Flores, Yessica | Chavez-Flores, David | Salmeron, Ivan | Molina-Guerrero, Carlos | Perez-Vega, Samuel
This research explores the effects of pressure and temperature on the supercritical extraction of polyphenols, antioxidant capacity, and total polyphenolic content from oats. Ethanol (80% v/v) was used as co-solvent, and experiments were controlled by response surface methodology (RSM). For polyphenols with C6-C1 structures (vanillin and vanillic acid), a maximum yield of 18.2 μg/g oats was obtained. Polyphenols with C6-C3 structures (caffeic, sinapic, coumaric, and ferulic acids) gave up to 1389 μg/g oats; where coumaric and ferulic acids were found in higher quantities. Avenanthramides (AVNs) yielded up to 34.52 μg/g oats, with 2p and 2c being found in higher quantities than 2f. The polyphenols, TPC (1.25 mg GAE/g of oats), and ORAC (117.88 μmol TE/g of oats) gave the highest yields at 38 MPa and 55 °C. Quadratic models adjusted very well, and a maximum polyphenol content of 1437.57 μg/g was predicted. Moreover, correlations among the polyphenols and antioxidant capacity were found, especially with the ORAC. As a result, the method here presented can be a new procedure for the extraction of polyphenols from oats.
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