Peanut skin phenolics obtained by green solvent extraction: characterization and antioxidant activity in pure chia oil and chia oil in water ( O/W ) emulsion

BODOIRA, ROMINA; MARTÍNEZ, MARCELA; VELEZ, ALEXIS; CITTADINI, MARIA C; RIBOTTA, PABLO; MAESTRI, DAMIÁN

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE

JOHN WILEY & SONS LTD

Lugar: Londres; Año: 2022 vol. 102 p. 2396 - 2403

0022-5142

BACKGROUND: The peanut skin (PS) is considered an industrial waste with undervalued applications. Although several studies report potent antioxidant capacities of PS phenolics, the effectiveness in highly unsaturated lipid systems has not yet been evaluated. The objectives of the present study were to twofold: a) to characterize a PS phenolic extract (PSE) obtained by means of a green technology, and b) to evaluate its antioxidant efficacy on pure chia oil, and chia oil in water (O/W) acid emulsion. RESULTS: The PSE was composed mainly of monomeric and condensed flavonoids (procyanidin and proanthocyanidin oligomers). The PSE displayed strong antioxidant properties as measured by different reducing power and radical scavenging capacities (IC50 = 0.36 µg dry extract (DE) mL-1 for FRAP; IC50 = 4.96 µg DE mL-1 for DPPH; IC50= 6.01 µg DE mL-1 for ABTS; IC50= 2.62 µg DE mL-1 for HO). It also showed high antioxidant efficacy when tested in pure chia oil under accelerated oxidation conditions (Rancimat, 100°C). When added to the O/W emulsions maintained at 40 °C for 15 days, the PSE was more effective than a synthetic antioxidant (Tert-butylhydroquinone) to minimize formation and degradation of lipid hydroperoxides.CONCLUSIONS: The antioxidant efficacy of PSE was primarily attributed to the abundance of compounds with high number of phenolic-OH groups. Since they were found to cover a relatively wide range of partition coefficients, the antioxidant properties could be also enhanced by effect of both interfacial and solubility phenomena. All these features allow inferring uses of PSE as natural antioxidant in different types of foods, including acid emulsion systems.