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, M. CECILIA; RIBOTTA, PABLO; MAESTRI, DAMIÁN

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE

JOHN WILEY & SONS LTD

Año: 2021

0022-5142

BACKGROUND: The peanutskin (PS) is considered an industrial waste with undervalued applications. Althoughseveral studies report potent antioxidant capacities of PS phenolics, the effectivenessin 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 greentechnology, 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 ofmonomeric and condensed flavonoids (procyanidin and proanthocyanidin oligomers).The PSE displayed strong antioxidant properties as measured by differentreducing power and radical scavenging capacities (IC50 = 0.36 µg dry extract (DE) mL-1 forFRAP; 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 oilunder accelerated oxidation conditions (Rancimat, 100°C). When added to the O/W emulsions maintained at 40 °C for 15days, the PSE was more effective than a synthetic antioxidant (Tert-butylhydroquinone) to minimizeformation and degradation of lipid hydroperoxides.CONCLUSIONS: The antioxidant efficacy of PSE was primarilyattributed to the abundance of compounds with high number of phenolic-OHgroups. Since they were found to cover a relatively wide range of partitioncoefficients, the antioxidant properties could be also enhanced by effect ofboth interfacial and solubility phenomena. All these features allow inferringuses of PSE as natural antioxidant in different types of foods, including acidemulsion systems.