| Abstrakt: |
Lipid oxidation causes the shelf-life reduction of many food products. With the aim of reducing toxic oxidative molecules, the use of plant phenolics is an interesting strategy. However, for food safety reasons, it is more appropriate to apply aqueous extracts than organic extracts. In the literature, polyphenol-rich potato peel aqueous extracts have never shown effectiveness for dietary oil stability. Therefore, we decided to compare the ability of water extract (WE) and methanol extract (ME) of potato peels from a somatic hybrid called CN1 (originated from protoplast fusion between dihaploid Cardinal and Nicola potato clones) to protect sunflower oil from oxidation. In the first step, phenolics and in vitro antioxidant activities were determined. ME contained 0.8-fold higher phenolics than WE. Antioxidant activities evaluated by the total antioxidant capacity, reducing power, hydrogen peroxide and radical scavenging abilities revealed that ME displayed significantly (p < 0.05) higher activities than WE, attributed to its richness in phenolics and clearly exceeded those of cv. Spunta and market potato as controls. In the second step, the ability of WE and ME from CN1 to inhibit the oil oxidation at 60 °C was monitored for 28 days. During the treatment, ME was more potent than WE in terms of peroxide value (PV, a primary oxidation indice), thiobarbituric acid (TBA) value and p-anisidine value (TBA value and AV, respectively, secondary oxidation indices). Thus, when considering the 28th day in which high oxidative changes occurred, WE exhibited PV reduction levels significantly (p < 0.05) comparable to ME (ANOVA test, p < 0.05). TBA proves that ME acted for a longer period than WE. The highest inhibition (significant at p < 0.05) was observed with regard to AV in the presence of 2000 ppm ME (52% vs. 31% for 200 ppm butylhydroxyanisole (BHA) and no significant effect with 2000 ppm WE). These results prove that WE and ME are an effective alternative to improve oil stability. [ABSTRACT FROM AUTHOR] |
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