Scientific journal

59 2020

Journal of Food and Nutrition Research
Summary No. 2 / 2020

Oancea, S. – Drăghici, O. – Perju, M. – Dulf, F. V.
Effects of roselle extract on the oxidative stability of hempseed oil
Journal of Food and Nutrition Research, 59, 2020, No. 2, s. 98-107

Simona Oancea, Department of Agricultural Sciences and Food Engineering, Faculty of Agricultural Sciences, Food Industry and Environmental Protection, “Lucian Blaga” University of Sibiu, Ion Ratiu 7-9, 550024 Sibiu, Romania. E-mail: simona.oancea@ulbsibiu.ro

Received 15 November 2019; 1st revised 26 March 2020; accepted 15 April 2020; published online 30 April 2020.

Summary: Hempseed oil is exceptionally rich in valuable unsaturated fatty acids if adequate oxidative protection is ensured. The aim of this study was to investigate its stability at 60 °C in the presence of roselle (Hibiscus sabdariffa) extract rich in anthocyanins (7206.6 mg·kg-1 dry weight) and characterized by high antioxidant and antiradical activities. Thermal degradation of the oil during storage was evaluated on the basis of the fatty acid profile using analysis by gas chromatography-mass spectrometry and kinetic studies based on peroxide value and differential scanning calorimetry measurements. The evolution of the unsaturated fatty acids showed protective properties of the natural extract against lipid oxidation. Accumulation of peroxides in oil was reduced by 56 % in the presence of roselle extract compared to untreated oil, which was confirmed by kinetic analysis of the induction period. The thermal degradation kinetics using the Ozawa-Flynn-Wall method indicated that 0.2% (w/w) addition of roselle extract to hempseed oil improved its stability due to higher activation energy compared to other samples. The antioxidant effect of Hibiscus extract was also validated by Fourier-transform infrared spectroscopy. Our findings indicate that H. sabdariffa can be a safe and effective natural alternative to synthetic antioxidants applied to hempseed oil.

Keywords: antioxidant; oxidative stability; gas chromatography-mass spectrometry; thermal analysis; Fourier-transform infrared spectroscopy; oilseeds

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