Journal of food science and technology(Iran)

Journal of food science and technology(Iran)

Evaluation of oxidative stability of Iranian virgin walnut kernel (Juglans regia L.) oil enriched with ultrasound-assisted extracted Iranian germinated paddy rice extract

Document Type : Original Research

Authors
1 Master's Graduate, Department of Food Science and Technology, Qazvin Branch, Islamic Azad University, Qazvin, Iran
2 Assistant Professor, Department of Food Science and Technology, Qazvin Branch, Islamic Azad University, Qazvin, Iran
10.48311/fsct.2026.83833.0
Abstract
The aim of this study was to evaluation of oxidative stability of Iranian virgin walnut kernel oil enriched with ultrasound-assisted extracted Iranian germinated paddy rice (GPR) extract under accelerated oxidation conditions. The powdered GPR sample was extracted with ethanol/H2O (70:30,V/V) using ultrasonic waves at the temperature of 50˚C and time of 30 minutes with the frequency of 40 KHZ and solid to solvent ratio of 1:20 (w/v) in an ultrasound water bath. The extraction yield (2.91%), DPPH radical scavenging activity (77.52%) and total phenolic contents (909.2 mg GAE/1000g DW) of GPR were determined. The protective effects of the GPR extract in stabilization of virgin walnut kernel oil at different concentrations (0 ppm,500 ppm,1000 ppm,1500 ppm,) were evaluated for a period of five days (120 h) by monitoring the peroxide, p-anisidine, totox values at an oven temperature of 90˚C (accelerated oxidation). Also, the oxidative stability index (OSI) was evaluated and compared with the synthetic antioxidant BHT (200 ppm). In oxidative stability tests of Iranian virgin walnut kernel oil supplemented with antioxidant extract, increasing the concentration of the extracts led to their better performance in delaying oxidative rancidity (p<0.01). According to the results, BHT (200 ppm) and the GPR extract (1500 ppm) showed the highest protective effects. In the rancimat test, the oxidative stability indices of the control sample, the sample of Iranian virgin walnut kernel oil containing 1500 ppm of GPR extract and BHT (200 ppm) were 3.25 h, 8.93 h and 12 h, respectively (p<0.01). Thus, BHT and GPR extract (1500 ppm) in comparison with the control sample, showed a significant effect on increasing the oxidative stability index of Iranian virgin walnut kernel oil. Therefore, GPR can be used as a source of antioxidant compounds in edible oils.
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