Investigation of the effects of uckun (Rheum ribesL.), quinoa (Chenopodium quinoaWilld.), and propolis extracts on the thermal oxidation of palm olein oil during the deep‐frying process

Abstract

Frying process was repeatedly carried out 12 times in a deep fryer at 180°C using palm olein oil with potatoes. The effect of deep frying on the chemical and physical properties of the oil has been investigated. Free fatty acidity (0.35%–1.39%), peroxide value (0.64–11.49 meqO2/kg), p-anisidine value (5.06–67.52), total oxidation value (7.66–91.11), conjugated diene (2.84–11.09) and triene (1.07–5.65), total polar matter, and viscosity (17.64–140 mPa s) analyses were performed in oil samples. In addition, uckun (Rheum ribes L.), quinoa (Chenopodium quinoa Willd.), and propolis extracts were obtained and added to the oils at the level of 1,000–1,500 ppm determined by preliminary studies. Beside that a kind of synthetic antioxidant (BHT as 200 ppm) was added to the oil samples. The results of the present study showed that the propolis extract (1,500 ppm) had the best results on the thermal-oxidative stability and closest values to BHT. Novelty impact statement İt was understood that propolis and quinoa extracts could be used in the oil industry. And also especially 1,500 ppm level of propolis extract may affect as much as BHT on the oxidation stability. By adding these extracts into oil, it was seen that oil can be used 12 times for deep frying.