Oxidative stability of sunflower and soybean oils enriched with black plum peel extract in comparison with synthetic antioxidants

Effects of adding green tea extract on the oxidative stability and shelf life of sunflower oil during storage

This study aimed to compare different concentrations effect of green tea extract (GTE) (200, 400, and 800 ppm) with TBHQ (75 ppm) in extend the shelf-life of sunflower oil (SO) and to evaluate the protective effect of GTE on the oxidation of refined SO. The sample's peroxide value (PV), acidity value (AV), anisidine value (pAV), Totox value (TV), oxidative stability, and total phenol content (TPC) were analyzed at specific intervals during 12-month at 25 °C and 60-day at 60 °C. The optimum kinetic model corresponding to the first order for PV, TV, and pAV was obtained at 25, 35, and 45 °C. SO containing GTE (800 ppm) had a similar performance to TBHQ at 25 °C and 60 °C and possessed a longer shelf life than samples treated with TBHQ. Due to synthetic antioxidant's health risk and toxicity, GTE can be a good substitute for TBHQ in the edible oil industry.

Antioxidant activity of selected plants extract for palm oil stability via accelerated and deep frying study

Antioxidants are organic compounds that help to prevent lipid oxidation and improve the shelf-life of edible oils and fats. Currently, synthetic antioxidants were used as oil stabilizing agent. However, synthetic antioxidants have been causing various health risks. As a result, natural antioxidants such as most parts of olive plant, green tea, sesame, medicinal plants were plays an important role to retard lipid oxidation. The palm oil was continuously frying at 180 °C for 6 days using Lepidium sativum (0.2%w/v) and Aframomum corrorima (0.3%w/v) seeds extracts as antioxidant. The physicochemical properties of oil in the herbal extract additive group significantly maintained the oil quality during frying compared to the normal control and the food sample containing group. The L. sativum extract had a greater oil stability compared to A. corrorima extract. However, the frying oil without herbal extract significantly increase the physicochemical properties of oil such as iodine value, acid value, free fatty acid, total polar compounds, density, moisture content, pH etc. during repetitive frying. The antioxidant activity of the plant extract was outstanding, with an IC₅₀ value in the range of 75-149.9 μg/mL when compared to the standard butyl hydroxy anisole, which had an IC₅₀ value in the range of 74.9 ± 0.06-96.7 ± 0.75 μg/mL. The total phenolic and flavonoid content of the extract for L. sativum was 128.6 ± 0.00 mg GAE/g, 127.0 ± 0.00 mg QE/g, and 130.16 ± 0.001 mg GAE/g, 105.76 ± 0.02 mg QE/g, respectively. The significant effect of the plant extract on the degradation of oil and the formation of free fatty acids was confirmed by Fourier transform infrared spectroscopy. The result of these study revealed that the ethanolic crude extract of L. sativum and A. corrorima had a potential natural antioxidant to prevent the degradation of palm oil.