Evaluation of antioxidant properties of Za'atar (Thymbra spicata) essential oils as natural antioxidant for stability of palm olein during deep-fat frying process

Effect of tunisian pomegranate peel extract on the oxidative stability of corn oil under heating conditions

The effect of pomegranate peel extract (PPE) on the oxidative stability of corn oil during heating was studied. Oxidation was followed by determining peroxide value (PV), p-anisidine value (p-AV), free fatty acid value (FFA), conjugated dienes (CD), conjugated trienes hydroperoxides (CT) and the calculated total oxidation value (TOTOX). Polyphenol (TPC) and ortho-diphenol (TOPC) contents as well as the antioxidant activity of each oil sample were evaluated before and after heating. PPE showed a significant inhibitory effect on lipid oxidation. Heating samples for 8 hours supplemented by PPE to a level of 1000 ppm resulted in the highest significant decreases in investigated indices compared to the control and BHT values. It was concluded that the antioxidant activity of PPE delayed oxidation and can be used in the food industry to prevent and reduce lipid deterioration in oil.

Antioxidant Activity and Sensory Improvement of Angelica dahurica cv. Yubaizhi Essential Oil on Sunflower Oil during High-temperature Storage

The oxidative state of sunflower oil during high-temperature storage has been facing large challenges. In the study, the antioxidant effect of the essential oil of Angelica dahurica cv. Yubaizhi (ADEO) in sunflower oil was explored. In the high-temperature storage for 24 days at 65 °C, ADEO (800 ppm) was able to markedly inhibit the development of the acid value (AV), peroxide value (PV), p-anisidine value (AnV), total oxidation value (TOTOX), thiobarbituric acid reactive substances (TBARS), total polar compounds (TPC), and the absorbance at 232 and 268 nm (p < 0.01 or p < 0.05) of sunflower oil and to prominently inhibit the transformation between unsaturated fatty acids (UFA) and saturated fatty acids (SFA). Interestingly, the synergistic effect of ADEO (400 ppm) and tert-butyl hydroquinone (TBHQ, 100 ppm) was demonstrated. Furthermore, the sensory attributes such as flavor, taste, and overall acceptability of oxidized sunflower oil added by ADEO at 200, 400, and 800 ppm were memorably elevated (p < 0.05). Besides, one of its main compounds, myrcene, was demonstrated to be its active compound during the whole investigation. Consequently, TBHQ at 200 ppm could be substituted by ADEO at 800 ppm and myrcene at 69.8 ppm in the high-temperature storage at 65 °C of sunflower oil.

Anti-oxidant and anti-microbial properties of mutton nuggets incorporated with blends of essential oils

The present study was carried out to evaluate effect of natural anti-oxidants on the quality of mutton nuggets. Different blends of essential oil were evaluated for incorporation in mutton nuggets and it was found that Blend-1 had significantly higher sensory scores. Then, Blend-1 was tried at 0.25, 0.5 and 0.75% levels and product containing 0.25% level received significantly higher sensory scores. Thereafter, two combinations of flaxseed flour and 0.25% Blend-1 were tried viz., 4% flaxseed flour + 0.25% Blend-1 and 8% flaxseed flour + 0.25% Blend-1. Evaluation of sensory and physico-chemical properties were done in mutton nuggets incorporated with 0.25% Blend-1 (T-1) and selected combination (4% flaxseed flour + 0.25% Blend-1) (T-2). T-2 had significantly higher dietary fiber and crude fiber than T-1 products. These products were then assessed for quality changes during storage at refrigerated temperature for 30 days at 5 days interval. Significantly lower TBARS values were recorded for treatment products than control at each interval of storage period. T-2 product showed significantly higher DPPH value than other products. Microbial count remained within the permissible limit of log₁₀4 cfu/g for TPC, PC, yeast and mould count up to 15th day, 25th day and 30th day for control, T-1 and T-2 products, respectively. Essential oil and their combination incorporated mutton nuggets had about 10 days longer shelf life than control.