Effect of kesse, koseret, and tosign extract treatments on the oxidative stability of oil during the repeated frying of potato chips

Fried food safety and quality are crucial concerns for consumers and the food industry due to the deterioration of oil quality and the loss of sensory properties during repeated frying. The current study investigated the use of leaf extracts from endemic dietary herbs: kesse (<i>Lippia adoensis</i> var. adoensis), koseret (<i>Lippia adoensis</i> var. koseret), and tosign (<i>Thymus schimperi</i> Ronninger) to enhance oil quality during the repeated frying of potato chips. The analysis of various parameters, including free fatty acids (FFA), iodine value (IV), peroxide value (PV), thiobarbituric acid reactive substances (TBARS), viscosity, and color (L*, a*, and b*), was conducted after every 5th frying cycle to assess oil quality. The results revealed significant (p < 0.05) decreases in deterioration markers for oils treated with herb extracts compared to the control oils. Specifically, after 20 frying cycles, oils treated with the dietary herb extracts exhibited lower percentage of FFA (0.63-1.05), IV (51.7-46.7), PV (6.69-7.68), and TBARS (50.27-56.08) compared to the control. The herb-treated oils also maintained lower FFA, PV, and TBARS values throughout the frying cycles and reduced viscosity, while IV gradually decreased. Furthermore, the L* value decreased gradually, and a* and b* values increased as the number of frying cycles increased. The herb extracts provided better protection against degradation compounds compared to BHT-treated and control oils, which was attributed to their lower FFA and PV. Sensory analysis indicated that potato chips fried in kesse extract-treated oil were the most preferred, followed by those treated with tosign extract. These findings highlight the potential application of herb extracts to increasing oil stability during repeated frying cycles, which add value at the interface between culinary excellence and health perspectives. Natural antioxidants from endemic herbs can maintain oil quality, reduce harmful compounds, and enhance the sensory properties of fried foods, making them a promising alternative to synthetic antioxidants.