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    Detoxification Effect of Rosemary Leaf Powder on Repeatedly Deep-Fried Hayat Palm Oil for Potato Chip Production
    (Mekelle University, 2025-01-25) ASSEFA MIESHO GEBRE
    Deep-frying with vegetable oils, particularly Hayat palm oil (HPO), is widespread activity in Tigrai; Northern Ethiopia. However, frequently frying with HPO can generate harmful chemicals to health. Therefore, the purpose of this study was to assess the detoxification effect of rosemary leave powder on HPO used for the preparation of potato chips. Different frying cycles (1st, 3rd, 5th, 7th, and 9th) with and without rosemary powder were employed for frying 500 g of row potato at 180 oC in 2L of Hayat palm oil at different doses of 100,150, 200, 250, and 300 mg/kg rosemary powder for 20 min. Oil samples were taken at 1st, 3rd, 5th, 7th, and 9th frying days. The result of the analyzed physical parameters such as moisture content for fried Hayat palm oil without rosemary (FHPO) was found in the ranges of 0.73 to 1.265% while fried Hayat palm oil with rosemary (FHPOR) varied from 0.19 to 0.538% and specific gravity from 0.8906 to 0.9226% for FHPO and 0.8868 to 0.9121% for FHPOR. The refractive index for FHPO was also recorded from 1.459 to 1.547, but FHPOR was obtained in the ranges of 1.453 to 1.459. The pH values were recorded between 4.058 to 4.57 for FHPO and 4.68 to 5.814 for FHPOR. In addition, the viscosity value also ranged from 73.635 to 88.415 cP for FHPO and 48.214 to 63.741 cP for FHPOR. Among the chemical parameters analyzed, peroxide values ranged from 10.167 to 14.578 meqO2/kg oil for FHPO and 6.463 to 9.8 meqO2/kg oil for FHPOR, iodine values from 57.34 to 53.54 g of I2/100g oil for FHPO, and from 45.55 to 50.465 g of I2/100g oil for FHPOR, acid values from 0.935 to 5.61mg KOH/g oil for FHPO and from 0.186 to 0.7922 mg KOH/g oil for FHPOR, saponification values from 204.5431 to 208.508 mg KOH/g oil for FHPO and 157.129 to 203.977 mg KOH/g oil for FHPOR, conjugated diene values from 3.079 to 4.374 % for FHPO and 0.2869 to 0.6432% for FHPOR. Statistical analyses using one-way ANOVA and Tukey’s test revealed significant differences (p < 0.05) across all studied physical and chemical parameters. GC-MS analysis also confirmed the removal of harmful chemicals such as alcohol, epoxide, ketone, and CDLA from FHPOR while oleic acid present, indicating that the oil had not decomposed. The level of heavy metal concentrations in FHPOR were found within the permissible limits (Pb: 0.01, Fe: 0.10, Cu: 0.10, Cd: 0.01, As: 0.01, Hg: 0.01) mg/100g, while FHPO exhibited higher levels (Pb: 0.10, Fe: 0.02, Cu: 0.11, Cd: 0.12, As: 0.11, Hg: 0.10) mg/100g. In conclusion, the incorporation of rosemary leaf powder into deep-frying practices significantly enhances the chemical profile of HPO by reducing toxicant chemicals and improving its oxidative stability. Generally, the present study showed the potential of rosemary as a natural additive for healthier cooking methods and improved oil quality