Oxidative and Frying Stabilities of Monodora myristica (Gaertn.) Dunal Seed Oil of Nigerian Origin

The demand for vegetable oils is on the increase. Deep frying is the commonest method by which vegetable oils are consumed. The aim of this study was to extract oil from an underutilized oil seed and compare its physicochemical properties, frying, and oxidative stability with those of commercial refined palm oil.

Oil was extracted from Monodora myristica seeds using a soxhlet fat extractor and the percentage oil yield was determined. The physicochemical, oxidative, and frying stabilities of the extracted M. myristica Seed Oil (MMSO) were evaluated based on the standard procedure of the Association of Official Agricultural Chemists and official methods and recommended practices of the American Oil Chemists Society and compared with those of commercial refined palm oil- Kings Vegetable Oil (KVO). Data were statistically analyzed using SPSS version 20.

The oil yield of M. myristica seed was 37.64%. The refractive index, specific gravity, moisture content (%), and peroxide value (mEq/kg) were respectively 1.470, 1.468, 0.923, and 0.917 for MMSO; and 0.220, 0.253, 1.05, and 3.50 for KVO. MMSO had better oxidative stability and showed 80% lesser peroxide formation than KVO. The frying stability of MMSO was better as it showed a lower increase in FFA (28.4%) and peroxide value (9.54 mEq/kg) than KVO (45.99% and 26.19 mEq/kg, respectively) after frying.

Deteriorative effect of oxidation and polymerization was lower in MMSO than in KVO indicating MMSO to be superior frying oil suitable for repeated frying.