Fatty Acid Profile and Oil Stability of Butter Made from Peanut Paste Supplemented with Sesame Seed Paste

The present study was conducted to assess the effect of supplementation of peanut paste with 0, 10, 20, 30, 40 and 50% sesame seed paste on the fatty acid profile and oil stability of butter made from the blends. Packaged samples from each blend were stored at ambient temperature (27±2oC) for 12 weeks and analysed for oil separation, peroxide value (PV) and acid value (AV) at four weeks interval. Unblended peanut and sesame seed butters served as control samples. The result showed that apart from behenic acid that was not detected in sesame butter oil, the other eight fatty acids detected in peanut butter oil were also found in sesame butter oil but in varying quantities. Oil extracted from 100% peanut and sesame seed butters contained slightly below 20% saturated fatty acids (SFAs) and slightly above 80% unsaturated fatty acids (UFAs). Palmitic, palmitoleic, oleic, linolenic, arachidic and behenic acids decreased while stearic, linoleic, and eicosenoic acids increased with increase in sesame paste supplementation. Butters made from blended pastes had higher percentages of SFAs and polyunsaturated fatty acids (PUFAs) but lower percentage of monounsaturated fatty acid (MUFAs) than 100% peanut butter oil. Oil separation, PV and AV significantly (P = .05) increased with storage time. Quantity of oil separated at week 12 ranged from 1.05% to 3.19%. The rate of peroxide formation decreased with increase in sesame paste supplementation. Consequently, at week 12, while 10% sesame paste supplemented butter recorded 263.12% increment in PV, the value for 50% sesame paste supplemented butter was 143.01%. The treatment had no effect on acid value during storage. At week 12, the AV increment for the butters from the blended pastes ranged from 179.59% to 181.82% while the values for 100% peanut butter and 100% sesame butter were 183.72% and 119.64% respectively. The study has shown that butter of high unsaturated fatty acids with delayed onset of oxidative deterioration could be produced from peanut paste supplemented with sesame seed paste.