Improvement of Physicochemical Properties of Refined Peanut Oil with Dried Olive Leaf: Gray Scale Optimization

Abstract

Peanut is a well-known lipid and protein source for nutrition and its oil is considered to be nutritious and healthy, owing to its fatty acid composition and the presence of natural bioactive components. Olive leafs are the major by-products of oil processing and its industry. The phenolic content of peanut oil was 78.15 and varied between 271.8 and 431.6 mg GAE/kg depending on the increasing amount of olive leafs respectively (2.5-7.5%). The scavenging activity of peanut oil was as 3.8% and varied between 40.17,82.5 and 91.01% respectively. The effects of olive leaf amount and storage time on the extinction coefficients of peanut oils (K225,K232 and K270) were statistically insignificant whereas PV (meO2/kg), total and free acidities (%) of peanut oils were affected significantly. Chlorophyll a and b values of refined peanut oils varied between 0.69 and 1.238 (mg/L);0.14 and 1.195 8-(mg/L) respectively. Olive leafs caused statistically decreased L* values but increased a* and b* values.