Physico‐chemical properties of palm olein fractions as a function of diglyceride content in the starting material

Crude olein preparations with different amounts of diacylglycerols (DAG) were refined, bleached and deodorized (RBD) prior to the dry fractionation process. The RBD olein samples with different amounts of DAG were then individually fractionated into low‐melting (super olein) and high‐melting fractions (soft stearin). Physical and chemical characteristics, i.e. iodine value, cloud point, slip melting point, triacylglycerol (TAG) and DAG profile, fatty acid composition, thermal profile and solid fat content, of the super olein and soft stearin fractions were analyzed. The TAG profile obtained from the RBD olein having a low DAG content (0.89%) showed a higher amount of the diunsaturated TAG, i.e. dioleyl pamitoyl glycerol, in the olein fraction (57.3%). This, consequently, led to super olein fractions with a better iodine value (IV 65) and the cloud point at 1.3 °C, compared to non‐treated super olein (DAG 5%) with an IV of 60.5 and the cloud point at 4.1 °C.     

Stability of Silica‐ and Enzyme‐Treated Palm Oil Under Deep Frying Conditions

The oxidative and thermal stability of low diglycerides palm oil produced via silica treatment (sPO) and enzymatic treatment (ePO) compared with standard quality palm oil (SQ) and premium quality palm oil (PQ) was investigated. Both of the oils displayed better oxidative stability compared with SQ as well as significantly higher (P < 0.05) thermal resistance and oxidative strength than SQ and PQ due to lower amounts of partial glycerides. Although the initial induction periods (IPs) of sPO and ePO were significantly lower compared with SQ and PQ, both the oils showed slower drops in their IP values. The darkening effect after frying was significantly (P < 0.05) slower in sPO compared with SQ, PQ, and ePO. Besides, there is no difference p > 0.05 in the rate of FFA formation between sPO and PQ. The anisidine value and peroxide values were lowest in sPO, followed by ePO, PQ, and SQ.