The effect of 0.1-0.7% (w/w) of polyglycerol esters (PGEmix-8) on palm oil crystallization was studied using focused beam reflectance measurement (FBRM) to analyze the in-line changes of crystal size distribution during the crystallization. FBRM results show that 0.1-0.5% (w/w) of PGEmix-8 did not significantly affect nucleation but slightly retarded crystal growth. The use of 0.7% (w/w) additive showed greater heterogeneous nucleation compared to those with lower dosages of additive. Crystal growth was also greatly reduced when using 0.7% (w/w) dosage. The morphological study indicated that the palm oil crystals were smaller and more even in size than when more additive was added. Isothermal crystallization studies using differential scanning calorimetry (DSC) showed increased inhibitory effects on palm oil crystal growth with increasing concentration of PGEmix-8. These results imply that PGEmix-8 is a nucleation enhancing and crystal growth retarding additive in palm oil crystallization at 0.7% (w/w) dosage.

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The quality of Malaysian palm stearin was monitored through a twelve-month survey in 2018, by participation of palm oil refineries and oleochemical plants from Peninsular Malaysia and Sarawak. Quality parameters requirement as listed in the Palm Oil Refinery Association of Malaysia (PORAM) specification such as moisture, impurities, free fatty acids, slip melting point, peroxide value and iodine value were determined. Other identity characteristics analyses as detailed in the palm stearin specification namely Malaysian Standard MS 815:2007 and Codex Alimentarius CXS 210-1999 documents were also analyzed, which were apparent density, refractive index, fatty acids composition, triacylglycerols, etc. Results obtained from this survey indicated that the quality of Malaysian palm stearin complied with the requirements specified in MS 815:2007 and Codex CXS 210-1999 documents. The iodine value determined was ranged from 28 g I2/100 g oil to 48 g I2/100 g oil, with 60.9% of the palm stearin tested were in the range of 30 g I2/100 g oil to 35 g I2/100 g oil. Meanwhile, some deviations are found in the average of parameter such as refractive index, apparent density, slip melting point, oleic and palmitic acids of the palm stearin produced. These deviations could be due to the improvement in current fractionation technologies causing less olein entrainment in stearin products, which resulted of harder stearin fraction in the sample itself, giving a more representative reading of the parameters.

Incorporation of oils from non-conventional sources into palm olein through the blending process generates a sustainable source of novel oleins with improved physicochemical and functional properties. The objective of this study was to evaluate the effects of blending winged bean (Psophocarpus tetragonolobus) seed oil (WBSO) and palm olein (POo) on the physicochemical properties of the blends. Blends of WBSO (25, 50 and 75% w/w) with POo were prepared and changes in fatty acid (FA) and triacylglycerol (TAG) compositions, iodine value (IV), cloud point and thermal behaviour were studied. Reductions in palmitic (C16:0) and oleic (C18:1) acids with concomitant increases in linoleic (C18:2) and behenic (C22:0) acids were observed as the amount of WBSO increased in the blends. Blending WBSO and POo at 75:25 increased the unsaturated FA content from 56% in palm olein to 64% in the blend, producing the highest IV of 70.5 g I2/100g. At higher WBSO ratios, triunsaturated and diunsaturated TAG species within the blends increased while disaturated TAG species decreased. The lowest cloud point (8.8 °C) was obtained in the oil blend containing 50% WBSO, while the cloud point further increased with increasing amount of WBSO in the blends. This was possibly attributed to increased trisaturated TAG with very long-chained saturated FA (C20 to C24) inherently present in WBSO within the blends. Thermal behaviour analysis by differential scanning calorimetry of the oil blends showed higher onset temperatures for crystallisation with increasing proportions of WBSO in POo, with melting thermograms correspondingly showing decreasing onset melting temperatures. These findings showed that blending WBSO with POo enhanced the physicochemical characteristics of the final oil blends, resulting in higher unsaturation levels and improved cloudiness resistance.