A method for determining shell in palm kernel cake (PKC) is described. This simple and rapid method requires little pretreatment compared with the method currently used in PKC trade, in which the sample undergoes defatting, acid and alkali digestion, and washing, before a chloroform-alcohol solution is used to separate the shells. In the proposed method, only defatting the sample is required. The shells are separated by the density difference between the shell and PKC in a potassium iodide solution. Recoveries of at least 93% were obtained, and the correlation coefficient between the actual shell content and the determined shell content was 0.999, with gradients of 0.97 and 0.98 for fine and coarse shell, respectively.
High-oleic palm oil (HOPO) with an oleic acid content of 59.0% and an iodine value (IV) of 78.2 was crystallized in a 200-kg De Smet crystallizer with a predetermined cooling program and appropriate agitation. The slurry was then fractionated by means of dry fractionation at 4, 8, 10, 12, and 15 degrees C. The oil and the fractionated products were subjected to physical and chemical analyses, including fatty acid composition, triacylglycerol and diacylglycerol composition, solid fat content, cloud point, slip melting point, and cold stability test. Fractionation at 15 degrees C resulted in the highest olein yield but with minimal oleic acid content. Due to the enhanced unsaturation of the oil, fractionation at relatively lower crystallization temperature showed a considerable effect on fatty acid composition as well as triacylglycerol and diacylglycerol composition of liquid fractions compared to higher crystallization temperature. The olein and stearin fractionated at 4 degrees C had the best cold stability at 0 degrees C and sharper melting profile, respectively.
This paper examines the processing steps of extracting palm oil from fresh fruit bunches in a way that may impact on the formation of chloropropandiol fatty esters (3-MCPD esters), particularly during refining. Diacylglycerols (DAGs) do not appear to be a critical factor when crude palm oils are extracted from various qualities of fruit bunches. Highly hydrolysed oils, in spite of the high free fatty acid (FFA) contents, did not show exceptionally high DAGs, and the oils did not display a higher formation of 3-MCPD esters upon heat treatment. However, acidity measured in terms of pH appears to have a strong impact on 3-MCPD ester formation in the crude oil when heated at high temperatures. The differences in the extraction process of crude palm oil from current commercial processes and that from a modified experimental process showed clearly the effect of acidity of the oil on the formation of 3-MCPD esters. This paper concludes that the washing or dilution step in palm oil mills removes the acidity of the vegetative materials and that a well-optimised dilution/washing step in the extraction process will play an important role in reducing formation of 3-MCPD esters in crude palm oil upon further heat processing.
Diacylglycerol (DAG) and monoacylglycerol (MAG) are two natural occurring minor components found in most edible fats and oils. These compounds have gained increasing market demand owing to their unique physicochemical properties. Enzymatic glycerolysis in solvent-free system might be a promising approach in producing DAG and MAG-enriched oil. Understanding on glycerolysis mechanism is therefore of great importance for process simulation and optimization. In this study, a commercial immobilized lipase (Lipozyme TL IM) was used to catalyze the glycerolysis reaction. The kinetics of enzymatic glycerolysis reaction between triacylglycerol (TAG) and glycerol (G) were modeled using rate equation with unsteady-state assumption. Ternary complex, ping-pong bi-bi and complex ping-pong bi-bi models were proposed and compared in this study. The reaction rate constants were determined using non-linear regression and sum of square errors (SSE) were minimized. Present work revealed satisfactory agreement between experimental data and the result generated by complex ping-pong bi-bi model as compared to other models. The proposed kinetic model would facilitate understanding on enzymatic glycerolysis for DAG and MAG production and design optimization of a pilot-scale reactor.