Crude palm oil (CPO) was physically refined in a 200-kg batch pilot refining plant. A study of the possible role of degumming and bleaching steps in the refining process for a possible critical role in the formation of 3-chloropropane-1,2-diol (3-MCPD) esters was evaluated. For the degumming step, different percentages of phosphoric acid (0.02-0.1%) as well as water degumming (2.0%) were carried out. Six different types of bleaching clays, mainly natural and acid activated clays were used for bleaching process at a fixed dose of 1.0%. Deodorization of the bleached oils was performed at 260°C for 90 min. Analyses showed that 3-MCPD esters were not detected in the CPO. Phosphoric acid degumming (0.1%) in combination with acid activated clays produced the highest levels (3.89 ppm) of 3-MCPD esters in the refined (RBD) oil. The esters were at the lowest levels (0.25 ppm) when the oil was water degummed and bleached with natural bleaching clays. However, the refined oil qualities were slightly compromised. Good correlation of 0.9759 and 0.9351 was obtained when concentration of the esters was plotted against acidity of the bleaching earths for the respective acid and water degumming processes. The findings revealed the contribution of acidic conditions on the higher formation of 3-MCPD esters. In order to lower the esters formation, it is important to reduce acid dosage based on the crude oil qualities or to find alternatives to acid degumming process. Neutralization of the acidity prior to deodorization was effective in reducing the formation of 3-MCPD esters.

Refined, bleached and deodorized palm olein (RBD POo) with an iodine value (IV) of 62 was chemically interesterified with methyl oleate (MO) at a ratio of 50:50 (w/w). The reaction was carried out at 110°C in the presence of sodium methoxide as a catalyst using a 100-kg pilot scale reactor. Randomization between 15 and 30 min resulted in less free fatty acid (FFA) formation and higher oleic content in the interesterified product as compared to longer reaction time of 60-90 min. Sodium methoxidecatalyzed ester interchange increased the oleic content of the interesterified product to more than 57% from its initial content of 45%. The product obtained also has an IV of more than 75. The interesterified oil was then subjected to dry fractionation in a 200-kg De Smet jacketed crystallizer at 8°C to further enhance the oleic content of the liquid olein fraction. The resulted olein had an improved cloud point and higher IV of 81. The solid stearin had a slightly higher IV and oleic content as compared to normal palm stearin. The solid fat content was comparable to normal palm oil. The pilot scale study has proven a successful conversion of laboratory findings to a larger scale production and gave the most realistic information for possible commercialization.

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.

No abstract

Solid fat from fractionation of palm-based products was converted into cake shortening at different processing conditions. High oleic palm stearin with an oleic content of 48.2 % was obtained from fractionation of high oleic palm oil which was produced locally. Palm product was blended with different soft oils at pre-determined ratio and further fractionated to obtain the solid fractions. These fractions were then converted into cake shortenings named as high oleic, N1 and N2 blends. The physico-chemical properties of the experimental shortenings were compared with those of control shortenings in terms of fatty acid composition (FAC), iodine value (IV), slip melting point (SMP), solid fat content (SFC) and polymorphic forms. Unlike the imported commercial shortenings as reported by other studies and the control, experimental shortenings were trans-free. The SMP and SFC of experimental samples, except for the N2 sample, fell within the ranges of commercial and control shortenings. The IV was higher than those of domestic shortenings but lower when compared to imported and control shortenings. They were also observed to be b tending even though a mixture of b and b was observed in the samples after 3 months of storage. The shortenings were also used in the making of pound cake and sensory evaluation showed the good performance of high oleic sample as compared to the other shortenings.

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.

Commercial oil D 0.06±0.00 f 3.0±0.0 a 5.83±0.05 c 2.66±0.31 c 2.59±0.18 c 1.20±0.10 b 0.76±0.03 d Commercial oil E 0.20±0.00 b 2.3±0.0 c 5.82±0.06 c 3.30±0.13 b 0.84±0.02 f 0.38±0.00 d 2.85±0.02 b Mean of triplicate analysis±SD Values within a column with different superscript letters are significantly different (p < 0.05)

objective of our study and the publication was to provide information on characteristics and composition of a high oleic oil obtained through the process of interesterifying palm oil with methyl oleate. Because of the newly developed biodiesel industry, palm-based methyl ester is readily available. For our work, methyl oleate was purchased; we did not conduct fractional distillation of palm methyl ester. The full process of starting from basic oil to methyl ester, followed by distillation was therefore not included, nor mentioned, but we expected interested parties would likely look into the full process if the industry has palm biodiesel product, or one may just start from appropriate raw materials. The reacted ester recovered from the process has many potential applications in biodiesel and oleochemical industries. It can also be recycled. All of these aspects were considered in our work in order to enhance the economic viability of the process, although not mentioned, because the paper was not written as a result of a graduate student thesis.Concerning Table 1. Dijkstra has rightly pointed out that columns 4 and 5, showing values for FAME before and after mixing, do not accurately show the composition of the 50:50 blend of palm olein and methyl oleate and that this is due to incompleteness of the reaction in the analysis of FAME, especially when methyl oleate was present in the mixture. These two columns were inadvertently placed into the table by mistake and we did not discuss the values in the two columns. The discussion was based on comparing the feed oil and the high-oleic oil obtained. From the table, the high-oleic palm oil (HOPO) composition did not deviate too far from the calculated average mixture.When discussing the results of the fatty acid compositions before and after randomization, we actually referred to the comparison of the feed oil and the HOPO, and not to the data from the two columns representing before and after reaction.For FAME preparation, the sample size was about 0.05 g. The reagent used was 0.5 M sodium methoxide and is therefore a liquid. We did not mention the details for preparing sodium methoxide because it is a commonly known reagent prepared from sodium metal and methanol. The mixture separated into two layers when water was added.The standard deviations of Tables 1 and 5 were generally higher than those of Tables 3 and 6. This is because data from Tables 1 and 5 were from pilot plant experiments, while Tables 3 and 6 were from laboratory experiments. The variability in the pilot-plant experiments was higher than in the laboratory experiments where better control can be achieved. The laboratory experiments were included at a later stage when requested by the reviewers