Refined palm stearin

Crude and refined palm oils, refined palm kernel oil, and refined palm stearin of iodine value (IV) 35 and 41 are commercial samples obtained from various refineries around the Klang Valley region and used without any treatment. 

Fig. 4. Avrami equation plots for refined palm stearin (PS) with an iodine value of 41 under isothermal crystallization. See Figure 1 for other abbreviation.

Avrami Exponents and Polymorphic Forms of Refined Palm Stearin ... 

Crude palm oil used to be the main form of export in the past. With the establishment of refineries especially in Malaysia during the mid-1970s and 1980s, refined palm oil products have replaced the crude as the main form of palm oil export. A wide range of processed or semiprocessed products are exported, and these include the different fractions of processed pahn oil known as palm olein (liquid) and palm stearin (solid). The availability of refineries also led to the production of specialty fats products aimed at the confectionery markets. A similar trend has been seen in the export of pahn kernel oil. Palm kernel oil is a coproduct to palm oil produced at a ratio of 10-13 tons of palm kernel oil for every 100 tons of palm oil. Even the export of refined palm kernel oil has begun to decline as more is being used locally by the oleochemical industry that has been estabhshed in recent years. 

As mentioned previously, partial glycerides are artifacts of the extraction process, especially the stages prior to sterilization. Oil obtained from unbruised sterilized fruits shows trace levels of partial glycerides. Random analyses of samples of refined palm oil, pahn olein, and palm stearin have shown the presence of about 2% of 1,2-diglycerides and about 4% of 1,3-diglycerides with trace amounts of monoglycerides. These partial glycerides are important as they are known to affect the crystallization behavior of the oil. 

Refining of Other Palm Products. Beside crude palm oil, crude palm olein, crude palm stearin, cmde kernel oil, crude palm kernel olein, and crude palm kernel stearin can also be refined by either chemical or physical processes described before. The basic unit operations and processing conditions for crude palm olein and stearin are similar to those of palm oil. However, in refining palm kernel products, due to the virtual absence of carotenoids, the earth dosage required in the bleaching stage is lower, usually less than 1.0%. Furthermore, due to the presence of shorter chain (C8-C14) fatty acids, the deodorization temperature required is about 230-250°C. Typical achievable quality of RBD/NBD palm kernel oil is given in Table 34. 

Refined, bleached, and deodorized palm stearine was obtained from CanAmera Foods (Toronto, Ontario, Canada) lard and canola oil were purchased from a local supermarket. Tween 80 was supplied by Quest International (Lachine, Quebec, Canada). Free fatty acid content was determined [as percentage oleic acid (w/w)] by titration (12). Free fatty acid contents were 0.03, 0.1, and 0.02%, respectively, for the lard, palm stearine, and canola oil. 

Table 3.22 Binary blends of refined palm oil (PO) and palm stearin (POs) ...

P. is used predominantly in food. Refined oil and palm stearin are common in the manufacture of margarine and shortenings, while the liquid palm olein is used in frying fats and shortenings. Technical palm oil fatty acids, obtained by - hydrolysis, contain 50% palmitic and 40% oleic acid. Technical uses are in - soap production and in metal tempering (- metal processing). 

A flow sheet for a semi-continuous interesterification line with postbleaching ability is shown in Fig. 34.27. The oil must be degummed, well-refined (<0.05 percent FFA), and free from peroxides and moisture that causes production of soaps. Palm oil stearin and completely saturated (<5 IV) Cl 8 hydrogenated fats generally are trans free and may be used as part of the feed. Reactions are run under vacuum, and oil is best stored under nitrogen between processes.44... 

By-products. Chemical Refining. The neutralization of free fatty acid in the crude pahn oil with caustic soda results in the formation of soapstock, which is treated with dilute sulfuric acid of pH 2.0-3.5 at 110-130°C for 30 min. A by-product called palm acid oil is then separated from the aqueous phase by centrifugation followed by hot-water washing. It consists mainly of free fatty acids, neutral oil, and partial glycerides. A small amount of unsaponifiable matter is also present. Characteristics and properties of palm acid oil (derived from chemical refining of crude pahn oil, stearin, and olein) are given in Table 35 (55). 

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