Interesterification palm stearin

Interesterification of milk fat with palm stearin, the harder fraction obtained on fractionation of palm oil, provides a possible route for the production of pastry margarine and bakery products. Milk fat by itself, unless fractionated into a hard fraction, is not very suitable in these applications because it lacks sufficient solids at high temperatures. 

One of the limitations encountered with the use of physical blends of different fats is incompatibility of the fats causing softening of fats due to eutectic effects. Nor Hayati et al. (2000) demonstrated that the eutectic effects observed in physical blends of milk fat and palm stearin was reduced on interesterification of the blend by a 1,3-specific enzyme (Lipozyme). The interesterified blend has better functionality for bakery products than milk fat. 

Nor Hayati, I., Aminah, A., Mamot, S., Nor Aini, I., Noor Lida, H.M., Sabariah, S. 2000. Melting characteristic and solid fat content of milk fat and palm stearin blends before and after enzymatic interesterification. J. Food Lipids. 7, 175-193. 

Margarine made, for example, by interesterification of palm stearin and sunflower oil (1 1), contains no hydrogenated fat and therefore no tranj -acids. 

Figure 3.10 Solid fat content of margarine using palm oil products (Noorlida and Mohd Suria 1995). PO palm oil POo palm olein POs palm stearin RSO rapeseed oil PKO palmkemel oil SBO soyabean oil IE interesterification. Key — —, POo/POs/RSO (40/10/50) 0, IE POs/PKO...

Trans-free vanaspati can be formulated using palm stearin with other oils (Table 3.23) (Nor Aini et al. 1997). Interesterification allows more palm stearin to be incorporated into the formula. Other trans-free formulations are obtained with ternary blends of palm oil/palm stearin/palm olein or palm oil/palm stearin/ palm kernel olein (Table 3.24). These products have characteristics similar to those of hydrogenated vanaspati. Formulations for vanaspati may be varied to suit the requirements of different consumers. Incorporation of more or fewer palm oil products in the formulation generally affects the melting point property, which is a limitation for certain countries. 

DeMan, J.M. (2000) Use of palm stearin as a component of interesterified blends, in The Future of Interesterification in Oil Processing, SCI seminar, UK, 15th November, 2000. 

The interesterification process has not found any significant application to CNO itself. The most important property of CNO and HCNO is their short plastic range and interesterification does not improve this very significantly. Nevertheless, some interesting products can be made by interesterfication of blends of CNO or PKO with palm oil and palm stearin to produce margarine fats, and these are described under PKO. 

Interesterification of PKO and PKOo with palm stearin and liquid oil has possibilities in trans-free margarine blends, especially during periods when the price of lauric oils is in line with that of other oils. Palm stearin is normally the lowest cost vegetable hard fat. The following results from our experiments show the effect of interesterification on HPKOo (Table 6.26). It should be noted that the SFC 20°C remains virtually the same, while the SMP is reduced by over 6°C. 

Costalez-Rodriguez, R Gibon, V Veriie, R De Greyt, W. Chemical and enzymatic interesterification of a blend of palm stearin soybean oil for low trans-Margarine formulation. J Am Oil Chem Soc, 2009 86 681—97. 

Siew WL, Cheah KY, Tang WL. Physical properties of lipase-catalyzed interesterification of palm stearin with canola oil blends. Eur J Lipid Sci Technol 2007 109 97-106. 

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... 

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