Membrane Processing of Oils and Fats

S. Sefa Koseoglu Extraction and Rehning Program, A Division of Eiltration and Membrane World LLC, College Station, Texas, Membrane Processing of Fats and Oils. 

Monoglyceride (MG) is one of the most important emulsifiers in food and pharmaceutical industries [280], MG is industrially produced by trans-esterification of fats and oils at high temperature with alkaline catalyst. The synthesis of MG by hydrolysis or glycerolysis of triglyceride (TG) with immobilized lipase attracted attention recently, because it has mild reaction conditions and avoids formation of side products. Silica and celite are often used as immobilization carriers [281], But the immobilized lipase particles are difficult to reuse due to adsorption of glycerol on this carriers [282], PVA/chitosan composite membrane reactor can be used for enzymatic processing of fats and oils. The immobilized activity of lipase was 2.64 IU/cm2 with a recovery of 24%. The membrane reactor was used in a two-phase system reaction to synthesize monoglyceride (MG) by hydrolysis of palm oil, which was reused for at least nine batches with yield of 32-50%. 

Fats and oils have major roles in human nutrition. They are concentrated dietary sources of energy, providing approximately 9 kcal/g when metabolized compared with 4 kcal/g for carbohydrates and proteins, and account for about 36 percent of domestic caloric intake per capita.19 Dietary lipids also can provide essential molecular structures that are synthesized by the body into compounds required for selective functioning of cell membranes and regulation of life processes. 

Fig. 34.23. Principle of membrane-type filtration of olein and stearin. (From Tirtiaux, A., in World Conference Proceedings, Edible Fats and Oils Processing Basic Principles and Modern Practices, D. R. Erickson (Ed.), pp. 136-141, AOCS, Champaign, IL, 1990. With permission.)...

Snape, J. B. and Nakajima, M. (1996) Processing of agricultural fats and oils using membrane teehnology. Journal of Food Engineering 30,1-41. 

Snape, J.B. and Nakqima, M. Processing of agriculturals fats and oils using membrane technology. J. Food Eng. 30, 1-41 (1996). 

The surface layer of the fat globule may act as a catalytic impurity (e.g., when it contains mono-glycerides or di-glycerides with long-chain fatty acid residues) however, there is still some uncertainty as to whether this process actually occurs (see Walstra, 1995). Although concentric layers of apparently crystalline fat have been observed in electron micrographs of freeze-etched or freeze-fractured milk or cream samples (Buchheim, 1970 Henson et al., 1971), these observations could not be confirmed by other microscopy techniques. Noda and Yamamoto (1994) reported that it is thermodynamically more favorable for fat crystals to be located at the oil/water interface, rather than in the interior of the droplet, which may explain the presence of fat crystals at the membrane. 

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