interesterifisering

Interesterificering, or interesterification, is a fat-processing process that redistributes fatty acids among triglycerides in fats and oils. By exchanging acyl groups between triglyceride molecules, the total fatty acid composition remains the same, but the arrangement on the glycerol backbone changes. This alters physical properties such as melting behavior, crystallization, and texture, which are important for spreads, margarines, shortenings, and other fat-based products.

Two main approaches exist: chemical and enzymatic interesterification. Chemical methods use catalysts, typically acid or base, at elevated temperatures to promote a random exchange of acyl groups. Enzymatic interesterification uses immobilized lipases under milder conditions, offering greater selectivity and the possibility to create structured lipids with specific fatty acids positioned at particular sn-1, sn-2, or sn-3 positions.

Interesterification can be random, yielding a statistical distribution of triglyceride species, or selective/regiospecific, aimed at producing structured lipids with targeted properties. Applications include margarines and spreads with optimized spreadability and melting profiles, shortenings for baking, and specialty fats for infant formula or other functional lipids.

Advantages include the ability to tailor melting behavior and texture without hydrogenation, thereby avoiding trans fat formation. Limitations involve higher processing costs, potential oxidation of unsaturated fats, and the need for catalyst handling or purification in enzymatic processes.

Regulatory aspects vary by jurisdiction; interesterified fats are generally approved as food ingredients, with labeling requirements differing between countries.