Interesterified

Interesterification is a process in fat chemistry in which fatty acids are rearranged on the glycerol backbone of triglycerides to form new triglyceride compositions. This reconfiguration alters the physical properties of fats, such as melting behavior, crystallization, and texture, without adding or removing fatty acids from the fat blend. Interesterified fats can be produced from existing fat sources, often blending plant oils and fats to achieve targeted functionality.

There are two main approaches: chemical and enzymatic interesterification. Chemical interesterification uses catalysts such as alkali residues to randomly exchange fatty acids at the three positions on glycerol under controlled temperature and time. Enzymatic interesterification uses immobilized lipases to catalyze fatty-acid exchange with greater specificity, typically at milder conditions. Enzymatic methods often aim to reduce trans-fat formation compared with some hydrogenation processes and can produce fats tailored to specific melting profiles.

Applications are widespread in the food industry. Interesterified fats are used to adjust spreadability and mouthfeel in margarines and shortenings, to modify crystallization in bakery fats and confectionery coatings, and to create fats with desired performance for frying and baking. They also enable the design of structured lipids for particular dietary or functional objectives.

Health and regulatory aspects vary by jurisdiction. Interesterification does not inherently create trans fats, unlike partial hydrogenation, and is often presented as a way to tailor functionality without trans-fat formation. Some considerations include changes in melting behavior and potential effects on digestion and metabolism, though these are areas of ongoing study.