Future of Structured Lipids: Enzymatic Synthesis and Their New Applications in Food Systems

Abstract

Structured lipids (SLs) refer to a new type of functional lipid obtained by modifying natural triacylglycerol (TAG) through the restructuring of fatty acids, thereby altering the composition, structure, and distribution of fatty acids attached to the glycerol backbones. Due to the unique functional characteristics of SLs (easy to absorb, low in calories, reduced serum TAG, etc.), there is increasing interest in the research and application of SLs. SLs were initially prepared using chemical methods. With the wide application of enzymes in industries and the advantages of enzymatic synthesis (mild reaction conditions, high catalytic efficiency, environmental friendliness, etc.), synthesis of SLs using lipase has aroused great interest. This review summarizes the reaction system of SL production and introduces the enzymatic synthesis and application of some of the latest SLs discussed/developed in recent years, including medium- to long-chain triacylglycerol (MLCT), diacylglycerol (DAG), EPA- and DHA-enriched TAG, human milk fat substitutes, and esterified propoxylated glycerol (EPG). Lastly, several new ways of applying SLs (powdered oil, DAG plastic fat, inert gas spray oil, and emulsion) in the future food industry are also highlighted.

Trends in Fat Modifications Enabling Alternative Partially Hydrogenated Fat Products Proposed for Advanced Application

“…Recent years have seen a visible shift in the direction of manufacturing new fat products, with a clear emphasis on the use of enzymatic esterification, both in basic research and implementation [ 65 ]. Some products are already on the market, and others are being developed, with ongoing development of completely new products, taking into account current nutritional trends and their quality and safety.…”

Isolation of Fatty Acids from the Enzymatic Hydrolysis of Capsaicinoids and Their Use in Enzymatic Acidolysis of Coconut Oil

“…Production of lipids with fatty acid composition tailored to specific functional demands (structured lipids) has been previously developed 40−42) . These efforts have several target products: i) medium-and long chain triglycerides (MLCTs) , ii) human milk fat substitutes (HMFSs) , iii) cocoa butter equivalents (CBEs) , iv) trans-free plastic fats (margarines and shortenings) , v) low-calorie fats/oils, vi) healthbeneficial FA-rich fats/oils, vii) monoacylglycerols/diacylglycerol, and viii) structurally modified phospholipids 33,40,43) .…”

“…However, in the context of preparation of food products enzymatic methods are preferred as the chemical ones usually require harsher conditions (e.g., high temperature) , which can lead to the formation of dangerous side product impurities 42) . Further advantages of enzymatic syntheses of structured lipids include high efficiency, selectivity, potential to eliminate solvents, and low energy consumption 40) . Structured lipids can be synthesized using several different reaction types.…”

“…Structured lipids can be synthesized using several different reaction types. Firstly, glycerol can be directly reacted with fatty acids in an esterification reaction 40,44) . For example, this approach is used in the production of medium chain triglycerides (MCTs) 44) .…”

“…Alternatively, the fatty acid composition of a fat or oil can be modified by the acidolysis and interesterification reactions 40,43) . The acidolysis reaction is a reaction between a fat or oil and a fatty acid, or a mixture of fatty acids, as an acyl donor 43) .…”