Effect of acyl migration in Lipozyme TL IM‐catalyzed interesterification using a triacylglycerol model system

Abstract

Lipase-(Lipozyme TL IM) catalyzed interesterification of triacylglycerols was studied at water activities (a w ) from 0.22 to 0.8. The substrates trilaurin (LLL) and 1,3-palmitin-2-olein (POP) were used in equimolar amounts to facilitate separate measurements of the interesterification in the sn-1,3 positions and changes in the fatty acid (FA) composition in the sn-2 position. The reaction at a w ¼ 0.35 was the fastest, and that at a w ¼ 0.84 the slowest, due to increased hydrolysis. The interesterification in the sn-1,3 positions was above 90% after 2 h reaction at a w ¼ 0.22, 0.35, and 0.54, and the main triacylglycerols were LLP, POL, LOL, and PLP. The FA composition in the sn-2 position was conserved during the first 1-2 h, and the randomization due to acyl migration was complete after 24 h. During the entire reaction, FA present in the sn-1,3 positions were removed from the triacylglycerols by the enzyme, and a fraction of them was released by hydrolysis. The gradual change in the composition of the free FA thus reflected the randomization of FA within the triacylglycerol molecules. Improved knowledge on the factors affecting the rates of interesterification, hydrolysis, and randomization is required to develop tailor-made lipid products. Practical applications:In an ideal 1,3-specific lipase-catalyzed interesterification reaction, the FA composition in the sn-2 position remains constant. In practice, small changes are seen in the FA composition in this position, and under certain conditions a completely randomized FA distribution can be obtained. Randomization is slower than interesterification. Uncontrolled hydrolysis should be avoided because it lowers the TAG yield. By varying the reaction time, different triacylglycerol mixtures can be produced: i.e. products originating from 1,3-specific interesterification, as well as partially or completely randomized products.

Enzymatic Interesterification of a Lard and Rapeseed Oil Equal-Weight Blend

“…The enzyme reacts on the sn-1,3 ester linkages, so the percentage of particular fatty acids in the sn-2 position of TAG in comparison with their counterparts in the initial blend remain nearly unchanged. The small changes in fatty acids at the sn-2 positions may result in part from experimental analytical precision and from acyl migration in the TAG species during interesterification time 23,24 .…”

The Effectiveness of Immobilized Lipase Thermomyces lanuginosa in Catalyzing Interesterification of Palm Olein in Batch Reaction

“…The pilot-scale interesterification increased the percentage of FFA, MAG, DAG and some TAG species. The increase of the FFA and MAG content is due to the hydrolysis activity in the enzyme system that also leads to slightly decrease of the TAG yield 21 . Overall, the total triunsaturated and trisaturated TAGs were increased, while total diunsaturated and disaturated TAGs were reduced at the end of the enzymatic interesterification reactions.…”

“…However after prolonged reaction, with the formation of 1,3-DAG, acyl migration occurred that permit some randomization of the sn-2 position fatty acids in the TAG backbone 6 . The factors of acyl migration were reaction time, reaction temperature, presence of water, reactor type and reaction system 21,22 . In other words, the specificity performance of enzyme is very dependent on the reaction system and conditions, as they can only perform their specificity under particular conditions 10,11 .…”

Lipase catalyzed interesterification of Amazonian patauá oil and palm stearin for preparation of specific-structured oils

“…These reactions initially were mainly produced following the conventional chemical process where one of the most commonly used catalysts is sodium methoxide, which is efficient in terms of reaction team and yields (Poppe et al 2015). However, lipase-catalyzed interesterification has many advantages compared to the corresponding chemical process (Svensson and Adlercreutz 2011). Fewer and simpler process steps are required, fewer by-products are created, less water is needed, and no aggressive chemicals are required to obtain the structured oils (Holm and Cowan 2008).…”

“…Fewer and simpler process steps are required, fewer by-products are created, less water is needed, and no aggressive chemicals are required to obtain the structured oils (Holm and Cowan 2008). Furthermore, these enzymes may be specific for the position or type of fatty acid in the glycerol, which allows the variety mixtures of oils, can be produced (Svensson and Adlercreutz 2011). However, as vegetable oils are heterogeneous substrates, containing triacylglycerol formed by very different fatty acids, it's difficult to find a lipase that acts efficiently on all available substrates (Poppe et al 2015;Issariyakul and Dalai 2014).…”