Regiospecific Positioning of Palmitic Acid in Triacylglycerol Structure of Enzymatically Modified Lipids Affects Physicochemical and In Vitro Digestion Properties

Abstract

Tripalmitin-(PPP, 81.2%), 1,3-dipalmitoyl-2-oleoylglycerol-(POP, 64.4%), 1,2-dipalmitoyl-3-oleoylglycerol-(PPO, 86.5%), and 1,3-dioleoyl-2-palmitoylglycerol-(OPO, 50.2%)-rich lipids with different regiospecific positions of palmitic acid (P) were synthesized via acetone fractionation and lipase-catalyzed acidolysis, and their physicochemical and hydrolytic characteristics were compared. Triacylglycerols (TAGs) with higher content of P, wherein P was at the sn-1 (or 3) position, had higher melting points, crystallization temperatures, and packing densities of fat crystals compared to those with a lower content of P, and with P at the sn-2 position. The in vitro digestion degree calculated as released fatty acid (FA) (%) at 30, 60, and 120 min was in the following order: OPO-rich > PPO-rich > POP-rich lipids. At 120 min, in vitro digestion of the OPO-rich lipid released 92.6% of fatty acids, resulting in the highest digestibility, while 89.7% and 87.2% of fatty acids were released from the OPO-rich and PPO-rich lipids, respectively. Over the digestion period, the TAG and monoacylglycerol (MAG) contents decreased, while the diacylglycerol (DAG) content initially increased and then decreased, and the 1,2-DAG content exceeded the 1,3-DAG content. Therefore, the content and stereospecific position of P attached to a specific TAG affected the physicochemical and in vitro digestion characteristics of the lipids.

Cholecalciferol‐ and α‐tocopherol‐loaded walnut oil emulsions stabilized by whey protein isolate and soy lecithin for food applications

“…The release of FFAs from all emulsions during the first 10 min was very fast. In the simulated small intestine stage, the lipids in the emulsion were emulsified by bile acids, and then fatty acids in the sn ‐1, 3 position of triglyceride (TAG) were hydrolyzed by small intestine lipase 45 . Within the initial 10 min, most lipases would quickly bind to the sn ‐1, 3 position of TAG in the emulsions, resulting in a maximum of enzyme–substrate bonding and rapid FFA production 46 .…”

Melting, Crystallization, and In Vitro Digestion Properties of Fats Containing Stearoyl-Rich Triacylglycerols

“…In addition, the incorporated FAs at the sn -1,3 position of OSO-rich fat were almost completely hydrolyzed by in vitro digestion for 120 min. The authors previously showed that OPO-rich lipid was more easily digested than PPO-rich lipid, as the amounts of FFAs (%) released from each at 30, 60, and 120 min were 88.6%, 91.35%, and 104.9%, and 64.9%, 69.7%, and 75.7%, respectively, during the same in vitro multi-step digestion [ 21 ]. Therefore, the in vitro digestibility of lipids was affected by the type of FAs incorporated at the sn -1,3 position of TAG, and the digestibility was increased by less saturation and FAs with shorter carbon chains in the following descending order of OPO- > PPO- > OSO- > SSO-rich fats.…”

“…SSO-rich and OSO-rich fats were synthesized from FHSBO (SSS-rich fat) and oleic acid rich fatty acids by lipase-catalyzed acidolysis followed by acetone fractionation, as presented in Figure 7 [ 21 ]. The completely dissolved FHSBO was mixed with oleic acid (1:2 molar ratio) in an Erlenmeyer flask (500 mL) with screw cap.…”

“…In vitro digestion rates of SSO-rich and OSO-rich fats were determined under simulated mouth, stomach, and small intestine digestive condition of the modified method of Versantvoort et al [ 28 ] and Chang and Lee [ 21 ]. The melted fat (100 mg) and saliva juice (1.2 mL) were mixed in a 100 mL Erlenmeyer flask in shaking water bath at 37 °C and 80 rpm for 5 min, and gastric juice (2.4 mL) was added and reacted for 2 h. Bile juice (1.2 mL), duodenal juice (2.4 mL), and NaHCO 3 solution (0.4 mL) were added, and the digestion of fat proceeded for 30, 60, and 120 min.…”

Preparation of human milk fat substitute and improvement of its oxidative stability

“…However, cow milk and vegetable oils generally contain SFAs esterified to the sn-1 and sn-3 positions and USFAs at sn-2 position. These differences not only affect the nutrition and digestion of fats, but also cause stool hardness and constipation due to the preferential hydrolysis of PA in the sn-1,3 positions by pancreatic lipase to form calcium soap which is water-insoluble and can hardly be absorbed in the intestine of babies (Lee and Chang, 2021). In contrast, when PA is esterified to the sn-2 position, the 2-monoacylglycerol formed is readily absorbed (Ghide and Yan, 2021), therefore, the kinetics of hydrolysis of different TAGs may induce a different digestive process.…”