INRA, UMR INRA1260, Marseille, France.
Mol Nutr Food Res. 2013 Jul;57(7):1237-45. doi: 10.1002/mnfr.201200720. Epub 2013 Mar 21.
Vitamin E is present in feed and food mainly as d-α-tocopherol (d-α-TOL) but also as all-rac-α-tocopheryl acetate (rac-α-TAC) through supplementation. Its absorption efficiency is low compared to that of triacylglycerols. The aim of this work was thus to study the fate of TAC during digestion.
Using an in vitro digestion model, we showed that TAC was distributed between mixed micelles (36%), liposomes (9%), and nonsolubilized food debris (52%). A significant fraction of TAC was also found in emulsions when fat hydrolysis was not complete. Among the candidate esterases tested, i.e. cholesteryl ester hydrolase, pancreatic lipase, and pancreatic lipase-related protein 2, only cholesteryl ester hydrolase was able to hydrolyze TAC to all-rac-α-TOL, about five times more efficiently when it was incorporated into mixed micelles or liposomes than into emulsions or in the food matrix. Caco-2 cells were able to hydrolyze TAC and to uptake TOL when TAC was incorporated into mixed micelles but not into emulsions.
During digestion, most TAC is recovered in matrices where its hydrolysis and its uptake by intestinal cells are markedly less efficient than in mixed micelles.
维生素 E 主要以 d-α-生育酚（d-α-TOL）的形式存在于饲料和食物中，但也可以通过补充全反式-α-生育酚乙酸酯（rac-α-TAC）的形式存在。与三酰甘油相比，其吸收效率较低。因此，这项工作的目的是研究 TAC 在消化过程中的命运。
使用体外消化模型，我们表明 TAC 分布在混合胶束（36%）、脂质体（9%）和未溶解的食物残渣（52%）之间。当脂肪水解不完全时，TAC 也会在乳液中发现大量存在。在所测试的候选酯酶中，即胆固醇酯水解酶、胰脂酶和胰脂酶相关蛋白 2，只有胆固醇酯水解酶能够将 TAC 水解为全反式-α-生育酚，当它被包裹在混合胶束或脂质体中时，其水解效率比在乳液或食物基质中高约五倍。当 TAC 被包裹在混合胶束中时，Caco-2 细胞能够水解 TAC 并摄取 TOL，但不能在乳液中进行。
在消化过程中，大多数 TAC 会在其水解和被肠道细胞吸收的效率明显低于混合胶束的基质中被回收。
