Enhancing vitamin E bioaccessibility: factors impacting solubilization and hydrolysis of α-tocopherol acetate encapsulated in emulsion-based delivery systems

Abstract

Oil-soluble vitamins are often encapsulated within emulsion-based delivery systems to facilitate their incorporation into aqueous-based products. We have examined the influence of carrier oil type and simulated small intestinal fluid (SSIF) composition on the bioaccessibility of emulsified vitamin E using a gastrointestinal model. Oil-in-water emulsions containing vitamin E acetate were prepared using bile salts as emulsifier, and either long chain triacylglycerols (glyceryl trioleate, LCT) or medium chain triacylglycerols (glyceryl trioctanoate, MCT) as carrier oils. The addition of calcium (CaCl₂) to the SSIF increased the extent of lipid digestion in LCT-emulsions, but had little impact in MCT-emulsions. The bioaccessibility of vitamin E increased in the presence of calcium and phospholipids (DOPC) in LCT-emulsions, but decreased in MCT-emulsions. The highest bioaccessibility (≈66%) was achieved for LCT-emulsions when the SSIF contained both calcium and phospholipids. The conversion of α-tocopherol acetate to α-tocopherol after in vitro digestion was considerably higher for LCT-emulsions when calcium ions were present in the SSIF, but was not strongly affected by SSIF composition for MCT-emulsions. In general, this research provides important information about the factors influencing the bioaccessibility of emulsified vitamin E, which could be used to design more effective emulsion-based delivery systems for increasing the oral bioavailability of this important bioactive component.

Influence of Oxidants on the Stability of Tocopherol in Model Nanoemulsions: Role of Interfacial Membrane Organized by Nonionic Emulsifiers

“…concentration was measured according to the method described by Yang et al [17] with slight modification. α-Tocopherol concentrations in emulsions were determined by first vigorously vortexing 2 g of emulsion with 4 g of dichloromethane for 2 min.…”

Boosting the bioavailability of hydrophobic nutrients, vitamins, and nutraceuticals in natural products using excipient emulsions

“…Fish oil contains long chain FFAs, but they are highly kinked, which may reduce the dimensions of the non-polar domains compared to saturated FFAs. Oil phase composition has also been shown to influence the bioaccessibility of vitamin D (Ozturk et al, 2015), vitamin E (Yang, Decker, Xiao, & McClements, 2015;Yang & McClements, 2013), Coenzyme Q10 (Cho et al, 2014), and curcumin (Ahmed, Li, McClements, & Xiao, 2012). Carotenoid bioaccessibility from salad vegetables has also been shown to depend on the nature of the lipid co-ingested with them, suggesting that excipient salad dressings could be developed to enhance the uptake of these potentially beneficial nutraceuticals (Huo et al, 2007a;Huo et al, 2007b).…”

Enhanced oral bioavailability and prophylactic effects on oxidative stress and hepatic damage of an oil solution containing a rosmarinic acid–phospholipid complex

“…Its characteristic structure and low toxicity also make it extensively used as oil phase in emulsion and other oral formulations (Yang, Decker, Xiao, & McClements, 2015). Among these MCT, Masester ® E6000, caprylic/capric triacylglycerol, can be rapidly digested in the gastrointestinal tract after being emulsified by endogenous emulsifier such as bile and then hydrolysed by pancreatic lipase.…”