Effects of Emulsifier Charge and Concentration on Pancreatic Lipolysis: 2. Interplay of Emulsifiers and Biles

Abstract

As a direct continuation of the first part of our in vitro study (Vinarov et al., Langmuir 2012, 28, 8127), here we investigate the effects of emulsifier type and concentration on the degree of triglyceride lipolysis, in the presence of bile salts. Three types of surfactants are tested as emulsifiers: anionic, nonionic, and cationic. For all systems, we observe three regions in the dependence degree of fat lipolysis, α, versus emulsifier-to-bile ratio, f(s): α is around 0.5 in Region 1 (f(s) < 0.02); α passes through a maximum close to 1 in Region 2 (0.02 < f(s) < f(TR)); α is around zero in Region 3 (f(s) > f(TR)). The threshold ratio for complete inhibition of lipolysis, f(TR), is around 0.4 for the nonionic, 1.5 for the cationic, and 7.5 for the anionic surfactants. Measurements of interfacial tensions and optical observations revealed the following: In Region 1, the emulsifier molecules are solubilized in the bile micelles, and the adsorption layer is dominated by bile molecules. In Region 2, mixed surfactant-bile micelles are formed, with high solubilization capacity for the products of triglyceride lipolysis; rapid solubilization of these products leads to complete lipolysis. In Region 3, the emulsifier molecules prevail in the adsorption layer and completely block the lipolysis.

Bile salts in digestion and transport of lipids

“…The formation of mixed micelles of BS and surfactants can also affect the degree and rate of lipolysis. Vinarov et al studied the effect of surfactant concentration and charge on the lipolysis of oil-in-water emulsions in the presence of porcine BE [142]. The researchers found optimum solubilisation capacities of mixed micelles formed by bile and either non-ionic T T olefinsulfonate, and sodium lauryl ether sulfate) emulsifiers at various surfactant-to-bile molar ratios.…”

Encapsulation of the therapeutic microbe Akkermansia muciniphila in a double emulsion enhances survival in simulated gastric conditions

“…3.5 ± 0.3 15.10.6 24.0 ± 0.9 24.7 ± 1.3 25.1 ± 1.5 Span 1.3 ± 0.1 1.5 ± 0.0 1.7 ± 0.1 1.6 ± 0.0 1.6 ± 0.1 (Maldonado-Valderrama et al, 2008). Bile salts aid lipolysis by competitively displacing protein emulsifier (Vinarov et al, 2012), and thus allowing lipase and colipase to adsorb on the lipid surface and carry out lipolysis (Maldonado-Valderrama, Wilde, Macierzanka, & Mackie, 2011), irrespective of droplet size (Begley, Gahan, & Hill, 2005).…”

Enhancing Nutraceutical Performance Using Excipient Foods: Designing Food Structures and Compositions to Increase Bioavailability

“…Surfactants may interact with digestive enzymes, such as amylase, lipase, or protease, which may alter their ability to break down pharmaceutical or food matrices (Delorme and others ). Surfactants may be incorporated into mixed micelles within the small intestine and enhance their solubilization capacity for lipophilic bioactive agents (Vinarov and others ). Surfactants may adsorb to the surfaces of fat droplets thereby inhibiting the adsorption of lipase, which would slow down the rate of lipid digestion (Li and others ; Troncoso and others ).…”