Tripalmitin–Sodium Dodecyl Sulfate Emulsion Droplet Liquid vs. Solid State Impacts in vitro Digestive Lipolysis

Abstract

Questions remain as to the impact of lipid structure, including crystallinity, on digestibility and metabolic response. This study was undertaken to determine the impact of triacylglycerol crystallinity on digestibility using undercooled (liquid emulsion, LE) and crystalline (solid emulsion, SE) particles exposed to an in vitro model simulating upper gastrointestinal tract (GIT) digestive conditions. By hot microfluidization, 10 wt% tripalmitin oil-inwater emulsions (D 3,2~0 .115 nm) with 0.9 wt% sodium dodecyl sulfate (SDS) were prepared. SE demonstrated complex melting behavior, was predominantly in the beta polymorph, and consisted of a heterogeneous mixture of anisometric particles. In vitro duodenal lipolysis was more extensive for the spherically shaped LE droplets vs. SE (P < 0.05), despite the fact that exposure to simulated gastric conditions (at pH 2, but not at pH 7) induced partial crystallization. Therefore, lipid droplet physical state impacted and was impacted by exposure to gastrointestinal conditions, with differences observed in fatty acid digestive release and implications for lipid absorption. Keywords Structure-functional properties Á Food and feed science Á Nutrition and health Á Emulsions Á Colloids Á Fat crystallization Á Polymorphism Á Lipid chemistry Á Lipid analysis J Am Oil Chem Soc (2018) 95: 161-170.

Attenuation of Palm Stearin Emulsion Droplet in Vitro Lipolysis with Crystallinity and Gastric Aggregation

“…Bonnaire et al 13 uniquely addressed this by comparing the in vitro digestibility of undercooled-liquid versus crystalline-solid tripalmitin and sodium dodecyl sulfate emulsion droplets, achieved by tempering the samples differently after hot, high-pressure homogenization. Huynh and Wright 14 replicated their finding that lipolysis was more extensive for the liquid droplets than for the solid droplets when a gastric phase was included in the in vitro model and also evidenced the induction of a small amount of crystallinity in the undercooled droplets. The solid and liquid particles were also found to have different morphologies, meaning that the comparison of physical state was partly confounded by differences in interfacial area.…”

“…Hydrogen-ion shielding of negatively charged emulsion droplets can decrease charge repulsion, thereby leading to droplet aggregation. 14,28,29 Moreover, the gastric pH of 3.0 is below the pK a reported for stearic acid (4.3−5.5) 30 such that ionization of any free stearic acid present from Span 60 or in the palm stearin is minimized. LE easily redispersed upon mixing and exposure to the duodenal fluids, indicating flocculation at the gastric stage.…”

Rice bran wax structured oleogels and in vitro bioaccessibility of curcumin

“…The trend of increasing SFC with RBW concentration is expected, considering that at 5°C (the temperature at which these measurements were taken) RBW is below its melting temperature and exists in the solid state (Pandolsook & Kupongsak, 2017). Increased SFC in oleogel systems has been previously demonstrated to reduce erosion of the system and decrease access of the lipase enzyme to carry out lipolysis on the lipids in the system (Calvo‐Lerma et al, 2018; Guo et al, 2014; Huynh & Wright, 2018; Iwanaga et al, 2012; O'Sullivan et al, 2016). Reduction in breakdown of the oleogel system during digestion would shield curcumin from exposure to the oxidative and hydrolytic environment of the digestive tract, and therefore formulation with higher concentrations of RBW would increasingly protect the curcumin and improve its oral bioaccessibility.…”

“…This prevention of mechanical breakdown would then prevent exposure of the solubilized curcumin in the continuous oil phase of the oleogels to the acidic and oxidizing gastric environment, which is known to lead the oxidation and hydrolysis of curcumin molecules (Kharat et al, 2017). The higher hardness of 10% RBW oleogels, and the corresponding higher SFC and denser crystal structure may protect the oleogel from mechanical and chemical erosion, thus limiting curcumin's exposure to the oxidizing environment during the gastric phase of digestion (Calvo‐Lerma et al, 2018; Guo et al, 2014; Huynh & Wright, 2018; Iwanaga et al, 2012; O'Sullivan et al, 2016). Gels with higher hardness have been shown to be less susceptible to lipolysis during digestion, due to lowered oil diffusion and inability of gastric enzymes to penetrate the lipophilic and crystallized gel matrix (Guo et al, 2014; Iwanaga et al, 2012; O'Sullivan et al, 2016).…”

In Vitro Gastrointestinal Digestion of Palm Olein and Palm Stearin-in-Water Emulsions with Different Physical States and Fat Contents

“…The lipid digestibility is affected by the composition, structure, and position of fatty acids in the triglycerides, the emulsified structures of lipids, such as interfacial composition and particle size of lipid droplets, and the physical state (i.e., liquid vs solid) of the lipid in food products. , Generally, lipids with high melting points containing solid fat at body temperature tend to have a slower digestion rate and impaired bioavailability compared with liquid oils, which was confirmed by in vitro, − animal, , and human studies. , For example, a 20% canola/hydrogenated fat-in-water emulsion with ∼25% solid fat content (SFC) exhibited a considerably lower rate and extent of in vitro lipolysis than a 20% canola oil-in-water (O/W) emulsion with 0% SFC, which subsequently correlated with its lower triglyceride absorption rate in a rat model . In support, human postprandial lipemia levels were reduced by 53% after the consumption of unrandomized shea butter and sunflower oil blends with 22% SFC at 37 °C compared to sunflower oil with 0% SFC at 37 °C .…”