In vitrolipid digestion of chitinnanocrystal stabilized o/w emulsions

Abstract

Chitin nanocrystals (ChN) have been shown to form stable Pickering emulsions. These oil-in-water emulsions were compared with conventional milk (whey protein isolate, WPI, and sodium caseinate, SCn) protein-stabilized emulsions in terms of their lipid digestion kinetics using an in vitro enzymatic protocol. The kinetics of fatty acid release were evaluated as well as the change in oil droplet size of the respective emulsions during lipid digestion. The interfacial pressure was measured by addition of the duodenal components using drop tensiometry and the electrical charge of the oil droplets was also assessed, in an attempt to relate the interfacial properties with the stability of the emulsions towards lipolysis. Lipid hydrolysis in the ChN-stabilized emulsion was appreciably slower and the plateau values of the total concentration of fatty acids released were much lower, compared to the WPI- and SCn-stabilized emulsions. Moreover, the ChN-stabilized emulsions were relatively stable to coalescence during lipid digestion, whereas the WPI- and SCn-stabilized emulsions exhibited a significant increase in their droplet size. On the other hand, no major differences were shown among the different emulsion samples in terms of their interfacial properties. The increased stability of the ChN-stabilized emulsions towards lipolysis could be attributed to several underlying mechanisms: (i) strong and irreversible adsorption of the chitin nanocrystals at the interface that might inhibit an extensive displacement of the solid particles by bile salts and lipase, (ii) network formation by the nanocrystals in the bulk (continuous) phase that may reduce lipid digestion kinetics, and (iii) the ability of chitin, and consequently of ChNs, to impair pancreatic lipase activity. The finding that ChNs can be used to impede lipid digestion may have important implications for the design and fabrication of structured emulsions with controlled lipid digestibility that could provide the basis for the development of novel products that may promote satiety, reduce caloric intake and combat obesity.

Effect of Gum Arabic, Gum Ghatti and Sugar Beet Pectin as Interfacial Layer on Lipid Digestibility in Oil-in-Water Emulsions

“…The lipid droplets in conventional emulsion would be coated by a thin monolayer of globular protein molecules, while the droplets in nanoemulsion would be coated by a much thicker layer of aggregated globular protein molecules due to the shrinkage of the droplets during their preparation by solvent evaporation [3]. Particle-stabilized interfaces also offer a promising template for controlling interfacial displacement by bile salts and thus lipid digestion, as was reported for chitin nanocrystals [10]. Sarkar et al revealed that the heat-induced microgel particle could achieve an increased coverage-fused network at the oil-water interface, which was more efficient in delaying the rate of lipid digestion compared to the intact whey protein microgel particles [11].…”

Soy glycinin as food-grade Pickering stabilizers: Part. I. Structural characteristics, emulsifying properties and adsorption/arrangement at interface

“…To date, a limited number of these food-grade Pickering particles have been reported in the literature, which encompass modified starch (Karger, Fayazmanesh, Alavi, Spyropoulos, & Norton, 2012;Tan et al, 2012), chitin nanocrystal particles (Tzoumaki, Moschakis, Kiosseoglou, & Biliaderis, 2011;Tzoumaki, Moschakis, Scholten, & Biliaderis, 2013), waterinsoluble zein (de Folter, van Ruijven, & Velikov, 2012), microcrystalline cellulose (MMC) (Karger et al, 2012), solid lipid nanoparticles (Gupta & Rousseau, 2012), and more recently, proteinbased particles or nanoparticles from whey protein (Destribats, Rouvet, Gehin-Delval, Schmitt, & Binks, 2014;Shimoni, Levi, Levi Tal, & Lesmes, 2013) and soy or pea protein isolate (Liang & Tang, 2014;Liu & Tang, 2013. Among these particles, colloidal particles or nanoparticles from food proteins seem to be most promising to perform as Pickering stabilizers.…”

In vitro digestion of Pickering emulsions stabilized by soft whey protein microgel particles: influence of thermal treatment

“…Even in the case of heat-treated whey protein isolate-stabilized emulsions, bile salts are known to create defects in the protein network at the cross-linked interface and thus access to lipase is established 18,46 . Both WPI and heat treated WPIstabilized emulsions generated approximately 46% of FFAs derived from the long-chain FFAs from sunflower oil that tend to activity 21,36 . However, in case of WPM and HT-WPM stabilized emulsions, the extent of fatty acid release was slightly lower than the WPI emulsions (46%) generating approximately 42% of FFAs.…”

“…Simplistically, one might expect lipid digestion to be controlled by strengthening the interfacial network that resists displacement by bile salts. Therefore, particle-stabilized interfaces offer a promising template for controlling displacement by bile and therefore lipid digestion, with the first evidence being reported on chitin nanocrystals 21 . If proven, Pickering emulsions could be used to address site-dependent controlled release of nutrients, drugs or bioactive moieties in food, pharmaceutical and personal care applications.…”