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This research evaluated the influence of natural emulsifier on the emulsion particle size of the black pepper oleoresin combined with a sucrose solution, and its effects on the kinetics of chayote osmodehydration and the extent of piperine fortification. Macroemulsions with gum arabic (GA) and nanoemulsions with whey protein concentrate (WPC) were prepared in a 50% sucrose solution. The mean particle size and polydispersity index of both sucrose-emulsion solutions were determined using dynamic light scattering, and the kinetics of water loss (W F L), solids gain (S G), water activity (a w), and water diffusion coefficients (D w) were obtained during the osmotic processing (25–45 °C). With a particle size of 165 nm, the WPC nanoemulsion had a higher viscosity than the GA emulsion, which measured 655 nm making them susceptible to coalescence. Scanning electron micrographs revealed that during osmotic dehydration, the WPC nanoemulsions formed dense layers within the chayote tissue. This resulted in reduced water loss kinetics and diffusivity, particularly at high temperatures. In terms of fortifying chayote with piperine, the use of a macroemulsion resulted in greater rates of impregnation (0.12 mg piperine (g wet solids min)−1) compared to the nanoemulsion, which had rates of 0.04 mg piperine (g wet solids min)−1. After 420 min of osmodehydration, it was observed that the GA macroemulsion resulted in higher levels of piperine impregnation than the WPC nanoemulsion. These findings have important implications for successfully fortifying fruits and vegetables with lipophilic bioactive compounds using emulsions in combination with the osmotic dehydration technique. [Display omitted] • Chayote was fortified with piperine through emulsions and osmotic dehydration. • The size of the emulsion influences the osmotic dehydration kinetics of chayote. • The size of the emulsion affects the viscosity of the osmotic solution. • The high viscosity of the osmotic medium decreases the diffusivity of water. • Fortification of chayote with piperine was achieved using a macroemulsion. [ABSTRACT FROM AUTHOR]

In this study, oil-in-water nanoemulsions of paprika oleoresin stabilized with soy lecithin, whey protein concentrate and gum Arabic were prepared by high-pressure homogenization. Oil-in-water nanoemulsions were characterized through interfacial tension, mean particle size, polydispersity index (PDI), and the physical and chemical stability during storage. Kinetic data for degradation of total carotenoids were used for estimating entropy and enthalpy of activation using transition state theory. Whey protein concentrate and soy lecithin were more effective to forming droplets at the nanometric range (d < 150 nm) than gum Arabic (d < 539.6 nm). The particle size of the nanoemulsions decreased as the interfacial tension increased. The carotenoids in nanoemulsions stability increased as the interfacial tension, PDI and entropy decreases. According to the enthalpy–entropy compensation, whey protein concentrated, and gum Arabic were enthalpy-driven, whereas soy lecithin was entropy-driven (T B < T hm). These results provide useful information for designing delivery systems to encapsulate and stabilize lipophilic molecules. Image 1 • Carotenoid nanoemulsions (d < 200 nm) were designed using natural emulsifiers. • The interfacial and thermodynamic properties on stability of nanoemulsions were studied. • Whey protein concentrate and soy lecithin were more effective than gum Arabic. • The stability increased as the interfacial tension, particle size and entropy decreases. [ABSTRACT FROM AUTHOR]