Food, nutrition, and pharmaceutical scientists are trying to elucidate the major factors impacting the bioavailability of macronutrients (e.g., lipids) and micronutrients (e.g., vitamins) so as to improve their efficacy. Currently, there is still a limited understanding of how food matrix effects impact digestion and bioaccessibility determined under the INFOGEST model, which is currently the most widely used standardized in vitro gastrointestinal model. Therefore, we examined the impact of corn oil concentration on lipid digestion and β-carotene bioaccessibility using model food emulsions. For all oil concentrations tested (2.5 to 20%), complete lipid digestion was achieved using fed-state gastrointestinal conditions, which could only be seen if a back-titration was performed. The particle size and negative surface potential on the mixed micelles formed at the end of the small intestine phase both increased with increasing oil concentration, which was attributed to the generation of more free fatty acids. The β-carotene bioaccessibility increased when the oil concentration was raised from 2.5 to 10% due to the increased solubilization capacity of the mixed micelles, but then it decreased when the oil concentration was raised further to 20% due to precipitation and sedimentation of some of the β-carotene. The maximum β-carotene bioaccessibility (93.2%) was measured at 10% oil. These results indicate that the oil concentration of emulsions influences β-carotene bioaccessibility by altering digestion, solubilization, and precipitation processes. This knowledge is important when designing more effective functional or medical food products.

This study investigated the possibility of using a phase separation, mixing, and enzymatic gelation approach to construct seafood analogs from plant protein-polysaccharide mixtures with properties mimicking real seafood. Heat-denatured pea protein (10%, w/w) and pectin (0–1%, w/w) were mixed to produce phase separated biopolymer blends. These blends were then subjected to mild shearing (350 rpm) to obtain fiber-like structures, which were then placed in molds and set by gelling the pea proteins using transglutaminase (2%, w/w). The appearance, texture, and cooking properties of the resulting scallop analogs were characterized and compared to those of real scallop. The presence of the pectin promoted the formation of a honeycomb structure in the scallop analogs, and microscopic orientation of the proteins was observed in the plane parallel to the applied shear flow. Lower pectin concentrations (0.5%, w/w) led to stronger gels with better water holding capacity than higher ones (1.0%, w/w). The appearance and texture of the plant-based scallop analogs were like those of real scallop after grilling, indicating the potential of using this soft matter physics approach to create plant-based seafood analogs. One of the main advantages of this method is that it does not require any expensive dedicated equipment, such as an extruder or shear cell technology, which may increase its commercial viability.

We systematically investigated the impact of oil droplet diameter (≈0.15, 1.6, and 11 μm) on the bioaccessibility of three oil-soluble vitamins (vitamin A palmitate, vitamin D, and vitamin E acetate) encapsulated within plant-based emulsions.

The oil droplets in commercial emulsified foods have dimensions that vary widely, from hundreds of nanometers to tens of micrometers. Previously, the size of the droplets in oil-in-water emulsions has been shown to impact their gastrointestinal behavior, which may influence their physiological effects. In this study, we analyzed the impact of oil droplet diameter (0.16, 1.1 and 8.2 μm) on lipid digestion and nutraceutical bioaccessibility using a widely used standardized gastrointestinal tract model: the INFOGEST method. The emulsions used consisted of corn oil droplets stabilized using a food-grade non-ionic surfactant (Tween 20), and the droplet size was controlled by preparing them with a microfluidizer (small), sonicator (medium), or high-shear blender (large). The surfactant-coated oil droplets were relatively resistant to size changes in the mouth and stomach, due to the strong surface activity and steric stabilization mechanism of the non-ionic surfactant used. As expected, the kinetics of lipid digestion were enhanced for smaller droplets because of their greater specific surface area. The degree of lipid digestion fell from 117% to 78% (p < 0.001) as the initial droplet diameter was raised from 0.16 to 8.2 μm. In addition, there was a reduction in β-carotene bioaccessibility from 83 to 15% (p < 0.001) with increasing droplet diameter. This result was ascribed to several effects: (i) some carotenoids were trapped inside the undigested oil phase; (ii) fewer mixed micelles were produced to internalize the carotenoids; and, (iii) a fraction of the carotenoids crystallized and sedimented. Our results underline the critical importance of considering droplet size when developing emulsified foods loaded with carotenoids. The results obtained by the INFOGEST method are consistent with those found using other in vitro methods in earlier studies.

Understanding the behavior and biological fate of silver nanoparticles (AgNPs) applied on plant surfaces is significant for their risk assessment. Our study's objective is to investigate the interactions between AgNPs and plant biomolecules as well as to monitor and quantify the penetration of AgNPs in spinach by an in situ and real-time surface enhanced Raman spectroscopic (SERS) mapping technique. AgNPs (2 μg per leaf) of different surface coatings (citrate, CIT, and polyvinylpyrrolidone, PVP) and sizes (40 and 100 nm) were foliarly applied onto spinach leaves with different exposure times (1–48 h). Cysteine is the major biomolecule that interacts with AgNPs in spinach based on the in situ and in vitro SERS pattern recognition. The interaction between CIT–AgNPs and cysteine happened in as early as 1 h after AgNP foliar deposition, which is faster than the interaction between PVP–AgNPs and cysteine. Also, the SERS depth mapping shows that particle size rather than surface coating determines the penetration capability of AgNPs in spinach, in which 40 nm AgNPs show a deeper penetration than the 100 nm ones. Last but not least, based on the results of SERS mapping, we detected significantly higher amounts of 40 nm CIT–/PVP–AgNPs than 100 nm CIT–AgNPs internalized in the leaf tissues after 1 h exposure. The estimated percentage of internalized AgNPs (0.2–0.8%) was significantly smaller than that of the total residual Ag (9–12%), indicating the potential transformation of the AgNPs into other Ag species inside the plant tissues. This study facilitates a better understanding of the behavior and biological fate of AgNPs in plant tissues.