Titanium dioxide (TiO) particles are used in some food products to alter their optical properties, such as whiteness or brightness. These additives typically contain a population of TiO nanoparticles (d < 100 nm), which has led to concern about their potential toxicity. The objective of this study was to examine the impact of TiO particles on the gastrointestinal fate of oil-in-water emulsions using a simulated gastrointestinal tract (GIT) that includes mouth, stomach, and small intestine phases. Theoretical predictions suggested that TiO nanoparticles might inhibit lipid digestion through two physicochemical mechanisms: (i) a fraction of the lipase adsorbs to TiO particle surfaces, thereby reducing the amount available to hydrolyze lipid droplets; (ii) some TiO particles adsorb to the surfaces of lipid droplets, thereby reducing the lipid surface area exposed to lipase. The importance of these mechanisms was tested by passing protein-coated lipid droplets (2%, w/w) through the simulated GIT in the absence and presence of TiO (0.5%, w/w) nanoparticles (18 nm) and fine particles (167 nm). Changes in particle characteristics (size, organization, and charge) and lipid digestion were then measured. Both TiO nanoparticles and fine particles had little impact on the aggregation state and charge of the lipid droplets in the different GIT regions, as well as on the rate and extent of lipid digestion. This suggests that the theoretically predicted impact of particle size on lipid digestion was not seen in practice.

We investigated the continuous extrusion foaming of poly­(vinyl alcohol) (PVOH)/microfibrillated cellulose (MFC) composites using supercritical carbon dioxide (scCO2) as the blowing agent. First, the as-received PVOH pellets were compounded with water to decrease their melting point. Then, they were compounded with an MFC solution to prepare the sample. Both scanning electron microscopy (SEM) and environmental scanning electron microscopy (ESEM) showed that the MFC dispersed well in the PVOH/MFC composites. Differential scanning calorimetry (DSC) results showed that adding MFC affected the thermal behavior. This, in turn, affected cell nucleation and cell growth phenomena during foam extrusion. Water also acted as a co-blowing agent, together with scCO2, in creating biodegradable polymer foams with a uniform cell structure and a high cell density. The effects of the MFC content, scCO2 content, and die temperature variations on the cell density and cellular morphology of the PVOH/MFC composite foams were examined systematically.

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Excipient emulsions have compositions and structures specifically designed to increase the bioavailability of nutraceuticals in foods that they are co-ingested with. In this study, olive oil excipient emulsions were shown to significantly increase the bioaccessibility of carotenoids from tomatoes using a simulated gastrointestinal tract (GIT) model (p<0.05): being 8.18±0.93%, 11.85±1.76% for raw tomato-buffer mixture, and cooked tomato-buffer mixture; While being 32.3±2.60%, 55.7±3.28% and 42.6±3.75% for raw tomato-emulsion mixture, cooked tomato-emulsion mixture (boiled together) and cooked tomato- emulsion mixture (tomato boiled alone). These effects were attributed to: (i) the ability of digested olive oil droplets to form mixed micelles in the small intestine that solubilized the carotenoids; and, (ii) the ability of natural antioxidants (phenolics) in the olive oil to protect the carotenoids from oxidation. Thermal treatment (boiling) significantly increased carotenoid bioaccessibility from the tomatoes digested with emulsion, which was attributed to plant tissue disruption at elevated temperatures facilitating carotenoid release (p<0.05). Carotenoid bioaccessibility was higher when the tomatoes were boiled with emulsions (55.7±3.28%) than when they were boiled alone and then added to emulsions (42.6±3.75%). In conclusion, this study indicates that olive oil emulsions boost the bioaccessibility and chemical stability of lipophilic nutraceuticals in tomatoes, which may make an important contribution to the potential health benefits of the Mediterranean diet.

A polarization splitter based on a new type of dual-core photonic crystal fiber (DC-PCF) is proposed. The effects of geometrical parameters of the DC-PCF on performances of the polarization splitter are investigated by finite element method (FEM). The numerical results demonstrate that the polarization splitter possesses ultra-short length of 119.1 μm and high extinction ratio of 118.7 dB at the wavelength of 1.55 μm. Moreover, an extinction ratio greater than 20 dB is achieved over a broad bandwidth of 249 nm, i.e., from 1417 nm to 1666 nm, covering the S, C and L communication bands.

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