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This study aimed to assess natural oils for their antioxidant and anti-hyaluronidase properties and select the most effective candidate for development into nanoemulsions (NE) for clinical evaluations. The oils were assessed using 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS•+) and ferric thiocyanate assays for antioxidant properties and an enzyme-substrate reaction assay for anti-hyaluronidase activity. The most potent oil was formulated into conventional emulsions (CE) and NE, which were characterized and evaluated for their stability, both in accelerated and long-term conditions. The irritation potential was assessed using both the hen's eggs chorioallantoic membrane test and a clinical trial. Skin hydration enhancement and skin wrinkle reduction efficacy were clinically assessed. Macadamia integrifolia oil exhibited significant potency as an ABTS•+ radical scavenger, lipid peroxidation inhibitor, and hyaluronidase inhibitor (p < 0.05). Both the CE and NE, comprising 15% w/w oil, 5% w/w Tween® 80 and Span® 80, and 80% w/w DI water, were found to be optimal. NE with an internal droplet size of 112.4 ± 0.8 nm, polydispersity index of 0.17 ± 0.01, and zeta potential of −31.5 ± 1.0 mV, had good stability and induced no irritation. Both CE and NE enhanced skin hydration and reduced skin wrinkles in human volunteers, while NE was outstanding in skin hydration enhancement. [ABSTRACT FROM AUTHOR]

BACKGROUND The interfacial activation mechanism of lipase enables it to exhibit high catalytic activity in water‐in‐oil (W/O) microemulsions. However, W/O microemulsions have obvious defects such as a small water pool and a large demand for surfactants. The present study investigated the substitutability of conventional oil‐in‐water (O/W) and W/O emulsions as lipase catalytic systems. Carbon nanotubes (CNTs)/gold nanoparticles (GNPs) or CNT–GNP electrostatically bonded complexes were added into the conventional emulsion system. RESULTS: The simulated biphasic system and fluorescence study showed different and even contradictory results for the interfacial behavior of CNTs and CNT–GNP complexes due to the variation of the dispersibility of CNTs in cetyltrimethylammonium bromide (CTAB). Results also showed that conventional O/W emulsions were more suitable for lipase catalysis than conventional W/O emulsions. When CNTs or CNTCATB–GNP complexes were added in a conventional O/W emulsion system, the catalytic activity of lipase was significantly promoted (up to 4.8‐fold using CNTs and 3.5‐fold using CNTCATB–GNP complexes compared with free lipase). CONCLUSIONS: The possible reason for this promotion may be due to the increase in the interface area. The current study was not only the latest exploration of lipase activity promotion via nanomaterials, but also explored a new lipase catalytic system and provides further insight into improving the catalytic performance of lipase in conventional emulsions. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Films obtained by casting, starting from conventional emulsions (CE), nanoemulsions (NE) or their gels, which led to different structures, with the aim of explore the relationship between structure and physical properties, were prepared. Sodium caseinate was used as the matrix, glycerol as plasticizer, glucono-delta-lactone as acidulant to form the gels, and TiO 2 nanoparticles as reinforcement to improve physical behavior. Structural characterization was performed by SAXS and WAXS (Small and Wide Angle X-ray Scattering, respectively), combined with confocal and scanning electron microscopy. The results demonstrate that the incorporation of the lipid phase does not notably modify the mechanical properties of the films compared to solution films. Films from NE were more stable against oil release than those from CE. Incorporation of TiO 2 improved mechanical properties as measured by dynamical mechanical analysis (DMA) and uniaxial tensile tests. TiO 2 macroscopic spatial distribution homogeneity and the nanostructure character of NE films were confirmed by mapping the q-dependent scattering intensity in scanning SAXS experiments. SAXS microscopies indicated a higher intrinsic homogeneity of NE films compared to CE films, independently of the TiO 2 load. NE-films containing structures with smaller and more homogeneously distributed building blocks showed greater potential for food applications than the films prepared from sodium caseinate solutions, which are the best known films. [ABSTRACT FROM AUTHOR]

Chia (Salvia hispanica L.) is an oilseed plant which contains proteins of high biological value and other healthy components with interesting technological properties. For these reasons, chia could be a promising option for the formation and stabilization of oil-in-water emulsions. The aim of this study is to evaluate the potential of chia protein (from chia flour) in the formation of emulsions. To that end, composition and technological and structural properties determined by infrared spectroscopy were investigated in conventional (EC) and gelled (EGC) emulsions with chia and compared with their corresponding soy protein emulsions with the same protein content [conventional (ES) or gelled (EGS)] used as reference. All emulsions containing chia had better fat and water binding properties than those elaborated with soy protein isolate (SPI). The color of the emulsions varied significantly depending on whether the emulsions were made with chia or SPI. EGS and EGC exhibited the greatest (p < 0.05) penetration force values, being EGC the firmest (p < 0.05). Depending on the type of emulsion, Attenuated Total Reflectance (ATR)-FTIR Spectroscopy revealed differences in their lipid structure and interaction in terms of lipid acyl chain mobility (order/disorder) and emulsion droplet size. These structural characteristics could be related to the textural behavior of emulsions.

• Tomato wastes reused and stable emulsions were prepared from tomato seed oil. • Nanoemulsion digested more and faster than conventional emulsion and bulk oil. • The bioaccessibility of lycopene increased in the presence of tomato seed oil. • Heating positively affected the lipid digestion and lycopene bioaccessibility. • Juice containing nanoemulsion exhibited the highest oxidation of oil over the time. In this study, tomato seed oil conventional emulsion (7 μm) and nanoemulsion (0.146 µm) with desirable stability were prepared, then the effect of tomato seed oil addition (bulk and emulsified forms) and thermal treatment on properties of tomato juice was evaluated. Tomato juice without oil and heat treatment exhibited the lowest bioaccessibility of lycopene (17.8 %). Incorporation of oil and applying heat treatment significantly increased the extent of lipid digestion and bioaccessibility of lycopene. In this regard, the nanoemulsion had the highest bioaccessibility (44.85 %) compared to conventional emulsion (33.90 %) and bulk oil (27.11 %), due to the smaller oil droplets. The oxidative stability of oil in heat-treated tomato juice samples decreased during 28 days of storage at 4 °C, whereas the nanoemulsion exhibited the highest peroxide value (4.43 meq O 2 /kg of oil) compared to conventional emulsion and bulk oil (3.91 and 3.49 meq O 2 /kg of oil, respectively) at the end of the period. [ABSTRACT FROM AUTHOR]

The 'interfacial quality' is the key influencing factor for lipase activities at interfaces, and thus, interfacial engineering has become an effective strategy to modulate lipase catalysis. In the current research, the triblock copolymers poly (ethylene oxide)-poly (propylene oxide)-poly (ethylene oxide) (PEO-PPO-PEO) were adopted to form conventional oil-in-water (O/W) emulsion systems. The results showed the different effects of PEO-PPO-PEO molecules on the spatial barriers, emulsion particle size, and ultimately interfacial adsorption properties of lipases. Since the molecular weight of Candida antarctica lipase B (CALB) is approximately half that of Candida rugosa lipase (CRL), it can more easily pass through the triblock copolymer adsorption layer, resulting in a higher adsorption ratio. The results confirmed that the catalytic efficiency of CALB at the emulsion interfaces was much lower than that of CRL due to its lack of a typical 'lid' structure. Both the effective amount of lipase molecules at the interfaces (controlled by the interfacial adsorption ratio) and the effective catalytic interface area (influenced by the specific surface area controlled by the average particle size of the O/W emulsion) impacted the catalytic activities of CRL. Na+ ions were found to have a certain inhibitory effect on the catalytic activity of CRL. • Conventional O/W emulsions as lipase catalytic systems have been investigated. • Triblock copolymers were introduced to modulate interfacial properties. • Lipase with 'lid' and without 'lid' showed different interfacial behaviors. • The spatial barriers of copolymer and the emulsion size impacted the catalysis. [ABSTRACT FROM AUTHOR]

Microemulsion (ME) and conventional emulsion (CE) co-polymerization of p-methyl styrene (pMSTY) with methyl methacrylate (MMA) are carried out at 70°C using n-pentanol (PA) and n-hexanol (HA), respectively, as co-surfactants along with sodium lauryl sulphate (SLS) as surfactant in the reaction media, and potassium persulphate (KPS) as initiator. The co-polymers are characterized by NMR and GPC techniques. The reactivity ratios are evaluated by employing Fineman–Ross (F–R), Kelen–Tüdös (K–T) and Mayo–Lewis integration (M–L-I) methods. The K–T method yields the reactivity ratios 0.68 ± 0.02 (rpMSTY), 0.40 ± 0.02 (rMMA), 0.68 ± 0.02 (rpMSTY) and 0.68 ± 0.02 (rMMA), respectively, for the ME and CE co-polymerizations of pMSTY and MMA with PA as co-surfactant in the reaction media. The K–T method yields the reactivity ratios 1.09 ± 0.02 (rpMSTY), 0.37 ± 0.02 (rMMA) and 0.78 ± 0.02 (rpMSTY) and 0.54 ± 0.02 (rMMA), respectively, for the ME and CE co-polymerization of pMSTY and MMA with HA as co-surfactant in the reaction media. [ABSTRACT FROM AUTHOR]