Construction of nanoscale liposomes loaded with melatonin via supercritical fluid technology.

Melatonin-loaded liposomes (MLL) were successfully prepared using rapid expansion of supercritical solution technology. The effects of supercritical pressure on encapsulation efficiency (EE) and average particle size were then analysed. Meanwhile, temperature, formation time and ethanol concentration in the products were studied and optimised based on the response surface methodology (RSM). An in vitro simulated digestion model was also established to evaluate the release performance of MLL. The results showed that 140 bar was the best pressure for maximising the EE value using RSM optimisation, reaching up to 82.2%. MLL characterisations were performed using analytic techniques including infrared spectroscopy, transmission electron microscopy, a laser scattering particle size analyser and gas chromatograph-mass spectrometer. The size distribution was uniform, with an average diameter of 66 nm. Stability tests proved that MLL maintained good preservation duration, and residual solvent experiments indicated that only 1.03% (mass ratio) of ethanol remained in the products. Simulated release experiments indicated the slow release feature in early digestive stages and more thorough characteristics in later stages of simulated digestion.

Inhibition of Salmonella typhimurium and Listeria monocytogenes in coconut juice by graphene-doped photocatalyst rGO/TiO2.

This research used the photocatalyst rGO/TiO2 prepared by hydrothermal method to inhibit the growth of these microorganisms in water and coconut juice. In coconut juice, the initial count of Salmonella typhimurium decreased from 3 × 105 CFU /mL to 6.3 × 104 CFU /mL, and the initial count of L. monocytogenes was reduced from 3 × 105 CFU/mL to 1.2 × 105 CFU/mL. Moreover, the chemical structure characterization rGO/TiO2 showed that the doping of rGO formed a compact composite, enhanced the transfer of photogenerated electrons, and improved the photocatalytic efficiency of TiO2. The active substances ·OH and ·O2- produced by photocatalysis directly destroyed the integrity of bacteria cells, led to leakage of protein and DNA in the cells, and resulted in inactivation of the microorganisms, although Salmonella typhimurium and Listeria monocytogenes have different cell structures. These results would provide a good candidate photocatalyst to resist Salmonella typhimurium and Listeria monocytogenes and promote the development of photocatalysis applications.

A simple nanocomposite photocatalyst HT-rGO/TiO2 for deoxynivalenol degradation in liquid food.

A simple nanocomposite photocatalyst HT-rGO/TiO2 for deoxynivalenol (DON) degradation was synthesized by hydrothermal method to maintain the quality of cereal grains and byproducts. The characterization of HT-rGO/TiO2 was analyzed by XRD, FTIR, Raman spectroscopy, and XPS. Moreover, according to UV-vis DRS analysis, HT-rGO/TiO2 had a smaller band gap, indicating a wider response range to light and a higher utilized rate of quantum photons. Additionally, the results of LC-MS showed that the hydroxyl group at the C3 position, and the unsaturated bond between C9 and C10, and the epoxy group at C12 and C13 positions of DON molecule were destroyed step by step by photocatalytic degradation. These groups have active effects on the DON toxicity, which means it is successful to degrade DON in liquid-food by HT-rGO/TiO2 photocatalyst.

Digestibility and structures of vinasse starches with different types of raw rice and fermented leaven.

In consideration of health benefits, more digestible vinasses were investigated, which are associated with the use of different raw cereals and fermented leavens. In an in vitro digestibility test, milled long-grain glutinous rice vinasse with Taibai rice leaven showed a slow glucose-controlled release potential, which contained 37.08% slowly digestible starch, after complete vinasse consumption. The crystalline structure, thermal properties and morphology of vinasse starches were analysed. The relatively long amylopectin chains, which originated from the starch structure present in raw rice and the higher glucoamylase activity of the fermented leaven, partly explained the slower digestion of vinasse. By the optimization of the type of fermented leaven used and the starch structure of the raw rice in fermentation, the rate of vinasse starch digestion could be controlled, resulting in improved nutritional value. The results of this study are important for designing healthy vinasse products by controlling starch structures and digestion rates.

A nano-delivery system for bioactive ingredients using supercritical carbon dioxide and its release behaviors.

For the purpose of ensuring the bioavailability of bioactive ingredients, a nano-delivery system with low toxicity was developed using supercritical carbon dioxide (SC-CO2). Compared to thin-film hydration (TFH), obtaining nano-scale liposomes is easier using SC-CO2. The characteristic of these liposomes was also demonstrated by the analysis of particle size and morphology. An in vitro release study showed that liposomes produced using SC-CO2 were resistant to low pH in simulated gastric conditions. In a simulated intestinal environment, enteric solubility of these liposomes was enhanced, which are important properties for controlled releasing bioactive ingredient. Furthermore, SC-CO2-produced liposomes had a higher storage stability than those produced using TFH. Analysis of the organic solvent residue in the liposomes by gas chromatography-mass spectrometry (GC-MS) indicated that SC-CO2-produced liposomes had lower toxicity than those produced by TFH. A chemical free nano-delivery system using SC-CO2 has been revealed for storage and controlled release of bioactive ingredients.

Enhanced photocatalytic disinfection of P. expansum in cold storage using a TiO2/ACF film.

Spores of Penicilliumexpansum are the most important airborne component of fungal contamination and are commonly present in the moist air in cold storage rooms where fruits and vegetables are stored. To improve the ability of activated carbon felt-supported titanium dioxide (TiO2/ACF) to remove spores of P. expansum from the atmosphere, measurements for the removal efficiency of the spores at a temperature of 3 degrees C+/-1 degrees C and relative humidity of 90%+/-3% had been made on photocatalytically-activated (PC) silver-doped TiO2/ACF prepared by ion sputtering in two different modes and photoelectrocatalytically-activated (PEC) TiO2/ACF films. The Weibull distribution model was used to define the degree of microbial inactivation attributable to the PC or PEC films. The key parameters of the PC or PEC affecting the disinfection efficiency in terms of the reliable life (t(R) value) of this model were studied. Both silver-doped TiO2/ACF and PEC on TiO2/ACF improved destruction of this airborne microbe. Silver deposited on the surface of the prepared ACF-supported TiO2 films (Ag/Ti=0.012, atomic ratios) dramatically reduced t(R) value. With respect to the PEC, a model was established using response surface methodology to describe the relationship between the t(R) value and the key affecting parameters, including light intensity and bias voltage. The optimized parameters were found to be a light intensity of 2.3 mW x cm(-2) with a bias voltage of 66.7 V.