Microencapsulation of sesame seed oil by tamarind seed mucilage.

Tamarind seed mucilage (TSM) was evaluated as a novel wall material for microencapsulation of sesame oil (SO) by spray-drying method. Wall material:core ratios of 1:1 (M1) and 1:2 (M2) were considered, and the corresponding physical and flow properties, thermal stability, functional groups composition, morphology, encapsulation efficiency, and oxidative stability were evaluated. Powder of M1 and M2 microcapsules exhibited free-flowing characteristics. The particle size distribution for M1 microcapsules was monomodal with diameter in the range 1-50 µm. In contrast, Microcapsules M2 presented a bimodal distribution with diameter in the ranges 1-50 µm and 50-125 µm. M1 microcapsules were thermally stable until 227 °C and microcapsules M2 until 178 °C. Microcapsules M1 and M2 exhibited a dominant amorphous halo and external morphology almost spherical in shape. Encapsulation efficiency was 91.05% for M1 and 81.22% for M2. Peroxide formation reached values after six weeks was 14.65 and 16.51 mEq/kgOil for M1 and M2 respectively. Overall, the results led to the conclusion that tamarind mucilage is a viable material for high microencapsulation efficiency, while offering protection against oxidation mechanisms of SO.

Effect of chia mucilage addition on oxidation and release kinetics of lemon essential oil microencapsulated using mesquite gum - Chia mucilage mixtures.

Lemon essential oil (LEO) emulsions were prepared using mesquite gum (MG) - chia mucilage (CM) mixtures (90-10 and 80-20 MG-CM weight ratios) and MG as control sample, LEO emulsions were thenspray dried for obtaining the respective microcapsules.LEO emulsions were analyzed by mean droplet size and apparent viscosity, while microcapsules were characterized through mean particle size, morphology, volatile oil retention (≤51.5%), encapsulation efficiency (≥96.9%), as well asoxidation and release kinetics of LEO. TheLEO oxidation kinetics showed that 90-10 and 80-20MG-CM microcapsules displayed maximum peroxide values of 91.6 and 90.5 meq hydroperoxides kg-1 of oil, respectively, without significant differences between them (p > .05).MG-CM microcapsules provided better protection to LEO against oxidation than those formed with MG; where the oxidation kinetics were well adjusted to zero-order (r2 ≥ 0.94).The LEO release kinetics from microcapsules were carried out at differentpH (2.5 and 6.5) and temperature (37 °C and 65 °C) and four mathematical models (zero-order, first-order, Higuchi and Peppas) were used to evaluate the experimental data; the release kinetics indicated that the 80-20 MG-CM microcapsules had a longer delay in LEO release rate, followed by 90-10 MG-CM and MG microcapsules, hence, CM addition in MG-CM microcapsules contributed to delay the LEO release rate. This work clearly demonstrates that use of a relatively small amount of CM mixed with MGimproves oxidative stability and delays the release rate of encapsulated LEO regarding MG microcapsules, therefore, MG-CM mixtures are interesting additives systems suitable for being applied in food industry.

Rheological properties of tamarind (Tamarindus indica L.) seed mucilage obtained by spray-drying as a novel source of hydrocolloid.

Tamarind seed mucilage (TSM) was extracted and obtained by spray drying. The power law model well described the rheological behavior of the TSM dispersions with determination coefficients R2 higher than 0.93. According to power law model, non-Newtonian shear thinning behavior was observed at all concentrations (0.5%, 1%, 1.5% and 2%) and temperatures (25, 30, 40, and 60°C) studied. Increasing temperature decreased the viscosity and increased the flow behavior index, opposite effect was observed when increasing the concentration. The temperature effect was more pronounced at 2.0% TSM concentration with an activation energy of 20.25kJ/mol. A clear dependence of viscosity on pH was observed, as pH increased from acidic to alkaline conditions, the viscosity increased. It was found that the rheological properties of TSM were affected by the sucrose and salts and their concentrations as well due to the addition of ions (or sucrose) decreases repulsion and allows molecule expansion promoting a significant reduction in viscosity. These results suggest that TMS could be applied in the production of foods that require additives with thickening capacity.

Solvent effect in the polyethylene recovery from multilayer postconsumer aseptic packaging.

Polyethylene films were separated and recovered from polyethylene-aluminum composites derived from recycling multilayer postconsumer aseptic packaging. A brief study about the separation process by dissolving PE-aluminum (PE-Al) composites into a series of organic solvents with a combination of time and temperature is presented. Through this procedure, 56% polyethylene is recovered from this kind of composites in optimized conditions. DSC and TGA studies were performed to determine the thermal stability of recovered polyethylene films and to establish a comparison with a PE reference commercial product, demonstrating that recovered polyethylene films kept their thermal properties.

Isoreticular metal-organic frameworks and their membranes with enhanced crack resistance and moisture stability by surfactant-assisted drying.

Here we report a new strategy that can not only prevent the formation of cracks and fractures in the crystals and films of metal-organic frameworks (MOFs) but also substantially enhance their stability with respect to moisture. It involves the addition of surfactants during a drying process. Surfactants reduce interfacial tension, thereby repressing the formation of fractures and cracks during the final drying process. It was found that, once dried, surfactants adsorbed on the crystal surface render the surface hydrophobic, leading to the enhancement in the stability toward moisture. Using this new strategy, the first crack-free IRMOF-3 membrane was successfully prepared, and its gas permeation performance was tested. IRMOF-3 membranes are found to favor CO2 over C3H8 mainly due to the affinity of CO2 to the amine groups in the structure. In addition, crack-free IRMOF-3 membranes were postsynthetically modified with heptanoic anhydride, thereby changing the effective pore size and surface property of the MOF. Once modified with the anhydride, the membranes favor C3H8 over CO2 due to the increased solubility of C3H8 in the presence of the hydrocarbon moiety.

Synthesis of zeolitic imidazolate framework films and membranes with controlled microstructures.

Zeolitic imidazolate frameworks (ZIFs) are hybrid organic-inorganic microporous materials that exhibit zeolite-like structures and can be synthesized with a wide range of pore sizes and chemical functionality. ZIFs as thin films and membranes are of interest for their applications in sensors and gas separation. Here, we report a method for ZIF film and membrane fabrication, based on support surface modification and in situ solvothermal growth, which has potential for general application to other ZIF membranes. Our simple surface modification method results in strong covalent bonds between α-Al(2)O(3) supports and imidazolate ligands, which promote the heterogeneous nucleation and growth of ZIF crystals. The microstructure of ZIF-8 films can be controlled by controlling the pH of the growth solution. ZIF-7 films were fabricated to demonstrate the potential for general applicability of our method. Finally, the separation performance of several ZIF-8 membranes was evaluated, revealing molecular sieving behavior with an ideal selectivity for H(2)/CH(4) of 13.