Encapsulation of gases in powder solid matrices and their applications: A review

Gas encapsulation in solid matrices can be an important means to sequester harmful or greenhouse gases and to store useful gases for their subsequent release for a targeted application. In this review, recent developments, the characteristics and gas adsorption capacity of non-organic and organic solid powder matrices (e.g. activated carbons, carbon nanotubes, zeolites, metal-organic frameworks, and cyclodextrins); and potential applications of their complexes in various fields (energy, environment protection, nano-device production, medicine, and food and agriculture productions) are described

Tribo-rheology and sensory analysis of a dairy semi-solid

Tribology science is devoted on explaining the friction behavior of interacting surfaces in relative motion. Several tribological systems have been used to measure coefficient of friction (CoF) vs sliding speed of entrained food layer between two rubbing surfaces. These results can be correlated with fat-related attributes perceived during oral processing. This study aims to investigate the effect of starch, carrageenan and fat on the friction profile; flow behavior and particle size distribution. Friction curves were obtained for custards using a tribo-rheometer with a rotating metallic geometry rubbing the surface of 3 M tape with roughness similar to that depicted by human tongue. Confocal Laser Scanning Microscopy (CLSM) images of custard collected during friction experiment helped to explain the characteristics of tribological regimes. As expected, fat-containing samples depicted remarkably lower CoF than skim compositions (fat: 0.2 < CoF < 0.08 and skim: 0.6 < Co

Encapsulation of CO<inf>2</inf> into amorphous and crystalline α-cyclodextrin powders and the characterization of the complexes formed

Carbon dioxide complexation was undertaken into solid matrices of amorphous and crystalline α-cyclodextrin (α-CD) powders, under various pressures (0.4-1.6 MPa) and time periods (4-96 h). The results show that the encapsulation capacity of crystalline α-CD was significantly lower than that of amorphous α-CD at low pressure and short time (0.4-0.8 MPa and 4-24 h), but was markedly enhanced with an increase of pressure and prolongation of encapsulation time. For each pressure level tested, the time required to reach a near equilibrium encapsulation capacity of the crystalline powder was around 48 h, which was much longer than that of the amorphous one, which only required about 8 h. The inclusion complex formation of both types of α-CD powders was confirmed by the appearance of a CO2 peak on the FTIR and NMR spectra. Moreover, inclusion complexes were also characterized by DSC, TGA, SEM and X-ray analyses

Optimization of supercritical carbon dioxide extraction of flaxseed oil using response surface methodology

The optimal conditions for the supercritical carbon dioxide (SC-CO2) extraction of flaxseed oil from flaxseed were determined using response surface methodology (RSM). A second-order regression for rotation-orthogonal composite design was used to study the effects of three independent variables: extraction pressure (MPa), extraction temperature (oC) and CO2 flow rate (L/h) on the yield of flaxseed oil. The independent variables were coded at five levels and their actual values selected on the basis of preliminary experiments. The results indicated that the yield of flaxseed oil was beyond 29% at a probability of 95% in the range of extraction pressure: 38.6-42.3 MPa, extraction temperature: 52.3-57.0 oC, and CO2 flow rate: 27.8-31.2 L/h. The optimal extraction conditions were extraction pressure of 41 MPa, extraction temperature of 56 oC and CO2 flow rate of 31 L/h according to the analysis of response surface. In this condition, the experimental yield of flaxseed oil was 29.96%, which was close to the predicted value of 30.52%

Fluidisation behaviour of cylindrical green bean particulates in drying

Fluidisation behaviour of cylindrical bean particulates were studies and empirical models were presente

Change of physical properties of green beans during drying and its influence on fluidization

Cylindrical green beans physical property was studied. Their effect on fluidization characteristics were described

Novel solid encapsulation of ethylene gas using amorphous α-cyclodextrin and the release characteristics

This research investigated the encapsulation of ethylene gas into amorphous α-cyclodextrins (α-CDs) at low (LM) and high (HM) moisture contents at 1.0-1.5 MPa for 24-120 h and its controlled release characteristics at 11.2-52.9% relative humidity (RH) for 1-168 h. The inclusion complexes (ICs) were characterized using X-ray diffractometry (XRD), nuclear magnetic resonance spectroscopy (CP-MAS (13)C NMR), and scanning electron microscopy (SEM). Ethylene concentrations in the ICs were from 0.45 to 0.87 mol of ethylene/mol CD and from 0.42 to 0.54 mol of ethylene/mol CD for LM and HM α-CDs, respectively. Ethylene gas released from the encapsulated powder at higher rates with increasing RH. An analysis of release kinetics using Avrami's equation showed that the LM and HM amorphous α-CDs were not associated with significant differences in release constant k and parameter n for any given RH condition. NMR spectra showed the presence of the characteristic carbon-carbon double bond of ethylene gas in the encapsulated α-CD powder

Water activity in food processing and preservation

No abstract available

Optimization of co-current spray drying process of sugar-rich foods. Part I - Moisture and glass transition temperature profile during drying

A steady state mathematical model for co-current spray drying was developed for sugar-rich foods with the application of the glass transition temperature concept. Maltodextrin-sucrose solution was used as a sugar-rich food model. The model included mass, heat and momentum balances for a single droplet drying as well as temperature and humidity profile of the drying medium. A log-normal volume distribution of the droplets was generated at the exit of the rotary atomizer. This generation created a certain number of bins to form a system of non-linear first-order differential equations as a function of the axial distance of the drying chamber. The model was used to calculate the changes of droplet diameter, density, temperature, moisture content and velocity in association with the change of air properties along the axial distance. The difference between the outlet air temperature and the glass transition temperature of the final products (AT) was considered as an indicator of stickiness of the particles in spray drying process. The calculated and experimental AT values were close, indicating successful validation of the model. (c) 2004 Elsevier Ltd. All rights reserved