Bio-nanocomposites for food packaging applications

Research and development of bio-nanocomposite materials for food applications such as packaging and other food contact surfaces is expected to grow in the next decade with the advent of new polymeric materials and composites with inorganic nano-particles. This article reviews different types of new bio-based materials, such as edible and biodegradable nanocomposite films, their commercial applications as packaging materials, regulations and future trends. Special emphasis is given to the advantages of nanotechnology application in order to improve the mechanical and oxidation stability, the barrier properties, and eventually the biodegradability of conventional polymeric matrices.

Potential perspectives of bio-nanocomposites for food packaging applications

Use of clays as drug delivery systems: Possibilities and limitations

Inorganic layered double hydroxides as a drug delivery system—intercalation and in vitro release of fenbufen

Adsorption removal of cesium from drinking waters: A mini review on use of biosorbents and other adsorbents

Intercalation compounds of ternary layered inorganic materials, synthetic mica (Na-TSM), with diclofenac sodium (DFS) and its drug release characteristics were investigated. Hygroscopic DFS was selected as a model drug to verify the anti-humidity and anti-oxidation of the intercalation compounds. Na-TSM powder was first mixed with the reduced-type phosphatidylcholine (H-PC) solution of chloroform or ethanol. DFS was then mixed with these solutions and heated at 37 °C to prepare the ternary Na-TSM/H-PC/DFS compound. A remarkable phenomenon was observed in the drug release study. The net amount of DFS from the DFS powder decreased apparently after 20 min arising from the decomposition of DFS in acidic medium. On the other hand, the net amount of the released DFS from the intercalation compound was invariant. Thermal analyses study indicated that DFS powder was hygroscopic and a significant endothermic peak was observed accompanied by a large weight loss due to the dehydration of adsorbed water from 40 to 90 °C. On the other hand, no significant dehydration reaction was observed in the intercalation compounds even in the sample stored under humid conditions. The present results indicated that the ternary intercalation compound was resistant to acid in addition to anti-humidity.

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Intercalation compounds of layered materials for drug delivery use. II. Diclofenac sodium.

There are many reports that the drug-induced taste disorder is ascribable to the chelate reaction of a drug with zinc ion and the following zinc deficiency. As a quantitative measure of the chelating ability of drugs with zinc ions, the chelating ability was estimated from the electrode potential change of the Zn2+/Zn(Hg) system during the addition of a drug. The electrode potential was measured in a water–N,N-dimethylformamide mixed solution and in an aqueous solution depending on the solubility of the drugs. The observed electrode potential change showed a positive correlation to the frequency of the drug-induced taste disorder that was supplied from the manufacturer of the original drug. The regression analysis was carried out assuming that the frequency of the taste disorder and the electrode potential change was linear. The F-values, p-values, and R2-values were 4.29, 0.13, 0.589, and 4.15, 0.13, 0.580, respectively. The positive correlation between the drug-induced taste disorder and the electrode potential change appeared evident if the uncertainty in the frequency of the taste disorder was taken into consideration. Thus the assumption of the zinc ion chelating mechanism on the drug-induced disorder was also evident except for cisplatin. The frequency of the drug-induced taste disorder of bezafibrate was estimated to be 0.4—0.5 from the regression analysis.

Relation between drug-induced taste disorder and chelating behavior with zinc ion; statistical approach to the drug-induced taste disorder, part II.

The ion-exchange property of sodium difluorotetrasilicate, Na-TSM, with potassium, rubidium and cesium ions was investigated in addition to two other typical layered inorganic materials. The selectivity sequence of Na-TSM was Cs+ > Rb+ > K+ and the selectivity difference of Na-TSM was highest among the examined layered materials. It was found from a chemical analysis that cesium ion-exchange participated in magnesium ions, which is a lattice component of Na-TSM, in addition to an ordinary ion-exchange reaction with the interlayer sodium ions. The exchange of cesium ions with magnesium ions was found to be stoichiometric, and was expected to be an ideal ion-exchange reaction. It was a peculiar phenomenon only on Na-TSM. Once cesium ions were exchanged in a Na-TSM lattice, they were hardly released, due to a reverse ion-exchange with sodium ions. The highest selectivity difference and tight binding of cesium ions were interpreted by an ion-exchange with lattice magnesium ion as well as decreased dehydration...

The Ion-Exchange Property of Some Layered Inorganic Materials with Potassium Ion, Rubidium Ion and Cesium Ion, and Selective Cesium Ion-Exchange of Synthetic Mica

Food samples undergo various physical changes during long period refrigeration and their taste gradually diminishes. The amount of squeezable drip and salt-soluble protein in beef fillet and salmon meat were measured as indices of taste during the course of refrigeration and compared with sensory tests. Both meat samples showed similar degradation tendency. The amount of squeezable drip increased rather rapidly within 15 h, although the increase did not directly correlate with the sensory tests. The amount of salt-soluble proteins, which is one of the typical indices of denaturation of protein, decreased gradually with lengthening refrigeration period and was well consistent with the sensory tests. The mobility of water molecules in the food samples was examined by measuring the spin-spin relaxation time T2 measured by the CPMG method of pulse NMR. The spin echo signals of pulse NMR were analyzed by Gauss-Newton nonlinear regression analysis. The experimental curves were satisfactorily taken into account according to the two-component approximation in which each sample was assumed to contain two kinds of water components with different relaxation times, short- and long-T2. The relative amount of the short-T2 component corresponded well with the sensory tests and also with the decrease in salt-soluble protein that was representative of the texture items. It was concluded that the mobility of water molecules as determined by the relaxation times holds promising information to evaluate the degradation degree of meat samples during long-period refrigeration.

Texture Change of Beef and Salmon Meats Caused by Refrigeration and Use of Pulse NMR as an Index of Taste

BACKGROUND

Expanded vermiculite is widely used in many fields, especially as an ameliorant in agriculture. Although it is known as a cation-exchanger, in a search for a new cesium adsorbent for environmental conservation, the ion-exchange behaviour of cesium on vermiculite in various grain sizes was investigated. The adsorption of cesium from artificial seawater was also investigated.



RESULTS

The effect of the vermiculite grain size was clearly identified. The preferred gain size for general use was found to be 500 µm. The amount of adsorption was low in these artificial seawater samples, however, almost similar ion-exchange behaviour was observed in both of the pure water and artificial seawater samples.



CONCLUSION

Adjustment of grain size according to the end use enables unlimited availability for application as an adsorbent of cesium. The results showed that vermiculite is a promising material for the recovery of cesium from contaminated seawater. © 2013 Society of Chemical Industry

Noriko Suzuki

Papers

Intercalation compounds of layered materials for drug delivery use. II. Diclofenac sodium.

Relation between drug-induced taste disorder and chelating behavior with zinc ion; statistical approach to the drug-induced taste disorder, part II.

The Ion-Exchange Property of Some Layered Inorganic Materials with Potassium Ion, Rubidium Ion and Cesium Ion, and Selective Cesium Ion-Exchange of Synthetic Mica

Texture Change of Beef and Salmon Meats Caused by Refrigeration and Use of Pulse NMR as an Index of Taste

Approaches for cesium uptake by vermiculite