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The retention of the enzyme activity of alcohol dehydrogenase (ADH) has been studied in various drying processes such as spray drying. The aim of this study is to encapsulate ADH in mannitol, either with or without additive in order to limit the thermal denaturation of the enzyme during the drying process. The retention of ADH activity was investigated at different drying temperatures. When mannitol was used, the encapsulated ADH was found inactive in all the dried powders. This is presumably due to the quick crystallization of mannitol during spray drying that resulted in the impairment of enzyme protection ability in comparison to its amorphous form. Maltodextin (dextrose equivalent = 11) was used to reduce the crystallization of mannitol. The addition of maltodextrin increased ADH activity and drastically changed the powder X-ray diffractogram of the spray-dried powders.

β-Maltose monohydrate was transformed into an anhydrous form by ethanol-mediated method under several temperatures with agitation. A new stable anhydrous form of β-maltose (Mβ(s)) was obtained, as substantiated by the X-ray diffraction patterns. Mβ(s) obtained by this method presented a fine porous structure, resulting in greater specific surface area compared to those of β-maltose monohydrate and anhydrous β-maltose obtained by vacuum drying (Mβ(h)). The crystal transformation presumably consisted of two steps: dehydration reaction from the hydrous to amorphous forms and crystal formation from the amorphous forms to the noble anhydrous form. The kinetics of these reactions were determined by thermal analysis using Jander's equation and Arrhenius plots. The overall activation energies of the dehydration reaction and the formation of anhydrous maltose were evaluated to be 100 and 90 kJ/mol, respectively., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Unlabelled: Oil mixtures of medium-chain triglycerides (MCT) and D-limonene in mixing ratios from 10 to 100 wt% were encapsulated in modified starch (wall material) by spray drying to produce oil-rich powders. The oil load (mass ratio of oil mixture to wall material) of the infeed emulsion markedly influenced the properties of the infeed liquid and the characteristics of the resulting powder. The viscosity of the infeed liquid and the particle size of the powder exponentially decreased with increasing oil load, while the emulsion droplet size in the infeed liquid increased. In addition, retention of D-limonene during spray drying also decreased markedly with increasing oil load. Irrespective of the different oil loads and concentrations of the wall material, D-limonene retention was well correlated with the emulsion droplet diameter of the infeed liquid. The encapsulation efficiency of the oil mixture exhibited a maximum value (almost 100%) at an oil load between 0.5 and 1.0, before decreasing at higher oil loads. At an oil load of 2.0, the encapsulation efficiency of D-limonene was reduced to almost zero, while around 40% of the initial MCT was encapsulated in the powder. The increase in oil load also led to increased amounts of surface oil of MCT and D-limonene in the resulting powder due to the increasing emulsion droplet diameter of the infeed liquids., Practical Application: This study proposes the microencapsulation of medium-chain triglycerides under high-oil-load conditions by spray drying. The powders prepared by this process provide significant benefits in terms of rapid energy conversion after consumption without accumulation in the body. Important quality factors of the powder products such as the encapsulation efficiency and the amount of surface oil were examined to understand the optimum process conditions for spray drying., (© 2012 Institute of Food Technologists®)

The dissociation of a crystalline complex of cyclomaltohexaose (alpha-cyclodextrin) and 1-methylcyclopropene has been studied in response to stepwise rising relative humidity at 50 degrees C using a dynamic vapor sorption instrument. The dissociation of the inclusion complex was monitored with a proton transfer reaction mass spectrometer. The increase in relative humidity generally triggered the complex dissociation. However, the dissociation was greatly retarded at 80% relative humidity, presumably owing to collapse of the crystalline structure. Abrupt dissociation was observed at 90% relative humidity which corresponded to complex dissolution. The changes in powder X-ray diffraction pattern of the inclusion complex during the storage period were also investigated., (Copyright 2010 Elsevier Ltd. All rights reserved.)

S-Adenosyl-L-methionine (SAM) is an essential metabolite in all living organisms. In clinical research, SAM has also been suggested as a chemotherapeutic agent in various diseases. The main problem of SAM is its instability at high temperatures, at neutral and alkaline pH, and in the presence of humidity. SAM retention in spray-dried powder was determined under various conditions of spray-drying. The highest SAM retention was obtained when maltodextrin (dextrose equivalent, DE, of 25) was used as the carrier solid with the SAM feed liquid at pH 4.0. The water content in the powder had a significant effect on the stability of SAM. SAM powder with lower water content exhibited higher stability.

The thermally stimulated dissociation of the inclusion complex of 1-methylcyclopropene (1-MCP) with alpha-cyclodextrin (alpha-CD) in solid state was studied by means of thermogravimetry (TG) and differential scanning calorimetry (DSC). The mass loss of 1-MCP/alpha-CD inclusion complex occurs in four separated phases with the thermal dissociation of the inclusion complex and release of 1-MCP taking place in the second phase between 90 and 230 degrees C. The kinetic parameters of the dissociation reaction (the apparent activation energy of dissociation, E(D), the reaction order of thermal dissociation, n, and the pre-exponential factor, k0) were evaluated. The dissociation reaction was satisfactorily described by the unimolecular decay law, where the reaction order, n = 1. The effect of the molar ratio of 1-MCP to alpha-CD (inclusion ratio) in the inclusion complex on the temperature dependence of the dissociation reaction was also studied. The E(D) decreased with increasing inclusion ratio indicating higher complex stability at lower inclusion ratios. The extrapolation of the E(D) of the inclusion complexes with different inclusion ratios to 1 mol 1-MCP/mol alpha-CD yielded the "true" E(D) of 20.9 +/- 2.8 and 18.1 +/- 0.2 kJ/mol for TG and DSC, respectively. The "true" ln k(0TG) and the "true" ln k(0DSC) were also determined by extrapolation, yielding values of +4.5 +/- 1.0 and -0.3 +/- 0.3, respectively.

The inclusion complexation behavior between 10-undecyn-1-ol and cyclodextrin (CD) derivatives, namely, randomly methylated beta-CD (RM-beta-CD) and hydroxypropyl-beta-CD (HP-beta-CD), was studied in terms of solubility improvement, apparent stability constant, and the inclusion ratios of the resultant inclusion complexes. The aqueous solubility of 10-undecyn-1-ol was greatly improved through complexation with the CD derivatives. RM-beta-CD is comparatively more efficient in solubilizing 10-undecyn-1-ol with an apparent stability constant outstripping that of HP-beta-CD by about an order of magnitude. Comparative in vitro evaluations of the growth inhibition effects of inclusion complex solutions toward Rosellinia necatrix, a phytopathogenic fungus, were performed. In comparison with the positive control, appreciable improvements of the antifungal activity of 10-undecyn-1-ol through the addition of CD derivatives were observed visually. The improvement was evaluated in terms of area covered by the mycelia of Rosellinia necatrix and their growth rate. RM-beta-CD was proven to be more effective compared to HP-beta-CD with regard to the reduction of both fungal mycelium-covered area and growth rate constant, presumably owing to greater solubility enhancement by RM-beta-CD and thus the bioavailability of 10-undecyn-1-ol. Inclusion complexation of 10-undecyn-1-ol with CD derivatives suggests a potential means for production of an environmentally friendly 10-undecyn-1-ol-based fungicide to counteract R. necatrix.

1-methylcyclopropene (1-MCP), an ethylene inhibiting regulator, is commercially available in the form of an inclusion complex with alpha-cyclodextrin (alpha-CD). In this study, molecular encapsulation of gaseous 1-MCP into aqueous alpha-CD was investigated in a closed, agitated vessel with a flat gas-liquid interface. Molecular encapsulation of gaseous 1-MCP by alpha-CD is a simultaneous two-step reaction which involves the aqueous dissolution of gaseous 1-MCP and the encapsulation of the dissolved molecules by alpha-CD. The kinetics and mechanism of molecular encapsulation were analyzed based on the depletion rate of 1-MCP in the headspace of the vessel. The encapsulation rates could be explained quantitatively by the gas absorption theory with a pseudo-first-order reaction between 1-MCP and alpha-CD. The negative value of the calculated apparent activation energy of encapsulation (-24.4 kJ/mol) implied the significant effect of exothermic aqueous dissolution of 1-MCP. An encapsulation temperature of 15 degrees C was optimal; at this temperature, the highest 1-MCP yield and best inclusion ratio of inclusion complex were obtained. Changes in the X-ray diffraction pattern suggested that the crystal lattice structure of alpha-CD was altered upon inclusion of 1-MCP.

The crystal transformation of dihydrate trehalose to anhydrous trehalose was investigated using ethanol and a new type of crystal particle with porous structure could be obtained. The specific surface area of the anhydrous crystal transformed at 50 degrees C was 3.3 m(2)/g, with a median pore diameter of 0.21 microm, and void volume of 0.22 mL/g. The crystal transformation was monitored by measuring the crystal moisture content. The crystal transformation rates could be correlated with the Avrami equation, using the mechanism parameter n=11.5, suggesting that the change of surface area occurred during crystal transformation from dehydrate to anhydrous trehalose. The apparent activation energy of the crystal transformation was 132 kJ/mol.