Spectrofluorimetric determination of biogenic amines (serotonin, dopamine) in Metechinorhynchus salmonis (Acanthocephala)

Identification of serotonin and dopamine in M. salmonis was conducted by means of some fluorometric methods. The presence of negligible amount of a serotonin-like component and substance close in its spectral characteristics to dopamine was shown.     

The influence of starter cultures on the formation of volatile compounds in dry smoked sausages

The differences between the composition of volatile substances in two specimens of dry smoked sausages produced using a standard and experimental (a mixture of propionic acid bacteria and bifidobacteria) cultures were studied by capillary gas chromatography. It was found that the experimental starter culture intensified the flavor-formation processes as compared with the standard culture. The experimental specimen had richer qualitative and quantitative compositions and displayed more intensive aroma and flavor. The contents of lactones and volatile terpenoids in the experimental specimen were much higher than in the control. The organoleptic characteristics of experimental dry smoked sausage specimen were considerably better.     

Binding of aromatic compounds to cornstarch polysaccharides

Sorption of aromatic compounds from aqueous solutions by cryotextures and suspensions of native cornstarches was studied by capillary gas chromatography. Acetophenone and benzyl alcohol were not sorbed by cryotropic-cornstarch gel and native-cornstarch suspension. A linear concentration dependence was found for aldehydes. Phenylethyl alcohol was characterized by a nonlinear concentration dependence. The presence of a benzene ring contributed to decreased binding (relative to the level characteristic of aliphatic compounds). The degree of binding depended considerably on the type of functional group in the aromatic compounds. Cryotextures were more potent than granules of native cornstarch in binding aromatic compounds.     

Binding of aliphatic aldehydes by cornstarch polysaccharides

Binding by cryotextured cornstarch of individual aliphatic aldehydes (C6-C10; saturated or unsaturated) and their mixtures from aqueous solutions has been studied using capillary gas chromatography. The amount of compounds absorbed by the cryotextures depended linearly on the concentration of aldehydes in the original gel. The majority of the compounds under study were bound irreversibly. Aldehydes with low molecular weight were better absorbed by the cryotextures than by granules of intact cornstarch. Data of IR spectrocopy demonstrated that binding to cornstarch polysaccharides decreased the conformational mobility of odorants. The appearance of binding isotherms depended of the extent of aldehyde sorption, suggesting the involvement of multiple mechanisms of binding. The formation of supramolecular complexes through cooperative hydrophobic interactions between aldehydes and cornstarch polysaccharides was the preferential mechanism of the sorption.     

The influence of the composition of essential lemon oils on their antioxidant properties and the stability of the components

The antioxidant properties of various essential oils of lemon (Citrus limon L.) were studied by capillary gas liquid chromatography and compared with those of individual limonene and citral and their mixture in model systems. Some differences in resistance towards oxidation of the major components of lemon oils were ascertained and the synergetic effects in the antioxidant activity of the components and their stability were found.     

Effect of the Compositions of Sample and Polymer Sorbents on the Extraction of Volatile Compounds by Solid-Phase Microextraction

A comparative study was performed by solid phase microextraction and capillary gas chromatography to establish the ability of four polymer sorbents of different compositions to extract and concentrate volatile organic compounds from the gas phase above an aqueous solution. All polymer sorbents sorbed nonpolar monoterpene hydrocarbons via a cooperative mechanism with almost equal and high efficiency. Sorbents based on polymethyl disiloxane and its mixture with divinylbenzene were more effective in extracting acetates and sesquiterpenes. As the concentration of these compounds in the gas phase increased, their binding by sorbents decreased. It was found that the determination of polar compounds depended on the presence of a solvent in the system. Compounds that are highly soluble in water (alcohols, ketones, etc.) had low coefficients of distribution between gas and water phases. Consequently, their sorption to any of the polymer sorbents was negligible. In the absence of the solvent, the degree of their extraction from the gas phase above the sample was high. It was shown that the actual composition of compounds in the initial mixture of essential oils could significantly differ from their composition in the gas phase. This method is convenient and informative for the purpose of studying the composition of volatile compounds in the gas phase that determine the flavor of the product.     

Retention of components in a mixture of volatile organic substances by maltodextrins

The effect of composition and origin of maltodextrins on the retention of 38 components in a mixture of volatile organic substances (odorants) during 6-month storage was studied by means of capillary gas-liquid chromatography. The retention of esters increased with an increase in their molecular weight. The retention of lactones, phenols, linalool, menthone, and damascone was 75–85%. Storage of aldehydes was accompanied by oxidation, and the retention of these substances did not exceed 55%. The retention of odorants increased with a decrease in the molecular weight of maltodextrins. The maximum retention was typical of maltodextrin from amylopectin starch not containing amylose.