Binding of Volatile Organic Compounds to Food Biopolymers

Capillary gas chromatography was used to study the influence of the composition and structure of different food polymers (polysaccharides, vegetable fibers, and animal protein gelatin) on the binding of essential oil components. The retention of volatile organic compounds on biopolymers was shown to depend on their molecule structure and the presence, type, and position of a functional group. The maximum extent of the binding was observed for nonpolar terpene and sesquiterpene hydrocarbons, and the minimum extent was observed for alcohols. The components of essential oils were adsorbed due mostly to hydrophobic interactions. It was shown that the composition and structure of a compound, its physico-chemical state, and the presence of functional groups influence the binding. Gum arabic and guar gum were found to bind nonpolar compounds to a maximum and minimum extent, respectively. It was demonstrated the minimum adsorption ability of locust bean gum with respect to all studied compounds.     

Inhibition of oxidation of unsaturated fatty acid methyl esters by essential oils

The essential oils from 16 various spice plants were studied as natural antioxidants for the inhibition of autooxidation of polyunsaturated fatty acids methyl esters isolated from linseed oil. The content of methyl oleate, methyl linoleate, and methyl linolenoate after 1, 2, and 4 months of autooxidation were used as criteria to estimate the antioxidant efficiencies of essential oils. In 4 months, 92% of the methyl linolenoate and 79% of the methyl linoleate were oxidized in a control sample of a model system. It was found that the most effective antioxidants were essential oils from clove bud, cinnamon leaves, and oregano. They inhibited autooxidation of methyl linolenoate by 76–85%. The antioxidant properties of these essential oils were due to phenols— eugenol, carvacrol, and thymol. Essential oil from coriander did not contain phenols, but it inhibited methyl linolenoate oxidation by 38%. Essential oils from thyme, savory, mace, lemon, and tea tree inhibited methyl linolenoate oxidation by 17–24%. The other essential oils had no antioxidant properties.     

Sorption of components from a mixture of essential oils by cryotextured cornstarches

Sorption by cryotextured cornstarches of components of the aqueous phase of a mixture of essential oils was studied by capillary gas chromatography. The amount of cryotexture-sorbed substances depended linearly on their concentration in the initial gel. The sorption of components from the mixture by starch polysaccharides was mainly associated with hydrophobic cooperative interactions, which resulted in the formation of supramolecular structures and inclusion complexes. The structure of the compounds was a major factor determining the degree of sorption. Sorption of monoterpene carbohydrates was the most pronounced. We revealed a synergistic increase in the degree of sorption from the mixture as compared to binding of individual compounds.     

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.     

Sorption of components from a mixture of odorants by polysaccharides of starch, chitosan, and carrageenan

Sorption of components from a mixture of odorants in aqueous suspensions of native cornstarch, chitosan, and carrageenan was studied by the method of capillary gas-liquid chromatography. Binding was primarily effected via hydrophobic cooperative interactions. The amount of sorbed odorants depended linearly on their initial concentration in the suspension. The differences in sorption characteristics of starch and chitosan were related to the presence of amino groups in the latter compound, which contributed to increased binding of aldehydes via polar interactions. Sorption of odorants by the sulfated polysaccharide carrageenan largely depended on the structure of odorants and properties of their functional groups. Carrageenan was potent in binding aldehydes, ketones, and esters. Alcohols were less strongly bound to this compound. Sorption of lactones and guaiacol by carrageenan was the least significant.     

Marker-assisted dissection of genetic influences on motor and neuroendocrine sensitization to cocaine in rats

This study investigated genetic influences on behavioral and neuroendocrine responses to cocaine sensitization. We used male and female rats of the inbred strains Lewis (LEW) and spontaneously hypertensive rats (SHR), which display genetic differences in stress-related responses. The influence of two quantitative trait loci (QTL; Ofil1 and Ofil2 on chromosomes 4 and 7), which modulate stress reactivity in rats, on the effects of cocaine was also investigated through the use of recombinant lines (derived from a LEW   ×   SHR intercross) selected by their genotype at Ofil1 and Ofil2 . Animals were given repeated cocaine or saline injections and tested for locomotion (induction of sensitization). Two weeks later, all animals were challenged with cocaine, and locomotion and corticosterone levels were measured (expression of sensitization). Results indicated that male SHR rats showed more behavioral sensitization than LEW rats, whereas no strain differences in sensitization were seen among females. When challenged with cocaine, LEW and SHR rats of both sexes pretreated with cocaine showed behavioral sensitization compared with saline pretreated animals; however, only LEW rats displayed an increase in the corticosterone levels. Ofil1 was found to influence the induction of sensitization in males and Ofil2 modulated the locomotor effect of cocaine in females. This study provides evidence of a genotype-dependent relationship between the induction and expression of cocaine sensitization, and between the behavioral and neuroendocrine responses induced by cocaine. Moreover, the Ofil1 and Ofil2 loci may contain one or more genes that control the behavioral effects of cocaine in rats.     

An experimental, NADPH-diaphorase histochemical and immunocytochemical study of Mesocestoides vogae tetrathyridia.

In order to test the role of nitric oxide in flatworms, Mesocestoides vogae tetrathyridia were incubated together with L-arginine, which is the substrate for nitric oxide synthesis, or with NG-nitro-L-arginine, which is an irreversible inhibitor of nitric oxide synthase. Normally, tetrathyridia attach to each other with the aid of their suckers, forming clusters. The rate of cluster formation was followed during the incubations. L-Arginine stimulated, and NG-nitro-L-arginine clearly inhibited, the cluster formation. This is the first time that an effect of nitric oxide has been observed in a flatworm. In addition, the pattern of the NADPH-diaphorase histochemical reaction in the nervous system and the pattern of F-actin filaments in the musculature stained with TRITC-labelled phalloidin were studied. NADPH-d staining occurred in the brain and the main nerve cords but also followed the muscle fibres stained with phalloidin. The pattern of the NADPH-d reaction was compared with that of 5-HT immunoreactivity. The implications of the results are discussed in relation to the background of data on neuronal signal substances in M. vogae.     

Sorption of Components from a Mixture of Essential Oils by Cryotextured Cornstarches

Sorption by cryotextured cornstarches of components of the aqueous phase of a mixture of essential oils was studied by capillary gas chromatography. The amount of cryotexture-sorbed substances depended linearly on their concentration in the initial gel. The sorption of components from the mixture by starch polysaccharides was mainly associated with hydrophobic cooperative interactions, which resulted in the formation of supramolecular structures and inclusion complexes. The structure of the compounds was a major factor determining the degree of sorption. Sorption of monoterpene hydrocarbons was the most pronounced. We revealed a synergistic increase in the degree of sorption from the mixture as compared to binding of individual compounds.__________Translated from Prikladnaya Biokhimiya i Mikrobiologiya, Vol. 41, No. 4, 2005, pp. 463–469.Original Russian Text Copyright © 2005 by Terenina, Misharina.