EVALUATION OF SUBLETHAL EFFECTS OF Ipomoea cairica LINN. EXTRACT ON LIFE HISTORY TRAITS OF DENGUE VECTORS

Plant derived insecticides have considerable potential for mosquito control because these products are safer than conventional insecticides. This study aimed to investigate sublethal activities of Ipomoea carica or railway creeper crude acethonilic extract against life history trait of dengue vectors, Aedes albopictus and Aedes aegypti. The late third instar larvae of Ae. albopictus and Ae. aegypti were exposed to a sublethal dose at LC50 and larvae that survived were further cultured. Overall, Ipomea cairica crude extracts affected the whole life history of both Aedes species. The study demonstrated significantly lower egg production (fecundity) and eggs hatchability (fertility) in Ae. albopictus. The sublethal dose of crude extracts reduced significantly the width of larval head capsule and the wing length of both sexes in both Aedes species. The significance of sublethal effects of I. cairica against Aedes mosquitoes was an additional hallmark to demonstrate further activity of this plant despite its direct toxicity to the larvae. The reduced reproductive capacity as well as morphological and physiological anomalies are some of the effects that make I. cairica a potential candidate to be used as a new plant-based insecticide to control dengue vectors

The Relationship Between the Physicochemical Properties of Antioxidants and their Ability to Inhibit Lipid Oxidation in Bulk Oil and Oil-in-Water Emulsions

Chain-breaking antioxidants differ in their effectiveness at inhibiting lipid oxidation because of their chemical properties and physical location within a food. Our objective was how the physicochemical properties of four structurally related lipid-soluble antioxidants were related to their antioxidant activity. Antioxidants differed in the number of methyl (α-tocopherol and δ-tocopherol) or hydroxyl (butylated hydroxytoluene (BHT) and 4-hydroxymethyl-2,6-ditertiarybutylphenol) groups. Surface activity of the antioxidants was in the order of δ-tocopherol \u3e α-tocopherol ≈ 4-hydroxymethyl-2,6-ditertiarybutylphenol \u3e BHT. Free-radical scavenging activity was similar between α-tocopherol and δ-tocopherol as well as BHT and 4-hydroxymethyl-2,6-ditertiarybutylphenol. In bulk menhaden oil, BHT was a more effective antioxidant than 4-hydroxymethyl-2,6-ditertiarybutylphenol while α-tocopherol was more effective than δ-tocopherol. In menhaden oil-in-water emulsions, BHT was a more effective antioxidant than 4-hydroxymethyl-2,6-ditertiarybutylphenol while δ-tocopherol was more effective than α-tocopherol. These results indicate that the surface activity and polarity of lipid-soluble antioxidants were not the only determinants of their antioxidant effectiveness in food lipids

Comparison of Physicochemical and Functional Properties of Chicken and Duck Egg Albumens

ABSTRACT The aim of this research was to investigate the physicochemical and functional properties of fresh and pasteurized chicken and duck egg albumens. The results showed that pasteurization of both chicken and duck albumens significantly decreased (p≤0.05) viscosity, but had no impact (p>0.05) on pH or free sulfhydryl groups. Chicken albumen was shown to have higher (p≤0.05) foam expansion, but lower (p≤0.05) foam stability than duck albumen. Pasteurization decreased (p≤0.05) the foam expansion of both albumens while decreasing (p≤0.05) the foam stability only of duck albumen. Investigation of the gel properties showed that duck albumen has greater hardness and lower expressible water (p≤0.05) than chicken albumen. Pasteurization increased the hardness and decreased the expressible water of both the chicken and duck albumen gels. This study suggests that the superior gel properties of duck albumen offer potential approaches to improving the quality of gel food products

Impact of Surface-Active Compounds on Physicochemical and Oxidative Properties of Edible Oil

The physical properties of lipids can have a major influence on lipid oxidation reactions. Edible oils contain surface-active compounds and water that can form physical structures such as reverse micelles. This study used the fluorescence probe, 5-dodecanoylaminofluorescein (DAF), to study both the physical and the chemical properties of stripped corn oil containing oleic acid and phosphatidylcholine. The fluorescence intensity of DAF increased with increasing water concentration in the edible oil. The addition of oleic acid decreased DAF fluorescence due to the ability of the free fatty acid to decrease the pH of the aqueous phase of the bulk oil. Phosphatidylcholine increased DAF fluorescence due to its ability to increase DAF exposure to the aqueous phase. Oleic acid had no impact on interactions between DAF and water-soluble peroxyl radicals, while phosphatidylcholine decreased peroxyl radical degradation of DAF. These results suggest that DAF could be a useful analytical tool to study the impact of the aqueous environment of bulk oil on lipid oxidation

Relationships between free radical scavenging and antioxidant activity in foods

Numerous attempts have been made to relate the free radical scavenging capacity of compounds to their antioxidant activity in foods even though antioxidant activity is dependent on both physical and chemical properties. The objective of this study was to compare the free radical scavenging activity of various compounds to their ability to inhibit lipid oxidation in foods. The order of free radical scavenging activity of polar compounds was ferulic acid \u3e coumaric acid \u3e propyl gallate \u3e gallic acid \u3e ascorbic acid as determined by a modified oxygen radical absorbance capacity, while the order of nonpolar compounds was rosmarinic acid \u3e butylated hydroxytoluene \u3eor= tert-butylhydroquinone (TBHQ) \u3e alpha-tocopherol as determined by the 2,2-diphenyl-1-picrylhydrazyl assay. Of these compounds, only propyl gallate and TBHQ were found to inhibit lipid oxidation in cooked ground beef as determined by thiobarbituric acid reactive substances, while only propyl gallate, TBHQ, gallic acid, and rosmarinic acid inhibited lipid oxidation in an oil-in-water emulsion as determined by lipid hydroperoxides and headspace hexanal. These data indicate that the free radical scavenging assays tested have limited value in predicting the antioxidant activity in complex foods