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

Mechanisms and Rationale for Targeted Therapies in Refractory and Unexplained Chronic Cough

Chronic cough, defined as a cough lasting > 8 weeks, is a common medical condition that exerts a substantial physical, mental, and social burden on patients. A subset of patients with chronic cough are troubled with a cough that persists despite optimal treatment of presumed associated common and uncommon conditions (refractory chronic cough; RCC) or in which no diagnosable cause for cough can be identified despite extensive assessment (unexplained chronic cough; UCC). Many of these patients exhibit clinical features of cough hypersensitivity, including laryngeal paresthesia, hypertussia, and allotussia. Over-the-counter cough remedies are ineffective and can lead to intolerable side effects when used for RCC/UCC, and the lack of approved treatments indicated for these conditions reflects a major unmet need. An increased understanding of the anatomy and neurophysiology of protective and pathologic cough has fostered a robust clinical development pipeline of several targeted therapies for RCC/UCC. This manuscript reviews the mechanisms presumed to underly RCC/UCC together with the rationale and clinical evidence for several targeted therapies currently under clinical investigation, including transient receptor potential channel antagonists, P2X3-receptor antagonists, voltage-gated sodium channel blockers, neuromodulators, and neurokinin-1-receptor antagonists. Finally, we provide an overview of targets that have been investigated in preclinical models of cough and other airway diseases that may hold future promise for clinical studies in RCC/UCC. Development of targeted therapies with different sites of action may foster a precision medicine approach to treat this heterogeneous, underserved patient population