Volatile Aldehydes (volatile + aldehyde)

Distribution by Scientific Domains

Selected Abstracts

Breath gas aldehydes as biomarkers of lung cancer

Patricia Fuchs
Abstract There is experimental evidence that volatile substances in human breath can reflect presence of neoplasma. Volatile aldehydes were determined in exhaled breath of 12 lung cancer patients, 12 smokers and 12 healthy volunteers. Alveolar breath samples were collected under control of expired CO2. Reactive aldehydes were transformed into stable oximes by means of on-fiber-derivatization (SPME-OFD). Aldehyde concentrations in the ppt and ppb level were determined by means of gas chromatography-mass spectrometry (GC-MS). Exhaled concentrations were corrected for inspired values. Exhaled C1,C10 aldehydes could be detected in all healthy volunteers, smokers and lung cancer patients. Concentrations ranged from 7 pmol/l (161 pptV) for butanal to 71 nmol/l (1,582 ppbV) for formaldehyde. Highest inspired concentrations were found for formaldehyde and acetaldehyde (0,55 nmol/l and 0,13 nmol/l, respectively). Acetaldehyde, propanal, butanal, heptanal and decanal concentrations showed no significant differences for cancer patients, smokers and healthy volunteers. Exhaled pentanal, hexanal, octanal and nonanal concentrations were significantly higher in lung cancer patients than in smokers and healthy controls (ppentanal = 0.001; phexanal = 0.006; poctanal = 0.014; pnonanal = 0.025). Sensitivity and specificity of this method were comparable to the diagnostic certitude of conventional serum markers and CT imaging. Lung cancer patients could be identified by means of exhaled pentanal, hexanal, octanal and nonanal concentrations. Exhaled aldehydes reflect aspects of oxidative stress and tumor-specific tissue composition and metabolism. Noninvasive recognition of lung malignancies may be realized if analytical skills, biochemical knowledge and medical expertise are combined into a joint effort. [source]

Voltammetric Determination of Free and Total Sulfur Dioxide in Beer

J. Almeida
Abstract A voltammetric method for the determination of free and total sulfur dioxide in beer is described. First, volatile aldehydes (mainly acetaldehyde) are purged with nitrogen from a beer sample diluted in alkaline medium, collected in an appropriate electrolyte trapping solution and determined, after derivatization with hydrazine, by voltammetry using a hanging mercury drop electrode. Then, the remaining beer solution is strongly acidified and (total) sulfur dioxide is purged with nitrogen, collected in an appropriate electrolyte trapping solution and determined by voltammetry. The free sulfur dioxide concentration is calculated by difference between (total) sulfur dioxide and acetaldehyde concentrations. The proposed method has a relative standard deviation of about 2.1% and 4.4%, respectively for (total) sulfur dioxide and free sulfur dioxide concentrations normally found in beer, and results are in good agreement with those obtained by the p -rosaniline reference method. [source]

Chemistry and Reactions of Reactive Oxygen Species in Foods

Eunok Choe
ABSTRACT: Reactive oxygen species (ROS) is formed enzymatically, chemically, photochemically, and by irradiation of food. It is also formed by the decomposition and the inter-reactions of ROS. The hydroxy radical is the most reactive ROS and then followed by singlet oxygen. Reactions of ROS with food components produce undesirable volatile compounds and carcinogens, destroy essential nutrients, and change the functionalities of proteins, lipids, and carbohydrates. Lipid oxidation by ROS produces low-molecular-weight volatile aldehydes, alcohols, and hydrocarbons. ROS causes crosslink or cleavage of proteins. ROS produces low-molecular-weight carbonyl compounds from carbohydrates. Vitamins are easily oxidized by ROS, especially singlet oxygen. The singlet oxygen reaction rate was the highest in ,-carotene followed by tocopherol, riboflavin, vitamin D, and ascorbic acid. [source]

Antioxidant Properties of Far Infrared-treated Rice Hull Extract in Irradiated Raw and Cooked Turkey Breast

S.-C. Lee
ABSTRACT: The antioxidant effect of far infrared-treated rice hull (FRH) extracts in irradiated turkey breast meat was compared with that of sesamol and rosemary oleoresin. The FRH extracts significantly decreased thiobarbituric acid-reactive substances values and volatile aldehydes (hexanal, pentanal, and propanal) and was effective in reducing the production of dimethyl disulfide responsible for irradiation off-odor in irradiated raw and cooked turkey meat during aerobic storage. The antioxidant activity of FRH extracts (0.1%, wt/wt) was as effective as that of rosemary oleoresin (0.1%). However, the addition of FRH extracts increased red and yellow color intensities and produced an off-odor characteristic to rice hull in raw and cooked meat. [source]

Physiological Responses of Limonium aureum Seeds to Ultra-drying

Yi Li
Abstract The seeds of Limonium aureum (L.) Hill. were dried from 8.92% to 2.88% moisture content in a desiccating container with silica gel. After ultra-drying the seeds were accelerated aged (50 C, 1 month), and some physiological indices, including the electrical conductivity, dehydrogenase activity, superoxide dismutase (SOD), peroxidase (POD), glutathione reductase (GR), ascorbate peroxidase (APX), catalase (CAT), volatile aldehydes and malondialdehyde (MDA) were tested. The results indicated that dehydrogenase, POD, SOD, GR, APX and CAT activities of the ultra-dry seeds were higher than the control seeds, while volatile aldehydes and malondialdehyde were lower than the control group. The results suggest that ultra-drying is beneficial for maintaining the vigor of L. aureum seeds at a high level. Thus, L. aureum seeds could be stored under ultra-dry conditions. (Handling editor: Jin-Zhong Cui) [source]