Twenty-one flavonol metabolites have been identified by LC/ESI-MS/MS in human urine, including isomers, after the consumption of cooked onions. Metabolites identified include quercetin monoglucuronides, methyl quercetin monoglucuronides,... more
Twenty-one flavonol metabolites have been identified by LC/ESI-MS/MS in human urine, including isomers, after the consumption of cooked onions. Metabolites identified include quercetin monoglucuronides, methyl quercetin monoglucuronides, a quercetin monoglucuronide sulfate, quercetin diglucuronides, a methyl quercetin diglucuronide, quercetin glucoside sulfates, methyl quercetin, quercetin, and kaempferol monoglucuronides. The fragmentation patterns of flavonol metabolites obtained by MS/MS were distinctive for some isomers, indicating that fragmentation patterns may be useful predictors of conjugation position. Two isomers of sulfate quercetin glucosides were also found in urine, suggesting that many of the quercetin glucosides in onion are absorbed intact and undergo metabolism to the sulfate conjugate. Additionally, the interindividual variation in urinary quercetin metabolite profiles was determined by comparing the relative level of six different quercetin metabolites excreted in the urine of healthy volunteers. The ranges of quercetin metabolites excreted were similar among volunteers, yet notable differences in the levels of metabolites among individuals were observed. This study demonstrates the potential of monitoring the range of quercetin metabolites to reveal information on interindividual biotransformation capacity in response to dietary manipulations and as a biomarker for flavonol consumption.
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Research Interests: Engineering, Chemistry, Food Science, Consumer Behavior, Medicine, and 15 moreFood Preservation, California, Humans, Descriptive Analysis, NUTS, Taste, Lipid Oxidation, Lipid peroxidation, CHEMICAL SCIENCES, Almond, Maillard reaction, Flavor, Roasting, Partial Least Squares Analysis, and food handling
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Research Interests: Biochemistry, Chemistry, Kinetics, Enzyme Inhibitors, Medicine, and 15 moreHumans, Mice, Animals, Male, Glutathione, Enzyme, Isoenzymes, Cysteine, Glutathione Transferase, Amino Acid Sequence, Enzymatic Activity, Catalytic Activity, Butyrolactone, Biochemistry and cell biology, and Medical biochemistry and metabolomics
Research Interests: Engineering, Chemistry, Food Science, Adolescent, Medicine, and 15 moreHumans, Fatty acids, Cooking, NUTS, Female, Male, CHEMICAL SCIENCES, Almond, Aged, Middle Aged, Adult, Food Storage, Humidity, Peroxide, and Peroxides
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Typical volatile heterocyclic compounds found in brewed coffee extracts-pyrroles, furans, thiophenes, and thiazoles-were examined for antioxidative activity, which was determined by measuring the oxidative conversion of hexanal to... more
Typical volatile heterocyclic compounds found in brewed coffee extracts-pyrroles, furans, thiophenes, and thiazoles-were examined for antioxidative activity, which was determined by measuring the oxidative conversion of hexanal to hexanoic acid using gas chromatography. 2-Acetylpyrrole, 1-methylpyrrole, and pyrrole inhibited hexanal oxidation by 98, 87, and 78%, respectively, at a concentration of 500 microgram/mL over a period of 30 days. 2-Methylfuran, which inhibited hexanal oxidation by 90% at all concentrations tested (500, 200, and 100 microgram/mL) for a 30-day period, exhibited the greatest activity among furans tested. Similarly, 2-methylthiophene, which inhibited hexanal oxidation by almost 100% at a concentration of 500 microgram/mL over 30 days, exhibited the greatest activity among the thiophenes tested. In general, thiazoles were ineffective antioxidants at all concentrations tested. However, 4,5-dimethylthiazole was able to inhibit hexanal oxidation by 50% at the highest level tested (500 microgram/mL). 2-Acetylpyrrole, 2-methylfuran, and 2-methylthiophene at concentrations of 500, 200, and 100 microgram/mL and furan at a concentration of 500 microgram/mL exhibited antioxidative activities comparable to that of the synthetic antioxidant butylated hydroxytoluene at a concentration of 50 microgram/mL.
Research Interests: Engineering, Chemistry, Coffee, Pharmacognosy, Medicine, and 15 moreAntioxidants, Identification, Cooking, Antioxidant, Gas Chromatography, Aroma, Agricultural, CHEMICAL SCIENCES, Antioxidant Activity, Flavor, Agricultural and Food Chemistry, Biological activity, Heterocyclic compounds, Aldehydes, and Butylated hydroxytoluene
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Artisanal honey usually originates from bees that forage on the nectar of one type of flower (monofloral honey), as opposed to the commercial product that comes from a variety of flowers and is mixed with other honeys. Monofloral honey... more
Artisanal honey usually originates from bees that forage on the nectar of one type of flower (monofloral honey), as opposed to the commercial product that comes from a variety of flowers and is mixed with other honeys. Monofloral honey gives distinctive flavors and aromas associated with the nectar source, and over 300 monofloral types are available in the United States. Studies on artisanal honey show levels of certain aroma-active volatile compounds that are present at lower concentrations in mass-produced honey. A focus in this chapter is on one artisanal producer who keeps their honey temperature low, unlike the large-scale product, to retain the naturally occurring pollen and enzymes. Every local honey is unique, and beekeepers often seek out specific forage areas to collect distinctive varietals for the product.
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Background Food and Drug Administration (FDA) Food Drug and Cosmetic (FD&C) synthetic color additives (SCAs) have been associated with attentional and behavioral problems in children. Efforts to quantify exposure have focused on foods,... more
Background Food and Drug Administration (FDA) Food Drug and Cosmetic (FD&C) synthetic color additives (SCAs) have been associated with attentional and behavioral problems in children. Efforts to quantify exposure have focused on foods, while the contribution of medications and supplements remains unknown. Objective To estimate exposures to SCAs in children (2–16 years) and pregnant women from intake of common over-the-counter (OTC) medications and vitamins. Methods We estimated single-day exposure (mg/kg/day) to FD&C SCAs based on measurements of 25 different products and recommended dosages on product labels. Exposures were compared to SCA exposure estimates from food we previously developed and acceptable daily intakes (ADIs) established by FDA and the World Health Organization. Results The highest exposure was found for FD&C Red No. 40 in a children’s cold/cough/allergy syrup. A child aged 12–16 years consuming the maximum daily dosage would have an exposure of 0.221 mg/kg/day, w...
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Lysyl oxidase (EC 1.4.3.13), a cuproenzyme, can account for 10-30% of the copper present in connective tissue. Herein, we assess the extent to which tissue copper concentrations and lysyl oxidase activity are related because the... more
Lysyl oxidase (EC 1.4.3.13), a cuproenzyme, can account for 10-30% of the copper present in connective tissue. Herein, we assess the extent to which tissue copper concentrations and lysyl oxidase activity are related because the functional activity of lysyl oxidase and the copper content of chick tendon are both related to dietary copper intake. Chicks (1-d old) were fed diets (basal copper concentration, 0.4 microg/g diet) to which copper was added from 0 to 16 microg/g diet. Liver and plasma copper levels tended to normalize in chickens that consumed from 1 to 4 microg copper/g of diet, whereas tendon copper concentrations suggested an unusual accumulation of copper in chickens that consumed 16 microg copper/g diet. The molecular weight of lysyl oxidase was also estimated using matrix-assisted laser desorption ionization/time-of-flight/mass spectrometry (MALDI/TOF/MS). A novel aspect of these measurements was estimation of protein mass directly from the surface of chick tendons an...