Concentrations of anthocyanins in common foods in the United States and estimation of normal consumption

Anthocyanins (ACNs) are water-soluble plant pigments that have important functions in plant physiology as well as possible health effects. Over 100 common foods were screened for ACNs, and 24 of them were found to contain ACNs. Concentrations of total ACNs varied considerably from 0.7 to 1480 mg/100 g of fresh weight in gooseberry ('Careless' variety) and chokeberry, respectively. Not only does the concentration vary, but the specific anthocyanins present in foods are also quite different. Only six common aglycones, delphinidin, cyanidin, petunidin, pelargonidin, peonidin, and malvidin, were found in all of these foods. However, their sugar moieties and acylation patterns varied from food to food. Results from this study will add to the available data for the USDA Nutrient Database of flavonoids. On the basis of the concentration data and updated food intake data from NHANES 2001-2002, the daily intake of ACNs is estimated to be 12.5 mg/day/person in the United States. Of the different aglycones, cyanidin, delphinidin, and malvidin were estimated to contribute 45, 21, and 15%, respectively, of the total ACN intake. Nonacylated contributed 77% compared to 23% from acylated ACNs.     

Some unusual minor volatile components of tomato

The identities and possible origins of three minor unusual volatile components of tomato are discussed. These are pentyl nitrate, the first identification of a volatile alkyl nitrate in a fresh vegetable or fruit; 5-ethyl-2(5H)-furanone, which, besides its presence in tomato, was found to be a major autoxidation product of pure (Z)-3-hexenal; and 5-ethylcyclopentene-1-carbaldehyde, a likely unusual linolenic acid oxidation product.     

Effect of acidic deposition on hybrid poplar- primary or predisposing stress?

Our research examined the role of acidic deposition as a primary, or predisposing, stress on 8–12 week old cuttings of hybrid poplar (Populos deltoides x nigra). Firstly, we examined the role of acidic deposition as a primary stress in terms of physiological indicators (gas exchange, chlorophyll concentrations, chlorophyll-a fluorescence). Our results suggest that levels of acid precipitation of > pH 3.5 did not act as a primary stress. Secondly, we hypothesized that acidic deposition could act by making trees more susceptible to drought. An acid treatment exposure regime was followed by 3–4 days of drought stress in a controlled environment. Preexposure to acidic deposition did not increase the degree, or rate of appearance, of water stress as indicated by predawn xylem pressure potentials and leaf conductances. Examination of cuticular water loss from excised leaves suggested that this parameter was insensitive to acidic deposition from pH 3.0 to 5.5.     

Anthocyanin glycosides from berry fruit are absorbed and excreted unmetabolized by both humans and rats

Anthocyanins, the red/blue pigments found in plants, are polyphenolic compounds consumed by humans and are part of a normal diet. Recent studies have shown that anthocyanins have substantial bioactivity including antioxidant activity and therefore may have beneficial effects on human health. Anthocyanins are a group of over 500 compounds of diverse structures containing different core phenolic aglycons and conjugated with sugars in a variety of glycosylation patterns. In this study, we have investigated the bioabsorption of 15 anthocyanins with structures containing different aglycons and conjugated sugars extracted from blueberry, boysenberry, black raspberry, and blackcurrant in both humans and rats. Intact and unmetabolized anthocyanins were detected in urine of rats and humans following dosing for all molecular structures investigated, thus demonstrating that anthocyanins with diverse molecular structure and from different dietary sources are bioavailable at diet relevant dosage rates. In addition, the relative concentrations of anthocyanins detected in urine following dosing varied, indicating that differences in bioavailability are due to variations in chemical structure. Our results suggest that the nature of the sugar conjugate and the phenolic aglycon are both important determinants of anthocyanin absorption and excretion in rats and humans.     

Predictive relationship between polyphenol and nonfat cocoa solids content of chocolate

Chocolate is often labeled with percent cocoa solids content. It is assumed that higher cocoa solids contents are indicative of higher polyphenol concentrations, which have potential health benefits. However, cocoa solids include polyphenol-free cocoa butter and polyphenol-rich nonfat cocoa solids (NFCS). In this study the strength of the relationship between NFCS content (estimated by theobromine as a proxy) and polyphenol content was tested in chocolate samples with labeled cocoa solids contents in the range of 20-100%, grouped as dark (n = 46), milk (n = 8), and those chocolates containing inclusions such as wafers or nuts (n = 15). The relationship was calculated with regard to both total polyphenol content and individual polyphenols. In dark chocolates, NFCS is linearly related to total polyphenols (r2 = 0.73). Total polyphenol content appears to be systematically slightly higher for milk chocolates than estimated by the dark chocolate model, whereas for chocolates containing other ingredients, the estimates fall close to or slightly below the model results. This shows that extra components such as milk, wafers, or nuts might influence the measurements of both theobromine and polyphenol contents. For each of the six main polyphenols (as well as their sum), the relationship with the estimated NFCS was much lower than for total polyphenols (r2 < 0.40), but these relationships were independent of the nature of the chocolate type, indicating that they might still have some predictive capabilities.     

Effects of meat consumption and vegetarian diet on risk of wrist fracture over 25 years in a cohort of peri- and postmenopausal women

BACKGROUND: Evidence suggesting that a diet high in fruits and vegetables may be beneficial to bone health has sparked interest in the potential benefit of a vegetarian diet. However, other studies have raised a question regarding the adequacy of protein in such a diet. OBJECTIVE: The aim of the present study was to take a whole foods approach in examining the effects of foods high in protein on the risk of wrist fracture (WF) in a cohort with a significant proportion consuming a meat-free diet. DESIGN: A cohort study of women who completed two lifestyle surveys 25 years apart. SUBJECTS: One thousand eight hundred and sixty-five peri- and postmenopausal women at the time of the first survey. RESULTS: There was a significant interaction between meat consumption and foods high in vegetable protein. Among vegetarians, those who consumed the least vegetable protein intake were at highest risk for fracture. However, increasing levels of plant-based high-protein foods decreased WF risk, with a 68% reduction in risk (hazard ratio (HR) = 0.32, 95% confidence interval (CI) 0.13-0.79) in the highest intake group. Among those with lowest vegetable protein consumption, increasing meat intake decreased the risk of WF, with the highest consumption decreasing risk by 80% (HR = 0.20, 95% CI 0.06-0.66). CONCLUSIONS: The finding that higher consumption frequencies of foods rich in protein were associated with reduced WF supports the importance of adequate protein for bone health. The similarity in risk reduction by vegetable protein foods compared with meat intake suggests that adequate protein intake is attainable in a vegetarian diet.     

Occurrence and Environmental Fate of Veterinary Antibiotics in the Terrestrial Environment

A wide variety of veterinary antibiotics (VAs) has been detected in environmental water samples, and this is of potential environmental concern due to their adverse effects. In particular, the potential for development of antibiotic-resistant bacteria has raised social concerns leading to intensive investigation regarding the influence of antibiotics on human and ecosystem health. One of the main sources of antibiotic effluence to the environment is livestock manures that often contain elevated levels of VAs that survive normal digestive procedures following medication in animal husbandry because unlike human waste, waste generated on farms does not undergo tertiary wastewater treatment, and consequently, the concentration of antibiotics entering the environment is expected to be larger from farming practices. Animal feed is often supplemented with VAs to promote growth and parasite resistance in the medicated animals, and this practice typically resulted in higher use of VAs and consequential excretion from livestock through urine and feces. The excretion rate varied depending on the type of VA used with around 75, 90, and 50?C100% being excreted for chlortetracycline, sulfamethazine, and tyolsin, respectively. The excreted VAs that initially present in livestock manures were degraded more than 90% when proper composting practice was used, and hence, this can be employed as a management strategy to decrease VA environmental loads. The reduction of VA concentrations during composting was mainly attributed to abiotic processes rather than biotic degradation. The VAs released to soils by the application of manure and manure-based composts can be degraded or inactivated to various degrees through abiotic process such as adsorption to soil components. Depending on the antibiotic species and soil properties, residues can be transferred to groundwater and surface water through leaching and runoff and can potentially be taken up by plants.     

Sorption and vapor transmission properties of uncompressed and compressed microcellular starch foam

Microcellular starch foams (MCFs) are made by a solvent-exchange process and consist of a porous matrix with pores generally ranging from approximately 2 microm to submicrometer size. MCF may potentially be useful as a slow-release agent for volatile compounds because of its ability to sorb chemicals from the atmosphere and to absorb liquids into its porous structure, and because it can be compressed to form a starch plastic. MCF made of high-amylose corn and wheat starches was prepared with or without 2% (w/w) silicone oil (SO) or palmitic acid (PA). The MCF was loaded with 1% of various volatile compounds with vapor pressures ranging from 0.02 to 28 mm. The MCF depressed the vapor pressure from 0.37 to 37% compared to a control containing no MCF. Incorporating SO or PA in the matrix of the MCF had little effect on sorption of volatiles. Compressing MCF at 1.4, 6.9, and 69 MPa made a starch plastic with varying porosity. The vapor transmission rate of various volatile compounds through MCF was positively correlated to the vapor pressure of the test compound but was inversely proportional to the compression force used to form the starch plastic. The results indicate that uncompressed and compressed MCFs could be effective slow-release agents for a variety of volatile compounds, especially if used together.     

“玉米带”改种多年生草类后对农田排水的水文效应模拟

该文针对美国密西西比河上游明尼苏达州农田排水氮素流失严重,近年来又大力发展生物燃料产业的现状,采用田间水文模型——DRAINMOD模拟分析了玉米-大豆轮作区改种多年生草类后对农田排水的水文效应。结果表明改种多年生草后,植物耗水量的增加使得农田排水量明显减少;较深的草根系,尤其是在干旱年份消耗了大量的深层土壤水,降低了地下水位。种草后的生物排水量远远大于其他工程措施（如增加排水间距或潜埋排水管等）,可显著减少农田排水氮素流失对水环境的影响。     

Effect of type of oil and addition of delta-tocopherol on model flavor compound stability during storage

The objective of this study was to investigate approaches to protect selected flavor compounds from deterioration when stored in an oil matrix. An aroma compound model mixture was prepared in a medium-chain triglyceride (MCT) or sunflower oil (SfO) matrix and stored under either an ambient air or argon atmosphere containing, respectively, ca. 20 and <0.5% residual oxygen as controls or containing a natural antioxidant, delta-tocopherol (0.01%). Samples were analyzed by static headspace GC/FID to determine the stability over time of the compounds in mixture. It was found that the type of oil had the greatest effect (P < 0.01) on overall compound stability. A low-oxygen atmosphere also had a significant (P < 0.05) protective effect on the aroma compounds in both oils. The addition of delta-tocopherol generally offered little additional protection. No significant relationship could be determined between the oxidation of the lipid matrix and the loss of oxidation-sensitive thiol compounds.