Endocrine disrupting nonylphenols are ubiquitous in food

4-Nonylphenols (NPs) are common products of biodegradation of a widely used group of nonionic surfactants, the nonylphenol ethoxylates (NPEs). These compounds are known to be persistent, toxic, and estrogen active. There is a worldwide scientific and public discussion on the potential consequences of human long term dietary exposure to such endocrine disrupters. Despite numerous determinations of NPs in environmental samples no systematical reports exist relating to concentrations of NPs in food. We analyzed NPs in 60 different foodstuff commercially available in Germany. The results indicate that NPs are ubiquitous in food. The concentrations of NPs on a fresh weight basis varied between 0.1 and 19.4 microg/kg regardless of the fat content of the foodstuff. Based on data on German food consumption rates and these first analyses of NPs in food, the daily intake for an adult was calculated to be 7.5 microg/day NPs. For infants exclusively fed with breast milk or infant formulas daily intakes of 0.2 microg/day and 1.4 microg/day NPs, respectively, can be estimated.     

Reactions of chlorogenic acid and quercetin with a soy protein isolate--influence on the in vivo food protein quality in rats

Plant phenolic compounds are known to interact with proteins producing changes in the food (e. g., biological value (BV), color, taste). Therefore, the in vivo relevance, especially, of covalent phenol-protein reactions on protein quality was studied in a rat bioassay. The rats were fed protein derivatives at a 10% protein level. Soy proteins were derivatized with chlorogenic acid and quercetin (derivatization levels: 0.056 and 0.28 mmol phenolic compound/gram protein). Analysis of nitrogen in diets, urine, and fecal samples as well as the distribution of amino acids were determined. Depending on the degree of derivatization, the rats fed with soy-protein derivatives showed an increased excretion of fecal and urinary nitrogen. As a result, true nitrogen digestibility, BV, and net protein utilization were adversely affected. Protein digestibility corrected amino acid score was decreased for lysine, tryptophan, and sulfur containing amino acids.     

Advanced solid-state NMR characterization of marine dissolved organic matter isolated using the coupled reverse osmosis/electrodialysis method

Advanced (13)C solid-state techniques were employed to investigate the major structural characteristics of two surface-seawater dissolved organic matter (DOM) samples isolated using the novel coupled reverse osmosis/electrodialysis method. The NMR techniques included quantitative (13)C direct polarization/magic angle spinning (DP/MAS) and DP/MAS with recoupled dipolar dephasing, (13)C cross-polarization/total sideband suppression (CP/TOSS), (13)C chemical shift anisotropy filter, CH, CH(2), and CH(n) selection, two-dimensional (1)H-(13)C heteronuclear correlation NMR (2D HETCOR), 2D HETCOR combined with dipolar dephasing, and (15)N cross-polarization/magic angle spinning (CP/MAS). The two samples (Coastal and Marine DOM) were collected at the mouth of the Ogeechee River and in the Gulf Stream, respectively. The NMR results indicated that they were structurally distinct. Coastal DOM contained significantly more aromatic and carbonyl carbons whereas Marine DOM was markedly enriched in alkoxy carbon (e.g., carbohydrate-like moieties). Both samples contained significant amide N, but Coastal DOM had nitrogen bonded to aromatic carbons. Our dipolar-dephased spectra indicated that a large fraction of alkoxy carbons were not protonated. For Coastal DOM, our NMR results were consistent with the presence of the major structural units of (1) carbohydrate-like moieties, (2) lignin residues, (3) peptides or amino sugars, and (4) COO-bonded alkyls. For Marine DOM, they were (1) carbohydrate-like moieties, (2) peptides or amino sugars, and (3) COO-bonded alkyls. In addition, both samples contained significant amounts of nonpolar alkyl groups. The potential sources of the major structural units of DOM were discussed in detail. Nonprotonated O-alkyl carbon content was proposed as a possible index of humification.     

Effects of dietary supplementation of vitamins D(3) and E on quality characteristics of pigs and longissimus muscle antioxidative capacity

The effects of addition of vitamin D₃ and vitamin E to pig diets on blood plasma calcium concentration, meat quality (longissimus muscle) and antioxidative capacity were investigated. Two treatments consisted of supplementation with vitamin D₃ (500,000 IU/d) for 5 days separately (group D) and a combination of vitamin E (500 mg α-tocopheryl acetate/kg diet) for 30 days and vitamin D₃ (500,000 IU/d) for 5 days (group D + E) to growing-finishing pigs before slaughter. Pigs fed with vitamin D₃ had higher (P < 0.01) plasma calcium concentration compared with control pigs. Dietary supplementation of vitamin E significantly (P < 0.05) increased the concentration of α-tocopherol in meat (longissimus muscle). Vitamin D₃ supplementation resulted in higher (P = 0.07) a^∗ values of loin chops at 5 days of storage. Vitamin D₃ and vitamin E supplementation did not affect other meat quality characteristics or tenderness (quantified by Warner–Bratzler shear force). Antioxidative capacity (measured as MDA production after incubation of longissimus muscle homogenates with Fe²⁺/ascorbate) was improved by vitamin E and partly by vitamin D₃ supplementation.     

Some practical procedures for the solution of nonlinear finite element equations

Procedures for the solution of incremental finite element equations in practical nonlinear analysis are described and evaluated. The methods discussed are employed in static analysis and in dynamic analysis using implicit time integration. The solution procedures are implemented, and practical guidelines for their use are given.     

The nutritional and physiological impact of milk in human nutrition

The nutritional value of milk as an important source of energy, high‐quality protein, calcium, and riboflavin has been recognized for many years. Currently, the widespread use and promotion of milk in the U.S. as well as developing countries has been questioned. This review examines the nutrient composition of dairy products, factors that account for variability in composition of milk, milk processing, preservation, quality control, and contaminants (such as minerals, radionuclides, antibiotics, microorganisms and their metabolites, herbicides, and insecticides) in milk. Consumption patterns for milk and evidence for its nutritional value, especially in children, are presented. Milk consumption has been related to disease or conditions such as atherosclerosis, milk allergy, lactose intolerance, anemia, dental problems, and others. Recent recommendations for dietary changes for individuals in the U.S. and other developed countries could affect the use of milk. In addition, the use of feeding programs in the U.S. and developing countries which are based primarily on milk has been criticized. The preparation of new types of milk designed to offset certain difficulties encountered with cow's milk are now being evaluated in humans.     

Isotachophoretische Bestimmung von Konservierungsstoffen

Zusammenfassung Die Konservierungsstoffe Sorbinsäure, Benzoesäure, PHB-Ester und Propionsäure können nebeneinander in einem Analysengang nach einer isotachophoretischen Trennung auf Grund ihrer unterschiedlichen Beweglichkeiten quantitativ bestimmt werden. Störende Lebensmittelinhaltsstoffe (Lipide) werden vor der eigentlichen Bestimmung durch Äther-Extraktion unter Verwendung von Extrelut-Säulen entfernt. Der hier mitgeteilte Analysengang zeichnet sich nach unserer Erfahrung durch einen geringen zeitlichen Aufwand bei gleichzeitig hohen Wiederfindungsraten aus. Zumindest bei den von uns untersuchten Lebensmittelgruppen konnte eine Störung der quantitativen Bestimmung durch Begleitsubstanzen nicht beobachtet werden. Der erfaßte Bereich ist groß und bestreicht praktisch das ganze Konzentrationsgebiet, in dem Konservierungsstoffe üblicherweise angewendet werden.

---

Isotachophoretic determination of preservatives

Summary The preservatives sorbic acid, benzoic acid, methyl-, ethyl-, propylester of p-hydroxybenzoic acid and propionic acid can be determined quantitatively in one step by isotachophoretic separation based on the different electrophoretic mobilities of these compounds. The determination involves a direct extraction step in the so called Extrelut-columns, where the preservatives are separated from the food sample, mainly from the lipid phase. The whole analysis procedure is short and recoveries for the preservatives in the samples tested are very good. There is no interference by other substances and the range of concentrations for which a determination is possible is large and encompasses virtually all concentrations used in commercial practices.

     

Low ergosterol content in yeast adh1 mutant enhances chitin maldistribution and sensitivity to paraquat-induced oxidative stress

Alcohol dehydrogenases catalyse the reversible oxidation of alcohols to aldehydes or ketones, with concomitant reduction of NAD(+) or NADP(+) . Adh1p is responsible for the reduction of acetaldehyde to ethanol, while Adh2p catalyses the reverse reaction, the oxidation of ethanol to acetaldehyde. Lack of Adh1p shifts the cellular redox balance towards excess NADH/NADPH and acetaldehyde, while absence of Adh2p does the opposite. Yeast mutant adh1Δ had a slow growth rate, whereas adh2Δ grew like the isogenic wild-type (WT) during prediauxic shift fermentative metabolism. After 48 h WT and mutants reached the same number of viable cells. When exponentially growing (LOG) cells were exposed to calcofluor white, only mutant adh1Δ displayed an irregular deposition of chitin. Quantitative analyses of both LOG and stationary-phase cells showed that adh1Δ mutant contained significantly less ergosterol than cells of WT and adh2Δ mutant, whereas the erg3Δ mutant contained extremely low ergosterol pools. Both adh1Δ and adh2Δ mutants showed higher-than-WT resistance to heat shock and to H(2) O(2) but had WT resistance when exposed to ultraviolet (UV) light and the DNA cross-linking agent diepoxyoctane, indicating normal DNA repair capacity. Mutant adh1Δ was specifically sensitive to acetaldehyde and to membrane peroxidizing paraquat. Our results link the pleiotropic phenotype of adh1Δ mutants to low pools of ergosterol and to reductive stress, and introduce the two new phenotypes, resistance to heat shock and to H(2) O(2) , for the adh2Δ mutant, most probably related to increased ROS production in mitochondria, which leads to the induction of oxidative stress protection.