Search

Brews from differently roasted Arabica coffees were shown to contain 8-12% ethanol soluble substances with molecular masses greater than 2 kDa, possibly contributing to their dietary fiber contents. About 13% of these substances were nondigestible carbohydrates, mainly arabinogalactans. The nondigestible high molecular weight ethanol soluble fraction (HESF) of the medium roasted coffee brew was further characterized and subjected to in vitro fermentation with human fecal bacteria. In addition to carbohydrates, HESF contained proteins/peptides (approximately 20%), but the main fraction was composed of structurally unknown Maillard reaction products. From NMR spectroscopy, we conclude that intact caffeic and ferulic acid derivatives were not incorporated into the melanoidins to a significant extent. Stepwise ultrafiltration and gel filtration indicated a large variation in the molecular weights of HESF constituents. Coffee HESF was shown to be less fermentable by fecal bacteria than soluble coffee fiber isolated by the enzymatic-gravimetric methodology, and because of its lower carbohydrate content, less short-chain fatty acids were produced during the fermentation. Total cell counts, destructive chemical analysis, and NMR spectroscopy indicated that coffee carbohydrates are the preferred substrates for colonic microbiota. However, NMR spectra, absorbances at 405 nm, and nonprotein nitrogen contents showed that noncarbohydrate and nonprotein compounds were also utilized to some extent but the bacterial species involved in this degradation remain to be identified.

Hen's egg allergy represents one of the most common and severe IgE-mediated reactions to food in infants and young children. It persists, however, in many cases also lifelong. Therefore, the aim of this study was the detailed analysis of a technological process used to reduce the allergenic potential of hen's egg. The investigation focused on the pasteurized egg as starting material, intermediate, and final products of a nine-step manufacturing process performed for use of eggs in convenience products appropriate for allergic individuals. The steps consisted of a combination of various heat treatments and enzymatic hydrolyses. The alterations were controlled by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting, enzyme allergosorbent test (EAST) inhibition, and mass spectrometry. Thereby it could be demonstrated that the allergenic potential of the raw material was reduced from step to step, and despite the known stability against heat and proteolysis of certain egg proteins, the total allergenic potential was finally below 1/100 that of the starting material without a significant change in texture and flavor as evaluated in various products.

Coffee brews contain considerable amounts of soluble dietary fiber, mainly low substituted galactomannans and type II arabinogalactans. Factors possibly influencing the content and structures of dietary fiber in coffee brews, such as type of coffee, roasting and grinding degree, and brewing procedure, were studied. In addition, several commercial samples such as instant espresso, instant coffee, instant cappuccino, decaffeinated coffees, and coffee pads were analyzed. The dietary fiber contents of the coffee brews ranged from 0.14 to 0.65 g/100 mL (enzymatic-gravimetric methodology), proving an influence of the factors investigated. For example, the drip brew of an arabica coffee contained significantly more soluble dietary fiber than the drip brew of a comparable robusta coffee, and depending on the brewing procedure, the soluble dietary fiber content of beverages obtained from the same coffee sample ranged from 0.26 to 0.38 g/100 mL. Dietary fiber contents of coffee brews were enhanced only up to a certain degree of roast. Drip brews of decaffeinated arabica coffees (commercial samples) contained significantly less dietary fiber than any non-decaffeinated drip brew investigated in this study. The observed differences in the dietary fiber contents were accompanied by changes in the structural characteristics of fiber polysaccharides, such as galactomannan/arabinogalactan ratio, galactose substitution degree of mannans, or galactose/arabinose ratio of arabinogalactans as analyzed by methylation analysis.

In this study, the proportions of conjugated linoleic acids (CLA) in total lipids of plasma, lipoproteins and erythrocytes from maternal blood and from venous cord blood of 20 pregnant women consuming conventional western diets after delivery were determined. cis-9, trans-11 CLA was the only isomer detected, and its proportions in maternal blood lipids were relatively low. Mean proportions in plasma, lipoproteins and erythrocytes of mothers were between 0.20 and 0.25 mol/100 mol of total fatty acids. Proportions in cord blood lipids were even lower than those of maternal lipids (values in mol/100 mol: plasma, 0.19+/-0.04; VLDL, 0.20+/-0.06; LDL, 0.15+/-0.03; HDL, 0.14+/-0.06; erythrocytes, 0.12+/-0.05). There was some significant (P<0.05) linear relationship between CLA in maternal lipids and neonatal lipids. The data of this study suggest that CLA proportions in fetal blood lipids are low if mothers are consuming conventional western diets. It is moreover concluded that CLA concentrations in fetal blood lipids are related with maternal CLA intake.

The aim of the present study was to find out whether the incorporation of organic dairy and meat products in the maternal diet affects the contents of the conjugated linoleic acid isomers (CLA) and trans-vaccenic acid (TVA) in human breast milk. To this purpose, milk samples from 312 breastfeeding mothers participating in the KOALA Birth Cohort Study have been analysed. The participants had documented varying lifestyles in relation to the use of conventional or organic products. Breast milk samples were collected 1 month postpartum and analysed for fatty acid composition. The content of rumenic acid (the main CLA) increased in a statistically significant way while going from a conventional diet (no organic dairy/meat products, 0.25 weight % (wt%), n 186) to a moderately organic diet (50-90 % organic dairy/meat, 0.29 wt%, n 33, P = 0.02) and to a strict organic diet (>90 % organic dairy/meat, 0.34 wt%, n 37, P

In this study the FA compositions of healthy and cancerous human renal tissues from the same patients are compared with special reference to the CLA and PUFA content. CLA was preferentially incorporated into neutral lipid compared with phospholipid classes. Its distribution profile was similar to that of monounsaturated FA, but unlike that found with 18:2n-6. Different incorporation patterns were found for individual CLA isomers. Comparing renal cell carcinoma (RCC) and healthy kidney, the total CLA content was significantly lower in the cholesterylester fraction and significantly higher in the PE and PS fractions from RCC. The most significant differences between healthy and cancerous renal tissue were in the content of t10,c12-CLA. Furthermore, the lipid class distributions of n-6 PUFA were determined, and several significant differences between RCC and healthy renal tissue were found. This is of interest, as it has been proposed that the anticarcinogenic properties of dietary CLA are associated with their interference in the metabolism of 20:4n-6. The involvement of CLA in preventing renal cancer cannot be definitively demonstrated from the design of this study, nor was it intended, but the complete determination of the FA composition of adjacent healthy and cancerous tissues may provide an insight if lipids are involved in this disease.

This study examined the effects of feeding pasture vs. concentrate on the distribution of CLA isomers in the lipids of longissimus and semitendinosus muscle, liver and heart muscle, and subcutaneous fat in beef bulls. Sixty-four German Holstein and German Simmental bulls were randomly allocated to either an indoor concentrate system or periods of pasture feeding followed by a finishing period on a concentrate containing linseed to enhance their beef content of n-3 PUFA and CLA. The concentrations of CLA isomers in the different tissues were determined by GC and silver ion HPLC. The diet affected the distribution of individual CLA isomers in the lipids of the different tissues. The concentration (mg/100 g fresh tissue) of the most prominent isomer, cis-9,trans-11 18:2, was increased up to 1.5 times in liver and heart tissue of bulls fed on pasture as compared with concentrate. However, no diet effect was observed for cis-9,trans-11 18:2 in the lipids of longissimus muscle and subcutaneous fat. In all tissues, the second-most abundant CLA isomer in concentrate-fed bulls was trans-7,cis-9 18:2. In contrast, trans-11,cis-13 18:2 was the second-most abundant CLA isomer in all investigated tissue lipids of pasture-fed bulls. The concentration of the trans-11,cis-13 18:2 isomer was up to 15 times higher in tissues of pasture-fed bulls as compared with concentrate-fed animals. Furthermore, diet affected the concentrations of the CLA trans,trans 18:2 isomers. Pasture feeding significantly increased the concentrations of some trans,trans 18:2 isomers as compared with concentrate, predominantly trans-12,trans-14 18:2 and trans-11,trans-13 18:2. Overall, pasture feeding resulted in significantly increased concentrations of the sum of CLA isomers in the lipids of longissimus muscle, subcutaneous fat, heart and liver muscle of German Holstein and German Simmental bulls, but not in semitendinosus muscle.

Differences in the FA composition of subcellular fractions from healthy and cancerous kidney tissues from the same patients were examined. Only minor differences in CLA content were found between the healthy and the cancerous tissue portions. Regarding the distribution pattern, CLA incorporation into nuclei and cytosol was significantly higher than incorporation into plasma membranes and mitochondria, which could be correlated to the neutral lipid content of these fractions. The subcellular distribution pattern of CLA was similar to that observed with monounsaturated FA but unlike that found with 18:2n-6, which underlines the different physiological properties of CLA and 18:2n-6. Because PUFA have been suggested to have an effect on cancer risk, the contents of n-3 and n-6 PUFA were determined in kidney and renal cell carcinoma (RCC). The 18:2n-6 content and delta5 desaturase activity were significantly lower, and the 18:3n-6, 20:3n-6, and 20:5n-3 contents and delta6 desaturase activity were significantly higher in RCC than in healthy renal tissue, indicating a changed PUFA metabolism in RCC. Previous research has suggested that CLA inhibits the elongation and desaturation of 18:2n-6 into 20:4n-6. In that case, one might speculate that a diet enriched in CLA would be a useful tool in preventing RCC. However, the involvement of CLA in preventing renal cancer could not be demonstrated definitively from the design of this experiment. Further understanding of the cause and/or consequence of the difference in FA metabolism may lead to a better understanding of RCC.

Plant cell walls containing suberin or lignin in the human diet are conjectured to protect against colon cancer. To confirm the existence of authentic lignin in cereal grain dietary fibers, the DFRC (derivatization followed by reductive cleavage) method was applied to different cereal grain dietary fibers. By cleavage of diagnostic arylglycerol-beta-aryl (beta-O-4) ether linkages and identification of the liberated monolignols, it was ascertained that lignins are truly present in cereal grains. From the ratios of the liberated monolignols coniferyl alcohol and sinapyl alcohol, it is suggested that lignin compositions vary among cereals. Furthermore, dimeric cross-coupling products, comprising ferulate and coniferyl alcohol, were identified in most cereal fibers investigated. These ferulate 4-O-beta- and 8-beta-coniferyl alcohol cross-coupled structures indicate radical cross-coupling of polysaccharides to lignin precursors via ferulate., (Copyright 2004 American Chemical Society)

In parallel with the rising popularity of exotic fruits in Europe, allergy against mango is of increasing importance. Because mangoes are also consumed as processed products such as chutneys or beverages, the influences of different process conditions on their allergenicity were investigated. Mango purees and nectars were manufactured at small pilot-plant scale, and the allergenic potencies of the resulting intermediate and final products were determined by means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), immunoblotting and inhibitive enzyme allergosorbent tests (EAST-inhibition), using a pool serum of 9 individuals with manifest mango allergy. The mango allergens were shown to be very stable during technological processing. Irrespective of enzymatic matrix decomposition, mechanical tissue disintegration and heating during peeling, mash treatment, and pasteurization, significant loss of allergenicity could not be observed in the extracts of mango purees and nectars derived thereof. These results were confirmed by analogous investigation of commercial mango drinks and nectars. Hence, conventional mango processing into pulp-containing products typical for this species obviously does not allow complete elimination of the allergenic potency.

We explored whether CLA isomers and other C18 FA affect (i) lipid content and FA concentrations in total adipocyte lipids, (ii) FA synthesis from glucose in TAG and phospholipids of primary brown (BAT) and white adipocytes (WAT), and (iii) mRNA expression of uncoupling protein 1 (UCP1) in primary brown adipocytes of Djungarian hamsters (Phodopus sungorus). c9,t11-CLA, oleic, linoleic, and alpha-linolenic acid increased whereas t10,c12-CLA decreased lipid accumulation in both adipocyte types. t10,c12-CLA treatment affected FA composition mainly in BAT cells. CLA incorporation into lipids, in particular c9,t11-CLA, was higher in BAT. In both cell types, t10,c12-CLA treatment reduced the incorporation of glucose 13C carbon into FA of TAG and phospholipids, whereas c9,t11-CLA, linoleic, and alpha-linolenic acid either did not influence or dose-dependently increased glucose carbon incorporation into FA. UCP1 mRNA expression was inhibited by t10,c12-CLA but increased by c9,t11-CLA, linoleic, and alpha-linolenic acid. It is concluded that c9,t11-CLA and t10,c12-CLA have distinctly different effects on lipid metabolism in primary adipocytes. The effects of c9,t11-CLA are similar to those of other unsaturated C18 FA. The opposite effects of c9,t11-CLA and t10,c12-CLA are evident in both WAT and BAT cultures; however, brown adipocytes seem to be more susceptible to CLA treatment.

Epidermal keratinocytes are exposed to a low water concentration at the stratum corneum-stratum granulosum interface. When epithelial tissues are osmotically perturbed, cellular protection and cell volume regulation is mediated by accumulation of organic osmolytes such as taurine. Previous studies reported the presence of taurine in the epidermis of several animal species. Therefore, we analyzed human skin for the presence of the taurine transporter (TAUT) and studied the accumulation of taurine as one potential mechanism protecting epidermal keratinocytes from dehydration. According to our results, TAUT is expressed as a 69 kDa protein in human epidermis but not in the dermis. For the epidermis a gradient was evident with maximal levels of TAUT in the outermost granular keratinocyte layer and lower levels in the stratum spinosum. No TAUT was found in the basal layer or in the stratum corneum. Keratinocyte accumulation of taurine was induced by experimental induction of skin dryness via application of silica gel to human skin. Cultured human keratinocytes accumulated taurine in a concentration- and osmolarity-dependent manner. TAUT mRNA levels were increased after exposure of human keratinocytes to hyperosmotic culture medium, indicating osmosensitive TAUT mRNA expression as part of the adaptation of keratinocytes to hyperosmotic stress. Keratinocyte uptake of taurine was inhibited by beta-alanine but not by other osmolytes such as betaine, inositol, or sorbitol. Accumulation of taurine protected cultured human keratinocytes from both osmotically induced and ultraviolet-induced apoptosis. Our data indicate that taurine is an important epidermal osmolyte required to maintain keratinocyte hydration in a dry environment.

The extracellular glutathione S-transferase from the filarial parasite Onchocerca volvulus (Ov-GST1) is a glutathione-dependent prostaglandin D synthase. Ov-GST1, located in the outer hypodermal lamellae and in parts of the cuticle, produces prostaglandin D(2) directly at the parasite-host interface. Ov-GST1 therefore has the potential to participate in the modulation of the host immune response by contributing to the production of prostanoids; this supports the predominant hypothesis that parasite-derived eicosanoids influence host inflammatory and immune cells.

Two 8-8-coupled sinapic acid dehydrodimers and at least three sinapate-ferulate heterodimers have been identified as saponification products from different insoluble and soluble cereal grain dietary fibers. The two 8-8-disinapates were authenticated by comparison of their GC retention times and mass spectra with authentic dehydrodimers synthesized from methyl or ethyl sinapate using two different single-electron metal oxidant systems. The highest amounts (481 microg/g) were found in wild rice insoluble dietary fiber. Model reactions showed that it is unlikely that the dehydrodisinapates detected are artifacts formed from free sinapic acid during the saponification procedure. The dehydrodisinapates presumably derive from radical coupling of sinapate-polymer esters in the cell wall; the radical coupling origin is further confirmed by finding 8-8 and 8-5 (and possibly 8-O-4) sinapate-ferulate cross-products. Sinapates therefore appear to have an analogous role to ferulates in cross-linking polysaccharides in cereal grains and presumably grass cell walls in general.

During gamma-irradiation (5 kGy) of aqueous tryptophan (Trp) solutions small amounts of 5-, 6-, and 7-hydroxytryptophan (OH-Trp) (0.04-0.08 Mol-%) are formed. Protein rich food like shrimps contain reasonable amounts of non-protein bound Trp (100 mg/kg). In order to detect the treatment of shrimps with gamma-irradiation a method for the determination of OH-Trp in gamma-irradiated shrimps was developed. After homogenization, squeezing of shrimp samples and protein precipitation, a two-step-SPE-clean up was performed using a C18-cartridge and a propylsulfonic acid cation-exchange SPE followed by HPLC analysis with electrochemical detection (750 mV). Results showed that 5-OH-Trp contents in shrimp samples increased with applied doses up to 3 kGy and then decreased with higher doses. Other OH-Trp isomers were not detectable in the irradiated shrimps. Similarly no formation of 4-, 6-, and 7-OH-Trp was detected in model solutions containing the same amino acid composition as in shrimps. This indicates a suppression of the reaction of OH-radicals with Trp by the 300 fold molar excess of other amino acids acting as well as radical scavengers. Therefore, non-physiological OH-Trp isomers formed from free Trp are not suitable as markers for the detection of gamma-irradiated protein-rich foodstuff.

The fate of 13C-labelled phenanthrene and fluoranthene in different soil systems during biodegradation was studied. The soil humic acid fraction was isolated followed by structural characterisation using 13C-cross polarisation magic angle spinning nuclear magnetic resonance spectroscopy (13C-CPMAS-NMR). It could be demonstrated that especially the ratio between the concentrations of polycyclic aromatic hydrocarbons (PAHs) and soil humus matrix limits the usefulness of this analytical tool. Based on these results a ratio of 13C-activity(PAH)/13C-activity(soil) approximately 1.5/1.0 in the test material was suggested. The chemical transformation of a PAH and its bound residue formation in a soil system detected by changes of chemical shifts in the 13C-NMR spectrum was proven for the first time. Structural information obtained by NMR spectra were verified by alkaline hydrolysis of PAH/humus-associations and following identification of cleavage products. Ester-bound phenanthrene metabolites such as 1-hydroxy-2-naphthoic acid, ortho-phthalic acid and 3,4-dihydroxybenzoic acid were detected. Additional structural assignments indicated the presence of ether-bound phenanthrene derivatives as well. Using isotopic labelling techniques a quantitative evaluation of bound residue distribution was undertaken. Fifty to seventy percent of phenanthrene metabolites which could be related to the added 13C(1)-phenanthrene were ester bound via their carboxyl groups.

Previous investigations of coffee flavor have been confined to the analysis of the aroma substances. These investigations showed that about 30 volatile compounds were substantially responsible for the coffee flavor. The aim of this study was to investigate the influence of different milk additives and one coffee whitener on the release of flavor impact compounds from coffee beverages. For the investigation of these effects an external static headspace technique was developed. With this technique the most potent odorants of the coffee beverage were determined. Analyses were performed by gas chromatography/olfactometry, flame ionization detection, and mass spectrometric detection. In addition, sensory studies of the odor profiles were performed. Milk and vegetable products as additives for coffee beverages affected the release of aroma substances in the brew through their lipid, protein, and carbohydrate components. All beverages with an additive showed reduced, but typical, odor profiles for each additive.