bluuebunny/crossref_metadata_2025_split huggingface dataset:
The role of (−)‐epicatechin and polyphenol oxidase in the coupled oxidative breakdown of theaflavins
Authors: Opie Shaun C. , Clifford Michael N. , Robertson Alastair 
Published: November 2006

AbstractAn enzymic in‐vitro model tea fermentation system has been used in combination with gradient elution reversed‐phase HPLC to study the oxidative breakdown of black tea theaflavins in the presence and absence of (−)‐epicatechin. It was found that theaflavin, theaflavin‐3‐monogallate, theaflavin‐3′‐monogallate and theaflavin‐3,3′‐digallate were not substrates for tea polyphenol oxidase (EC 1. 14. 18. 1) whereas (−)‐epicatechin alone, or mixtures of (−)‐epicatechin and a theaflavin were rapidly converted to a complex mixture of thearubigin‐like substances. While the chromatographic profiles varied with the identity of the theaflavin precursor each resembled the equivalent profile obtained with a whole black tea liquor. It is concluded that theaflavins are degraded by a coupled oxidation with (−)‐epicatechin–quinone. It is suggested that thearubigins may form via these pathways during black tea manufacture.
The nutritive value of sun‐dried pelagic fish from the rift valley in Africa
Authors: Steiner‐Asiedu Matilda , Lied Einar , Lie Øyvind , Nilsen Rune , Julshamn Kåre 
Published: November 2006

AbstractThe small pelagic fish caught in the freshwaters of Africa are mostly sundried and used in meal preparation. They are not generally used in weaning foods. With a view to incorporating fish into weaning diets, the nutritional quality of fish samples from the lakes along the Rift Valley in Africa was assessed.Fish are good sources of protein, ash, and fat. They are poor in vitamins A and E and their contribution to the diet will depend on the amount eaten. Fish lipids are good sources of essential fatty acids. Docosahexaenoic acid and eicosapentanoic acid which are important in brain development are present in substantial amounts. Fish is generally low in thiamine and pyridoxine but high in niacin. The content of calcium in whole fish is very high and there are appreciable quantities of zinc and iron. The amino acid profiles are in good agreement with the FAO provisional pattern and to the requirements of infants. The limiting amino acid is tryptophan.
Influence of ice storage on ray (raja clavata) wing muscle
Authors: Pastoriza Laura , Sampedro Gabriel 
Published: November 2006

AbstractDeterminations of pH, urea, extractable protein (EP), apparent viscosity (AV), water‐binding capacity (WBC), hardness (H), Hunter L, a and b values and sensory evaluation (SE) (raw and cooked), as well as microbiological analysis, were used to study the effects of ice storage on the stability of ray (Raja clavata) muscle. Significant changes were found in pH, bacterial growth and sensory assessment (ammoniacal odour and colour) during the storage period. Urea content, EP, AP, WBC (measured as water loss) and Hunter L value (in cooked muscle) decreased significantly. Statistical analyses did not show significant differences in H and Hunter L value (in raw muscle). The decrease in urea concentration can be described as a linear function of the number of microorganisms suggesting the microbiological character of the process. No dependence was observed between pH or number of microorganisms and EP, whereas AP was much more affected and showed a marked dependence on these two parameters treated independently. The results of this research showed that wings could be stored in ice for 9–10 days without causing important loss of quality. The fish was considered excellent up to day 7 and acceptable after 9 days but unacceptable after 11–12 days onwards. Nonetheless, the shelf‐life of the ray in the iced state can vary depending upon the initial state of freshness, handling and the biological conditions of the fish. Microbiological analysis, pH, EP, AV, WBC, SE and Hunter L value have been demonstrated to be factors which could be used to monitor the deterioration of ray during ice storage.
Strawberry juice colour: A study of the quantitative and qualitative pigment composition of juices from 39 genotypes
Authors: Bakker Johanna , Bridle Peter , Bellworthy Sara Jane 
Published: November 2006

AbstractThe juices from 39 strawberry genotypes were analysed for anthocyanin composition and colour characteristics. No single cultivar or breeding line possessed the innate pigment characteristics thought to confer greater colour stability on strawberry juices but the anthocyanin patterns were far more complex than hitherto reported in strawberries. Thirteen different peaks were observed during high‐performance liquid chromatography of the juices and tentative identifications are proposed for two previously unidentified strawberry anthocyanins. The occurrence of pelargonidin 3‐rutinoside was confirmed. Colour quality measurements derived from CIELAB L*a*b* values are reported for the fresh juices.
Immunochemical detection of ovalbumin in dairy‐based foods
Authors: Turin Lauretta , Bonomi Francesco 
Published: November 2006

AbstractCommercially available antibodies were used for the detection and quantitation of ovalbumin in ice cream and cheese. Electrophoretic separation of protein components, followed by blotting and immunochemical recognition of ovalbumin allowed the detection of the addition of 50 g kg‐1 egg white to processed cheese and allowed detection of egg in ice cream. For quantitative purposes a competitive ELISA method was set up. Calibration curves for ovalbumin in various products were obtained. A marked matrix effect was evident in ice cream, cheese and yoghurt. Different types of cheese gave nearly identical matrix effects. Analytical application of the method should therefore be possible, at least within a given class of products. A study on the influence of thermal treatments on the ELISA response showed that melting of cheese at various temperatures modifies only slightly the ELISA response for ovalbumin.
In‐vitro rates of rumen proteolysis of ribulose‐1,5‐bisphosphate carboxylase (rubisco) from lucerne leaves, and of ovalbumin, vicilin and sunflower albumin 8 storage proteins
Authors: McNabb Warren C , Spencer Donald , Higgins Thomas J , Barry Tom N 
Published: November 2006

AbstractLaboratory systems were developed, based upon in‐vitro incubations with rumen fluid, to examine the rate of proteolysis (ie degradation) of sunflower albumin 8 (SFA 8; 24% sulphur amino acids; SAA) from sunflower seeds, ovalbumin (6% SAA) from chicken egg white, ribulose‐1,5‐bisphosphate carboxylase (Rubisco; 3% SAA) from lucerne leaves, and vicilin (0% SAA) from pea seeds. After fractionation by SDS‐PAGE, proteins were analysed by either Western blotting, using specific antibodies (SFA 8, vicilin and ovalbumin) or by Coo‐massie blue staining (Rubisco). Proteolysis of the large subunit of Rubisco occurred very quickly and as two components, with half‐lives of 11.6 and 1.5 h. The small subunit of Rubisco was more resistant to degradation, with a half‐life of 17.3 h. Vicilin was degraded extremely rapidly (half‐life 0.16 h). SFA 8 and ovalbumin both showed resistance to degradation, but by two different mechanisms. Ovalbumin was not degraded at all during the initial 16 h of incubation, but then degraded with a half‐life of 8.7 h. SFA 8 (mol wt 12 100) disappeared very rapidly, with a half‐life of 3.0 h. The degradation of SFA 8 was associated with the appearance of a polypeptide (mol wt 8000), which was extremely resistant to degradation, with a half‐life of 69.3 h. It was concluded that both the number of disulphide linkages and tertiary structure were important in determining resistance of proteins to rumen degradation, and that incorporation of SFA 8 and ovalbumin proteins into forages using genetic engineering techniques would be likely to increase the quantity of SAA by passing rumen fermentation.
The sorption of aroma components from tomato juice by food‐contact polymers
Authors: Leufvén Anders , Hermansson Charlotte 
Published: November 2006

AbstractThe sorption of some aroma components from tomato juice by polyethylene terephthalate (PET) was shown to be less than the sorption of the same components by polyethylene (PE) and wet ethylene/vinylalcohol copolymer (EvOH) polymers. Furthermore, sorption by PET was less influenced by pH than sorption by the PE and EvOH polymers. The amounts of aroma compounds extracted from the polymers varied with type of polymer, type of aroma compound, pH and time of storage.
Determination of egg content in egg pasta by an indirect elisa procedure
Authors: Pressi Giovanna , Curioni Andrea , Peruffo Angelo D B , Furegon Luca , Zamorani Arturo 
Published: November 2006

AbstractPolyclonal antibodies have been raised against a highly purified egg yolk protein, which appears to be unaffected by thermal treatments and whose content is constant in eggs of different origin. The antibodies are able to bind specifically to the egg yolk protein and can be used for the quantification of the egg content in egg pasta. For this purpose an indirect ELISA procedure has been developed.
Roles of structural phenylpropanoids in forage cell wall digestion
Authors: Besle Jean‐Michel , Cornu Agnès , Jouany Jean‐Pierre 
Published: November 2006

AbstractPhenolic constituents (lignins and phenolic acids) and carbohydrates are assembled in a tight architecture which differs according to the plant species. During cell wall digestion, the hydrolysis kinetics differ between carbohydrates and seem to depend chiefly on the content and organisation of tissue phenolics. Among the phenylpropanoids, ferulic acid is released more quickly than p‐coumaric acid. Lignins remain largely in the cell walls. They also undergo transformations, chiefly solubilisation as lignin‐carbohydrate complexes. The limiting effect of lignins on cell wall degradation increases with increasing content. However, their effect on degradation might also depend on qualitative factors such as lignin structure and polymer organisation in walls and tissues. When various grasses (normal and selected genotypes), or grasses and legumes are compared, correlations between certain factors such as lignin uncondensed fraction, syringyl units or phenolic acids contents and cell wall degradation emerge but not clear causal relationship has been shown. Nonetheless, other structural characteristics, related to the alkali reactivity of lignins, seem to have a stronger influence on cell wall degradation. Phenylpropanoids seem to act mainly as a physical and (bio)chemical barrier to the action of the microbial enzymes. In addition, their reactivity as phenolic compounds and their hydrophobicity seem to play a role. Digestion is not limited only by phenolics. The factors that limit glycanolysis—the accessibility, crystallinity and capillary structure of cellulose and the branching of hemicelluloses—seem to have little or no effect on cell wall degradation in vivo. In contrast, other antiquality substances (tannins, cutin and silica), plant antomy, environmental factors, factors modulating microbial growth and animal physiology influence cell wall utilisation. Future research in this field should focus on the effects of phenolic structure and of cell wall and tissue organisation on carbohydrate degradation.
Uniformly 15N‐labeled soybean seeds produced for use in human and animal nutrition studies: Description of a recirculating hydroponic growth system and whole plant nutrient and environmental requirements
Authors: Grusak Michael A , Pezeshgi Shahrbanu 
Published: November 2006

AbstractA recirculating hydroponic technique which enables the uniform 15N‐labeling of soybean plants has been developed. Daily net influx of nitrate, potassium, calcium, chloride and phosphate, as well as total solution uptake, was measured for a crop of 60 plants grown in a 3 m2 area. A protocol is presented which (i) maintains adequate nutrient concentrations for the crop, (ii) adds nutrients and water as required with no exchange of solution, and (iii) minimizes the addition and use of 15N. With this technique, 6.5 mol of 15N were used to generate 1 kg (DW) of soybean seeds (350 g protein kg‐1; 98 atm% 15N) and 3.1 kg (DW) total biomass; recovery of nitrogen in the total biomass was 95%. 15N‐labeled soy protein isolate or harvested plant parts (eg leaves or stems) can be used to investigate nutrient absorption and metabolism in human or animal studies.
A comparison of the hplc, mass spectra, and acid degradation of theafulvins from black tea and proanthocyanidin polymers from wine and cider
Authors: Bailey R G , Nursten H E , McDowell I 
Published: November 2006

AbstractThe HPLC chromatograms, mass spectra, and acid degradation of a theafulvin fraction (a fraction of polymeric thearubigins) and proanthocyanidin polymers from cider and wine were compared. The cider, wine, and theafulvin fractions ran as broad bands on a Hamilton PRP‐1 column. The cider and wine polymers gave positive‐ion FAB spectra characteristic of proanthocyanidin polymers, but the theafulvins gave low‐molecular‐mass flavanol fragments only. The cider and wine polymers gave cyanidin on acid degradation, the reaction products being analysed by HPLC on a Hamilton PRP‐1 column. The theafulvins gave mainly material that ran close to the void volume of the HPLC column. These experiments provided support for previous conclusions, that the theafulvins are flavanol polymers with different intermonomer linkages to the proanthocyanidin polymers.
The effect of cultivar, sample date and grazing on the concentration of s‐methylcysteine sulphoxide in oilseed and forage rapes (brassica napus)
Authors: Griffiths D Wynne , Macfarlane‐Smith William H , Boag Brian 
Published: November 2006

AbstractA study of the S‐methylcysteine sulphoxide (SMCO) concentration in foliage from four double‐zero, three single‐zero cultivars of oilseed rape and four cultivars of forage rape revealed little inter‐cultivar variation. Significant differences were however found with respect to harvest date, with the concentration of SMCO remaining fairly constant over the early winter period but then increasing as the plants commenced regrowth in the late winter‐early spring. Continual exposure of plots to grazing wild rabbits produced small but statistically significant changes in SMCO concentration but compared with seasonal differences the changes due to grazing were small and inconsistant. These findings are discussed in relation to the recently reported harmful effects of double zero oilseed rape cultivars on browsing wildlife.
Effect of rice variety, rice flour concentration and enzyme levels on composite bread quality
Authors: Noomhorm Athapol , Bandola D C , Kongseree N 
Published: November 2006

AbstractA study was conducted to determine the suitability of substituting portions of wheat flours with rice flours for breadmaking. The levels of substitution were 50, 100, 150 and 200 g kg−1. Two kinds of enzymes, barley malt and fungal amylase, were added to composite flours, and their effects on the volume and quality of the rice‐based bread were determined. The results showed that the enzymes, levels of replacement and the varieties of rice had significant effects on weight, specific volume and overall acceptability of the bread samples. However, the enzymes did not have significant effects on the volume, protein and fat contents or on the character and color of the crust in the sensory analysis. Comparisons were made of the nutritional and sensory qualities of the bread made entirely from wheat flour, and the sample which performed best, the bread with 50 g kg−1 of flour from low amylose variety (183.3 g kg−1) with barley malt, showed non‐significant differences. The overall acceptability of the products showed that it is acceptable to substitute wheat flour with flours generated from rice up to the 150 g kg−1 replacement level only.
Volatile oil composition of Turkish rose (Rosa damascena)
Authors: Bayrak Ali , Akgül Attila 
Published: November 2006

AbstractTwo kinds of rose (Rosa damascena Miller) oil were used: decanted oil distilled from the fresh petals (DOFP) and blended oil distilled from the paled (fermented) petals (BOPP). Eight samples from Gülbirlik cooperative factories (three DOFP, four BOPP) and a private factor (one BOPP) were of 1990 produce, and seven samples from Gülbirlik (two DOFP, four BOPP) and a private factory (one BOPP) were of 1991 produce. In all, 15 samples were analysed for density, refractive index and optical rotation, and their chemical composition by GC and GC‐MS. The samples showed some differences in the optical rotation. DOFP had high density and refractive index values. In general, 68 components were identified, representing c 88–98% of the oils: 27 hydrocarbons, 19 alcohols, eight aldehydes, six oxides and ethers, five esters, two ketones and one phenol. Citronellol (24.47–42.97%), nonadecane (6.44–18.95%), geraniol (2.11–18.04%), ethanol (0.00–13.43%), heneicosane (2.28–8.90%), nerol (0.75–7.57%) and 1‐nonadecene (1.80–5.40%) were the major components as overall ranges of the samples. Percentages of certain components differed between the factories, years and oil types (DOFP and BOPP). The results indicated that an extensive and detailed research from harvesting to end‐product storage was needed for the establishment of the material and technology requirements to obtain a Turkish rose oil with standard composition and high quality.
Biological variability in lignification of maize: Expression of the brown midrib bm2 mutation
Authors: Chabbert B , Tollier M T , Monties B , Barrière Y , Argillier O 
Published: November 2006

AbstractThe cell wall phenolic components in the internodes of three maize genotypes, namely normal, bm2 and bm3 maize, were determined. The bm2 and bm3 brown midrib mutations lowered the lignin content of the bottom, middle and top internodes to a similar extent. However, unlike bm3, the bm2 trait did not induce a sharp reduction of the level of ester‐bound p‐coumaric acid in maize internodes. The other main alkali labile phenolic acid, ferulic acid, reached similar levels in the three genotypes. The main difference between bm2 and bm3 mutations occurred in the alkyl aryl ether linked structures of the lignin component. In contrast to bm3 lignins, which are characterised by a low syringyl content, the bm2 lignin had a lower content of guaiacyl units than lignin of normal maize internode. Consequently, the syringyl/guaiacyl molar ratio of bm2 lignin gave higher values (2.7–3.2) than those from either normal (0.9–1.5) or bm3 lignins (0.3). The alkali solubility of lignin was also compared between the three genotypes. Incorporation of the bm3 trait in maize led to a high recovery of alkali soluble lignin whereas the bm2 lignin had a similar solubility to the normal one in 2 M NaOH. The monomeric composition of the alkali soluble lignins was consistent with the non‐condensed structures of the in‐situ polymer. Although the bm3 and bm2 mutations had different effects on lignification, the modification of the cell wall phenolic level was also found in the bm2 maize stem as previously studied.
Solid‐state 13C NMR study of palm trunk cell walls
Authors: Gallacher James , Snape Colin E , Hassan Kamaruddin , Jarvis Michael C 
Published: November 2006

AbstractTrunk material from the oil palm Elaeis guineensis was dissected into parenchyma and vascular bundle fractions, which were individually examined by 13C solid‐state nuclear magnetic resonance at low field (25 MHz). Cross‐polarisation and magic‐angle spinning were used with dipolar dephasing to reveal the aromatic carbons of lignin free from interference by carbohydrate. The lignin contents of the parenchyma and vascular bundles were found to be 240 g kg−1 and 130 g kg−1, respectively. The lignin appeared to contain a high proportion of aryl ether‐linked syringyl units, but little or no ferulic or p‐coumaric acid. The cellulose of both fractions had a high proportion of the crystalline component. The acetyl content was c 6 mol %C. The in‐vitro digestibility of the two fractions was measured using the rumen liquor‐pepsin method and was found to be low compared with forage materials: 19.5% in the parenchyma and only 11.1% in the vascular bundles.
Effect of extrusion‐cooking on the hypoglycaemic properties of citrus fibre: An in‐vitro study
Authors: Gourgue Claudine , Champ Martine , Guillon Fabienne , Delort‐Laval Jean 
Published: November 2006

AbstractOrange and lemon peels were extruded under controlled conditions of varying severity, and their physico‐chemical characteristics and effect on the enzymatic hydrolysis of starch and glucose diffusion were studied. Extrusion‐cooking treatment increased the soluble fraction of dietary fibre as well as solubilised pectic substances and arabino‐galactomannan chains. The apparent viscosities of aqueous extracts of extruded fibre were increased slightly for orange and more markedly for lemon fibre. With both fibre sources, viscosities values were higher in Tris‐maleate buffer (0.1 M) than in NaCl (154 mM). However, these modifications had no effect on starch hydrolysis and glucose diffusion in vitro.
Hake natural actomyosin interaction with free fatty acids during frozen storage
Authors: Careche Mercedes , Tejada Margarita 
Published: November 2006

AbstractThe interaction of hake muscle actomyosin with free fatty acids in 0.6 M KCl pH 7 during frozen storage has been studied up to 280 days. ATPase activity, protein solubility and relative viscosity measurements were performed. Oleic and myristic acid had a detrimental effect on these properties during frozen storage. Oleic acid was bound to the protein from the beginning, mainly to the insoluble fraction. The diminishment of functionality following addition of oleic acid is not due to aggregation caused by covalent‐type bonds, since it occurs well before the electrophoretic change is appreciable.
Fractionation of fungal pectic enzymes by immobilised metal ion affinity chromatography
Authors: Cañizo Agustin Navarro Del , Hours Roque A , Miranda María V , Cascone Osvaldo 
Published: November 2006

AbstractA juice‐clarifying fraction that will not produce methanol was obtained from a commercial pectic enzyme by separating the pectin lyase (EC4.2.2.10) from pectinesterase (EC3.1.1.11). This was achieved by immobilised metal ion affinity chromatography (IMAC) on Sepharose—iminodiacetic acid—Cu(II). Pectin lyase did not bind to the chromatographic matrix at pH 8.0, while pectinesterase was retained and only eluted when the pH of the buffer was brought down to 3.0. Polygalacturonase activity (EC3.2.1.15) was found in both fractions thus suggesting that IMAC can discriminate between two forms of that enzyme Both fractions have the ability to clarify apple juice, the first without producing methanol. The behaviour of each of the above enzymes in IMAC suggests that pectin lyase lacks accessible histidine residues, while pectinesterase could have one or more of them.