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Free Amino Acids (free + amino_acids)
Kinds of Free Amino Acids Selected AbstractsRELATION BETWEEN THE FREE AMINO ACIDS, ANSERINE AND THE TOTAL VOLATILE BASIC NITROGEN PRODUCED IN MUSCLE OF HAKE (MERLUCCIUS MERLUCCIUS, L.) DURING ICED STORAGEJOURNAL OF FOOD BIOCHEMISTRY, Issue 1 2002CLAUDIA RUIZ-CAPILLAS This work studied the development of free amino acids (FAAs) and dipeptide anserine as quality indices for gutted hake stored in ice for 25 days. The correlation of these compounds was determined with total volatile basic nitrogen (TVBN) which has been used as a quality index, for fish stored in ice. The most abundant free amino acids in hake muscle were found to be threonine, glycine, alanine, glutamic acid, ,-alanine methylhistidine. lysine and the dipeptide, anserine. The only hydrophobic free ammo adds which exhibit significant differences (P<0.05) throughout storage was tryptophan. moreover, this amino acid exhibited a very high correlation (r=0.951) with TVBN. A significant decrease in anserine (P<0.05) correlated with the increases in 1-methylhistidine and ,-alanine throughout storage. These changes also exhibited a very high correlation with TVBN. Therefore, 1-methylhistidine, ,-alanine anserine and tryptophan could be used as quality parameters for hake stored in ice. [source] Free Amino Acids in Botanicals and Botanical PreparationsJOURNAL OF FOOD SCIENCE, Issue 5 2008B. Carratù ABSTRACT:, Numerous studies were carried out about aminoacidic composition of vegetable proteins, but information about the free amino acid pool and the role of these substances is very incomplete. The aim of this paper was to contribute to the scarce knowledge concerning the composition of free amino acids in botanicals and botanical preparations widely used as food, in dietary supplements, and in pharmaceutical products. This work studied the composition of free amino acids, identified the major components of 19 species of plants, and evaluated the influence of different types of extraction on the amino acid profile. Amino acids were determined using an automatic precolumn derivatization with fluorenylmethyl-chloroformate and reversed-phase liquid chromatography with fluorescence and ultraviolet detection. The amounts of total free amino acids varied widely between plants, from approximately 12 g in 100 g of Echinacea pallida extract to less than 60 mg in the same amount of Coleus forskohlii, Garcinia cambogia, and Glycine max. In 13 plants arginine, asparagine, glutamine, proline, and ,-aminobutyric acid were the free amino acids found in preponderant quantities. The levels of free amino acids above the quantification limit in 36 assayed samples of botanicals, extracts, and supplements are shown. [source] Seasonal nitrogen storage and remobilization in the forb Rumex acetosaFUNCTIONAL ECOLOGY, Issue 3 2001U. Bausenwein Summary 1,The contribution of N storage and remobilization to the vegetative and reproductive growth of the forb Rumex acetosa was quantified using 15N labelling techniques with plants derived from semi-natural grasslands in Scotland. 2,The contribution of remobilized N to the total N in the new above-ground tissues was highest at the beginning of the growing season at 58%. New leaves and reproductive organs contained equal amounts of remobilized N. 3,During early vegetative growth, the taproot was the main source of remobilized N, whereas during reproductive growth, N was additionally remobilized from fine roots and leaves. 4,Free amino acids (mainly arginine and glutamine) and proteins were identified as the main storage compounds in the taproots. The protein pool did not show any seasonal variations that indicated the existence of a vegetative storage protein, indicating that such proteins are not a necessary component of N storage/remobilization in all species. 5,The ability to store and remobilize N provides a mechanism for growth in the spring when the availability of soil N is low, and means that growth depends upon environmental conditions during more than one year. [source] Effects of timing and rate of N supply on leaf nitrogen status, grape yield and juice composition from Shiraz grapevines grafted to one of three different rootstocksAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 1 2007B.P. HOLZAPFEL Abstract Yeast cells have a minimum N requirement to ferment a must through to dryness, so that grape N content (hence must N) becomes critical in meeting that prerequisite. Viticultural practices aimed at meeting that N requirement are of special relevance because interactions between rootstock and vineyard nitrogen supply strongly influence scion mineral nutrient status as well as shoot vigour, and via those processes, fruit composition. Such outcomes were investigated in a field trial involving Shiraz on three rootstocks viz. Teleki 5C, Schwarzmann and Ramsey. Five N supply regimes, varying from 0 to 80 kg/(haseason), were imposed through a drip-irrigation system during two periods (either flowering to veraison, or post-harvest to leaf-fall, or both) over three successive growing seasons. Post-harvest N supply increased scion leaf N and nitrate N concentrations at flowering for vines on Teleki 5C and Schwarzmann. By veraison, N recently applied in the flowering to veraison period elevated these indicators of N status in all vines on all rootstocks. Grape yields from vines on Teleki 5C and Schwarzmann were elevated by N supply after harvest, whereas juice soluble solids levels were lowered. Free amino acids in Shiraz juice were dominated by non-assimilable N, amounting to about 50% or more of the total free amino-N in the juice. Increasing N supply increased free amino acid concentrations in the juice of berries from vines on all rootstocks, but only vines on Schwarzmann derived any benefit from N supplied after harvest. The highest concentrations of free amino acids were measured in the berries from vines on Schwarzmann receiving 80 kg N/(ha.season). Of immediate practical relevance for N management of Shiraz grapevines on either Teleki 5C or Ramsey rootstocks, the minimum value for assimilable free amino-N concentration required to ferment a must through to dryness was not achieved if vineyard N application was limited to the post-harvest period. [source] Effects of supplemental L-methionine on E-64 [trans-epoxysuccinyl-1-leucyl-amido (4-guanido) butane]-induced dysmorphology in rat embryos cultured in vitroCONGENITAL ANOMALIES, Issue 4 2003Kouichi Yoshidome ABSTRACT E-64 [trans-epoxysuccinyl-1-leucylamido (4-guanido) butane] is teratogenic, inducing a spectrum of malformations in vivo and producing similar effects in vitro. Numerous studies support the concept that E-64-induced malformations result from embryonic nutritional deficiency, without affecting the maternal nutritional status. This has provided a useful model with which to investigate the nutritional requirements of the early embryo, as well as the role of various nutrients in the etiology of congenital defects. In the current investigation, we examined effects of L-methionine on E-64-induced embryotoxicity in vitro. For these experiments, we cultured rat embryos 9.5 days postconception (p.c.) for 48 hours with E-64 and/or L-methionine. We found that the addition of L-methionine to E-64-exposed cultures reduced optic abnormality and increased embryo protein. These results suggest that embryopathy largely results from a deficiency of L-methionine although E-64 limits the supply of all amino acids to the embryo. Furthermore, although endocytosis and degradation of proteins by the visceral yolk sac (VYS) supply most amino acids to the embryo, free amino acids may be compensatory when this source is reduced. These results support those of previous investigations that suggest L-methionine is a limiting nutrient for embryonic development. [source] Flavour formation by lactic acid bacteria and biochemical flavour profiling of cheese productsFEMS MICROBIOLOGY REVIEWS, Issue 3 2005Gerrit Smit Abstract Flavour development in dairy fermentations, most notably cheeses, results from a series of (bio)chemical processes in which the starter cultures provide the enzymes. Particularly the enzymatic degradation of proteins (caseins) leads to the formation of key-flavour components, which contribute to the sensory perception of dairy products. More specifically, caseins are degraded into peptides and amino acids and the latter are major precursors for volatile aroma compounds. In particular, the conversion of methionine, the aromatic and the branched-chain amino acids are crucial. A lot of research has focused on the degradation of caseins into peptides and free amino acids, and more recently, enzymes involved in the conversion of amino acids were identified. Most data are generated on Lactococcus lactis, which is the predominant organism in starter cultures used for cheese-making, but also Lactobacillus, Streptococcus, Propionibacterium and species used for surface ripening of cheeses are characterised in their flavour-forming capacity. In this paper, various enzymes and pathways involved in flavour formation will be highlighted and the impact of these findings for the development of industrial starter cultures will be discussed. [source] THE ROLE OF BACTERIAL SYMBIONTS IN AMINO ACID COMPOSITION OF BLACK BEAN APHIDSINSECT SCIENCE, Issue 3 2003Xue-xia Miao Abstract To evaluate the role of bacterial symbionts (Buchnera spp.) in the black bean aphids (Aphis craccivora Koch), the aphids were treated with the antibiotic, rifampicin, to eliminate their intracellular symbiotic bacteria. Analysis of protein and amino acid concentration in 7-day-old of aposymbiotic aphids showed that the total protein content per mg fresh weight was significantly reduced by 29%, but free amino acid titers were increased by 17%. The ratio of the essential amino acids was in general only around 20% essential amino acids in phloem sap of broad bean, whereas it was 44% and 37% in symbiotic and aposymbiotic aphids, respectively, suggesting that the composition of the free amino acids was unbalanced. For example, the essential amino acid, threonine represented 21.6% of essential amino acids in symbiotic aphids, but it was only 16.7% in aposymbiotic aphids. Likewise, two nonessential amino acids, tyrosine and serine, represented 8.9% and 5.6% of total amino acids in symbiontic aphids, respectively, but they enhanced to 21.1% and 13.6% in aposymbiotic aphids. It seems likely that the elevated free amino acid concentration in aposymbiotic aphids was caused by the limited protein anabolism as the result of the unbalanced amino acid composition. [source] Stratum corneum keratin structure, function and formation , a comprehensive reviewINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 6 2006L. Norlén Synopsis A comprehensive review on stratum corneum keratin organization, largely based on the recently published cubic rod-packing and membrane templating model [J. Invest. Dermatol., 123, 2004, 715], is presented. Keratin is the major non-aqueous component (wt/wt) of stratum corneum. As 90,100% of the stratum corneum water is thought to be located intracellularly one may presume that keratin also is a major factor (together with filaggrin-derived free amino acids) determining stratum corneum hydration level and water holding capacity. This water holding capacity depends in turn on the structural organization of the corneocyte keratin intermediate filament network. The cubic rod-packing model for the structure and function of the stratum corneum cell matrix postulates that corneocyte keratin filaments are arranged according to a cubic-like rod-packing symmetry. It is in accordance with the cryo-electron density pattern of the native corneocyte keratin matrix and could account for the swelling behaviour and the mechanical properties of mammalian stratum corneum. The membrane templating model for keratin dynamics and for the formation of the stratum corneum cell matrix postulates the presence in viable epidermal cellular space of a highly dynamic small lattice parameter (<30 nm) membrane structure with cubic-like symmetry, to which keratin is associated. It further proposes that membrane templating, rather than spontaneous self-assembly, is responsible for keratin intermediate filament formation and dynamics. It is in accordance with the cryo-electron density patterns of the native keratinocyte cytoplasmic space and could account for the characteristic features of the keratin network formation process, the dynamic properties of keratin intermediate filaments, the close lipid association of keratin, the insolubility in non-denaturating buffers and pronounced polymorphism of keratin assembled in vitro, and the measured reduction in cell-volume and hydration level between stratum granulosum and stratum corneum. Résumé, La kératine est le composant majeur anhydre de la couche cornée. Etant donné que l'on considère que 90 à 100% de l'eau de la couche cornée est localisée à l'intérieur des cellules, on peut penser que la kératine joue également un rôle important (en association avec les acides aminés libres dérivés de la filagrine) dans le niveau d'hydratation de la couche cornée et sa capacité de rétention de l'eau. Cette capacité de rétention de l'eau dépend elle-même de l'organization structurelle du réseau de filaments intermédiaires de la kératine des cornéocytes. Le modèle de cylindre en réseau cubique appliquéà la structure et aux fonctions de la matrice des cellules de la couche cornée stipule que les filaments de la kératine des cornéocytes sont disposés symétriquement, les paquets de fibrilles formant une structure cubique. Ceci est conforme au modèle de densité cryo-électronique de la matrice kératinique des cornéocytes natifs et pourrait expliquer le comportement de gonflement et les propriétés mécaniques de la couche cornée des mammifères. Le modèle d'assemblage membranaire appliquéà la dynamique de la kératine et à la formation de la matrice cellulaire du stratum cornéum postule la présence dans l'espace cellulaire viable de l'épiderme d'une structure membranaire hautement dynamique présentant un petit paramètre de maille (<30 nm) et une organization en forme de cube, à laquelle la kératine est associée. D'autre part, ce modèle suggère qu'un assemblage membranaire plutôt qu'un auto-assemblage spontané puisse être à l'origine de la formation des filaments intermédiaires de kératine et de leur dynamique. Ceci concorde avec les modèles de densité cryo-électronique du cytoplasme des kératinocytes natifs et pourrait expliquer les caractéristiques du processus de formation du réseau kératinique, les propriétés dynamiques des filaments intermédiaires de kératine, l'association de la kératine avec les lipides, l'insolubilité dans les tampons non dénaturants, le polymorphisme caractéristique de la kératine assemblée in vitro, ainsi que la diminution mesurée du volume cellulaire et du niveau d'hydratation entre le stratum granulosum et le stratum corneum. [source] Ripening of Camembert-type cheese made from caprine milk using calf rennet or kid rennet as coagulantINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 1 2005NIAMH A O'SULLIVAN Camembert-type cheese was made from caprine milk using either calf rennet or kid ,Grandine' rennet as coagulant. The pH of all cheeses increased throughout ripening and levels of pH 4.6-soluble nitrogen increased from 8.1 to 18.2% of total nitrogen (TN) and from 6.9 to 20% TN for the cheeses made using calf rennet and kid rennet, respectively. Degradation of ,-casein, measured by urea,polyacrylamide gel electrophoresis, and total and free amino acids were greater in the cheese made using kid rennet. Production of peptides, analysed by high performance liquid chromatography (HPLC), was slightly more extensive in the Camembert-type cheese made using calf rennet as coagulant. In general, a higher degree of proteolysis was found in Camembert-type cheese made from caprine milk using kid rennet than in cheese made using calf rennet as coagulant. [source] Proteolysis and texture changes of a Spanish soft cheese (,Torta del Casar') manufactured with raw ewe milk and vegetable rennet during ripeningINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 3 2010Delgado Francisco-José Summary Proteolysis and textural changes of the Spanish ewe raw milk soft cheese of the Protected Designation of Origin Torta del Casar were studied in four different stages of ripening, with 1, 30, 60 and 90 days. In general, proteolysis in Torta del Casar cheese was weak at 1 and 30 days and it was more intense between the 30,60 days of ripening. Soluble nitrogen non-protein nitrogen, polypeptide N and free amino acids values significantly increased during cheese ripening. Protein and casein nitrogen decreased significantly after 60 days of ripening resulting in the increase of the other nitrogen fractions measured. Caseins changes determined by capillary zone electrophoresis showed that proteolysis of ,-casein occurred faster than ,s1-casein but the latter suffered higher proteolytic degradation at the end of ripening (day 90). This pattern of degradation of caseins is reversed in other cheeses made with animal rennet. Texture analysis showed that firmness and consistency decreased along ripening while adhesiveness increased. Highly significant correlations were found between textural parameters, residual caseins levels and nitrogen fractions during maturation, which shows the importance of proteolytic changes for an optimal texture formation. [source] Effects of pulsed electric fields on bioactive components, colour and flavour of green tea infusionsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2009Wei Zhao Summary Green tea is an unfermented tea containing a higher quantity of bioactive components. In this paper, the effects of pulsed electric field (PEF) treatments on the bioactive components (polyphenols, catechins and free amino acids), colour and flavour of green tea infusions were studied. PEF as a promising non-thermal sterilisation technology could efficiently retain polyphenols, catechins and original colour of green tea infusions with electric field strength from 20 to 40 kV cm,1 for 200 ,s. PEF treatments caused a significant increase in the total free amino acids of green tea infusions. The total free amino acids increased by 7.5% after PEF treatment at 40 kV cm,1. The increase in total amino acids induced by PEF treatment, especially to theanine, is beneficial for the quality of commercial ready-to-drink green tea infusion products. There was no significant effect of PEF treatment at 20 or 30 kV cm,1 on flavour compounds of green tea infusions. However, PEF treatment caused losses of volatiles in green tea infusions to different extents when PEF dosage was higher than a critical level. The total concentration of volatiles lost was approximately 10% after PEF treatment at 40 kV cm,1 for 200 ,s. [source] Chemical components of Aspergillus -type Douchi, a Chinese traditional fermented soybean product, change during the fermentation processINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 3 2007Jian-Hua Zhang Summary Douchi, a traditional fermented soybean product that originated in China, has been consumed since ancient times as a food seasoning. The influence of fermentation on the chemical components of naturally fermented douchi and Aspergillus egypticus pure-cultured douchi was investigated. Changes in per cent and/or concentration of amino-type nitrogen, total acid, reducing sugar, organic acid, amino acids (AA) and isoflavone, along with the neutral protease and , -glucosidase activities during the fermentation, were analysed. The results indicated that fermentation had a significant effect on the concentration of chemical components. The concentration of all free amino acids (FAA) increased gradually during fermentation, to a maximum of 109.54 mg g,1 in 15-day fermented products. The main organic acids in douchi are 7.788 and 17.778 mg g,1, respectively. During fermentation, the contents of daidzin and genistin decreased from 160.7 and 207.9 to 7.54 and 24.12 ,g g,1 respectively. Daidzein and genistein increased from 18.2 and 16.9 to 63.4 and 84.6 ,g g,1, respectively. [source] Formation and reactions of cluster ions from aromatic carboxylic acids together with amino acidsISRAEL JOURNAL OF CHEMISTRY, Issue 2 2001Anja Meffert The cluster formation of several aromatic carboxylic acids, ferulic acid, vanillic acid, sinapinic acid, and 3,4-dihydroxybenzoic acid was investigated by means of laser desorption into a supersonic beam followed by multiphoton ionization-time-of-flight mass spectrometry. The formation of not only homogeneous clusters, but also of heterogeneous clusters with some small amino acids was studied. The different neutral clusters formed in the supersonic expansion were ionized by a multiphoton process employing either nano- or femtosecond laser pulses. Strong differences in the detection of cluster ions due to the laser pulse length employed for multiphoton ionization were observed. Only femtosecond activation led to mass spectra with intense signals of the cluster ions. In addition, in the case of femtosecond ionization, protonated amino acids were detected in the mass spectra. As direct ionization of the free amino acids is not possible under the chosen ionization conditions because they lack an adequate chromophore, these protonated amino acids are assumed to be formed via an intracluster proton transfer in the heterogeneous dimer and subsequent decay of the ionized cluster (dissociative proton transfer). Such well-known processes for heterogeneous clusters consisting of a substituted aromatic molecule and small polar solvent molecules may be involved in the matrixassisted laser desorption ionization (MALDI) process. [source] Amino acid concentrations in blood serum of horses performing long lasting low-intensity exerciseJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3-6 2005D. Bergero Summary The aim of this work was to evaluate the changes in the concentrations, after two rides different for distance covered, of different amino acids in endurance horses. Blood samples have been collected from horses just before the start, at the top of a steep slope (819 m difference in height) and just at the end of a 32-km endurance ride. A second group, competing in a 72 km endurance ride, has also been sampled immediately before and after the race. In serum samples, the concentrations of alanine, arginine, asparagine, glycine, isoleucine, histidine, leucine, lysine, methionine, ornithine, phenylalanine, tryptophan, tyrosine and valine have been measured by high-performance liquid chromatography (HPLC). anova and t -test have been used to study the differences in the concentrations of the amino acids. The pre-ride concentrations of the free amino acids were different between the two races, except for methionine and leucine. Differences between start and end race have been found for both groups for all the considered parameters except asparagine, isoleucine, leucine and lysine for the 72 km ride. Increases have been recorded for the shorter and decreases for the longer ride in the blood serum concentrations. Significant increases have also been found between the starting sampling and the second, at the top of the slope, only for alanine, arginine, asparagines, phenylalanine and lysine. The ride length has a significant impact on blood serum amino acids mobilization and uptake; in the shorter race the increases stand only for mobilization, whereas in the longer the decrease can be considered the effect of the onset of the amino acids catabolism. [source] Nutritional evaluation of fermented black gram (Phaseolus mungo) seed meal in compound diets for rohu, Labeo rohita (Hamilton), fingerlingsJOURNAL OF APPLIED ICHTHYOLOGY, Issue 1 2007S. Ramachandran Summary Six isonitrogenous (approximately 35% crude protein) and isocaloric (approximately 4.0 kcal g,1) diets were formulated incorporating raw and fermented black gram, Phaseolus mungo, seed meal at 20%, 30% and 40% levels by weight into a fishmeal-based control diet fed to rohu, Labeo rohita, fingerlings (mean weight, 1.81 ± 0.21 g) for 80 days for a study of fish performance. A particular bacterial strain (Bacillus sp.) isolated from the intestine of adult common carp (Cyprinus carpio) reared in the wild having significant amylolytic, cellulolytic, lipolytic and proteolytic activities was used for fermentation of seed meal for 15 days at 37 ± 2°C. Fermentation of P. mungo seed meal was effective in significantly reducing the crude fibre content and antinutritional factors such as tannins and phytic acid, and enhancing available free amino acids and fatty acids. In terms of growth, feed conversion ratio and protein efficiency ratio, the 30% fermented black gram seed meal incorporated diet resulted in a significantly (P < 0.05) better performance of rohu fingerlings. In general, growth and feed utilization efficiencies of diets containing fermented seed meal were superior to diets containing raw seed meal. The apparent protein digestibility (APD) values decreased with increasing levels of raw seed meal in the diets. The APD for raw seed meal was lower at all levels of inclusion in comparison to those for the fermented seed meals. The maximum deposition of protein in the carcass was recorded in fish fed the diet containing 40% fermented seed meal. The results indicate that fermented black gram seed meal can be incorporated in carp diets up to the 30% level compared to the 10% level of raw seed meal. [source] Optimization of agro-residual medium for ,-amylase production from a hyper-producing Bacillus subtilis KCC103 in submerged fermentationJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2009Gobinath Rajagopalan Abstract BACKGROUND: Although submerged fermentation (SmF) is the conventional method in industry, use of low-cost agro-residues for ,-amylase production in SmF has not been well established. Here we optimized agro-residue-based medium and culture conditions for ,-amylase production in SmF using a hyper-producing Bacillus subtilis KCC103. RESULTS:B. subtilis KCC103 produced ,-amylase in SmF by utilizing agro-residues. Wheat bran (WB) and sunflower oil cake (SFOC) were selected as the best substrates using shake flasks. Medium containing WB (carbohydrate rich) and SFOC (rich in protein and free amino acids) at 1:1 (w/w) ratio produced high levels (90 IU mL,1) of ,-amylase at 30,36 h in a shake flask. The ,-amylase yield was 14-fold enhanced (1258 IU mL,1) by optimizing process parameters and medium composition following response surface methodology in a bioreactor. The optimal conditions were: WB 1.27%, SFOC 1.42%, pH 7, 37 °C and 10,12 h. Both in shake flask and bioreactor ,-amylase synthesis was not repressed by the release of simple sugars into the medium. CONCLUSION: KCC103 with catabolite derepression and hyperproducing ability is useful for economic ,-amylase production using low-cost agro-residual substrates in conventional SmF. Since the production time (10,12 h) is much shorter than other strains this would improve productivity and further reduce the cost of ,-amylase production. Copyright © 2008 Society of Chemical Industry [source] Plant amino acid uptake, soluble N turnover and microbial N capture in soils of a grazed Arctic salt marshJOURNAL OF ECOLOGY, Issue 4 2003Hugh A. L. Henry Summary 1The uptake of free amino acids by the grass Puccinellia phryganodes was investigated in soils of an Arctic coastal salt marsh, where low temperatures and high salinity limit inorganic nitrogen (N) availability, and the availability of soluble organic N relative to inorganic N is often high. 2Following the injection of 13C15N-amino acid, 15N-ammonium and 15N-nitrate tracers into soils, rates of soluble nitrogen turnover and the incorporation of 13C and 15N into plant roots and shoots were assessed. Chloroform fumigation-extraction was used to estimate the partitioning of labelled substrates into microbial biomass. 3Free amino acids turned over rapidly in the soil, with half-lives ranging from 8.2 to 22.8 h for glycine and 8.9 to 25.2 h for leucine, compared with 5.6 to 14.7 h and 5.6 to 15.6 h for ammonium and nitrate, respectively. 15N from both organic and inorganic substrates was incorporated rapidly into plant tissue and the ratio of 13C/15N incorporation into plant tissue indicated that at least 5,11% of 13C15N-glycine was absorbed intact. 4Microbial C and N per unit soil volume were 1.7 and 5.4 times higher, respectively, than corresponding values for plant C and N. Plant incorporation of 15N tracer was 56%, 83% and 68% of the comparable incorporation by soil microorganisms of glycine, ammonium and nitrate ions, respectively. 5These results indicate that P. phryganodes can absorb amino acids intact from the soil despite competition from soil microorganisms, and that free amino acids may contribute substantially to N uptake in this important forage grass utilized by lesser snow geese in the coastal marsh. [source] EFFECT OF ARTIFICIAL FEEDING ON DIGESTIVE EFFICIENCY, GROWTH AND QUALITIES OF MUSCLE AND OOCYTE OF MATURING ATLANTIC MACKEREL (SCOMBER SCOMBRUS L.)JOURNAL OF FOOD BIOCHEMISTRY, Issue 6 2007KRISNA RUNGRUANGSAK-TORRISSEN ABSTRACT Maturing Atlantic mackerel with and without artificial feeding, kept in sea pens (September to May), showed differences in digestive efficiency (protease activity ratio of trypsin to chymotrypsin), muscle growth (concentrations of RNA, protein, RNA/protein ratio and free amino acids [FAA]) and oocyte quality (trypsin-like specific activity, and concentrations of RNA, RNA/protein ratio and FAA). The artificially fed mackerel had higher body weights (1.7 times) but with less white muscle protein concentration (0.5 time), compared to the control group. Both groups showed higher levels of capacity for protein synthesis in the oocytes than in the white muscle, but it was about two times higher in the artificially fed fish whereas about four times higher in the control group. This indicated that, during maturation, development of oocytes and muscle for growth occurred concurrently in higher growth mackerel, while development of oocytes dominated in slower growth fish. A higher trypsin-like specific activity with higher FAA levels in the oocytes from females fed with an artificial diet, compared to the control group, suggested differences in development and quality between the gametes of the fish with different feedings. PRACTICAL APPLICATIONS The work illustrates differences in digestive efficiency and the quality of growth performance (growth and protein metabolism in muscle and oocytes) in fish with different feedings. The use of various methods for evaluating digestive efficiency and the quality of fish growth performance could provide reasonable information for some important biological differences between fish groups, especially when the number of samples are low. It is more advantageous to apply different methods simultaneously than using growth parameter alone in order to study for precise evaluation of the quality of fish growth performance. The methods are very practical for studying food utilization and growth quality of fish in different environmental conditions and with different behaviors in aquaculture as well as in natural ecosystem where food consumption rate and feeding regime cannot be under control. [source] RELATION BETWEEN THE FREE AMINO ACIDS, ANSERINE AND THE TOTAL VOLATILE BASIC NITROGEN PRODUCED IN MUSCLE OF HAKE (MERLUCCIUS MERLUCCIUS, L.) DURING ICED STORAGEJOURNAL OF FOOD BIOCHEMISTRY, Issue 1 2002CLAUDIA RUIZ-CAPILLAS This work studied the development of free amino acids (FAAs) and dipeptide anserine as quality indices for gutted hake stored in ice for 25 days. The correlation of these compounds was determined with total volatile basic nitrogen (TVBN) which has been used as a quality index, for fish stored in ice. The most abundant free amino acids in hake muscle were found to be threonine, glycine, alanine, glutamic acid, ,-alanine methylhistidine. lysine and the dipeptide, anserine. The only hydrophobic free ammo adds which exhibit significant differences (P<0.05) throughout storage was tryptophan. moreover, this amino acid exhibited a very high correlation (r=0.951) with TVBN. A significant decrease in anserine (P<0.05) correlated with the increases in 1-methylhistidine and ,-alanine throughout storage. These changes also exhibited a very high correlation with TVBN. Therefore, 1-methylhistidine, ,-alanine anserine and tryptophan could be used as quality parameters for hake stored in ice. [source] PROTEOLYSIS IN SALMON (SALMO SALAR) DURING COLD STORAGE; EFFECTS OF STORAGE TIME AND SMOKING PROCESSJOURNAL OF FOOD BIOCHEMISTRY, Issue 5 2001KAREN ENGVANG LUND ABSTRACT Changes in free amino acids (FAAs), small peptides and myofibrillar proteins were investigated in salmon (Salmo salar) muscle stored at OC for up to 23 days and after the stored salmon was smoked. Storage time and smoking process did not increase the formation of FAAs and small peptides indicating low exopeptidase activity. During storage, SDS PAGE analysis of myofibrils showed an increase in density of bands at 16, 37, 60, 64, 67, 76 and 130 kDa, a decrease of a 32 kDa band and the appearance of four new bands of 30, 90, 95 and 113 kDa. These results indicate proteolytic degradation. A little change of myosin and no change of ,-actinin and actin were observed. The smoking process itself enhances the intensity of bands, but does not change the pattern markedly except for the appearance of a 25 and 70 kDa band. Degradation pattern after smoking was not affected by storage time. [source] Identification of Candidate Amino Acids Involved in the Formation of Blue Pigments in Crushed Garlic Cloves (Allium sativum L.)JOURNAL OF FOOD SCIENCE, Issue 1 2009Jungeun Cho ABSTRACT:, The color-forming ability of amino acids with thiosulfinate in crushed garlic was investigated. We developed reaction systems for generating pure blue pigments using extracted thiosulfinate from crushed garlic and onion and all 22 amino acids. Each amino acid was reacted with thiosulfinate solution and was then incubated at 60 °C for 3 h to generate pigments. Unknown blue pigments, responsible for discoloration in crushed garlic cloves (Allium sativum L.), were separated and tentatively characterized using high-performance liquid chromatography (HPLC) and a diode array detector ranging between 200 and 700 nm. Blue pigment solutions exhibited 2 maximal absorbance peaks at 440 nm and 580 nm, corresponding to yellow and blue, respectively, with different retention times. Our findings indicated that green discoloration is created by the combination of yellow and blue pigments. Eight naturally occurring blue pigments were separated from discolored garlic extracts using HPLC at 580 nm. This suggests that garlic discoloration is not caused by only 1 blue pigment, as reported earlier, but by as many as 8 pigments. Overall, free amino acids that formed blue pigment when reacted with thiosulfinate were glycine, arginine, lysine, serine, alanine, aspartic acid, asparagine, glutamic acid, and tyrosine. Arginine, asparagine, and glutamine had spectra that were more similar to naturally greened garlic extract. [source] Free Amino Acids in Botanicals and Botanical PreparationsJOURNAL OF FOOD SCIENCE, Issue 5 2008B. Carratù ABSTRACT:, Numerous studies were carried out about aminoacidic composition of vegetable proteins, but information about the free amino acid pool and the role of these substances is very incomplete. The aim of this paper was to contribute to the scarce knowledge concerning the composition of free amino acids in botanicals and botanical preparations widely used as food, in dietary supplements, and in pharmaceutical products. This work studied the composition of free amino acids, identified the major components of 19 species of plants, and evaluated the influence of different types of extraction on the amino acid profile. Amino acids were determined using an automatic precolumn derivatization with fluorenylmethyl-chloroformate and reversed-phase liquid chromatography with fluorescence and ultraviolet detection. The amounts of total free amino acids varied widely between plants, from approximately 12 g in 100 g of Echinacea pallida extract to less than 60 mg in the same amount of Coleus forskohlii, Garcinia cambogia, and Glycine max. In 13 plants arginine, asparagine, glutamine, proline, and ,-aminobutyric acid were the free amino acids found in preponderant quantities. The levels of free amino acids above the quantification limit in 36 assayed samples of botanicals, extracts, and supplements are shown. [source] Effect of Combining Proteolysis and Lactic Acid Bacterial Fermentation on the Characteristics of Minced MackerelJOURNAL OF FOOD SCIENCE, Issue 3 2005Li-Jung Yin ABSTRACT: To improve the quality of fish muscle, mackerel muscle protein was hydrolyzed by proteases from Aspergillus oryzae, and then fermented by lactic acid bacteria (LAB). The highest protease activities were obtained from A. oryzae after 72 h incubation at 25°C. Acidic protease activity was much higher than neutral and alkaline proteases. SDS-PAGE indicated the degradation of muscle proteins after 1 or 2 h hydrolysis by A. oryzae proteases at 50°C. During 48 h fermentation by Pediococcus pentosaceus L and S at 37°C, rapid growth of LAB, decline in pH, and suppression in the growth of microflora, Enterobacteriaceae, Staphylococcus, and Pseudomonas, occurred while increases in whiteness, nonprotein nitrogen, sensory quality, and free amino acids were observed. These data suggested that the acceptability of LAB -fermented mackerel hydrolysates could be substantially improved. [source] Preparation and Characterization of Hydrolyzed Proteins from Defibrinated Bovine PlasmaJOURNAL OF FOOD SCIENCE, Issue 2 2002P.K.J.P.D. Wanasundara ABSTRACT: Proteins from defibrinated bovine blood plasma were enzymatically hydrolyzed with food-grade microbial proteases Alcalase 2.4 L® and Flavourzyme L&TM;, and a substrate consisting of small peptides and free amino acids was obtained. Hydrolysis of the plasma proteins with Flavourzyme resulted in a maximum degree of hydrolysis of 43% at an enzyme concentration of 110 LAPU/g protein after 15.5 h of hydrolysis. Among the free amino acids in the hydrolysate, hydrophobic amino acids were predominant. The major plasma proteins were degraded due to hydrolysis; peptides of less than 1.04 kDa were dominant in the product when a high degree of hydrolysis was employed. [source] Solid-phase peptide synthesis using acetonitrile as a solvent in combination with PEG-based resinsJOURNAL OF PEPTIDE SCIENCE, Issue 10 2009Gerardo A. Acosta Abstract This manuscript shows that ACN can be an excellent choice for the coupling of hindered amino acids as illustrated by the coupling of Fmoc-amino acids on free amino acids anchored on a BAL synthesis. Furthermore, ACN can be a good alternative for solid-phase peptide synthesis in the absence of DMF (washings, removal of Fmoc, and coupling). Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd. [source] Effect of cultivar and roasting method on composition of roasted soybeansJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2009Emily L Boge Abstract BACKGROUND: The composition of raw soybeans and the roasting method have an important impact on the quality of roasted soybeans. The objective of the study was to determine the effect of food-grade soybean cultivars (IA 2064, IA 1008, IA 1008LF, Prairie Brand 299, Asgrow 2247) and roasting method (oil- and dry-roasting) on the composition of roasted soybeans. RESULTS: Moisture content decreased after roasting, with oil-roasted soybeans having a significantly lower moisture content than the dry-roasted soybeans. With the exception of the low linolenic acid cultivar (IA 2064), there were no significant differences in total lipid and fatty acid contents of the five cultivars. Oil-roasted soybeans had significantly higher lipid content than raw and dry-roasted soybeans owing to the absorption of oil. The soluble sugars and free amino acids contents of the five soybean cultivars were not significantly different. Decreases in the contents of free amino acids, but not soluble sugars, occurred during roasting. Greater reductions were seen in oil-roasted soybeans because of the higher roasting temperature. CONCLUSION: Roasting method, rather than cultivar, had the greatest effect on the composition of roasted soybeans. The food-grade soybean cultivars evaluated in this study were similar in composition. Copyright © 2009 Society of Chemical Industry [source] Nitrogen release dynamics and transformation of slow release fertiliser products and their effects on tea yield and qualityJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2008Dr Wen-Yan Han Abstract BACKGROUND: Tea (Camellia sinensis (L.) O. Kuntze) is a perennial leaf harvested crop. It requires more nitrogen than most other crops and preferentially utilises NH4+ to NO3, when both are available in the soil. It is expected that slow release fertilisers coupled with a nitrification inhibitor could improve the N use efficiency and simultaneously reduce environmental pollution. In this study, three slow release fertilisers were developed and tested: CaMg phosphate coated urea with dicyandiamide (DCD) as a nitrification inhibitor and polyolefin coated urea with and without DCD. The main aim was to compare the nitrogen release dynamics and transformation of these fertilisers and their effects on tea yield and quality. RESULTS: The results showed that the coatings significantly slowed N release and kept mineral N in soils at a higher concentration for a longer time compared to uncoated urea. Polyolefin was a superior coating to CaMg phosphate. DCD was an effective nitrification inhibitor and significantly reduced the ratio of nitrate to total mineral N in a highly acidic tea soil. The 15N use efficiency was 29% where uncoated fertiliser was applied and 46% where polyolefin coated fertiliser with DCD was applied. The application of slow release fertilisers increased the chlorophyll content in mature leaves and enhanced the uptake of mineral elements by tea plants. Bud sprouting, shoot growth and mature leaf longevity were significantly improved, resulting in higher biomass of tea plants. Slow release fertilisers increased the yield of shoots by 51,143% (mean, 106%) in a pot experiment and 4,14% (mean, 9%) in a field experiment compared to uncoated urea. Tea quality parameters, especially free amino acids, were also significantly increased. CONCLUSION: Slow release fertilisers, especially polyolefin coated urea with DCD could significantly increase the N use efficiency and improve tea growth. Their uses in tea fields not only improved the profit margin, but possibly reduced environmental pollution. Copyright © 2008 Society of Chemical Industry [source] Polyphenol oxidase activity in grass and its effect on plant-mediated lipolysis and proteolysis of Dactylis glomerata (cocksfoot) in a simulated rumen environmentJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2006Michael RF Lee Abstract Little is known about the level or activity of polyphenol oxidase (PPO) in grasses and its potential impact on proteolysis and lipolysis. Six grass species were initially screened for PPO activity (740.6, 291.9, 213.6, 119.0, 16.3 and 6.5 U g,1 fresh weight (FW) for cocksfoot, hybrid ryegrass, Italian ryegrass, perennial ryegrass, timothy and tall fescue respectively). Cocksfoot, which expressed the highest activity, was then used to determine the effect of PPO on plant-mediated proteolysis and lipolysis in a simulated rumen environment. Sourced cocksfoot was macerated and incubated in an antibiotic-containing anaerobic medium with or without ascorbate to deactivate PPO in the dark at 39 °C over five time points. At each time point (0, 1, 2, 6 and 24 h), six replicate samples were destructively harvested; three of the replicates were used for lipid analysis and the other three for protein, free amino acid and bound phenol determination. Characterisation of the herbage showed PPO activities of 649.6 and 0 U g,1 FW, which were reflected in the extent of phenol (derived from quinones) binding to protein after 24 h of incubation, namely 65.1 and 29.6 mg bound phenol g,1 protein (P < 0.001) for cocksfoot and cocksfoot + ascorbate respectively. Proteolysis, measured as free amino acids released into the incubation buffer, was significantly reduced (P < 0.001) with increasing PPO activity, with values after the 24 h incubation of 0.03 and 0.07 mmol L,1 g,1 FW for cocksfoot and cocksfoot + ascorbate respectively. Lipolysis, measured as the proportional decline in the membrane lipid polar fraction, was likewise reduced (P < 0.001) with increasing PPO activity, with values after the 24 h incubation of 0.43 and 0.65 for cocksfoot and cocksfoot + ascorbate respectively. Changes that occurred in protein and the lipid fractions (polar fraction, monoacylglycerol + diacylglycerol, triacylglycerol and free fatty acids) during the incubations are also reported and discussed. These results support the selection of forages high in PPO activity to reduce protein and lipid losses in silo and potentially in the rumen. Copyright © 2006 Society of Chemical Industry [source] Extractive components of boiled,dried scallop adductor muscle and effect on the taste of soup after mixing with chicken leg meatJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2005Chie Yoneda Abstract The extractive components of raw and boiled,dried scallop adductor muscle were examined. On a dry weight basis the levels of total free amino acids, total adenosine triphosphate (ATP) and related compounds, and betaines in the boiled,dried sample were lower than those in the raw muscle, which may have been due to the outflow of these compounds during boiling. Soup prepared from the boiled,dried scallop and chicken leg meat was assessed by sensory evaluation. This soup cooked with the scallop and chicken was stronger in sweetness, umami and body and rated higher in overall preference than the soup containing these ingredients after cooking separately. The inosine monophosphate (IMP) level in the former soup was 4.4 times higher than that in the latter. The adenosine monophosphate (AMP) deaminase (EC 3.5.4.6) activity in the crude extract from the chicken meat was 9.16 units l,1, whereas no activity could be detected in the crude extract from the boiled,dried scallop. It is concluded that AMP, which was mainly derived from the boiled,dried scallop, was converted to IMP by AMP deaminase from the chicken meat during the preparation of the soup, resulting in an improvement in the taste. Copyright © 2004 Society of Chemical Industry [source] Papain hydrolysates of casein: molecular weight profile and encapsulation in lipospheresJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2004Cristiane MS Barbosa Abstract Some reaction parameters were tested in the hydrolysis of casein by papain, in order to prepare hydrolysates with high oligopeptide contents, for either dietetic or pharmaceutical purposes. Five casein hydrolysates were prepared and then fractionated by size-exclusion HPLC. The rapid correct fraction area method was used for quantifying peptides and free amino acids. Among the five reaction conditions tested, three produced similar peptide profiles. However, the use of a temperature of 37°C and an E:S ratio of 2% is probably the most economical condition for use in large-scale manufacture. With the aim of masking the bitterness of these preparations, a new method, based on the encapsulation in lipospheres, was used. Also, second derivative spectrophotometry was used for the first time to measure the extent of encapsulation of protein hydrolysates, which changed from 50% to 83%. Moreover, the efficiency of this system was evaluated by analysing other parameters, which showed a reduction of hydrophobicity and bitterness of all samples, as well as good chemical stability during 60 days of storage under refrigeration. The electron microscopical analysis of liposheres showed an average size around 5.0 ± 1.0 µm. Copyright © 2004 Society of Chemical Industry [source] | ||||||||||||||||