Free amino acids and sugars in rye grain: implications for acrylamide formation

Acrylamide forms from free asparagine and sugars during cooking, and products derived from the grain of cereals, including rye, contribute a large proportion of total dietary intake. In this study, free amino acid and sugar concentrations were measured in the grain of a range of rye varieties grown at locations in Hungary, France, Poland, and the United Kingdom and harvested in 2005, 2006, and 2007. Genetic and environmental (location and harvest year) effects on the levels of acrylamide precursors were assessed. The data showed free asparagine concentration to be the main determinant of acrylamide formation in heated rye flour, as it is in wheat. However, in contrast to wheat, sugar, particularly sucrose, concentration also correlated both with asparagine concentration and with acrylamide formed. Free asparagine concentration was shown to be under genetic (G), environmental (E), and integrated (G × E) control. The same was true for glucose, whereas maltose and fructose were affected mainly by environmental factors and sucrose was largely under genetic control. The ratio of variation due to varieties (genotype) to the total variation (a measure of heritability) for free asparagine concentration in the grain was 23%. Free asparagine concentration was closely associated with bran yield, whereas sugar concentration was associated with low Hagberg falling number. Rye grain was found to contain much higher concentrations of free proline than wheat grain, and less acrylamide formed per unit of asparagine in rye than in wheat flour.

Standardised ileal digestibility of crude protein and amino acids of UK-grown peas and faba beans by broilers

In view of the increasing interest in home-grown legumes as components of diets for non-ruminant livestock and in an attempt to reduce the reliance on imported soya bean meal (SBM), two experiments were conducted to evaluate samples of peas and faba beans for their standardised ileal digestibility (SID) of amino acids determined with young broiler chicks. Experiment 1 evaluated six faba bean and seven pea cultivars and Experiment 2 evaluated two faba bean and three pea cultivars as well as a sample of soya bean meal provided as a reference material. Peas and beans were added at 750g/kg as the only source of protein/amino acids in a semi-synthetic diet containing the inert marker titanium dioxide; SBM was added, in a control diet, at 500g/kg. Each diet was fed to six replicates of a cage containing two Ross-type broilers for 96h at which point birds were culled allowing removal of ileal digesta. Chemical analyses allowed the calculation of the coefficient of SID of amino acids. There were no differences between samples of the same pulse species (P>0.05) but peas had higher values (P<0.05), similar to SBM, than beans. Trypsin inhibitor content (expressed as g trypsin inhibitor units/mg sample) of all pea samples was low and in the range 0.83–1.77mg/kg. There was relatively little variation in bean tannin content and composition amongst the coloured-flowered varieties; however, the white-flowered cultivar had no tannins. There was no correlation between tannin content and coefficient of SID. The content of SID of amino acids (g/kg legume) was higher in SBM when compared with peas and beans by virtue of having higher total concentrations.

Concentrations of free amino acids and sugars in nine potato varieties: effects of storage and relationship with acrylamide formation

Acrylamide forms during cooking and processing predominately from the reaction of free asparagine and reducing sugars in the Maillard reaction. The identification of low free asparagine and reducing sugar varieties of crops is therefore an important target. In this study, nine varieties of potato (French fry varieties Maris Piper (from two suppliers), Pentland Dell, King Edward, Daisy, and Markies; and chipping varieties Lady Claire, Lady Rosetta, Saturna, and Hermes) grown in the United Kingdom in 2009 were analyzed at monthly intervals through storage from November 2009 to July 2010. Acrylamide formation was measured in heated flour and chips fried in oil. Analysis of variance revealed significant interactions between varieties nested within type (French fry and chipping) and storage time for most free amino acids, glucose, fructose, and acrylamide formation. Acrylamide formed in chips correlated significantly with acrylamide formed in flour and with chip color. There were significant correlations between glucose or total reducing sugar concentration and acrylamide formation in both variety types, but with fructose the correlation was much stronger for chipping than for French fry varieties. Conversely, there were significant correlations with acrylamide formation for both total free amino acid and free asparagine concentration in the French fry but not chipping varieties. The study showed the potential of variety selection for preventing unacceptable levels of acrylamide formation in potato products and the variety-dependent effect of long-term storage on acrylamide risk. It also highlighted the complex relationship between precursor concentration and acrylamide risk in potatoes.

Polyamines, amino acids, IAA and ABA contents during Ocotea catharinensis seed germination

The aim of this work was to Study biochemical variations of IAA (indole-3-acetic acid), ABA (abscisic acid). PAs (polyamines) and amino acids at endogenous levels, during seed germination in Ocotea catharinensis. Seeds were germinated in a vermiculite substratum (100%), samples being collected after 15, 30 and 60 days. Total amino acid levels decreased during the first 15 days. Followed by all increment at the end of germination. Among amino acids, higher concentration was observed in asparagine, this being the predominant amino acid during the whole germination period. Total PAs (free + conjugated) content increased during the first 15 days, followed by a decrease and stabilization between 30 and 60 days of germination. Among the PAs, free putrescine levels rose during the first 15 days, followed by a drop and Stabilization up to 60 days of germination, while spermidine and spermine (spm) contents diminished during the period. Only spin was detected in a conjugated form, with increasing concentrations starting from 30 days on. IAA levels increased during tire first 15 days. followed by a decrease and stabilization until the end of germination (60 days), while ABA contents dwindled during the first 15 days, with similar Values until the end of germination.

Amino acids and diabetes: implications for endocrine, metabolic and immune function

Aberrant alterations in glucose and lipid concentrations and their pathways of metabolism are a hallmark of diabetes. However, much less is known about alterations in concentrations of amino acids and their pathways of metabolism in diabetes. In this review we have attempted to highlight, integrate and discuss common alterations in amino acid metabolism in a wide variety of cells and tissues and relate these changes to alterations in endocrine, physiologic and immune function in diabetes.

Pearl millet utilization in ccommercial laying hen diets formulated on a total or digestible amino acid basis

An experiment was carried out to evaluate the effect of replacing corn with pearl millet in commercial layer diets, formulated according to the minimal requirements for total and digestible amino acids. Two hundred and forty Lohmann LSL laying hens with 25 weeks of age were distributed in a completely randomized experimental design according to a 2 x 5 factorial arrangement with 3 replicates of 8 birds. Feed was formulated on two amino acid basis (total or digestible) according to Rostagno et al. (2000) and there were five pearl millet inclusion levels (0%, 25%, 50%, 75%, and 100%). Performance and egg quality were evaluated during five periods of 21 days.At the end of each period, feed intake, egg production, egg weight and feed conversion were evaluated. In the last three days of each period, the following egg quality parameters were evaluated: Haugh Unit, yolk pigmentation index, egg specific weight, shell percentage and shell thickness. Digestible amino acid requirements resulted in decreased feed intake (p<0.01) and increased production costs per mass of eggs (kg) or per dozen eggs (p<0.01) compared to total amino acid requirements. There was a linear reduction in feed intake, egg production, egg weight and yolk pigmentation index with increasing inclusion levels of pearl millet. Therefore, increasing levels of replacement of corn by pearl millet affected bird performance negatively. Besides, production costs were higher with increasing pearl millet levels.

Amino Acids on Mango Yield and Fruit Quality at Submedio Sao Francisco Region, Brazil

Farmers of the Submedio Sao Francisco Region (Brazil) have been spraying amino acids on mango trees with the objective of increasing panicle length and improving fruit retention and quality. This study, done in two experiments, tested the effect of amino acids sprayings at concentrations of 0.0%; 0.02%; 0.04% and 0.06%, on mango plants, 'Tommy Atkins', on the budding phase (panicles with 5 cm), fruit set and fruit growth (5 cm diameter). They were carried out from June to October in 2003, that is the natural period for harvest in the region, and from January to May, in 2004. There were no statistical differences in the first experiment among treatments regarding panicle length and fruit production, probably due to an appropriate management of nutrition, water and plant growth regulators, besides climatic conditions, mainly temperature and solar radiation. In the second experiment, significant increments in the panicle length of 13.37%, 11.70% and 21.4% were observed with amino acids concentrations, compared to the control. Increasing amino acids doses also enhanced the number of fruits per plant, thirty days before the harvest, in 16.17%, 45.32% and 37.38%, respectively, compared to the control, but there were no significant statistical differences. Characteristics of fruit quality during storage, as weight loss, total soluble solids, total titratable acidity and pulp firmness were not significantly affected by amino acids spraying. Changes on those variables were registered as a consequence of fruit ripening. Amino acids sprays lightly delayed the evolution of skin luminosity and Hue of pulp, but the differences could not be visually identified. The concentrations of amino acids were not efficient for improving the natural concentrations of these substances in the leaves, which could be the reason for the non significant effects on the variables analyzed.

Effects of intrauterine malnutrition on brain free amino acids of young rats, after nutritional recovery during lactation period

The effect of protein-calorie malnutrition during gestation on the brain amino acids of rat pups was studied following nutritional recovery during lactation. The brain amino acids of rat pups born to dam rats malnourished during gestation were studied after these rat pups received proper nutrition during lactation. Pregnant rats were fed a 1% protein diet with total caloric intake restricted to half that of controls. After birth, the offspring of rats fed on deficient diets were nurtured up to the 28th day postpartum by foster mothers receiving adequate diets. At this time, the offspring were killed. The control group consisted of offspring from pregnant rats fed a diet with adequate protein (21%) and calories during the entire gestation and lactation period. Quantitation of brain amino acids in the pups at 28 days postpartum showed lower concentrations of essential and nonessential amino acids in the rats malnourished during gestation. Concentrations of histidine, glycine, and α-aminobutyric acids were all reduced. These findings demonstrate that the brains of rat pups malnourished during gestation show persistent decreases in specific brain amino acids after adequate postpartum nutrition.

Lipoic acid and ascorbic acid affect plasma free amino acids selectively in the teleost fish pacu (Piaractus mesopotamicus)

Most studies on the antioxidants, lipoic acid (LA) and ascorbic acid (AA), focused on species that, unlike teleost fish, are not scurvy-prone, and are able to synthesize AA. The antioxidant properties of LA may make it useful in aquaculture nutrition, but several effects must first be investigated, and we address here plasma free amino acids (FAA). In mammals, LA and AA in high doses were claimed to alter plasma FAA profile; to our knowledge, however, no data are available in fish. We therefore studied the effects of dietary LA and AA on plasma FAA in the South American teleost fish pacu, which is being used increasingly in aquaculture. LA treatment decreased concentrations of 18 of 23 individual FAA; specifically, dispensable and total FAA were significantly affected. Ornithine was elevated (+26%) in LA-treated fish and significantly decreased ratios of plasma [Arg]/[Orn] and other individual [FAA]/[Orn] were observed. LA and AA both affected sulfur FAA concentrations. Plasma cystine levels were significantly increased in the LA-supplemented groups. AA had little effect on most amino acids, and no interaction with LA was detected. AA supplementation did, however, significantly lower taurine (-42%) and cystathionine (-31%) levels in plasma. No effect on the branched chain:aromatic amino acid ratios was observed. The data indicate that at the dietary level studied, LA and AA independently affect selected plasma FAA in pacu, and suggest that any use of LA in particular as a dietary supplement should take into account an altered plasma FAA profile.

Different criteria for feed formulation based on digestible amino acids for broilers

An experiment was carried out to evaluate different criteria in feed formulation based on digestible amino acids for broilers during the grower phase. Diets were formulated according to the recommendations for digestible methionine, methionine + cysteine, lysine, and threonine. A total number of six hundred Cobb 500 male day-old chicks were distributed in a completely randomized experimental design, with three formulation criteria supplying the recommendations established by Baker & Chung (1992), Degussa (1997), and Rostagno et al. (2000), with 4 replicates of 50 birds each. No significant differences were observed for weight gain and feed intake. However, feed conversion ratio improved when birds were fed the diets containing the profiles recommended by Baker & Chung (1992) and Degussa (1997). No difference was observed in terms of leg, wings, back, and head yields. Broilers fed with the profile of Baker & Chung (1992) presented worst breast yield, whereas those fed the Degussa (1997) standard had better carcass yield.

Free Amino Acids in Pacu, Piaractus mesopotamicus, Eggs and Larvae

Free amino acids (FAA) are used principally as substrate in protein synthesis and the source of energy in aerobic catabolism. In marine fish, embryo and larvae FAA are used to maintain body fluid osmolality during fish early development. However, there is essentially no information about FAA concentrations in early ontogeny of freshwater neotropical species in comparison to marine fishes. Therefore, the aim of this study was to evaluate the FAA concentrations in pacu, Piaractus mesopotamicus, eggs and larvae. Broodstock fish were induced to spawn and ovulated females were stripped of their eggs and immediately sampled for analysis. Larvae were sampled right after hatching (HL) and after the completion of the yolk-sac absorption (YSA). The wet weight of the HL and YSA larvae amounted to 0.5±0.1mg and 1.1±0.3mg, respectively. HL larvae showed higher levels of most of the indispensable amino acids (IAA) in comparison to eggs and YSA larvae. Exceptions were observed with His and Trp that showed higher or similar levels, respectively, in YSA larvae. The FAA Orn, Tau, Glu, Gln, Gly, and Tyr increased concentrations in both larval stages while that of Tau was found in higher concentration in all analyzed stages. Also, the concentrations of Asn, Ala, Pro, Ser, and Asp were higher in HL larvae. Both larval stages displayed a rise in total free IAA/total free DAA (dispensable amino acids) ratio. The authors conclude that the highest level of FAA in HL pacu larvae is indicative of active proteolysis of yolk reserves and a probable catabolism regulation of some FAA through spare-effect. In addition, Tau is one of the major FAA occurring during pacu ontogeny and may be performing regulation on body fluid osmolality regulation. © Copyright by the World Aquaculture Society 2013.

Transport of amino acids from milk whey by Caco-2 cell monolayer after hydrolytic action of gastrointestinal enzymes

The bioavailability of amino adds from milk whey protein hydrolysates was evaluated using diffusion of the substances through semi-permeable membranes (dialyzability) and transport by Caco-2 cell cultures. The hydrolysates with low degree of hydrolysis (LDH) and high degree of hydrolysis (HDH) were obtained after 120 min of reaction time at 50 degrees C after the initial addition of pepsin, followed by the addition of trypsin, chymotrypsin and carboxypeptidase-A. The proteins and hydrolysates were further subjected to in vitro digestion with pepsin plus pancreatin. HPLC was used to determine the concentrations of dialyzable amino adds (48.4% of the non-hydrolyzed proteins, 63.2% of the LDH sample and 58.3% of the HDH sample), demonstrating the greater dialyzability of the hydrolysates. The LDH and HDH whey protein hydrolysates prepared with pepsin, trypsin, chymotrypsin and carboxypeptidase-A showed only 14.7% and 20.8% of dialyzable small peptides and amino acids, respectively. The efficiency of absorption was demonstrated by the preferential transport of Ile, Lou and Arg through a layer of cells. In the LDH hydrolysate, Tyr was also transported. Prior high- and low-degree hydrolysis of the whey provided transport by 5.7% and 6.6%, respectively, in comparison with 23% for non-hydrolyzed proteins, considering the total amount of these amino adds that was applied to the cells. (C) 2014 Elsevier Ltd. All rights reserved.

Amino acids in interstitial waters from ODP Sites 126-790 and 126-791

Sites 790 and 791 lie in the eastern half graben of the Sumisu Rift, a backarc graben west of the active Izu-Bonin arc volcanoes Sumisu Jima and Tori Shima, at 30°54.96'N, 139°50.66'E, in 2223 m water depth and 30°54.97'N, 139°52.20'E, in 2268 m water depth, respectively. A small decrease in the sulfate concentration in the interstitial waters from these sites suggests fairly low microbial activity by sulfate-reducing bacteria. The values of the dissolved free amino acids (DFAA) in the interstitial waters from both sites range from 1.26 to 6.82 µmol/L, with an average of 3.81 µmol/L. The acidic, basic, neutral, aromatic, and sulfur-containing amino acids have average values of 0.32, 0.50, 2.71, 0.15, and 0.09 µmol/L, respectively. The relative abundances of the acidic, basic, neutral, aromatic, and sulfur-containing amino acids average 8, 13,72, 4, and 1 mol%, respectively. Glycine, serine, alanine, ornithine, and aspartic acid are major constituent amino acids. The dissolved combined amino acids (DCAA) values range between 1.25 and 44.35 µmol/L, with an average of 10.36 µmol/L. The mean concentrations and relative abundances of the acidic, basic, neutral, aromatic, and sulfur-containing amino acids are 2.29 (22 mol%), 0.60 (6 mol%), 6.70 (65 mol%), 0.09 (1 mol%), and 0.00 µmol/L (0 mol%), respectively. Glycine is the most abundant amino acid residue, followed by glutamic acid, serine, and alanine. The predominance of DCAA over DFAA present in the interstitial waters from Sites 790 and 791 is consistent with previous results from interstitial-water and seawater analyses. The most plausible source for the DCAA is biogenic calcareous debris. A much greater depletion of aspartic acid and the basic fraction, except for ornithine, is found in the DCAA. The decomposition of the basic amino acid fraction or its incorporation to clay minerals would result in a decrease in its relative abundance, whereas ornithine is produced during early diagenesis. The characteristics of the amino acids in the interstitial waters are (1) a greater depletion of the acidic amino acid fraction in the DFAA than in the DCAA and (2) the enrichment of glycine and serine in both. The adsorption or reaction of the amino acids in interstitial waters with biogenic carbonates would be responsible for the lower relative abundance of the acidic fraction of the DFAA. The production of glycine during early diagenesis and its stability in solution would raise its relative abundance in the interstitial waters.

Amino acids and carbohydrates in sediments and interstitial waters of ODP Site 112-681

Total organic carbon (TOC), dissolved organic carbon (DOC), total hydrolyzable amino acids (THAA), amino sugars (THAS), and carbohydrates (THCHO) were measured in sediments and interstitial waters from Site 681 (ODP Leg 112). TOC concentrations vary between 0.75% and 8.2% by weight of dry sediment and exhibit a general decrease with depth. DOC concentrations range from 6.1 to 49.5 mg/L, but do not correlate with TOC concentrations in the sediment. Amino compounds (AA and AS) and sugars account for 0.5% to 8% and 0.5% to 3% of TOC, respectively, while amino compounds make up between 2% and 27% of total nitrogen. Dissolved hydrolyzable amino acids (free and combined) and amino sugars were found in concentrations from 3.7 to 150 µM and from 0.1 to 3.7 µM, respectively, and together account for an average of 8.5% of DOC. Dissolved hydrolyzable carbohydrates are in the range of 6 to 49 µM. Amino acid spectra are dominated by glycine, alanine, leucine, and phenylalanine; nonproteinaceous amino acids (gamma-amino butyric acid, beta-alanine, and ornithine) are enriched in the deeper part of the section, gamma-amino butyric acid and beta-alanine are thought to be indicators of continued microbial degradation of TOC. Glycine, serine, glutamic acid, alanine, aspartic acid, and ornithine are the dominating amino compounds in the pore waters. Spectra of carbohydrates in sediments are dominated by glucose, galactose, and mannose, while dissolved sugars are dominated by glucose and fructose. In contrast to the lack of correlation between abundances of bulk TOC and DOC in corresponding interstitial waters, amino compounds and sugars do show some correlation between sediments and pore waters: A depth increase of aspartic acid, serine, glycine, and glutamic acid in the pore waters is reflected in a decrease in the sediment, while an enrichment in valine, iso-leucine, leucine, and phenylalanine in the sediment is mirrored by a decrease in the interstitial waters. The distribution of individual hexoseamines appears to be related to zones of bacterial decomposition of organic matter. Low glucoseamine to galactoseamine ratios coincide with zones of sulfate depletion in the interstitial waters.