The influence of the operation conditions (temperature and residence time) of a thermic treatment on the total amount (free and protein-bound) of amino acid enantiomers of dry fullfat soya was investigated. Total amino acid content was determined using conventional ion-exchange amino acid analysis of total hydrolysates and chiral amino acid analysis was performed by HPLC after precolumn derivatization with o-phthaldialdehyde and 1-thio-beta-D-glucose tetraacetate. Contrary to corn that was investigated previously, notable racemization was detected even at lower temperatures. At 140 degrees C the ratio of the D-enantiomer was 0.87% for glutamic acid, 2.81% for serine, and 1.92% for phenylalanine; at 220 degrees C the ratios of the D-enantiomer of the above amino acids were 1.43, 4.61, and 4.68%, respectively. The concentration of several L-amino acids decreased. At 220 degrees C there was 10% less L-glutamic acid, 17% less L-serine, 5% less L-phenylalanine, 6.6% less L-aspartic, acid and 21% less L-lysine than in the control; their loss can be assigned to different degrees of L - D conversion. While nearly complete transformation of L-phenylalanine can be attributed to racemization, the main cause of the loss of L-lysine is not racemization. The treatments in the same order of magnitude resulted in the formation of more D-amino acids and greater extent of racemization of amino acids in fullfat soya than that of maize.
Abstract. In total, 30 Hungarian Simmental bulls were reared to 300.07 ± 43.78 kg initial live weight and 274.57 ± 19.73 d of age. Animals were distributed into three feeding groups with different maize silage to concentrate ratios (670 : 330 = F/ HC; 750 : 250 = F/ LC 1; 800 : 200 = F/ LC 2) based on dry matter. The low concentrate groups (F/ LC 1 and F/ LC 2) received linseed supplemented concentrate during the fattening period. Feeding high concentrate (F/ HC) caused the significantly highest daily gain. The slaughter weights, dressing (%), lean (%) and fat (%) did not show any significant differences between feeding groups. Carcass conformation of all groups was assessed mainly as U. Bulls of group F/ LC 2 had the lowest amount of kidney fat. Bone proportion of the carcasses was affected by the diet (F/ HC: 18.65 %; F/ LC 1: 18.41 %; F/ LC 2: 17.91 %). The tendon proportions were lower in groups F/ LC 1 and F/ LC 2 but not significantly (F/ HC: 1.15 %; F/ LC 1: 1.1 %; F/ LC 2: 1.08 %). The intramuscular fat content varied between the three muscles investigated. Psoas major muscle contained the highest fat concentration in all three feeding groups. The mineral content of muscles (iron [Fe], copper [Cu], zinc [Zn]) was only affected by muscle type, but not by diet. In linseed supplemented groups (F/ LC 1 and F/ LC 2) the palmitic acid and palmitoleic acid proportion was decreased (P<0.05) in all muscles and the linolenic, eicosapentaenoic and the sum of n-3 fatty acid (P<0.05) was increased compared to the F/ HC group. The beef from groups F/ LC 1 and F/ LC 2 bulls showed a lower n-6 to n-3 fatty acids ratio (P<0.05). The relative and absolute concentration of CLAcis-9,trans-11 was unaffected by diet but muscle type caused changes.
Abstract. The changes in the concentration and that of composition of alanine, aspartic acid and glutamic acid enantiomers were investigated during manufacture of Cheddar cheese. The amount of D-alanine increased continuously during ripening following the liberation of L-alanine originated from the proteolysis of milk proteins. There was slightly more D-aspartic and D-glutamic acid in the dry matter of curd after pressing than before pressurization. The D-amino acid content and the ratio of the D-enantiomers related to the total amount of free amino acids differed significantly among cheeses produced with different single-strain starters. The D-amino acid composition changed during manufacture, but the influence of the strain selection was not significant on the D-amino acid pattern.
Weaned piglets (n = 3 × 6) were fed 0, 15 and 30 mg/kg diet fumonisin (FB1, FB2 and FB3, i.e., FBs, a sphinganine analogue mycotoxin), from the age of 35 days for 21 days, to assess mycotoxin induced, dose-dependent changes in the red cells’ membrane. Ouabain sensitive Na+/K+ ATPase activity was determined from lysed red cell membranes, membrane fatty acid (FA) profile was analysed, as well as antioxidant and lipid peroxidation endpoints. Final body weight was higher in the 30 mg/kg group (vs. control), even besides identical cumulative feed intake. After 3 weeks, there was a difference between control and the 30 mg/kg group in red cell membrane sodium pump activity; this change was dose-dependent (sig.: 0.036; R2 = 0.58). Membrane FA profile was strongly saturated with non-systematic inter-group differences; pooled data provided negative correlation with sodium pump activity (all individual membrane n6 FAs). Intracellular antioxidants (reduced glutathione and glutathione peroxidase) and lipid peroxidation indicators (conj. dienes, trienes and malondialdehyde) were non-responsive. We suppose a ceramide synthesis inhibitor (FB1) effect exerted onto the cell membrane, proven to be toxin dose-dependent and increasing sodium pump activity, with only indirect FA compositional correlations and lack of lipid peroxidation.
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