The California Mastitis Test was used as an indicator of mastitis. Five cows were chosen for each of the five scores from 0 to 4. Milk samples were analysed for free amino acids and free D-amino acids. The contents of free amino acids, free D-amino acids and the ratio of free D-amino acids to free amino acids increased significantly as score increased. The free D-amino acids content of foremilk (first milk jets) from nonmastitic cows (score = 0) was approximately five times that of samples drawn later from the same udders.

Protein is one of the most valuable components of the fodder, therefore there is a concern preserving of these components in an available form during the different treatments wherein heating is applied. The aim of the research was to investigate the influence of toasting of fullfat soybean and air-drying of corn on the amino acid profile of the products. Dried corn was sampled at two Hungarian drying plants. The corn was dried with an industrial Babolna B1-15 type gravitational dry- ing tower. The influence of toasting on two sorts of fullfat soybean products (hydrothermic soy coarse and natural hydrothermic soy) was investi- gated. Soybeans were heat processed with an industrial KAHL HR-1600

Free amino acid and total amino acid content, water soluble vitamin content (vitamin C, B1, B2, B6 and B12) and utilizable lysine, lysinoalanine and hydroxymethyl furfurol content of milk were examined after the samples were pasteurized using different heat treatment. They analyzed the effect of microwave treatment on the amino acids, free amino acid content and biological value compared to the conventional heat treatment technology. In was established that the two applied heat treatments caused practically no change in the amino acid composition of the milk protein neither in case of the essential nor in the case of the non-essential amino acids. The total free amino acid content of the raw milk (20.67 mg/100 g milk) reduced in the milk pasteurized in the traditional way to 8.02, whereas in the microwave pasteurized milk to 8.96 mg amino acid/100 g milk.

A kutatas soran megvalositottuk a Trp-enantiomerek elvalasztasat a feherjekben előfordulo egyeb aminosavaktol 1-tio-beta-D-glukoz-tetraacetattal es o-ftalaldehiddel kepzett diasztereoizomerek formajaban. Megvizsgaltuk a legnagyobb kitermelessel jaro savas feherjehidrolizis-modszereket a Trp-enantiomerek meghatarozasa szempontjabol. Merkapto-etan-szulfonsav jelenleteben nem megy vegbe a szarmazekkepzesi reakcio, a MES-felesleg megkoteset, eltavolitasat csak nagyon nehezen lehet megoldani. A p-toluol-szulfonsavas modszert vizsgaltuk onmagaban, ill. triptamin es 3-indol-propionsav vedőreagens jelenleteben. PTS jelenlete a szarmazekkepzest nem zavarta, azonban csupan PTS-at alkalmazva hidrolizalo reagenskent a Trp visszanyerese nagyon alacsony. Amennyiben triptamint is adunk a rendszerhez a hidrolizis soran a Trp indolgyűrűjenek megvedese erdekeben, a szarmazekkepzeskor csapadek kepződott, igy az elvalsztast HPLC-vel nem tudtuk megvalositani. 3-indol-propionsavat alkalmazva vedőreagenskent a szarmazekkepzes lejatszodott, a triptofan visszanyerese 75% felettinek adodott. A fentieken tul vizsgaltuk a Trp racemizaciojat szabad formaban es feherjeben kotve modelloldatokkal, valamint kulonboző ideig sutott husokban, illetve lugosan kezelt vagohidi hulladekokban. | During the research we accomplished the separation of the enantiomers of Trp from the other protein amino acids, in the form of diastereoisomers formed with 1-thio-beta-D-glucose tetra acetate and o-phtaldialdehyde. We examined the acidic protein hydrolysis methods providing the highest recovery in respect of determination of Trp enantiomers. In the presence of 2-mercaptoethane sulfonic acid (MESA) no derivatization takes place, the excess of MESA can be eliminated with much difficulty only. The p-toluenesulfonic acidic (pTSA) method was examined without using a protecting agent, and in the presence of protecting agents tryptamine and 3-indolyl propionic acid, respectively. The presence of pTSA does not disturb the derivatization, however, if solely pTSA is used as hydrolyzing agent, the recovery of Trp is very low. If also tryptamine was added in order to protect the indole group of Trp during the hydrolysis, precipitation occurred during the derivatization, so the separation was not possible by HPLC. If 3-indolyl propionic acid is applied as protecting agent, the derivatization takes place with a recovery above 75% for Trp. Beyond the above, we also examined racemization of free and protein-bound Trp with model solutions, as well as in meats fried for different durations, and in alkaline treated slaughterhouse waste material, respectively.

Performic acid oxidation of cysteine and methionine resulting in the formation of cysteic acid and methionine sulphon has been applied in order to avoid the loss of these two sulphur containing amino acids during the acidic hydrolysis of proteins that is necessary prior to amino acid analysis. The aim of the research was assigned by the increasing demand for the determination of the amount of amino acid enantiomers: the applicability of performic acid oxidation was evaluated from this point of view. Racemization of L-cysteine and L-methionine was found not significant during oxidation with performic acid, therefore this process can be applied before hydrolysis during quantification of cysteine and methionine enantiomers. Additionally, the quantification of cysteic acid and methionine sulphon enantiomers was accomplished in the form of their diastereoisomer derivatives via the development of a reversed phase of high performance liquid chromatography method.

Abstract. Title of the paper: Effect of feeding on the composition of the intramuscular fat in longissimus muscle and different fatty tissues of Hungarian Grey and Holstein Friesian bulls. 1. Fatty acid profile The aim of this study was to analyse the effect of nutrition, genotype and nutrition x genotype interaction on the fatty acid composition of intramuscular fat from longissimus dorsi muscle and different fat deposits using Hungarian Grey cattle bulls (HG) in comparison to Holstein Friesian bulls (HF) kept under extensive and intensive conditions. The extensive group was kept on pasture and was fed a concentrate supplemented with linseed meal in the last month of the trial. The extensive diet influenced the linoleic and linolenic acid ratio and the CLA content of longissimus muscle more advantageous concerning human nutrition. The meat from HG contained more CLA and less n-6 fatty acids also in case of the intensive diet than that of HF bulls. In the fat deposits from HF the PUFA mainly the linoleic acid was in a significant higher proportion available, however in the fat deposits of HG was the percentage of linol- and linolenic acid favourable. The extensive nutrition resulted in a lower linoleic acid and a higher linolenic acid content in both breeds and all three fat deposits. The PUFA content in the fat samples was altered contrary in both analysed breeds because of the different diet. In case of the extensive UG was the PUFA higher in all three fat deposits. In conclusion, the fatty acid composition of beef can be modified favourably by extensive feeding and concentrate which is rich in unsaturated fatty acids, however the beef of Hungarian Grey has a more wholesome influence on human health, than that of Holstein-Friesian bulls.

The aim of this study was to analyse the effect of nutrition, genotype and nutrition x genotype interaction on the fatty acid composition of intramuscular fat from longissimus dorsi muscle and different fat deposits using Hungarian Grey cattle bulls (HG) in comparison to Holstein Friesian bulls (HF) kept under extensive and intensive conditions. The extensive group was kept on pasture and was fed a concentrate supplemented with linseed meal in the last month of the trial. The extensive diet influenced the linoleic and linolenic acid ratio and the CLA content of longissimus muscle more advantageous concerning human nutrition. The meat from HG contained more CLA and less n-6 fatty acids also in case of the intensive diet than that of HF bulls. In the fat deposits from HF the PUFA mainly the linoleic acid was in a significant higher proportion available, however in the fat deposits of HG was the percentage of linol- and linolenic acid favourable. The extensive nutrition resulted in a lower linoleic acid and a higher linolenic acid content in both breeds and all three fat deposits. The PUFA content in the fat samples was altered contrary in both analysed breeds because of the different diet. In case of the extensive UG was the PUFA higher in all three fat deposits. In conclusion, the fatty acid composition of beef can be modified favourably by extensive feeding and concentrate which is rich in unsaturated fatty acids, however the beef of Hungarian Grey has a more wholesome influence on human health, than that of Holstein-Friesian bulls.

Mercaptoethanesulfonic acid (MES-OH) can be applied for hydrolyzing proteins. The aim of our research was to examine if it can be used also as a derivatization reagent for fluorescens detection of amino acids together with OPA (o-phthaldialdehyde) instead of ME (mercaptoethanol) owning to its thiol-group. Corn, soybean and meatmeal samples were hydrolized with hydrochloric acid or MES-OH, derivatized with ninhydrin or OPA/ME or OPA/MES-OH and analysed with IEC (ion exchange chromatography) or RP-HPLC (reversed phase high performance liquid chromatography). There were no significant differences among the amino acid composition results of samples irrespective of choice of the hydrolysis or derivatization methods. MES-OH can be applied not only for hydrolysis but also for derivatization of amino acids. In case of samples with high protein content (>50%), due to the dilution after hydrolysis the MES-OH concentration could be insufficient for derivative formation, in these cases an extra MES-OH addition is required prior to derivatization.

In the quantitative analysis of cystine, cysteine and methionine content of foods and feeds, the sulphur containing amino acids are often oxidised by performic acid before hydrolysis of the protein to make the determination more punctual. The applicability of the performic acid oxidation to the quantification of the enantiomers of sulphur-containing amino acids has been examined. An reversed phase high performance liquid chromatography (RPHPLC) method was developed for determination of the amount of cysteic acid and methionine-sulphon enantiomers and the rate of the conversion during oxidation from cystine and cysteine into cysteic acid and from methionine to methionine-sulphon was determined. Racemization of the L-cysteine and Lmethionine was negligible during performic acid oxidation, and therefore the process can be applied before hydrolysis of the protein during quantification of enantiomers of sulphur containing amino acids. The separation between the acidic amino acids (Asp, Glu) and the oxidised from of the sulphur-containing amino acids at the applied gradient system is very good, and the resolution of the peaks were better than 1.4 in every case.

In recent decades several methods have been developed for determination of the proportion of nitrogen-containing substances passed from the rumen into the abomasum, or small intestine, which are of microbial origin. Recently, when examining thed-amino acid content of foodstuffs, particularly milk and milk products, it was observed that, in addition tod-alanine (d-Ala,d-glutamic acid (d-Glu) andd-aspartic acid (d-Asp) can also be detected in similar quantities, primarily in products which have links with bacterial activity. This gave rise to the idea of examining the diaminopimelic acid (DAPA),d-Glu, andd-Asp content of bacteria extracted from the rumen of cattle, and that of chyme from the same cattle, to establish whetherd-Asp andd-Glu can be used to estimate protein of bacterial origin.