Takarmánypremixek anorganikus szeléntartalmának spektrofotometriás meghatározása

A takarmánypremixekben nátrium-szelenitként jelenlevő szelént híg sósavas kioldás után 2,3-diamino-naftalin felhasználásával spektrofotometriásán határoztuk meg. A zavaró nehézfém-ionok eltávolítását vagy cink-hexaciano-ferrát(II) kollektor-csapadék alkalmazásával, vagy H+-formára hozott, erős kationcserélő műgyanta segítségével eszközöljük. Mindkét módszer megbízhatósága megfelel a gyakorlati követelményeknek. The selenium present in the feed premixes as sodium-selenite was determined with spectrophotometry using 2,3-diamino-naphthalene after an extraction with diluted hydrocloric acid. The heavy metal ions disturbing the examination can be removed using either zitic-ferrocyanide collector precipitate or cation exchange resin in H+ form. The reliability of both methods meets the practical requirements. Das in Futtermittelvormischungen als Natriumselenit vorhandene Selen wird nach Extraktion mit verdünnter Salzsäure unter Anwendung von 2,3-DiaminoNaphtalin spektrophotometrisch bestimmt. Die Entfernung der störenden Schwermetallionen wurde entweder m it Zinkhexacyanoferrat (II) — Kollektor-Niederschlag oder m it in H+ gebrachten starkem Kationaustauscher durchgefürt. Die Zuverlässigkeit beider Methoden erfüllt die praktischen Anforderungen

EFFECT OF MICROORGANISMS ON FREE AMINO ACID AND FREE D-AMINO ACID CONTENTS OF VARIOUS DAIRY PRODUCTS

Free amino acid and free D-amino acid contents of milk samples with different microorganism numbers and composition of dairy products produced from them were examined. Total microorganism number of milk samples examined varied from 1.25x106 to 2.95x106. It was established that concentration of both free D-amino acids and free L-amino acids increased with an increase in microorganism number. However, increase in D-amino acid contents was higher considering its proportion. There was a particularly significant growth in the microorganism number range from 1.5x106 to 2.9x106. Based on analysis of curds and cheese samples produced using different technologies we have come to the conclusion that for fresh dairy products and for those matured over a short time there was a close relation between total microorganism number and free D-amino acid and free L-amino acid contents. At the same time it was found that the ratio of the enantiomers was not affected by the total microorganism number. For dairy products, however, where amino acid production capability of the microbial cultures considerably exceeds, production of microorganisms originally present in the milk raw material, free amino acid contents of the milk product (both D- and L-enantiomers) seem to be independent of the composition of milk raw material

CHANGES IN FATTY ACID COMPOSITION OF DIFFERENT MILK PRODUCTS CAUSED BY DIFFERENT TECHNOLOGY

The fatty acid composition of cow’s milk with fat contents of 3.6%, Dalia cheese with fat contents of 44%, butter with fat contents of 80% and margarine with fat contents of 24% was determined after a heat treatment performed on cooking plate and microwave treatment, respectively of different durations. The biggest difference was obtained for oleic acid and elaidic acid since, with the exception of the margarine, in each case proportion of the cis-configurated oleic acid decreased while that of the trans-configurated elaidic acid increased. For all of the other fatty acids in the foodstuffs examined no such differences were obtained regarding change in fatty acid composition whose differences could influence healthy nutrition to considerable extent. Therefore we can take it as a fact that neither heat treatment performed on a traditional cooking plate nor microwave treatment affects considerably the composition of food fats