Fluorescencija peptidne frakcije kravljeg i kozjeg mlijeka (CROSBI ID 362183)
Ocjenski rad | diplomski rad
Podaci o odgovornosti
Eškit, Marina
Strelec, Ivica
hrvatski
Fluorescencija peptidne frakcije kravljeg i kozjeg mlijeka
Cilj istraživanja bio je ustanoviti može li se fluorescencijom i određivanjem intenziteta fluorescencije peptidne frakcije mlijeka, te u njoj prisutne količine ukupnog amino dušika kao i peptida/proteina detektirati zamjena dijela kozjeg sa kravljim mlijekom, te odrediti donji limit detekcije. Analizirane su peptidne frakcije kravljeg mlijeka (sirovo, pasterizirano, UHT i rekonstiturano) i kozjeg mlijeka (sirovo, UHT). Peptidne frakcije dobivene su taloženjem sa 40 % TCA te centrifugiranjem pri 3000 g. Analizom spektra fluorescencije i određivanjem intenziteta fluorescencije dokazano je da se peptidne frakcije kravljeg i kozjeg mlijeka razlikuju. Spektri fluorescencije peptidne frakcije kravljeg i kozjeg mlijeka pokazuju dva vrha fluorescencije. Dominantni vrh fluorescencije peptidne frakcije kravljeg mlijeka nalazi se pri 280/425 nm, a kozjeg mlijeka 290/390 nm, što je naknadno dokazano normalizacijom intenziteta fluorescencije. Peptidna frakcija kozjeg mlijeka sadrži više ukupnog amino dušika i pokazuje pet do deset puta veći intenzitet fluorescencije pri 290/340 i 290/390 nm za razliku od kravljeg mlijeka. Donji limit detekcije za određivanje patvorenja kozjeg mlijeka sa kravljim pri 290/340 nm i pri 290/390 nm iznosio je 10 %.
fluorescencija; patvorenje; peptidna frakcija; kravlja i kozja mlijeka
nije evidentirano
engleski
Fluorescence of peptide fraction of cow's and goat's milk
The aim of the study was to determine the possibility of detection of goat milk alduteration with cow’s milk by fluorescence measurement of non-protein nitrogen (NPN) fraction of milk, and in the content of total amino nitrogen, as well as to determine the lower limit of substitution detection. NPN fractions were obtained by precipitation with 40% TCA followed by the centrifugation at 3000 g. The NPN fractions of cow's milk (raw, pasteurized, UHT and reconstitution) and goat's milk (raw, UHT) were investigated. The analysis of the fluorescence spectrum and intensity of fluorescence showed that cow and goat milk NPN fractions differs in fluorescence intensity and fluorescence peaks wavelenghts. Fluorescence spectra of peptide fractions of cow's and goat's milk showed two peaks of fluorescence. Dominant peak of fluorescence of peptide fractions of cow's milk was centered at 280/425 nm and at 290/390 nm for goat milk. Peaks were confirmed by normalization of fluorescence intensities. NPN fraction of goat's milk contains higher amount of total amino nitrogen compared to cow’s milk. Fluorescence intenisity of goat’s milk NPN fractions were five to ten-fold higher compared to intensities of cow’s milk NPN fractions. The lower limit of detection for the determination of adulteration of goat milk with cow's milk at 290/340 and at 290/390 nm was 10%.
Fluorescence; adulteration; peptides fractions; cow´s and goat´s milks
nije evidentirano
Podaci o izdanju
62
06.12.2010.
obranjeno
109:210313
Podaci o ustanovi koja je dodijelila akademski stupanj
Prehrambeno-tehnološki fakultet Osijek
Osijek
