magistrsko delo
Sabina Jurak (Avtor), Matjaž Kristl (Mentor), Janja Kristl (Komentor)

Povzetek

V magistrski nalogi smo določili vsebnost Ca, Mg in P v jajčni lupini. Namen magistrskega dela je bil preučiti, ali imata način vzreje kokoši in vrsta perutnine (prepelice in race) vpliv na mineralno sestavo jajčne lupine. S statističnim programom R smo primerjali vsebnosti Ca, določenega s titracijo in plamensko atomsko absorpcijsko spektrometrijo (FAAS), z izgubo mase, izmerjeno s termogravimetrično analizo (TG). V raziskavo smo vključili pet jajc iz ekološke, proste, hlevske in baterijske reje kokoši nesnic, ki so bile iste pasme in starosti ter pet prepeličjih, račjih in sedemnajst nekvalificiranih jajc. Jajcem smo fizično odstranili beljak, rumenjak in notranji membrani. Lupine smo pri 100 °C posušili do konstantne mase in jih zmleli v fini prah. Vsebnost CaCO3 smo določili s titracijo. Vzorec smo raztopili v 1 M HCl in presežek kisline titrirali s standardno raztopino NaOH (0,1 M). Pred meritvami vsebnosti Ca, Mg in P smo naredili kislinski razklop vzorcev. Koncentracije Ca in Mg smo izmerili z AAS in P z merjenjem absorbance rumeno obarvanega kompleksa pri valovni dolžini 406 nm. Pri merjenju izgube mase s TG smo uporabili temperaturno območje od 30 °C do 900 °C. Način reje kokoši ni imel značilnega vpliva na vsebnost Ca v jajčni lupini. Značilne razlike opazimo med vrstami perutnine in pri nekvalificiranih jajcih. Značilno najnižja vsebnost Ca je bila v jajčni lupini prepeličjih jajc. Najvišja vsebnost Mg je bila v lupini prepeličjih jajc in najnižja v lupini račjih jajc. Povprečne vrednosti P v jajčnih lupinah se statistično razlikujejo glede na vrsto perutnine. Najvišja vsebnost je v lupini prepeličjih jajc. Statistična primerjava vsebnosti CaCO3, ki smo jo določili s titracijo, in izmerjene izgube mase je pokazala, da je napaka, ki jo naredimo, če vsebnost CaCO3 v jajčni lupini izračunamo iz izgube mase, ki jo izmerimo s TG v temperaturnem območju od 550 °C do 900 °C, 0,1 %.

Ključne besede

termogravimetrična analiza;jajčne lupine;kalcijev karbonat;atomska absorpcijska spektrometrija;magistrske naloge;

Podatki

Jezik: Slovenski jezik
Leto izida:
Tipologija: 2.09 - Magistrsko delo
Organizacija: UM FKKT - Fakulteta za kemijo in kemijsko tehnologijo
Založnik: [S. Jurak]
UDK: 543.573(043.2)
COBISS: 22201622 Povezava se bo odprla v novem oknu
Št. ogledov: 1082
Št. prenosov: 171
Ocena: 0 (0 glasov)
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Ostali podatki

Sekundarni jezik: Angleški jezik
Sekundarni naslov: The use of thermogravimetric analysis in determination of properties of eggshells relative to the production system of hens
Sekundarni povzetek: In the master's thesis, we determined the content of Ca, Mg in P in the egg shell. The purpose of the master's thesis was to study if the production system of hens and different type of poultry (quails and duck) has any influence on the mineral composition of the eggshell. With the statistical program R, we have compared the Ca content, which was determined by titration, and flame atomic absorption spectrometry (AAS) with the weight loss measured by a thermogravimetric analysis (TG). We included five eggs from organic farming, free range production, deep-litter system and battery-cage system, which were the same breed and age, and five quail eggs, five duck eggs and seventeen unclassed eggs. We physically removed the white, the yolk and the inner and outer shell membrane from the eggs. The empty eggshells were dried at 100 °C to a constant mass and milled into fine powder. The CaCO3 content was determined by titration. The sample was dissolved in 1 M HCl and titrated the excess acid with a standard NaOH solution (0.1 M). Before the measurements of the Ca, Mg and P content, the acid digestion of the samples was done. The Ca and Mg concentrations were measured with AAS and P by measuring the absorbance of the yellow-colored complex at a wavelength of 406 nm. The temperature ranging from 30 °C to 900 ° C was used to measure the loss of mass with TG. The production system of hens did not have a significant influence on the content of Ca in the eggshell. Characteristic differences are observed between types of poultry and unclassed eggs. The characteristic lowest of Ca content was in the shell of quail eggs. The maximum of Mg content was in the shell of quail eggs and the lowest in the shell of duck eggs. The average values of P in eggshells are statistically different depending on the type of poultry. The highest content is in the shell of quail eggs. A statistical comparison of the CaCO3 content determined by titration and the measured mass loss showed that the error that we make if the content of CaCO3 in the egg shell is calculated from the loss of mass measured with TG in the temperature range from 550 °C to 900 °C, 0,1 %.
Sekundarne ključne besede: thermogravimetric;eggshell;calcium carbonate;atomic absorption spectrometry;
URN: URN:SI:UM:
Vrsta dela (COBISS): Magistrsko delo/naloga
Komentar na gradivo: Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Strani: X, 50 str.
ID: 11026801