Določanje skupnih ogljikovih hidratov v pivu

diplomsko delo univerzitetnega študijskega programa

Neja Tevž (Author), Mitja Kolar (Mentor), Iztok Jože Košir (Co-mentor)

Abstract

Namen diplomskega dela je razvoj in vpeljava UV-VIS sprektrofotometrično metode za določanje skupnih ogljikovih hidratov v pivu. Vpeljali smo jo z namenom, ker morajo biti po novi evropski zakonodaji za označevanje živil in pijač, vse hranilne vrednosti živil in pijač jasno podane na emabalaži le teh. Metoda temelji na merjenju absorbance kompleksa antrona in prisotnih ogljikovih hidratov v pivu pri 625 nm, z uporabo eksternega standarda. Eden izmed namenov diplomskega dela je tudi validacija metode, ki je podana z nekaterimi osnovnimi parametri, kot so natančnost, točnost, obnovljivost, ponovljivost, heteroscedastičnost, mejo določljivosti (LOQ) in mejo zaznavnosti (LOD), za katero pa smo že na začetku dela ugotovili, da je ni potrebno določevati, saj je v vseh realnih vzorcih koncentracija analita tako visoka, da je dosti nad mejo določljivosti in pade v naše merilno območje. Z izdelavo umeritvene krivulje smo potrdili, da je merilno območje metode ustrezno linearno na širšem območju, od 5-125 mg/l in ne le od 20-80 mg/L, kot je to podano v osnovni metodi. Z optimizacijo metode smo preverili čas obstojnosti barvnega kompleksa in čas segrevanja raztopin. Preverili smo ali je pomembno vzorce pred delom ohlajati, in ali je pred vsakim merjenjem potrebna priprava svežega reagenta. Posneli smo tudi spektre čiste raztopine reagenta in vzorca, kjer smo pokazali, da sam reagent absorbira pri drugi valovni dolžini, kot vzorec, kjer je razvit barvni kompleks in s tem potrdili selektivnost metode.

Keywords

spektrometrija;ogljikovi hidrati;pivo;validacija;antron;

Data

Language:	Slovenian
Year of publishing:	2015
Typology:	2.11 - Undergraduate Thesis
Organization:	UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher:	[N. Tevž]
UDC:	543.544.3:663.476(043.2)
COBISS:	19034902
Views:	1296
Downloads:	139
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	THE DETERMINATION OF THE TOTAL CARBOHYDRATE CONTENT IN BEER
Secondary abstract:	The purpose of the thesis is the development and introduction of the UV-VIS spectrophotometric method, for the determination of total carbohydrates in beer. We introduced it with a purpose, because all of the nutritional values of food and beverages must be clearly specified on the packaging, due to the new European legislation on labeling of foods and drinks. The method is based on measuring the absorbance of the complex Anthrone and carbohydrate in beer at 625 nm, using an external standard. One of the purposes of the thesis is the method validation, which is performed with certain basic parameters, such as precision, accuracy, reproducibility, repeatability, heteroscedasticity, the limit of quantification (LOQ) and the limit of detection (LOD), for which we already, at the beginning of our work determined, that it is not necessary to define, since all real samples contain the analyte concentration well above the limit of quantification, and that it falls in our measurement range. With the preparation of the calibration curve we confirmed, that the measurement range of the method is adequate linear to a broader range, from 5-125 mg/l, and not only from 20 to 80 mg/L, as is given in the basic method. By optimizing the method we tested time stability of the colour complex, and heating time of the solutions. We checked, whether it is important to cool the samples before working, and whether before each measurement, the preparation of a fresh reagent is obligatory. We recorded the spectra of the pure solution of the reagent and sample, where it was shown that a single reagent is absorbed in a different wavelength, as the sample where the color complex is developed, thus confirming the selectivity of the method.
Secondary keywords:	spectrophotometry;carbohydrates;beer;validation;anthrone;
URN:	URN:SI:UM:
Type (COBISS):	Bachelor thesis/paper
Thesis comment:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages:	VIII, 36 str.
ID:	8888731