Vrednotenje barve rumenjakov

diplomsko delo

Anja Gašperlin (Author), Lea Demšar (Reviewer), Jasna Bertoncelj (Mentor)

Abstract

Jajca spadajo med živila z veliko biološko in prehransko vrednostjo. So bogat vir beljakovin, vitaminov in mineralov ter esencialnih maščobnih kislin in aminokislin. Barva jajčnih rumenjakov je eden od parametrov kakovosti jajc, odvisna je od sestave krme, predvsem vsebnosti barvil, načina reje kokoši ter genetskih vplivov. V eksperimentalnem delu diplomskega dela smo ovrednotili barvo rumenjakov s pomočjo barvne pahljače, instrumentalno s kromometrom Minolta ter s spektrofotometrično določitvijo vsebnosti β-karotena z metodo AOAC. Rezultati so pokazali, da se pojavljajo razlike v barvi rumenjaka glede na način reje kokoši. Najbolj opazne razlike so bile med jajci ekološke in baterijske reje. Rumenjaki jajc iz ekološke reje so bili najsvetlejši in so vsebovali najmanj karotenoidov, rumenjaki jajc iz baterijske reje pa so bili najtemnejši, z največjo vsebnostjo karotenoidov. Barvo rumenjakov smo ovrednotili tudi senzorično. Senzorični panel so sestavljali študenti študija Živilstva in prehrane, ki so razvrščali rumenjake po intenzivnosti in všečnosti barve. Prednost so dali rumenjakom oranžno-rumene barve. Dodatno so študenti izpolnili tudi anketni vprašalnik o uživanju in nakupu jajc. Rezultati ankete so pokazali, da študentje jajc ne uživajo pogosto. Z jajci se preskrbujejo z nakupom v trgovini ali pa jih dobijo od sorodnikov, znancev. Večina uživa jajca iz proste in talne reje. Najpomembnejši kriterij za nakup jajc večini anketiranih predstavlja način reje.

Keywords

jajca;rumenjak;barva;karotenoidi;spektrofotometrija;kromometer;barvna pahljača;senzorična analiza;potrošniki;

Data

Language:	Slovenian
Year of publishing:	2018
Typology:	2.11 - Undergraduate Thesis
Organization:	UL BF - Biotechnical Faculty
Publisher:	[A. Gašperlin]
UDC:	637.41:547.979.8:543.2/.9
COBISS:	4921464
Views:	1161
Downloads:	395
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Evaluation of egg yolk colour
Secondary abstract:	Eggs are nutrient-dense food with high biological value. They are a rich source of protein, vitamins, minerals, essential fatty acids and amino acids. The colour of egg yolks is an important parameter of egg quality. It is affected by the composition of poultry feed, mostly the pigment content, egg farming method and genetic effects. In the experimental part the colour of egg yolks was evaluated using a DSM colour fan and Minolta chromometer, and the spectrophotometric determination of β-carotene content with the AOAC method. The results showed that there are differences in egg yolks colour according to the egg farming method. The most noticeable differences were detected between organic and caged eggs. Organic egg yolks were the brightest and contained the least carotenoids, while cage eggs yolks were the darkest, with the highest content of carotenoids. The colour of egg yolks was also evaluated with sensory analysis. The sensory panel consisted of students of Food Science and Nutrition who ranked the samples according to the intensity and likeness of the yolk colour. The students gave preference to orange-yellow colour of egg yolk. They also completed a questionnaire about consumption and purchase of eggs. The results showed that students do not consume eggs often. They buy eggs in the markets or get them from relatives or acquaintances. Most of the students consume free-range or barn eggs. The most important criterion for the purchase is egg farming method.
Secondary keywords:	eggs;egg yolk;colour;carotenoids;spectrophotometry;chromometer;colour fan;sensory analysis;consumers;
Type (COBISS):	Bachelor thesis/paper
Study programme:	0
Thesis comment:	Univ. v Ljubljani, Biotehniška fak., Oddelek za živilstvo
Pages:	VIII, 25 f., [6] str.
ID:	10942577