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Photocolorimetric determination of yolk colour in relation to selected quality parameters of eggs
Author(s) -
Dvořák Petr,
Doležalová Jana,
Suchý Pavel
Publication year - 2009
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.3668
Subject(s) - yolk , mathematics , breed , gloss (optics) , zoology , food science , chemistry , biology , organic chemistry , coating
Abstract BACKGROUND: Determination of egg yolk colourity and colour was carried out by means of a new photocolorimetric methodology based on the CIELAB system. Measurements (after gloss elimination) were performed using a Color Guide Sphere Spex photocolorimeter. For comparison, a standard method according to the Yolk Colour Fan ® (Roche) was used. RESULTS: Yolk colourity was measured in 252 eggs from layers of Isa Brown breed (aged 51–80 weeks). The colourity parameter L * ranged from 43.42 to 68.51. The parameter a * ranged from 0.05 to 13.49 and the parameter b * ranged from 22.38 to 48.18. The normal (Gaussian) distribution curve for the individual parameters was validated. The resulting number of 8700 combinations of yolk colour parameters was given by multiplication of possible results in the experiment while taking into account the instrumental accuracy. All results according to the Yolk Colour Fan ® (Roche) scale represented a range of three colour stripes. CONCLUSION: The photocolorimetric determination is more precise than the Yolk Colour Fan ® (Roche) method. No correlation between yolk colourity parameters and yolk cholesterol concentration was found. The highest correlation ( r = −0.919) was observed between yolk colourity parameter b * (yellow colour) and total egg weight. Copyright © 2009 Society of Chemical Industry