title: Influence of pasteurization, spray- and freeze-drying, and storage on the carotenoid content in egg yolk.
abstract: A liquid chromatography-atmospheric pressure chemical ionization mass spectrometry [LC-(APCI)MS] method was developed to identify and quantify the carotenoids present in fresh, pasteurized, and freeze- and spray-dried egg yolk in two independent batches. The egg yolk powders in each batch were stored in the dark for 6 months at -18 or 20 degrees C. Carotenoids were isolated by solvent extraction without saponification and analyzed by HPLC using a C(30) column coupled to a photodiode array and mass detector. The most abundant carotenoids were all-E-canthaxanthin, all-E-lutein, all-E-zeaxanthin, 9-Z-canthaxanthin, and beta-apo-8'-carotenoic acid ethyl ester. Pasteurization of the egg yolk caused no critical changes in the carotenoid content. On the contrary, drying to a dry matter of 98-99% led to higher carotenoid contents, induced by a denaturation of binding proteins, and a destabilization of the cell matrix. After the 6 months of storage, the contents of all main carotenoids in the egg yolk powder were significantly lower. The synthetic carotenoids canthaxanthin and beta-apo-8'-carotenoic acid ethyl ester showed a higher retention rate, and the greatest losses occurred within the first 8 weeks. Statistical tests (ANOVA, P < 0.05) also proved that after 26 weeks, the egg yolk powders stored at -18 degrees C showed only a slightly higher retention of carotenoids when compared to the powders stored at 20 degrees C.
authors.affiliation: Department of Food Technology, University of Applied Sciences Fulda, Marquardstrasse 35, 36039 Fulda, Germany. michael.wenzel@hs-fulda.de
authors.forename: Michael
authors.initials: M
authors.lastname: Wenzel
authors.forename: Ingrid
authors.initials: I
authors.lastname: Seuss-Baum
authors.forename: Elmar
authors.initials: E
authors.lastname: Schlich
mesh_terms: D000818:Animals; D002338:Carotenoids / Q000032:analysis*; D002645:Chickens; D004530:Egg Yolk / Q000737:chemistry*; D005260:Female; D005511:Food Handling / Q000379:methods*
chemical_list: D002338:Carotenoids