1. Microwave treatment of dietary gelatin does not generate cis-4-hydroxy-l-proline, an inhibitor of collagen biosynthesis
- Author
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Erbe, Thorsten and Bruckner, H.
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Gas chromatography -- Usage ,Gelatin -- Chemical properties ,Mass spectrometry -- Usage ,Microwave ovens -- Usage ,Food research ,Business, international - Abstract
Byline: Thorsten Erbe (1), H. Bruckner (1) Keywords: Key wordsaAmino acid epimerization; Infant formulae; Food proteins; Hydroxyproline stereoisomers; Gas chromatography-mass spectrometry Abstract: aAqueous solutions (5g/100ml) of commercial preparations of (a) an enzymatic partial hydrolysate of gelatin and (b) type A gelatin were subjected to threefold heating to boiling in a domestic microwave oven at 750W and to conventional heating. Then samples were totally hydrolyzed (6M hydrochloric acid, 110aadegC, 24h) and investigated for the presence of eight possible stereoisomers of 3- and 4-hydroxyproline (Hyp) using capillary gas chromatography. Amino acids were analyzed as N(O)-trifluoroacetyl 2-propyl esters on Chirasil-l-Val and detected by selected ion monitoring mass spectrometry. Blanks of (a) and (b) were analyzed in parallel. Relative amounts of 5.0+-0.2% cis-4-d-Hyp were generated from native trans-4-l-Hyp as a result of total hydrolysis in all samples and independent of previous treatment. Notably, neither cis-3-l-Hyp nor cis-4-l-Hyp could be detected in either of the gelatin samples. Thus a report on the generation of antifibrotic and therefore potentially hazardous cis-3-l-Hyp and cis-4-l-Hyp from protein-bonded native trans-3-l-Hyp and trans-4-l-Hyp on microwave heating of infant formulae could not be confirmed. Author Affiliation: (1) Institute of Nutritional Science, Department of Food Sciences, Justus-Liebig-University of Giessen, Sudanlage 6, D-35390 Giessen, Germany e-mail: hans.brueckner@ernaehrung.uni-giessen.de, DE Article note: Received: 22 May 1998 / Revised version: 27 July 1998
- Published
- 1999