Original Article
European Journal of Clinical Nutrition advance online publication 23 September 2009; doi: 10.1038/ejcn.2009.116
Patterns of free amino acids in German convenience food products: marked mismatch between label information and composition
M Hermanussen1, U Gonder2, C Jakobs3, D Stegemann4 and G Hoffmann4
- 1University of Kiel Germany, Aschauhof, Altenhof, Germany
- 2Nutritionist, Hünstetten, Germany
- 3Metabolic Unit, Department of Clinical Chemistry, VU University, Medical Center, Amsterdam, The Netherlands
- 4Department of General Pediatrics, Children's University Clinic, Heidelberg, Germany
Correspondence: Professor M Hermanussen, University of Kiel Germany, Aschauhof 3, Altenhof 24340, Germany. E-mail: hermanussen.aschauhof@t-online.de
Received 24 April 2009; Revised 30 July 2009; Accepted 5 August 2009; Published online 23 September 2009.
Abstract
Background/Objectives:
Free amino acids affect food palatability. As information on amino acids in frequently purchased pre-packaged food is virtually absent, we analyzed free amino acid patterns of 17 frequently purchased ready-to-serve convenience food products, and compared them with the information obtained from the respective food labels.
Subjects/Methods:
Quantitative amino acid analysis was performed using ion-exchange chromatography. 
-Aminobutyric acid (GABA) concentrations were verified using a stable isotope dilution gas chromatography/mass spectrometry (GC-MS) method. The patterns of free amino acids were compared with information obtained from food labels.
Results:
An obvious mismatch between free amino acid patterns and food label information was detected. Even on considering that tomatoes and cereal proteins are naturally rich in glutamate, the concentrations of free glutamate outranged the natural concentration of this amino acid in several products, and strongly suggested artificial enrichment. Free glutamate was found to be elevated even in dishes that explicitly state 'no glutamate added'. Arginine was markedly elevated in lentils. Free cysteine was generally low, possibly reflecting thermal destruction of this amino acid during food processing. The meat and brain-specific dipeptide carnosine (CARN) was present in most meat-containing products. Some products did not contain detectable amounts of CARN in spite of meat content being claimed on the food labels. We detected GABA at concentrations that contribute significantly to the taste sensation.
Conclusion:
This investigation highlights a marked mismatch between food label information and food composition.
Keywords:
amino acids, convenience food, GABA, glutamate, monosodium glutamate
