How much chicken is food? Questioning the definition of food by analyzing amino acid composition of modern convenience products.

BACKGROUND: Substantial differences exist between traditionally cooked and chemically designed ready-to-serve products and raise questions about the general principles and requirements of current food law. METHODS: Differences in amino acid patterns were analyzed in four examples of chicken preparations (boiled chicken meat, traditionally prepared broth from whole chicken, and two commercial chicken broths), and four examples of vegetable broth (traditionally prepared, two commercial products one of which was claimed a BIO-product, and the classic German bouillon cube). RESULTS: Chicken meat contained 284 mg of free amino acids in 100 ml of the boiled meat homogenate, with physiological peaks of glutamate (14.5 mg/100 ml), glutamine (8.5 mg/100 ml), anserine (88 mg/100 ml) and carnosine (55 mg/100 ml). The patterns significantly differ in industrially designed chicken soups with elevated peaks of glutamate, and missing anserine or carnosine. Similar results were obtained in vegetable broths. In the classic German bouillon cube, glutamate accounts for 96% of all free amino acids. CONCLUSIONS: The amino acid composition of modern ready-to-serve chicken soups and vegetable broths are far from being similar to any natural composition. We need to question current legal definitions of food, and consider its impact on eating habits, appetite regulation and obesity.

Patterns of free amino acids in German convenience food products: marked mismatch between label information and composition.

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. gamma-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.