Patterns of Free Amino Acids in German Convenience Food Products: Marked Mismatch Between Label Information and Composition
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European Journal of Clinical Nutrition (2010) 64, 88–98 & 2010 Macmillan Publishers Limited All rights reserved 0954-3007/10 $32.00 www.nature.com/ejcn ORIGINAL ARTICLE 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, Hu¨nstetten, Germany; 3Metabolic Unit, Department of Clinical Chemistry, VU University, Medical Center, Amsterdam, The Netherlands and 4Department of General Pediatrics, Children’s University Clinic, Heidelberg, Germany 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. g-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. European Journal of Clinical Nutrition (2010) 64, 88–98; doi:10.1038/ejcn.2009.116; published online 23 September 2009 Keywords: amino acids; convenience food; GABA; glutamate; monosodium glutamate Introduction humans (Finlayson et al., 2007), with food palatability being the strongest predictor of food intake when availability is not Louis-Sylvestre et al. (1984) showed in rats that the daily limited (Mattes, 2008). Recent innovations in food techno- presentation of a new choice of palatable food led to a logy using fermentation, extraction, encapsulation, fat sustained increase in nutrient intake and to overweight, and replacement and many other techniques, leading to new concluded that variety and high palatability are per se food ingredients, reduction or removal of undesirable sufficient factors to overcome weight-regulatory mechan- food components, addition of specific functional ingredi- isms. A complex reward system with distinct ‘liking’ ents, modification of food composition and masking of (hedonic/affective) and ‘wanting’ (incentive salience/moti- undesirable flavors (Hsieh and Ofori, 2007), further vation) components mediates food choice, controls appetite improved palatability. Consumption of convenience food and helps regulate the overall nutrient consumption also in (percentage of total food intake) increases with age from approximately 3% in 3- to 8-year-old children to 7% in 14- to Correspondence: Professor M Hermanussen, University of Kiel Germany, 18-year-old boys and to 5% in 14- to 18-year-old girls. Aschauhof 3, Altenhof 24340, Germany. Currently, German adolescents consume more than 700 E-mail: [email protected] Received 24 April 2009; revised 30 July 2009; accepted 5 August 2009; chemically designed convenience food creations with, on published online 23 September 2009 average, 14 ingredients and a high number of flavorings and Free amino acids in German convenience food products M Hermanussen et al 89 food additives (Alexy et al., 2008). Similar data were observed Table 1 Top-30 list of most frequently purchased ready-to-serve by the German Market Research Institute (Gesellschaft fu¨r German convenience food products Konsumforschung), Nuremberg, Germany: the total super- Maggi ravioli pikanta market selling subdivides into 45% non-alcoholic and Maggi ravioli tomato saucea alcoholic beverages, 22% fresh articles (vegetables, fruit, Schnell&Lecker TK chicken fricassee a meat and meat products), 13% milk and dairy products, 3% Lidl pizza salami a deep frozen products and 2% sweets, with the remaining Primana peas Gut Frielingshof TK chicken breast fillet percentage consisting of canned goods, dressings, oil and Miracoli spaghetti (4 persons)a so on. (German Market Research Institute, personal Wagner pizza piccolinia communication, August 2008). Pastini spaghetti tomato Apart from its effect on palatability, food processing affects Dr Oetker oven fresh pizza pepperoni salami Lentils ‘chef’a free amino acid contents. However, as information on amino Meica curry king sausagea acids in frequently purchased pre-packaged food is virtually Dr Oetker pizza pizza ristorante salame absent, we analyzed the free amino acid patterns of 17 Knorr gourmet forest mushrooms frequently purchased ready-to-serve convenience food pro- Miracoli spaghetti (2 persons) Primana lentilsa ducts and compared them with information obtained from Gut Frielingshof TK chicken cordon bleua the respective food labels. Wagner stone oven pizza The national food law requires labeling, and declaring Gut Frielingshof TK chicken nuggets pan macronutrient and energy contents and the relative con- Dr Oetker oven fresh pizza speziale Primana spaghetti tomato saucea centrations of major ingredients of pre-packaged food. Yet, Wagner stone oven pizza salami the exact composition of these products usually remains Knorr gourmet onions obscure. We contacted 15 market leaders before this study Maggi master class onions a requesting additional information on their products, but all Erasco chicken noodles Cucina lasagne Bolognese requests remained unanswered. Similar experience has been Dr Oetker pizza ristorante speziale reported by other researchers (Kersting, personal commu- Landgut TK chicken fricassee nication, 2007). We therefore decided to simply use food Dulano lasagne label information and to derive estimates of all major com- Primana chicken fricassee ponents by inferring from gross macronutrient content, and Five additional frequently purchased convenience food dishes. the ranking order of the listed ingredients. We inferred protein Bassermann ravioli; Maggi 5-minute terrine (potatoes with roasted onions); and protein-bound amino acid compositions, and related Erasco rice pot with dumplings; Maggi Magic Asia fried noodles with them to the free amino acid patterns analyzed in this study. vegetables; and Lidl masters herbal baguette. aDishes that underwent analysis. Five additional products were recommended by the German Market Research Institute (Gesellschaft fu¨r Konsumforschung) Nuremburg, Germany. Materials and methods The top-30 list of most frequently purchased German ready- Table 2 Percentage of macronutrient content of frequently purchased to-serve convenience food products in 2006 was provided by convenience food products and percentage of water content of ready-to- the German Market Research Institute (Gesellschaft fu¨r serve dish Konsumforschung), Nuremburg, Germany. Top hits were Protein Carbo Fat %Water Maggi ravioli pikant and Maggi ravioli tomato sauce; the a following items consisted of eight types of pizza: seven Maggi ravioli pikant 17 50 33 84 a preparations of chicken meat (Cordon Bleu, soups, fricassee Maggi ravioli tomato 17 65 18 82 Lidl pizza salamia 14 50 36 53 and so on), four types of spaghetti, two lasagnes, two lentil Primana peasa 25 42 33 88 products, three ready-to-eat soups, one pot of peas and one Miracoli spaghettia 13 64 23 69 a curry sausage (Table 1). Of these, we chose a representative Wagner pizza piccolini 17 43 41 54 a sample of 12 dishes for analysis, and for a variety of reasons Lentils ‘chef’ 24 47 28 79 Meica curry sausagea 16 20 64 64 we added another five frequently purchased dishes that were Primana lentilsa 25 58 17 79 not listed among the top-30. All products contained multiple Chicken cordonbleua 44 36 20 65 a additives stimulating sweet, sour, salt and umami taste and Primana spaghetti 18 72 10 70 a were considered appropriate for ‘full lunch’. The dishes are Erasco chicken noodles 24 38 39 90 Bassermann ravioli 11 73 15 85 usually consumed as ‘single-pot meals’ and supposed to Maggi 5-min-terrine 13 80 5 79 satisfy the consumer without additional appetizer or side Erasco rice pot 14 42 44 86 dishes. None of the products was particularly spicy. Flavoring Maggi noodles ‘asia’ 11 60 29 66 with monosodium glutamate was explicitly mentioned in Lidl herbal baguette 8 53 38 39 some dishes. Most products were high in protein, but aProducts belonging to the top-30 list of frequently purchased convenience otherwise roughly in accordance with current national food food. European Journal of Clinical Nutrition Free amino acids in German convenience food products M Hermanussen