Chemistry, analysis, nutritional value, and toxicology of tryptophan in food. A review

Friedman, Mendel; Cuq, Jean-Louis

doi:10.1021/jf00083a042

Cited by 119 publications

(103 citation statements)

References 112 publications

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“…The relative nutritional potency of d-Trp compared to l-Trp in mice is strongly dose-dependent, being inversely related to the dietary concentration and ranging from 29 to 64% (Fig. 11) [209]. The maximum growth obtainable for l-Trp occurred at 0.174% in the diet.…”

Section: 4mentioning

confidence: 97%

Origin, Microbiology, Nutrition, and Pharmacology of D‐Amino Acids

Friedman

2010

Chemistry & Biodiversity

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159

108

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Exposure of food proteins to certain processing conditions induces two major chemical changes: racemization of all L-amino acids (LAAs) to D-amino acids (DAAs) and concurrent formation of cross-linked amino acids such as lysinoalanine (LAL). The diet contains both processing-induced and naturally-formed DAA. The latter include those found in microorganisms, plants, and marine invertebrates. Racemization impairs digestibility and nutritional quality. Racemization of LAA residues to their D-isomers in food and other proteins is pH-, time-, and temperature-dependent. Although racemization rates of LAA residues in a protein vary, relative rates in different proteins are similar. The nutritional utilization of different DAAs varies widely in animals and humans. Some DAAs may exert both adverse and beneficial biological effects. Thus, although D-Phe is utilized as a nutritional source of L-Phe, high concentrations of D-Tyr in such diets inhibit the growth of mice. Both D-Ser and LAL induce histological changes in the rat kidney. The wide variation in the utilization of DAAs is illustrated by the fact that, whereas D-Meth is largely utilized as a nutritional source of the L-isomer, D-Lys is not. Similarly, although L-CysSH has a sparing effect on L-Meth when fed to mice, D-CysSH does not. Since DAAs are consumed as part of their normal diet, a need exists to develop a better understanding of their roles in foods, microbiology, nutrition, and medicine. To contribute to this effort, this overview surveys our present knowledge of the chemistry, nutrition, safety, microbiology, and pharmacology of DAAs. Also covered are the origin and distribution of DAAs in food and possible roles of DAAs in human physiology, aging, and the etiology and therapy of human diseases.

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Section: 4mentioning

confidence: 97%

Origin, Microbiology, Nutrition, and Pharmacology of D‐Amino Acids

Friedman

2010

Chemistry & Biodiversity

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159

108

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“…However, the role of W in insulin secretion has not been extensively studied. This may arise from limitations in the analytical methodologies used to quantify free amino acids 55 which often lead to a heat-induced destruction of W, thus making it challenging to quantify 92 . However, different strategies for W residue protection during acid hydrolysis involving the utilisation of antioxidants (e.g.…”

Section: Peptidesmentioning

confidence: 99%

“…The stability of W and W-bound peptides/proteins to different 10 processing conditions has been reviewed 92 . W is relatively stable to processing conditions (steam sterilisation, industrial and home cooking) in comparison to other amino acids such as K, M and C 92,133 .…”

Section: Effect Of Processing Conditions On W Stability and Bioactivitymentioning

confidence: 99%

Milk proteins as a source of tryptophan-containing bioactive peptides

Nongonierma

Fitzgerald

2015

Food Funct.

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Tryptophan (W) is an essential amino acid which is primarily required for protein synthesis. It also acts as 5 a precursor of key biomolecules for human health (serotonin, melatonin, tryptamine, niacin, nicotinamide adenine dinucleotide (NAD), phosphorylated NAD (NADP), quinolinic acid, kynureric acid, etc.). Among dietary proteins, milk proteins are particularly rich in W. W residues within milk proteins may be released by proteolytic/peptidolytic enzymes either as a free amino acid or as part of peptide sequences. Different W-containing peptides originating from milk proteins have been shown in vitro to display a 10 wide range of bioactivities such as angiotensin converting enzyme (ACE) inhibition along with antioxidant, antidiabetic and satiating related properties. Free W has been shown in certain instances to have an effect on cognition and the aforementioned bioactive properties. However, a higher bioactive potency has generally been observed with specific W-containing peptides compared to free W. Since W is thermolabile, the impact of processing on the stability of W-containing peptides needs to be considered. 15Milk protein-derived W-containing peptides may have significant potential as natural health promoting agents in humans.

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“…L-Trp is a nutritionally limiting amino acid in maize (Friedman and Cuq 1988). Replacement of L-Trp with D-Trp in the diet followed a simple pattern, similar to the L-and D-Phe responses, not influenced by toxicity or by sparing effects (Fig.…”

Section: D-tryptophanmentioning

confidence: 74%

Nutritional and medicinal aspects of d-amino acids

2011

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This paper reviews and interprets a method for determining the nutritional value of D-amino acids, D-peptides, and amino acid derivatives using a growth assay in mice fed a synthetic all-amino acid diet. A large number of experiments were carried out in which a molar equivalent of the test compound replaced a nutritionally essential amino acid such as L-lysine (L-Lys), L-methionine (L-Met), L-phenylalanine (L-Phe), and L-tryptophan (L-Trp) as well as the semi-essential amino acids L-cysteine (L-Cys) and L-tyrosine (L-Tyr). The results show wide-ranging variations in the biological utilization of test substances. The method is generally applicable to the determination of the biological utilization and safety of any amino acid derivative as a potential nutritional source of the corresponding L-amino acid. Because the organism is forced to use the D-amino acid or amino acid derivative as the sole source of the essential or semi-essential amino acid being replaced, and because a free amino acid diet allows better control of composition, the use of all-amino-acid diets for such determinations may be preferable to protein-based diets. Also covered are brief summaries of the widely scattered literature on dietary and pharmacological aspects of 27 individual D-amino acids, D-peptides, and isomeric amino acid derivatives and suggested research needs in each of these areas. The described results provide a valuable record and resource for further progress on the multifaceted aspects of D-amino acids in food and biological samples.

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Chemistry, analysis, nutritional value, and toxicology of tryptophan in food. A review

Cited by 119 publications

References 112 publications

Origin, Microbiology, Nutrition, and Pharmacology of D‐Amino Acids

Origin, Microbiology, Nutrition, and Pharmacology of D‐Amino Acids

Milk proteins as a source of tryptophan-containing bioactive peptides

Nutritional and medicinal aspects of d-amino acids

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