Racemization kinetics of amino acid residues in alkali-treated soybean protein

Friedman, Mendel; Liardon, R.

doi:10.1021/jf00064a025

Cited by 73 publications

(67 citation statements)

References 8 publications

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“…After prolonged or severe heat treatments, a degree of racemization rate was reported (Liardonn and Hurrell, 1983;Bada, 1984;Friedman and Liardon, 1985;Luzzana et al 1999). In our results, the prolonged heat treatment (115°C, 180 min) revealed a D-Asp content of 28.1%, that reasonably agree with previously reported D-Asp racemization rates on heated (121°C) chicken muscle protein, 22.4% and 26.3%, after 4 h and 8 h, respectively (Liardon and Hurrell, 1983).…”

Section: Resultssupporting

confidence: 92%

The Impact of Processing on Amino Acid Racemization and Protein Quality in Processed Animal Proteins of Poultry Origin

Bellagamba

Caprino

Mentasti

et al. 2015

Italian Journal of Animal Science

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Re-authorization of processed animal proteins (PAPs) in EU, derived from by-products of human food production, could increase manufacturing of proteins for feed ingredients and reduce the need of imported proteins mainly of plant origin. The PAPs production is largely done by the rendering process during which authorized animal by-products are heat treated to extract valuable protein and animal fat, ensuring sterilizing conditions of raw incoming materials. Proteins exposure to certain processing conditions induces two important chemical changes, racemization of amino acids and formation of cross-linked amino acid. These changes are associated with appreciable reduction of protein digestibility and nutritional value. The aim of this study was to verify the effect of heat treatment on amino acid racemization in processed animal proteins of poultry origin and related nutritional implications by evaluation of their in vitro digestibility. The results reported confirm the detection of racemized amino acids in processed animal proteins, especially D-aspartic acid, as realistic indicators of thermal treatments during PAP manufacturing. In our results, the severe (115°C) and prolonged heat treatment (180 minutes) revealed a D-Asp content of 28.1%.Prolongation of temperature treatment (20, 30 and 180 min, at 115°C) significantly (P<0.05) affects in vitro protein digestibility, which decrease from 86.0%, in no-treated sample, to 78.3% and 79.1% after 20 and 30 min, respectively, and to 76.3% after 180 min. The processing conditions applied during PAPs preparations and the racemization of proteins amino acids may reasonably be involved in the loss of protein quality.

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Section: Resultssupporting

confidence: 92%

The Impact of Processing on Amino Acid Racemization and Protein Quality in Processed Animal Proteins of Poultry Origin

Bellagamba

Caprino

Mentasti

et al. 2015

Italian Journal of Animal Science

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“…Whether or not other D-amino acids are derived from yeasts is still open to discussion. Previous studies indicated that heat treatment contributed to significant racemization in bread and soybean protein and that racemization was not obtained in hamburgers [14,16]. In the present study, the ratio of D-pipecolic acid in tofu, made from soybeans, beef, bovine liver and bread, did not increase after heat treatment.…”

Section: Discussioncontrasting

confidence: 61%

“…In other words, food proteins are treated with heat or alkali conditions before consumption. Some studies have reported that heat, alkali or the combination of both treatments caused amino acid racemization in food proteins [14][15][16]. Therefore, D-amino acids may be detected in human physiological fluids, since the above-mentioned natural and processed foods are typical of the modern diet.…”

Section: Discussionmentioning

confidence: 99%

“…Pipecolic acid has an inhibitory action on the central nervous system and is of significance in mammals, although the origin has not yet been clarified. Studies have shown that D-amino acids are mainly distributed in various foods, such as dairy products fermented by bacteria (yogurt, cheese) and processed foods (after heat or alkali treatments of food proteins) [13][14][15][16]; therefore, these foods also have the possibility of containing D-pipecolic acid. When the causal relationship between the origin of pipecolic acid, particularly D-pipecolic acid, and food intake is discussed, it is probably appropriate that not only raw food but also processed food samples are analyzed, since many foods are generally treated with heat or alkali before consumption.…”

Section: Introductionmentioning

confidence: 99%

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Determination of <i>D</i>- and <i>L</i>-Pipecolic Acid in Food Samples Including Processed Foods

Fujita¹,

Fujita²,

Kodama³

et al. 2003

Ann Nutr Metab

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Background: Pipecolic acid, a metabolite of lysine, is found in human physiological fluids and is thought to play an important role in the central inhibitory γ-aminobutyric acid system. However, it is unclear whether plasma D- and L-pipecolic acid originate from oral food intake or intestinal bacterial metabolites. Methods: We analyzed the contents of D- and L-pipecolic acid in several processed foods including dairy products (cow’s milk, cheese and yogurt), fermented beverages (beer and wine) and heated samples (beef, bovine liver, bread and tofu) to clarify the relationship between plasma D- and L-pipecolic acid and dietary foods. Results: Our study revealed that some of the samples contained high concentrations of total pipecolic acid, and a higher proportion of L- than D-isomers. The other samples also showed high proportions of L-pipecolic acid. It was also shown that there is no significant change in the ratio of the D-isomer before and after heat treatment. The heat treatments could not cause the racemization of pipecolic acid in this study. Conclusion: These findings suggest that plasma pipecolic acid, particularly the D-isomer, does not originate from direct food intake and that D- and L-pipecolic acid can possibly be derived from intestinal bacterial metabolites.

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“…Relationship between racemization rates (k) relative to Ala, and the inductive constant (s*) of the amino acid side chain R in RCH(NH 2 )COOH. Adapted from [199] and [93].…”

Section: 4mentioning

confidence: 99%

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

Friedman

2010

Chemistry & Biodiversity

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162

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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Racemization kinetics of amino acid residues in alkali-treated soybean protein

Cited by 73 publications

References 8 publications

The Impact of Processing on Amino Acid Racemization and Protein Quality in Processed Animal Proteins of Poultry Origin

The Impact of Processing on Amino Acid Racemization and Protein Quality in Processed Animal Proteins of Poultry Origin

Determination of <i>D</i>- and <i>L</i>-Pipecolic Acid in Food Samples Including Processed Foods

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

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