THE D-AMINO ACID CONTENT OF FOODSTUFFS SUBJECTED TO VARIOUS TECHNOLOGICAL PROCEDURES
D-amino acids occurring in dietary proteins originate as a consequence of technological intervention while basic materials are being prepared for consumption. Foodstuffs are the most significant sources of D-amino acids, as in the process of cooking or during the various processing procedures used...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Faculty of Agrobitechnical Sciences Osijek
2000-06-01
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| Series: | Poljoprivreda |
| Subjects: | |
| Online Access: | http://poljoprivreda.pfos.hr/upload/publications/36_CSAPO.pdf |
| Summary: | D-amino acids occurring in dietary proteins originate as a consequence of technological intervention while
basic materials are being prepared for consumption. Foodstuffs are the most significant sources of D-amino
acids, as in the process of cooking or during the various processing procedures used in the food industry
dietary proteins undergo racemisation to a greater or lesser degree. Food stores are now selling increasing
quantities of foods (such as breakfast cereals, baked potatoes, liquid and powdered infant foods, meat
substitutes and other supplements) which in some cases contain substantial quantities of D-amino acids,
which in turn possess characteristics harmful with respect to digestion and health. Alkali treatment catalyses
the racemisation of optically active amino acids. The degree of racemisation undergone varies from protein to
protein, but the relative order of the degree of racemisation of the individual amino acids within proteins
shows a high level of similarity. The principal factors influencing racemisation are the pH of the medium, heat
treatment, the duration of the application of alkaline treatment and the structure of the respective amino acids.
D-amino acids formed in the course of treatment with alkalis or heat give rise to a deterioration in quality and
reduce the extent to which food thus treated can be used safely. The presence of D-amino acids in proteins
leads to a decrease in digestibility and the availability of the other amino acids. This results in a reduction in
the quantities of the L-enantiomers of the essential amino acids, as the peptide bonds cannot split in the
normal way. Some D-amino acids can exert an isomer-toxic effect and have the capacity to give rise to
changes in the biological effect of lysinoalanine. |
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| ISSN: | 1330-7142 1848-8080 |