Characterisation and quantification of protein oxidative modifications and amino acid racemisation in powdered infant milk formula
Research output: Contribution to journal › Journal article › Research › peer-review
Standard
Characterisation and quantification of protein oxidative modifications and amino acid racemisation in powdered infant milk formula. / Chen, Zhifei; Leinisch, Fabian; Greco, Ines; Zhang, Wei; Shu, Nan; Chuang, Christine Y.; Lund, Marianne N.; Davies, Michael J.
In: Free Radical Research, Vol. 53, No. 1, 2019, p. 68-81.Research output: Contribution to journal › Journal article › Research › peer-review
Harvard
APA
Vancouver
Author
Bibtex
}
RIS
TY - JOUR
T1 - Characterisation and quantification of protein oxidative modifications and amino acid racemisation in powdered infant milk formula
AU - Chen, Zhifei
AU - Leinisch, Fabian
AU - Greco, Ines
AU - Zhang, Wei
AU - Shu, Nan
AU - Chuang, Christine Y.
AU - Lund, Marianne N.
AU - Davies, Michael J.
PY - 2019
Y1 - 2019
N2 - Modification of proteins in infant milk formula (IF) is of major concern to the dairy industry and consumers. Thermal treatment is required for microbiological safety, but heat, light, metal-ions and other factors may induce oxidative damage, and be a health risk. In this study protein modifications in IFs were quantified. IFs contained both reducible (disulphide) and non-reducible (di-tyrosine, lanthionine, lysinoalanine) protein cross-links. Dehydroalanine and the cross-linked species lanthionine and lysinoalanine were detected. Protein carbonyls were detected predominantly on high molecular mass materials. Oxidation products of phenylalanine (m-tyrosine), tryptophan (N-formylkynurenine, kynurenine, 3-hydroxykynurenine), tyrosine (di-tyrosine) and methionine (methionine sulphoxide) were detected, consistent with amino acid modification. Higher levels of most of the markers of protein modification were present in the hydrolysed protein brand, when compared to the conventional IF samples, indicative of increased damage during additional processing. Significant levels of racemised (D-) amino acids were present. These data indicate that amino acids in proteins in IFs are modified to a significant extent during manufacture, with hydrolysed IF being particularly prone.
AB - Modification of proteins in infant milk formula (IF) is of major concern to the dairy industry and consumers. Thermal treatment is required for microbiological safety, but heat, light, metal-ions and other factors may induce oxidative damage, and be a health risk. In this study protein modifications in IFs were quantified. IFs contained both reducible (disulphide) and non-reducible (di-tyrosine, lanthionine, lysinoalanine) protein cross-links. Dehydroalanine and the cross-linked species lanthionine and lysinoalanine were detected. Protein carbonyls were detected predominantly on high molecular mass materials. Oxidation products of phenylalanine (m-tyrosine), tryptophan (N-formylkynurenine, kynurenine, 3-hydroxykynurenine), tyrosine (di-tyrosine) and methionine (methionine sulphoxide) were detected, consistent with amino acid modification. Higher levels of most of the markers of protein modification were present in the hydrolysed protein brand, when compared to the conventional IF samples, indicative of increased damage during additional processing. Significant levels of racemised (D-) amino acids were present. These data indicate that amino acids in proteins in IFs are modified to a significant extent during manufacture, with hydrolysed IF being particularly prone.
KW - Cross-links
KW - di-tyrosine
KW - infant milk formula
KW - kynurenine
KW - methionine sulphoxide
KW - protein carbonyls
KW - protein oxidation
KW - racemisation
U2 - 10.1080/10715762.2018.1554250
DO - 10.1080/10715762.2018.1554250
M3 - Journal article
C2 - 30646774
VL - 53
SP - 68
EP - 81
JO - Free Radical Research
JF - Free Radical Research
SN - 1071-5762
IS - 1
ER -
ID: 216204230