Peptide profiling of bovine kefir reveals 236 unique peptides released from caseins during its production by starter culture or kefir grains

Autor: Maria Fedorova, Jennifer Ebner, Ayşe Aşci Arslan, Ralf Hoffmann, Ahmet Küçükçetin, Monika Pischetsrieder
Rok vydání: 2015
Předmět:
Zdroj: Journal of Proteomics. 117:41-57
ISSN: 1874-3919
DOI: 10.1016/j.jprot.2015.01.005
Popis: Kefir has a long tradition in human nutrition due to its presupposed health promoting effects. To investigate the potential contribution of bioactive peptides to the physiological effects of kefir, comprehensive analysis of the peptide profile was performed by nano-ESI-LTQ-Orbitrap MS coupled to nano-ultrahigh-performance liquid chromatography. Thus, 257 peptides were identified, mainly released from ß-casein, followed by ?S1-, ?-, and ?S2-casein. Most (236) peptides were uniquely detected in kefir, but not in raw milk indicating that the fermentation step does not only increase the proteolytic activity 1.7- to 2.4-fold compared to unfermented milk, but also alters the composition of the peptide fraction. The influence of the microflora was determined by analyzing kefir produced from traditional kefir grains or commercial starter culture. Kefir from starter culture featured 230 peptide sequences and showed a significantly, 1.4-fold higher proteolytic activity than kefir from kefir grains with 127 peptides. A match of 97 peptides in both varieties indicates the presence of a typical kefir peptide profile that is not influenced by the individual composition of the microflora. Sixteen of the newly identified peptides were previously described as bioactive, including angiotensin-converting enzyme (ACE)-inhibitory, antimicrobial, immunomodulating, opioid, mineral binding, antioxidant, and antithrombotic effects. Biological significance: The present study describes a comprehensive peptide profile of kefir comprising 257 sequences. The peptide list was used to identify 16 bioactive peptides with ACE-inhibitory, antioxidant, antithrombotic, mineral binding, antimicrobial, immunomodulating and opioid activity in kefir. Furthermore, it was shown that a majority of the kefir peptides were not endogenously present in the raw material milk, but were released from milk caseins by proteases of the microbiota and are therefore specific for the product. Consequently, the proteolytic activity and the composition of the peptide profile can be controlled by the applied microflora (grains or starter culture). On the other hand, a considerable portion of the peptide profile was identified to be typical for kefir in general and independent from production parameters.In summary, the generated kefir peptide profile helped to reveal its origin and to identify bioactive peptides in kefir, which may advance the understanding of health benefits of this food product. The results further indicate that subsets of the kefir peptide list can be used as markers to control food authenticity, for example, to distinguish different types of kefir. © 2015 Elsevier B.V.
Türkiye Bilimsel ve Teknolojik Araştirma Kurumu: 1100797 01DL12033
The present study was funded by the Intensified Cooperation Program (IntenC) for the Promotion of German-Turkish Higher Education Research of the International Bureau of the German Federal Ministry of Education and Research (grant No. 01DL12033 ) and Turkey's Scientific and Technological Research Council (TÜBITAK, grant No. 1100797 ). The funders were not involved in study design, the collection, analysis and interpretation of data, writing the report or in the decision to submit the article for publication.
Databáze: OpenAIRE
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