Fermented milks are a source of bioactive peptides and may be considered as functional foods. Among these, sheep's milk fermented with kefir has not been widely studied and its most relevant properties need to be more thoroughly characterized. This research study is set out to investigate and evaluate the antioxidant and antimicrobial properties of peptides from fermented sheep's milk in Brazil when produced by using kefir. For this, the chemical and microbiological composition of the sheep's milk before and after the fermentation was evaluated. The changes in the fermented milk and the peptides extracted before the fermentation and in the fermented milk during its shelf life were verified. The antimicrobial and antioxidant activities of the peptides from the fermented milk were evaluated and identified according to the literature. The physicochemical properties and mineral profile of the fermented milk were like those of fresh milk. The peptide extract presented antimicrobial activity and it was detected that 13 of the 46 peptides were able to inhibit the growth of pathogenic microorganisms. A high antioxidant activity was observed in the peptides extracted from fermented milk (3.125 mg/mL) on the 28th day of storage. Two fractions displayed efficient radical scavenging properties by DPPH and ABTS methods. At least 11 peptides distributed in the different fractions were identified by tandem mass spectrometry. This sheep's milk fermented by Brazilian kefir grains, which has antioxidant and antimicrobial activities and probiotic microorganisms, is a good candidate for further investigation as a source for bioactive peptides. The fermentation process was thus a means by which to produce potential bioactive peptides.

No abstract

Este é um artigo publicado em acesso aberto (Open Access) sob a licença Creative Commons Attribution, que permite uso, distribuição e reprodução em qualquer meio, sem restrições desde que o trabalho original seja corretamente citado. Queijo de coalho artesanal: fonte alternativa de peptídeos antimicrobianosArtisanal AbstractThe aim of this research was to extract the crude peptide extracts from two samples of artisanal "Coalho" cheese produced in the city of Venturosa in the drylands of the State of Pernambuco -Brazil, and evaluate their peptide profile and antimicrobial activity. Electrophoresis showed evidence of 12 to 15 bands and mass spectrometry identified 24 peptide fragments. Furthermore, the crude extract presented antimicrobial activity against Enterococcus faecalis ATCC 6057, Bacillus subtilis ATCC 6633, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853 at a concentration of 225 mg/mL. The present results suggest that peptides capable of inhibiting the growth of the pathogenic microorganisms tested can be found in approximately 5g of the cheese. Thus "Coalho" cheese can be indicated for its functional character. Keywords: SDS-PAGE electrophoresis; MALDI-ToF spectrometry; Antimicrobial activity; Bioactive peptides. Meire dos Santos

The current preliminary study thus identified potentially carcinogenic proteins in obese patients. Surgical weight loss resulted in the not detection of these proteins.

No abstract