Ovine caseinate hydrolyzed with Bacillus sp. P7 protease presented antioxidant, antihypertensive, and antimicrobial activities. Hydrolysis time was observed to affect the evaluated bioactivities. Such hydrolysates might have potential applications in the food industry.

Water soluble extracts (WSE) of ewe's cheeses produced in Uruguay and Brazil were evaluated for their biological activities. Feta-type, Roquefort-type and Pecorino-type cheeses from Brazil, Pecorino Sardotype and Cerrillano cheese samples from Uruguay, were analyzed. Antioxidant properties were evaluated using distinct methods. Scavenging of the cation radical of 2,2′-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) ranged from 32 to 45% for Feta-type cheeses to 87% for Roquefort-type cheese. A similar trend was observed for the reducing power, where WSE from Roquefort-type cheese showed the highest activity among the evaluated cheese. Iron chelating activity was quite variable among the different WSE, being higher (50%) for a Pecorino-type cheese. Thiobarbituric acid reactive substance (TBARS) analysis presented similarity among most of the cheese samples, with inhibition values ranging from 25 to 51%. Scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical was observed only for Roquefort-type cheese. All WSE samples showed a prominent inhibition of angiotensin I-converting enzyme (ACE), ranging from 46% for a Feta-type cheese to 80% for Roquefort-type cheese. No antibacterial activity was observed for the different WSE. The results indicated that the evaluated cheeses could be sources of bioactive peptides with different modes of action. WSE of Roquefort-type cheese showed the best set of biological activities. Nano-ESI-MS/ MS analysis allowed the identification of peptides that may contribute to the observed bioactivities.

Enzymatic proteolysis may be employed to release bioactive peptides, which have been investigated for potential benefits from both technological and human health perspectives. In this study, sheep cheese whey (SCW) was hydrolyzed with a protease preparation from Bacillus sp. P7, and the hydrolysates were evaluated for antioxidant and angiotensin I-converting enzyme (ACE)-inhibitory activities. Soluble protein and free amino acids increased during hydrolysis of SCW for up to 4h. Antioxidant activity of hydrolysates, evaluated by the 2,2'azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid radical scavenging method, increased 3.2-fold from 0 h (15.9%) to 6h of hydrolysis (51.3%). Maximum Fe(2+) chelation was reached in 3h hydrolysates, and the reducing power peaked at 1h of hydrolysis, representing 6.2 and 2.1-fold increase, respectively, when compared to that of non-hydrolyzed SCW. ACE inhibition by SCW (12%) was improved through hydrolysis, reaching maximal values (55% inhibition) in 4h, although 42% inhibition was already observed after 1h hydrolysis. The peptide LAFNPTQLEGQCHV, derived from β-lactoglobulin, was identified from 4-h hydrolysates. Such a biotechnological approach might be an interesting strategy for SCW processing, potentially contributing to the management and valorization of this abundant dairy byproduct.

The biological activity and the presence of genes sfp and ituD (surfactin and iturin A) among Bacillus strains isolated from the Amazon basin were determined. Bacillus spp. were tested for hemolytic activity and inhibition of fungal growth by agar plate assays in parallel with PCR for identification of sfp and ituD genes. All strains tested produced surface-active compounds, giving evidence by lysis of erythrocytes and emulsifying activity on mineral oil and soybean oil. These strains of Bacillus caused growth inhibition of several phytopathogenic fungi, including Fusarium spp., Aspergillus spp., and Bipolaris sorokiniana. The presence of genes ituD and sfp was confirmed by PCR and sequence analysis. The only exception was Bacillus sp. P34 that lacks sfp gene. Lipopeptides were isolated from culture supernatants and analyzed by mass spectrometry. Characteristic m/z peaks for surfactin and iturin were observed, and some strains also produced fengycin and bacillomycin. The remarkable antifungal activity showed by the strains could be associated with the co-production of three or more lipopeptide antibiotics. Screening for novel bacteria producing useful biosurfactants or biocontrol agents for agriculture is a topic of greatest importance to eliminate chemical pollutants.

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