The influence of ripening temperature and sampling site on the proteolysis in Reggianito Argentino cheese

Salt Distribution in Raw Sheep Milk Cheese during Ripening and the Effect on Proteolysis and Lipolysis

The salt distribution process in artisanal sheep cheese with an innovative shape of eight lobes was investigated. The cheese was subjected to two brining conditions: 24 h with brine at 16°Baumé and 12 h at 22°Baumé. The chemical composition (pH, water activity, dry matter, fat, and protein content), proteolysis (nitrogen fractions and free amino acids), and lipolysis (free fatty acids) were evaluated in two sampling zones (internal and external) at 1, 15, 30, 60, 90, 120, 180, and 240 days of ripening. The whole cheese reached a homogeneous salt distribution at 180 days of ripening. Brining conditions did not have an influence on the rate of salt penetration, but on the final sodium chloride (NaCl) content. Cheese with higher salt content (3.0%) showed increased proteolysis and lipolysis as compared to cheese with lower salt content (2.2%). Proteolysis index and total free fatty acids did not differ significantly (p > 0.05) between internal and external zones of cheese. It is suggested that producers start marketing this artisanal cheese at 6 months of ripening, when it has uniform composition and salt distribution.

Proteomic and peptidomic profiling of Brazilian artisanal 'Coalho' cheese

BACKGROUND

Artisanal 'Coalho' cheese is a product typically popular in the Brazilian north-eastern region. Production of this cheese represents about 9.2% of the internal crude product of Pernambuco State. Several peptides are generated from hydrolysis of αS1 -, αS2 -, β-, and κ-caseins during manufacture of this cheese. The commercial importance of Brazilian artisanal 'Coalho' cheese justifies the examination of both the protein and peptide profiles of cheeses from six cities of the semi-arid region of Pernambuco State, Brazil.

RESULTS

SDS-PAGE of the aqueous extracts of 'Coalho' cheeses (WSP) showed bands of lactoferrin, β-lactoglobulin, β-lactoglobulin (dimer), α-lactoalbumin, bovine serum albumin, α-casein, β-casein, κ-casein and para-κ-casein. A total of 57 to 72 peptides were confirmed by mass spectra in the different samples of 'Coalho' cheese which 32 known peptides (11 from αS1 -casein, three from αS2 -casein, 15 from β-casein and three from κ-casein), comprising seven caseinphosphopeptides. Among the unidentified peptides, three showed high intensity peaks in all 'Coalho' cheeses studied (with molecular weights of 1597, 1725/1726, 2778/2779 Da).

CONCLUSION

The proteomic studies revealed peptides that may represent molecular markers or fingerprints for investigating the quality control and regional characterisation of these 'Coalho' cheeses. © 2016 Society of Chemical Industry.

Changes of proteolysis and angiotensin-I converting enzyme-inhibitory activity in white-brined cheese as affected by adjunct culture and ripening temperature

The effects of use of adjunct cultures (Lactobacillus helveticus and Lb. casei) and ripening temperatures (6 or 12 °C) on proteolysis and angiotensin-I converting enzyme (ACE)-inhibitory activity in white-brined cheeses were investigated during 120 d ripening. Proteolysis was monitored by urea-polyacrylamide gel electrophoresis (urea-PAGE) and reversed phase-HPLC (RP-HPLC) of water-insoluble and -soluble fractions of the cheeses, respectively. Urea-PAGE patterns of the samples revealed that the intensities of the bands representing casein fractions decreased in the experimental cheeses, being more pronounced in the cheeses made with adjunct cultures. Similarly, peptide profiles and the concentrations of individual and total free amino acids were influenced by both the adjunct cultures and ripening temperatures. The ACE-inhibitory activity of the water-soluble extracts of the cheeses were higher in the cheeses made using adjunct cultures (especially Lb. helveticus) and ripened at 12 °C. The ACE-inhibitory activity did not decrease during ripening. The contribution of Lb. helveticus to the development of proteolysis and ACE-inhibitory peptide activities were higher than that of Lb. casei. To conclude, the use of Lb. helveticus as adjunct culture in white-brined cheese and ripening at 12 °C would be recommended to obtain white-brined cheese with high ACE-I-inhibitory peptides activity and higher levels of preoteolysis.