Blue cheeses owe their distinctive texture, flavor, and aroma to Penicillium roqueforti. Understanding the technological traits and secondary metabolite production of this species is essential for cheese quality and safety. Here, 20 P. roqueforti isolates from traditional Turkish blue cheeses, including Tulum and Civil, were evaluated for growth at different temperatures, salt tolerance, proteolytic and lipolytic activities, and production of mycophenolic acid (MPA) and roquefortine C (ROQC). Marked strain-level variation was observed. Hierarchical clustering and principal component analysis grouped the isolates into three clusters. Civil cheese isolates showed improved growth under temperature and salt stress and produced lower ROQC than Tulum isolates, suggesting adaptation to distinct cheese environments. Selected isolates were tested in model Tulum cheeses, where all successfully colonized and formed blue veins. Secondary metabolite levels in cheese were low. These results highlight the diversity of Turkish P. roqueforti isolates and support the development of cheese-specific starter cultures.
This study characterized a novel extracellular acid protease from Lacticaseibacillus paracasei (APLP) and evaluated its potential as a milk-clotting enzyme for cheese making. APLP was purified by heat treatment, ammonium sulfate precipitation, and size-exclusion chromatography, yielding a 30 kDa enzyme that showed effective milk-clotting activity at pH 6 and 35 degrees C, despite optimal proteolytic activity at pH 8.5 and 50-75 degrees C. Under equal-volume conditions (1 mL enzyme extract per 10 mL milk), APLP achieved flocculation in 71 s, substantially faster than the commercial comparator Presurpara 1/5000 (484 s). Coagulation activities were 13.9 PU/mL versus 2.04 PU/mL, respectively. APLP also exhibited superior specific activity (8.74 PU/mg) and coagulation power (1/42,810) compared to Presurpara 1/5000 (1.17 PU/mg and 1/25,196, respectively). A prototype cheese (Lacticop) produced with APLP and enriched with rosemary received favorable sensory evaluation scores. These findings indicate that APLP is a promising microbially derived coagulant for large-scale cheese production.
Calcium carbonate (CaCO3) addition to milk represents a promising approach to reduce phosphorus bioavailability in cheese for consumers with impaired renal function, but no data is available on the structural, sensory characteristics of cheese. This study evaluated the effects of CaCO3 supplementation (2 g/L) on physico-chemical, structural, sensory properties of Caciotta cheese. CaCO3 significantly increased cheese porosity, likely due to CO2 release under mildly acidic conditions, while textural and rheological properties were unaffected. Low-field NMR relaxometry revealed reduced proton relaxation times in specific water populations, suggesting altered water-protein interactions for CaCO3-enriched cheese. Sensory analysis indicated slightly lower but positive consumer acceptability scores for CaCO3-enriched cheese, mainly related to appearance and flavor, whereas texture perception remained unchanged. Overall, CaCO3 supplementation enabled the production of nutritionally functional Caciotta cheese preserving satisfactory structural and sensory quality. These findings provide useful insights into the development of dairy products targeted at special nutritional needs.
The current study aims to understand the contribution of koku-active substances such as gamma-glutamyl peptides and volatile compounds to the overall perception of koku-related sensory properties using multivariate statistical analysis. Specifically, we examined blue-mould, smear-ripened and hard yellow type cheeses and cheese powders. The results highlighted blue-mould cheese and cheese powder among other cheese types, showing the highest diversity and quantity of gamma-glutamyl peptides. Among the seven different measured kokumi peptides, gamma-Glu-Thr and gamma-Glu-Glu showed the strongest correlations with koku-related descriptors such as mouthfulness, richness, and persistence of aftertaste. Volatile markers, including esters, alcohols, terpenes, and sulfur compounds, were strongly linked to sensory attributes typically associated with smear- and blue-mould-type cheeses, such as 'smear flavour', 'blue cheese culture', or 'mouldy'. These findings confirm the synergistic role of gamma-glutamyl peptides and volatiles in shaping flavour complexity and koku perception. The proposed multivariate framework offers a robust tool for guiding formulation strategies in cheese-based products.
This study investigated the surface characteristics and the rehydration behavior of sodium caseinate powder obtained from camel and bovine milk (CMSCP, BMSCP, respectively). Both powders exhibited similar total fat and ash contents, whereas CMSCP contained slightly lower protein and higher lactose quantity than BMSCP. Despite having comparable fat content, the X-ray photoelectron spectroscopy indicated that CMSCP exhibited greater surface fat (48.9 +/- 2.4%) and lower protein (50.4 +/- 2.5%) contents than BMSCP. This highlighted the hydrophobic nature of CMSCP surface which was confirmed by its higher C/O ratio (5.6 +/- 0.3). FT-IR spectroscopy confirmed the structural differences between both powders. CMSCP displayed strong hydrophobic protein-protein interaction and a higher beta-sheet structure, as well as a unique glycerol-casein band at 1037 cm-1, indicating the development of insoluble aggregates. Such protein aggregations, surface fat coverage and surface hydrophobicity deeply reduced the rehydration behavior of CMSCP which was confirmed by the turbidity measurements.
