Relationships between cheese-processing conditions and curd and cheese properties to improve the yield of Idiazabal cheese made in small artisan dairies: A multivariate approach.

Very diverse cutting and cooking intensity processes are currently used in small artisan dairies to manufacture Idiazabal cheese. The combination of the technical settings used during cheese manufacturing is known to affect cheese composition and yield, as well as whey losses. However, the information regarding the effect on microstructure and texture of cheese is scarce, especially in commercial productions. Therefore, the effect of moderate- and high-intensity cutting and cooking processes on whey losses, curd-grain characteristics, microstructure and cheese properties, and yield were analyzed. Three trials were monitored in each of 2 different small dairies during the cheesemaking of Idiazabal cheese, which is a semihard cheese made from raw sheep milk. The role and know-how of the cheesemakers are crucial in these productions because they determine the cutting point and handle semi-automatic vats. The 2 dairies studied used the following settings: dairy A used moderate-intensity cutting and cooking conditions, and dairy B used high-intensity cutting and cooking settings. Multiple relationships between cheese-processing conditions and curd, whey, and cheese properties as well as yield were obtained from a partial least square regression analysis. An increased amount of fat and casein losses were generated due to a combination of an excessively firm gel at cutting point together with high-intensity cutting and cooking processes. The microstructural analysis revealed that the porosity of the protein matrix of curd grains after cooking and cheese after pressing was the main feature affected, developing a less porous structure with a more intense process. Moderate-intensity cutting and cooking processes were associated with a higher cheese yield, regardless of the longer pressing process applied. No significant differences were observed in cheese composition. After 1 mo of ripening, however, the cheese was more brittle and adhesive when the high-intensity cutting and cooking process was applied. This could be associated with the composition, characteristics, and size distribution of curd grains due to differences in the compaction degree during pressing. These results could help to modify specific conditions used in cheesemaking, especially improving the process in those small dairies where the role of the cheesemaker is crucial.

Consideraciones analíticas en la determinación de gluten en alimentos / No disponible

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Seasonal changes in the technological and compositional quality of ewe's raw milks from commercial flocks under part-time grazing.

Rennet coagulation parameters, curd texture and gross compositional variables were studied in ewes' raw milk samples from nine commercial flocks using different concentrate:forage ratios and grazing times. From early lactation to March flocks were fed concentrate pellets and hay whereas from April to the end of lactation flocks were allowed to graze from 6 to 19 h/day receiving concentrate supplementation in the morning and evening. Milk from late-lactation flocks, when allowed to graze, showed higher content of fat, dry matter, protein, casein, soluble protein, total calcium, curd firmness and curd resistance to compression than the milk from early lactation flocks. Higher total calcium content and lower fat content were found when the early lactation flocks were fed high concentrate:forage ratio than when the flocks were fed low ratio. Curd firmness were lower for milk from flocks fed high concentrate:forage ratio, and the curd resistance to compression was greater, than for milk from flocks fed low ratio. At late lactation, when flocks grazed for a long time per day the total calcium content was higher than when the flocks grazed for a short time per day. Principal component analysis showed that protein and fat content were highly correlated with coagulum and curd firmness, whereas total calcium content was highly correlated with curd resistance to compression, and milk pH with rennet coagulation time.