Proteolysis in Manchego-Type Cheese Salted by Brine Vacuum Impregnation

¹ Tecnologia dels Aliments, Centre de Referència en Tecnologia dels Aliments (CeRTA), Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain

A new salting procedure based on the brine vacuum impregnation of porous products was tested on Manchego-type cheese and compared with conventional brine immersion. Its effect on cheese proteolysis throughout a 90-d ripening period was determined. Three cheese regions were evaluated (the rind, the middle, and the internal regions). The parameters analyzed were total N, water-soluble N, soluble Nin trichloroacetic acid and soluble N in phosphotungstic acid by using the Kjeldahl method, casein profile by urea-PAGE, and peptide profile of the water soluble nitrogen extract by reverse-phase HPLC. Free amino acid formation was monitored with a spectrophotometric method by using a Cd-ninhydrin reagent. Globally, proteolysis was significantly affected by ripening stage (increasing throughout all the maturation period studied) and cheese region (rind showed a proteolysis pattern different from the middle and internal regions). The salting procedure only affected cheese proteolysis in the rind, whereas conventional brine-salted cheeses showed lower proteolysis than vacuum-impregnated cheeses.

Key Words: Manchego • salting • proteolysis

Submitted on August 16, 1999
Accepted on January 11, 2000