Biochemical changes during ripening of bovine cheese produced with extracts of Cynara scolymus.

CRISTINA BRUTTI; C. MARCHESICH; M. CABRERA; M. VICTORIA DELPINO; F. MARCHESOTTI; BERTA LLORENTE

Italia

Congreso; IV Internacional Congress on Artichoke; 2000

Abstract Changes in the biochemical characteristics of bovine milk cheese (gouda) manufactured with aqueous extracts of flowers of Cynara cardunculus L var scolymus (L) Fiori were studied throughout ripening. Cheese manufactured using said extracts as coagulant was salted by immersing it in a ClNa solution (20 Beaumé) during two different periods of time (30 h or 40 h). Different salt treatments were studied due to the fact that casein proteolysis is influenced by NaCl. Cheese produced from animal rennet was used as a control. Cheese-making of gouda was carried out on standard conditions. At the 42 days of ripening the pH in the centre was 5,1 and 5,0 for cheese made of 30 and 40 hour salted vegetal rennet, respectively; whereas the pH at the top of the cheese was 5,17 and 5,05. The moisture content values were 41% and 39%. In order to study proteolysis during ripening the nitrogen content in water soluble fractions (% total nitrogen) were determinate by micro-Kjeldhal procedure and Urea-PAGE was performed on water soluble and water insoluble extracts. Casein hydrolysis was more extensive an faster in cheese made of vegetable rennet than of animal rennet. The amount of water soluble nitrogen in cheese made using 30 hour salted vegetal rennet was the double than in cheese made using animal rennet throughout the whole ripening. Casein hydrolysis was also affected by  salt concentration. At the beginning of the ripening, less salted vegetable cheese contained more soluble nitrogen than more salted vegetable cheese. However, after 22 days of ripening there were no differences between then. Urea-polyacrlylamida gel electrophoresis of water insoluble fractions indicated decreased contents in residual a-casein and b-casein and electorphoregrams of water soluble fractions showed more mobile components in cheese obtained from vegetable rennet, being higher in 30 hours salted cheese ( at the  beginning of the ripening ). Our data showed that proteolytic activity of artichoke could be reduce by increasing the salted of the cheese and better results could be obtained with a short ripening period.