Influence of pasteurization of milk and addition of starter cultures on protein breakdown in ovine cheeses manufactured with extracts from flowers of Cynara cardunculus

Abstract

Ovine cheeses were manufactured from raw milk (R), pasteurized milk without starter addition (P), and pasteurized milk with starter addition (PS), using in all cases extracts of Cynara cardunculus as rennet and mimicking as far as possible the traditional manufacture process. The microbial counts were higher in R cheeses than in P cheeses, and the lowest microbial counts were found for PS cheeses. Such physicochemical characteristics as moisture, fat, protein, NaCl content, and pH of the three types of cheeses were similar to one another at each sampling time. In particular, pasteurization had no significant effect on protein breakdown as evaluated by either the water-soluble nitrogen, the trichloroaceticacid (TCA)-soluble nitrogen, or the phosphotungstic acid (PTA)-soluble nitrogen fractions. However, the TCA-soluble and the PTA-soluble fractions for the PS cheeses ripened for more than 28 days were higher than those for the R or P cheeses at similar ripening times. The cheeses and their water-soluble extracts could not be distinguished by urea-polyacrylamide gel electrophoresis for up to 7 days, but clear differences were apparent at 68 days of ripening for the PS cheeses with respect to the R and P cheeses.

Advances in the role of a plant coagulant (Cynara cardunculus) in vitro and during ripening of cheeses from several milk species

“…Ovine cheeses manufactured from raw milk exhibited higher microbial counts than those from pasteurised milk without starter addition [51]; however, the lowest microbial counts were recorded in cheese with starter added [7,51]. Pasteurisation [51] and addition of starter cultures [7,51] were found to have no detectable effects on the characteristics of the cheeses throughout ripening; nevertheless, differences were found between the cheeses in terms of WSN/TN, as well as between cheeses manufactured from pasteurised milk without starter addition and those manufactured from pasteurised milk with starter addition in terms of TCASN and PTASN [51].…”

“…Pasteurisation [51] and addition of starter cultures [7,51] were found to have no detectable effects on the characteristics of the cheeses throughout ripening; nevertheless, differences were found between the cheeses in terms of WSN/TN, as well as between cheeses manufactured from pasteurised milk without starter addition and those manufactured from pasteurised milk with starter addition in terms of TCASN and PTASN [51]. Proteolysis was generally more intense and rapid in cheeses containing starter cultures than in starter-free cheeses [7,49].…”

“…Proteolysis was generally more intense and rapid in cheeses containing starter cultures than in starter-free cheeses [7,49]. Sousa and Malcata [51] reported that cheeses manufactured with raw milk, pasteurised milk without starter or pasteurised milk with starter addition could not be distinguished by urea-PAGE; this means that caseins were apparently degraded into products that originated similar electrophoretic patterns. However, their WSF showed differences by long ripening times for pasteurised milk cheeses with starter addition relative to raw milk cheeses and pasteurised milk cheeses without starter addition; furthermore, a higher number of peptides was present in pasteurised milk cheeses with starter addition [49].…”

“…Several studies have meanwhile been performed using extracts of C. cardunculus as coagulant in cheese, in attempts to further characterise this plant coagulant as a proteolytic [7,24,[51][52][53]56] and lipolytic [54,57] agent during cheese ripening.…”

Supplementation of enzyme-treated soy protein saves dietary protein and promotes digestive and absorptive ability referring to TOR signaling in juvenile fish

“…ETSP (Fortide, from Chengdu Mytech Biotech Co., Ltd., Sichuan, China) was provided in premix form to ensure that ETSP was at the concentration of 0, 0, 10, 15, 20, 25, and 30 g/kg diet, respectively. Acid-soluble nitrogen was measured with the method of trichloroacetic acid precipitation, as described by Sousa and Malcata (1996). The molecular weight distribution of peptide was determined by matrix-assisted laser desorption ionization time-offlight (TOF) mass spectrometry according to Gobom et al (2002).…”