Influence of addition of plasmin or mastitic milk to cheesemilk on quality of smear-ripened cheese

Abstract

-Smear-ripened cheese varieties are characterised by the growth of a smear culture, containing predominantly Brevibacterium linens, on the cheese surface during ripening. In such cheese, considerable zonal differences in biochemistry of ripening exist, due to moisture loss from, and growth and metabolic activity of smear microflora at, the cheese surface. In this study, the effects of adding exogenous plasmin or small amounts of mastitic milk to good quality milk on the quality of smear-ripened cheese made subsequently was examined. Addition of plasmin did not influence cheese composition immediately after manufacture, but slightly decreased the rate of moisture loss during cheese ripening. Plasmin activity decreased during the early stages of ripening, but subsequently increased towards the end of ripening, perhaps due to changing pH conditions in the cheese. Addition of plasmin increased rates of primary proteolysis in cheese, as measured by levels of pH 4.6-soluble N and urea-PAGE, although production of later products of proteolysis appeared less affected. Addition of mastitic milk had largely similar effects to addition of exogenous plasmin, which may reflect a high content of plasmin or plasminogen activators in such milk. Overall, changes in milk quality and enzymology appear to influence the quality of smear-ripened cheese.Plasmin / cheese / smear-ripened Résumé -Influence de l'addition de la plasmine ou du lait de mammite sur l'affinage des fromages à pâte pressée et croûte lavée. Les fromages à croûte lavée ont leur surface caractérisée par la croissance de bactéries corynéformes, contenant Brevibacterium linens de manière prédominante. Dans un tel fromage, la biochimie de l'affinage présente des différences de zone considérables, dues à la perte en humidité de la surface du fromage et à la croissance et l'activité métabolique de la microflore à la surface du fromage. Cette étude traite des effets de l'ajout de plasmine exogène ou de petites 305

Relationships between ruminant management and sensory characteristics of cheeses: a review

“…Addition of mastitis milk to cheese milk has recently been demonstrated to have largely similar effects (on moisture and the proteolytic pattern of cheese) to addition of exogenous plasmin [92]. This reflects that milks rich in SCC have a higher level of plasmin and cell lysosome-derived proteolytic enzymes [3,52] and that SCC also possess a plasminogen activator activity [125].…”

“…They lead to low cheese yield, due to protein and fat losses in whey. Cheese moisture content is higher [52,92,103], associated with an increase in the proteolysis rate and a modification of the proteolysis pattern [25,92].…”

Mastitis impact on technological properties of milk and quality of milk products—a review

“…This in turn influences milk coagulation properties, cheese yield (McSweeney et al 1994) and cheese ripening (O'Farell et al 2002). Moreover, plasmin is heat stable with large amounts surviving pasteurization.…”

Interactions between bacteria type, proteolysis of casein and physico-chemical properties of bovine milk

“…Plasmin (PL) is the most important protease in milk from both healthy udders and udders with elevated SCC, but the non-plasmin proteases become more important with increasing severity of udder inflammation (O'Farrell, Sheehan, Wilkinson, Harrington, & Kelly, 2002;Verdi & Barbano, 1988;Verdi, Barbano, Dellavalle, & Senyk, 1987 relative proportion of caseins (CNs) (especially b-CN and a s1 -CN) with simultaneous clear increased levels of g-CNs and proteose peptones (Auldist et al, 1996;Barbano et al, 1991;Le Roux, Colin et al, 1995;Le Roux, Girardet et al, 1995;Urech et al, 1999).…”