ELISA for monitoring the cleavage of β-casein at site Lys²⁸–Lys²⁹ by plasmin during Comté cheese ripening

Abstract

Proteolysis of casein is the principal cause of textural changes and flavour development in ripened cheese (Fox & McSweeney, 1996). Caseins are degraded into small peptides and free amino acids during a complex process, described by Grappin et al. (1985) as a two-step scheme. Caseins are initially broken down into large, well characterised fragments. This initial step, called primary proteolysis, is catalysed principally by the residual coagulant (chymosin and pepsin), and to a variable extent by endogenous milk proteases, such as plasmin, cathepsin D, and possibly somatic cell proteinases. Enzymes originating from either rennet or milk are active in most ripened cheese varieties. However, their relative contributions vary substantially depending on manufacturing practices. For instance, in Swiss-type cheeses, cooking the curd extensively inactivates the coagulant, and simultaneously enhances plasmin activity, which therefore becomes predominant (Ollikainen & Kivela, 1989).

Occurrence of β-casein fragments in cold-stored and curdled river buffalo (Bubalus bubalis L.) milk

“…Although classical analytical techniques adequately define the proteolytic patterns occurring in dairy products, they are of limited use in quantifying the early proteolytic products of plasmin action. To monitor the proteolysis phenomena in Swiss-type cheese, Senocq et al (2002) and Dupont et al (2003) overcame this problem by producing anti-peptide antibodies against major cleavage sites of plasmin in β-CN sequence. Such an approach can also be applied to the quantitative evaluation of proteolysis during preservation processes of raw matters.…”

Quantification of β-Casein in Milk and Cheese Using an Optical Immunosensor

“…Plasmin could be responsible for the proteolysis during preripening and ripening in the warm room. Recently, Senocq et al (38) have demonstrated, by the measurement of β-casein cleavage by plasmin at the Lys28-Lys29 site, that during ripening in the warm room, the activity of plasmin was intense. The cheese sample 4 presented a more important degree of proteolysis than the other three cheeses.…”

Recent developments in antibody‐based analytical methods for the differentiation of milk from different species

“…Apart from the identification of milk species in dairy products, ELISAs have also been used in many fields of dairy research; for example, for the detection and immunological characterization of individual caseins 14–17 or of their fragments using antipeptide antibodies, 18–23 for monitoring proteolysis during cheese ripening, 21,23 for the evaluation of the early Maillard lactose casein compounds in heated and powdered milk, 20 for the detection of residual chymosin in cheese 24 or for the determination of native and heat‐denatured whey proteins 25–29 …”