rennetcurd

Rennetcurd refers to the curd produced when milk is coagulated by rennet, an enzyme complex used in cheese making. Rennet contains proteolytic enzymes, chiefly chymosin, that cleave κ-casein on the surface of casein micelles. This cleavage destabilizes the micelles and causes milk to coagulate into a gel, with liquid whey separating from the curd.

Formation and processing: After rennet is added to warm milk, coagulation typically begins within minutes to an hour, depending on milk composition and rennet activity. The curd is cut into pieces to promote whey drainage, then heated and stirred to expel more whey. The curd is drained, salted, and often pressed and aged, depending on the cheese being produced. The moisture content and firmness of the rennetcurd influence the texture of the finished cheese.

Types of rennet and their effect: Traditional animal rennet uses calf stomach membranes, while microbial rennet produced by fungi and plant-based or recombinant rennets offer vegetarian options. Different rennets have distinct protease profiles, which can affect curd formation, texture, and aging behavior. Milk type (cow, goat, sheep) and fat content also influence the characteristics of the rennetcurd.

Uses and relevance: The rennetcurd stage is foundational in the production of many cheeses, including hard, semi-hard, and soft varieties. The specific handling of rennetcurd—cutting size, temperature, and pressing—shapes the final cheese. Markets may require labeling to indicate the source of rennet, with vegan or vegetarian options using non-animal enzymes.

Safety and regulation: Rennetcurd is produced under standard dairy safety practices, including pasteurization when applicable and hygiene controls. Labeling and regulatory requirements vary by jurisdiction, particularly regarding vegetarian or vegan claims.