Rennets rennet substitutes

Coagulant. Most of the coagulant is lost in the whey but some is retained in the curd. Approximately 6% of added chymosin is normally retained in Cheddar and similar varieties, including Dutch types the amount of rennet retained increases as the pH at whey drainage is reduced. As much as 20% of added chymosin is retained in high-moisture, low-pH cheese, e.g. Camembert. Only about 3% of microbial rennet substitutes is retained in the curd and the level retained is independent of pH. 

Creamer, L. K. 1972. Chinese gooseberry protease unsuitable as a rennet substitute. New Zealand J. Dairy Sci. and Technol 7, 23-23. 

Green, M. L. 1972. Assessment of swine, bovine and chicken pepsins as rennet substitutes for Cheddar cheesemaking. J. Dairy Res. 39, 261-273. 

Puhan, Z. 1969. Composition and properties of a rennet substitute from Bacillus subtilis. J. Dairy Sci. 52, 889-889. 

Rao, K. S. N., Krishna, N., Nand, K., Srikanta, S., Krishna-Swamy, M. A., and Murthy, V. S. 1979. Changes during manufacture and ripening of Cheddar cheese prepared with fungal rennet substitute of Rhizopus oligosporus. Nahrung 23, 621-626. 

It is interesting to know that the plant yellow bedstraw Galium verum) has been used formerly in Britain to curdle milk although it never became a useful rennet substitute. 

Chicken pepsin is the least suitable of these and is used widely only in Israel. Bovine pepsin is probably the most satisfactory and many commercial calf rennets contain up to 50% bovine pepsin its proteolytic specificity is generally similar to that of calf chymosin. The proteolytic specificities of the three principal fungal rennets are considerably different from that of calf chymosin but the acceptability of most cheese varieties made using fungal rennets is fairly good. Microbial rennets are widely used in the United States but to only a limited extent in Europe. The extensive literature on rennet substitutes has been reviewed by Sardinas (1972), Emstrom and Wong (1974), Nelson (1975), Green (1977), and Phelan (1985). 

The action of chymosin on the B-chain of insulin indicates that it is specific for hydrophobic and aromatic amino acid residues (Fish, 1957). Chymosin is relatively weakly proteolytic indeed, limited proteolysis is one of the characteristics to be considered when selecting proteinases for use as rennet substitutes (Fox, 1989a). 

A series of microbial proteases useful in food production, especially as rennet substitutes, has been isolated (45). Many of these have an optimum pH below 6 and are inhibited by specific pepsin inhibitors described above. 

M. pusillus var. Lindt protease has given satisfactory results as a chymosin substitute in the manufacture of a number of cheese varieties, but not all varieties of M. pusillus var. Lindt are capable of producing acceptable cheese (Babel and Somkuti 1968). The clotting activity of M. pusillus var. Lindt protease is more sensitive to pH changes between 6.4 and 6.8 than chymosin, but is much less sensitive than that of porcine pepsin (Richardson et al 1967). The same authors reported that CaCL added to milk affected the clotting activity of M. pusillus var. Lindt rennet more than it did that of chymosin rennet. They also reported that this rennet was more stable than chymosin between pH 4.75 and 6.25. M. pusillus var. Lindt rennet is not destroyed during the manufacture of Cheddar cheese, although less than 2% of the enzyme added to the milk remains in the curd. Nearly all of it is found in the whey (Holmes et al. 1977). Mickelsen and Fish (1970) found M. pusillus var. Lindt rennet to be much less proteolytic than E. parasitica rennet but more proteolytic than chymosin rennet on whole casein, a8-casein and /3-casein at pH 6.65. 

Shovers, J. and Bavisotto, V. S. 1967. Fermentation derived enzyme substitute for animal rennet. J. Dairy Sci. 50, 942-942. 

Other Food Uses. Papain has also been used to hydrolyze renderer s meat scraps to make a product which can be used for feeding farm animals. Because of their abihty to coagulate casein in much the same fashion as rennet, papain and ficin have been used as milk-clotting agents in place of rennet in the production of cheese. Papain may be substituted... 

Use Medicine (digestive ferment) substitute for rennet in cheese making. 

Later, cheese makers either placed strips of kid, lamb or calf stomach directly into the warm milk or prepared a crude rennet extract by soaking the strips in salt water. World production of rennet now exceeds 25 million litres per year [1]. In the 1960s, however, the Food and Agricultural Organization of the United States predicted that an increased demand for meat would lead to more calves being reared to maturity, so that less rennet would be available. Consequently, over the last 30 years several substitutes for calf rennet have been developed, including... 

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