Rennets

Food. Food-grade calcium chloride is used in cheese making to aid in rennet coagulation and to replace calcium lost in pasteurization. In the canning iadustry it is used to firm the skin of fmit such as tomatoes, cucumbers, and jalapenos. It acts as a control in many flocculation, coagulation systems (37). Food-grade calcium chloride is used in the brewing iadustry both to control the mineral salt characteristics of the water and as a basic component of certain beers (see Beer). 

Property Rennet Lactic acid Sulfuric acid Cheese... 

Fig. 3. Schematic process flow diagram for an imitation cheese product having the following formulation dry ingredients, calcium caseinate (or rennet casein), 24.5 wt % tapioca flour, 3.0 wt % salt, 2.16 wt % adipic acid, 0.6 wt % vitamins and minerals, 0.1 wt % sorbic acid (mold inhibitor), 0.5 wt % fat—color blend, soybean oil hydrogenated to a Wiley melting point of 36°C, 21.3 wt % lactylated monoglycerides, 0.05 wt % red-orange coloring, 0.01 wt...

Microbial rennets from a number of producers, eg. Novo Nordisk, Gist Brocades, and Miles, have been available since the 1970s and have proved satisfactory for the production of different kinds of cheese. Their price is considerably lower than that of chymosin. Their properties have proven very similar to those of chymosin (89,90), and only slight modifications of the traditional cheesemaking technique are required in practice. 

Includes everything except rennet and papain bulk share is in the detergent industry. 

Destruction of the casein micelles in the milk with subsequent precipitation of the casein can be accomplished in a number of ways. The action of heat or the action of alcohols, acids, salts and the enzyme rennet all bring about precipitation. In commercial practise the two techniques used employ either acid coagulation or rennet coagulation mechanisms. 

Although acid caseins are employed for a number of purposes, rennet caseins in which the protein remains associated with calcium and phosphate are preferred for plastics applications. Rennet is the dried extract of rennin, obtained from the inner lining of the fourth stomach of calves, and is a very powerful coagulant. As little as 0.2 parts per million are said to be sufficient to coagulate slightly acidic milk. Its coagulating power is destroyed at 100°C. 

In the rennet coagulation process fresh skimmed milk is adjusted to a pH of six and about 40 ounces of a 10% solution of rennet are added per 100 gallons of milk. The initial reaction temperature is about 35°C and this is subsequently raised to about 60°C. The coagulation appears to take place in two stages. Firstly the calcium caseinate is converted to the insoluble calcium paracaseinate and this then coagulates. 

Table 30.1 Properties of rennet casein. Determined according BS1416 1961...

Kase-lab, n. rennet, -leim, m. casein glue, k sen, v.i. curd, curdle. 

Labdan-gummi, -harz, n. labdanum, ladanum. Labdriise,/. peptic gland, laben, c.f. curdle with rennet refresh. Laberdan, m. salted codfish. 

Lab-essenz,/. rennet extract, rennet, -ferment, n. rennet ferment, rennin. labil, a. labile, unstable. 

Lab-probe, /. curd test, -pulver, n. rennet powder. 

With rennet to make cheese (leaving whey)... 

Milk from cows contains 3.2% protein, about 80% of which is casein. Casein is isolated by a precipitation process from milk, involving heating, rinsing to remove whey, and drying to a powder. The yield is about 3 kg/ 100 kg skim milk. Rennet casein is obtained when the casein is precipitated by chymosin enzyme, also known as rennet, and acid casein is produced when precipitation is accomplished by acidification. Acid casein is usually found in the form of sodium caseinate or calcium caseinate, which are water-soluble salts. Caseinates are made by reacting NaOH or CaOH with a slurry of casein curd or powder and then spray drying (Southward, 2010). 

Coextrusion is the process of extruding two or more materials simultaneously or in tandem. It allows a combination of an ingredient such as wheat flour, which is inexpensive and easily enriched with vitamins and minerals, with dairy protein, which provides functionality and texture. For example, an early coextrusion of wheat flour and rennet casein was performed by van de Voort et al. (1984), who obtained products with varying characteristics depending on process parameters. 

The pH of the reconstituted milks was adjusted to 6.4 with 1 N HCL. First, the acidification phase was carried out with glucono(5)lactone (2 g/L) at 30°C in order to exponentially decrease the pH and obtain a stabilized value corresponding to pH = 6.0 after 2 h incubation. Then, rennet was added to the acidified reconstituted milks at a final concentration of 19.5 mg/L and the coagulation phase was performed at 30°C for 3h. 

FIG. 5 Laurdan fluorescence excitation spectra recorded between 250 and 420 nm (emission wavelength, 439 nm) at different times during the acidification and the rennet-induced coagulation kinetics of BLG5 reconstituted milk 35, 70, 125, 175, and 300 min. A.U. = arbitrary units. 

The principal component 1 (PCI) separated the acidification phases of BLG5, CREAM, BCAS, and MP clustered with negative values, from their rennet-induced coagulation phases that spread in a specific order associated with time from the left to the right of the map. These results showed that acidification and gelation of reconstituted milks induced different modifications in the fluorescence properties of Laurdan. 

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