Hydrolysis whey proteins

Nakamura, T., (1993). Production of low antigenic whey protein hydrolysates by enzymatic hydrolysis and denaturation with high pressure, Milchwiss., 48, 141-147. 

Figure 8. Effect of enzymatic hydrolysis on specific volume of foam obtained by whipping a heated whey protein sol (4% w/w, 85°C, 6 min whipping) (43)...

A cheese-like spread, which is similar to processed cheese spread, is prepared by combining hydrolyzed Swiss-or Cheddar-whey protein and cultured cream. The whey protein is precipitated by heat and acid. The granular, chalky precipitate then acquires a smooth texture by enzymatic hydrolysis with Rhozyme P-11 at 39.5 to 40.5 °C for 30 min. The product is heated to 85 °C for 15 min to inactivate the enzymes then it is homogenized and blended with an equal quantity of 45° cream culture containing Lactobacillus casei (Webb and Whittier 1970). 

Enzymatic gelation of partially heat-denatured whey proteins by trypsin, papain, pronase, pepsin, and a preparation of Streptomyces griseus has been studied (Sato et al., 1995). Only peptic hydrolysate did not form a gel. The strength of the gel depended on the enzyme used and increased with increasing DH. Hydrolysis of whey protein concentrate with a glutamic acid specific protease from Bacillus licheniformis at pH 8 and 8% protein concentration has been shown to produce plastein aggregates (Budtz and Nielsen, 1992). The viscosity of the solution increased dramatically during hydrolysis and reached a maximum at 6% DH. Incubation of sodium caseinate with pepsin or papain resulted in a 55-77% reduction in the apparent viscosity (Hooker et al., 1982). 

In addition, peptides binding different minerals have been found in whey proteins, i.e., from (3-lg, a-la and LF. Since these proteins are not phosphorylated, the minerals seem to bind through other binding sites than caseins. Seventeen (17) different peptides have been identified by hydrolysis of (3-lg with thermolysin using two different concentrations of calcium. Also, peptides from a-la and LF using trypsin, chymotrypsin or pepsin have been reported. Studies with 3-lg and a-la peptides have shown a higher affinity for iron than the native proteins (Vegarud et al., 2000). 

Hydrolysis of proteins has marked effects on their emulsifying properties. Hydrolyzed whey protein with a degree of hydrolysis of between 10% and 20% had good emulsifying properties (Dalgleish and Singh,... 

Euston et al. (2001) found that whey protein concentrates with low degree of hydrolysis (4—10%) impaired the emulsifying capacity of whey protein concentrate but increasing the degree of hydrolysis to 10-27% improved emulsifying capacity. However, further increases in the degree of hydrolysis reduced emulsion stability and heat stability of emulsions. 

Hydrolysis of proteins can be used to manipulate gel properties of whey... 

Konrad, G., Kleinsclamidt, T., Rohenkohl, H., and Reimerdes, E.H. (2005). Peptic partial hydrolysis of whey protein concentrate for modifying tire surface properties of whey protein. II. Effects on the emulsifying and foaming properties. Milchwissenschaft 60,195-198. 

A membrane cell recycle reactor with continuous ethanol extraction by dibutyl phthalate increased the productivity fourfold with increased conversion of glucose from 45 to 91%.249 The ethanol was then removed from the dibutyl phthalate with water. It would be better to do this second step with a membrane. In another process, microencapsulated yeast converted glucose to ethanol, which was removed by an oleic acid phase containing a lipase that formed ethyl oleate.250 This could be used as biodiesel fuel. Continuous ultrafiltration has been used to separate the propionic acid produced from glycerol by a Propionibacterium.251 Whey proteins have been hydrolyzed enzymatically and continuously in an ultrafiltration reactor, with improved yields, productivity, and elimination of peptide coproducts.252 Continuous hydrolysis of a starch slurry has been carried out with a-amylase immobilized in a hollow fiber reactor.253 Oils have been hydrolyzed by a lipase immobilized on an aromatic polyamide ultrafiltration membrane with continuous separation of one product through the membrane to shift the equilibrium toward the desired products.254 Such a process could supplant the current energy-intensive industrial one that takes 3-24 h at 150-260X. Lipases have also been used to prepare esters. A lipase-surfactant complex in hexane was used to prepare a wax ester found in whale oil, by the esterification of 1 hexadecanol with palmitic acid in a membrane reactor.255 After 1 h, the yield was 96%. The current industrial process runs at 250°C for up to 20 h. 

Although the volume of foam was increased by limited proteolysis, the stabilities of the foams, defined as the time required for one half of the weight of the foam to drain from the foam as free liquid, were greatly decreased by this same limited proteolysis. Presumably the increased initial polypeptide concentration in the hydrolysates favors more air incorporation. However, the polypeptides apparently do not have the surface activity required to give a stable foam. The decrease in foam stability becomes evident in the first 30 min of the enzyme reaction. Further hydrolysis results in peptides which lack the ability to stabilize the air cells of the foam. Thus a limited hydrolysis may be advantageous for utilizing whey proteins in foams since the specific volumes of the foams were increased 25% by such treatment. The decrease in foam stability which results from limited hydrolysis can be compensated for by adding stabilizers such as carboxymethyl cellulose (19,27). 

Limited hydrolysis of protein concentrates such as egg albumen and whey proteins... 

One of the current approaches to the improvement of the functional properties of proteins is enzymatic hydrolysis [148], The emulsifying ability of soy protein isolate can be increased by treatment with neutral fungal protease however, this treatment decreases emulsion stability [163], Partial hydrolysis of fish protein concentrate improves both emulsification and stability [164]. On the other hand, treatment of whey protein concentrate with pepsin, pronase, and pro-lase leads to a decrease in emulsification ability, suggesting that there... 

With casein and whey proteins, hydrolysis depressed functionality with a number of enzymes. The result of this observation was that the activity of these enzymes could not be well controlled [139]. Controlled hydrolysis is available for producing a product with desired functionality. 

Ultrafiltration treatment of enzymatic hydrolysates can further reduce the immunoreactivity of whey protein in vitro [179]. Nakamura and coworkers [176,177] stated that combinations of hydrolysis and membrane treatment (microfiltration or ultrafiltration) result in a desirable hypoallergenic peptide. The antigenicity of the fractions decreased with the decreasing of the pore size of the ultrafiltration membrane. 

Hydrolysis of whey proteins Polysulfone UF membrane Production of... 

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