Casein hydrolysate

The subsequent advance was rather fortuitous and rested more with serendipity than with scientific logic. A search was made for cheaper more effective replacements for casein hydrolysate. Amongst the tested materials was com steep liquor (CSL). CSL is a by-product of the manufacture of starch from maize kemals. Whole maize is incubated in warm water, at 50°C acidified with SO2. Thermophilic bacteria hydrolyse proteins and other components of the kemals, thereby loosening the starch granules. These are removed, leaving behind the steep liquor which is used to treat further maize kemals. Ultimately, the liquor is too viscous to re-use and the liquor is concentrated and used as cattle feed. It was this material that was used for penicillin fermentation. Surprisingly, the yield of penicillin increased by a further 5-10 fold giving yields of 50-100 ig ml. 

Miguel, M., Contreras, M. M., Redo, 1., and Aleixandre, A. (2009). ACE-inhibitory and antihjqjertensive properties of a bovine casein hydrolysate. Food Ghent. 112, 211-214. 

P.W. Robertson, L.R. Whybin, and J. Cox, Reduction in non-specific binding in enzyme immunoassays using casein hydrolysate in serum diluents. J. Immunol. Methods 76, 195—197 (1985). 

Although these experiments showed growth was possible using casein hydrolysate, Rose also demonstrated that when the amino acid mixture was used rather than the intact protein, additional calories had to be provided as fat plus carbohydrate, if nitrogen balance was to be maintained. It was later shown that the carbohydrate was needed to protect the free amino acids from oxidation in the intestinal epithelium in the course of absorption. Further, amino acids are poorly tolerated by mouth, causing vomiting and/or diarrhea. After World War II attempts to feed very emaciated prisoners in concentration camps with protein hydrolysates were unsuccessful. It was then recognized that osmotic effects from the amino acids were responsible for the unpleasant consequences. 

This kind of experiment was performed in an attempt to show that reduction in labelled amino acid uptake into the soluble pool, observed after as little as 15 min of ozonation (Fig. 6), could be an early or primary event in ozone damage to the soybean trifoliate leaf. It was necessary in this case for the pools to be loaded with unlabelled casein hydrolysate after treatment of the plant, in order to maintain vivo ozone treatment and because it has been reported that high endogenous amino acid levels can confer a degree of resistance to ozone damage (14, 15). 

Plants were ozonated at 50 5 pphm for 90 min freshly cut discs were shaken for 60 min in 50 mg/100 ml casein hydrolysate or in distilled water -protein hydrolysate was added and the discs were incubated for 60 min in the light discs were then washed in running cold tap water for 10 min and homogenized in TCA/acetone. Thus, a total of 3 3/4 hr elapsed after the onset of ozonation and before homogenization, as opposed to 55 min in the case of 15 min ozonation followed by 30 min labelling time plus 10 min washing time (Fig. 6). 

Table IV shows typical results of the pool overloading experiments in the soybean trifoliate leaf. Visible damage to ozonated plants after 24 hr incubation was, as usual, taken as necessary for an experiment to be valid. Clearly, incorporation of label into protein was reduced where casein hydrolysate had been used in control and treated discs to overload the soluble pools. Just as clearly, total counts present in the soluble pool of treated tissue were reduced by ozonation whatever the after-treatment. The reduction of label in the soluble pool in control and ozonated discs due to casein treatment was approximately 30% in each case the reduction of label incorporation due to ozone was about 36% in the case of water treatment and about 14% in the case of casein treatment.

Mostly bovine serum albumin (BSA) is used. Gelatin from cold fish, inactivated calf serum, casein hydrolysate, non-fat dry mUk, polyvinylpyrrolidone, or Tween 20 are also suitable. Concentrations from 0.1 to 0.5% (w/v) are sufficient. Casein and mfik are not of first choice if (strept)avidin conjugates are used. 

The electronic property of the amino acid on the C-terminus also has an effect on antioxidant activity (Li et al., 2011), that is, the larger the electronic property, the higher is the activity. The C-terminus is a polar position that is thus affected by its electrostatic potential, to some extent therefore, the amino acids Trp, Glu, Leu, lie, Met, Val, Tyr, etc. are suitable at the C-terminus. Some researchers have speculated that the identity of the amino acid on the C-terminus would play an important role in its activity. Suetsuna (2000) separated and identified a radical scavenging peptide, Tyr-Phe-Tyr-Pro-Glu-Leu, from casein hydrolysate, and it was confirmed that the Glu-Leu on the C-terminus mainly contributed to its antioxidant activity. Kim et al. (2009) speculated that the hydrophobic property of the amino acid on the C-terminus, for example, Val and Leu, had a distinct effect on the activity, as determined from the analysis of antioxidative peptides derived from venison hydrolysate. 

This subject is dealt with in Chapter 10. Suffice it to say here that K-casein is the only major casein hydrolysed by rennets during the primary phase of milk coagulation, which is the first step in the manufacture of most cheese varieties. 

Bitter peptides Casein hydrolysate Cheese, casein... 

The specific activities of penicillolysin for clupeine and casein hydrolysates were 3.04 x 10 1 and 5.23 x 10 3 katal/kg protein at pH 7.0, respectively (Table 9) [69], The rate of clupeine hydrolysis was 60-fold greater than that for casein hydrolysis. When zinc is removed, the enzyme is completely inactive, and readdition of zinc restores the dual activities towards clupeine and casein (Table 9). Depending on the casein substrate, the cobalt-penicillolysin (Co-penicillolysin) could be up to ca 1.6 times more active than the native zinc enzyme. On the other hand, in clupeine-hydrolysis, the cobalt enzyme is about 70% as active as the native enzyme. Thus, replacement of the zinc-penicillolysin with cobalt markedly decreases the activity towards clupeins while increases it towards casein. 

Siitas, Y., Hurme, M., and Isolauri, E. 1996. Downregulation of antiCD3 antibody-induced IL-4 production by bovine caseins hydrolysed with Lactobacillus GG-derived enzymes. Scand J Immunol 43 687-689. 

Bormann, E.J. and Roth, M. 1999. The Production of Polyhydroxybutyrate by Methylobacterium Rhodesianum and Ralstonia Eutropha in Media Containing Glycerol and Casein Hydrolysates. Biotechnol. Lett., 21, 1059-1063. 

The potentiality of a protein to cause an allergic reaction is related to the size of the protein, its primary, secondary and tertiary structures. Antigenicity of casein hydrolysate prepared by using pancreatic proteases was studied by Mahmoud et al. (1992). 

Haque, Z.U. and Mozaffar, Z. 1992. Casein hydrolysate. II. Functional properties of peptides. Food Hydrocoil. 5, 559-571. 

Slattery, H. and FitzGerald, R.J. 1998. Functional properties and bitterness of sodium caseinate hydrolysates prepared with a Bacillus proteinase. J. Food Sci. 63, 418-422. 

Chaud, M.V., Izumi, C., Nahaal, Z., Shuhama, T., De Lourdes, M., Bianchi, P., and De Freitas, O. 2002. Iron derivatives from casein hydrolysates as a potential source in the treatment of iron deficiency. J. Agric. Food Chem. 50, 847-877. 

Chiang, W.E., Cordle, C.T., and Thomas, R.L. 1995. Casein hydrolysate produced using a formed-in-place membrane reactor. J. Food Sci. 60, 1349-1352. 

Maeno, M., Yamamoto, N., and Takano, T. 1996. Isolation of an antihypertensive peptide from casein hydrolysate produced by a proteinase from Lactobacillus helveticus CP790. J. Dairy Sci. 79, 1316-1321. 

Rival, S.G., Boeriu, C.G., and Wichers, H.J. 2001a. Caseins and casein hydrolysates. 2. Antioxidative properties and relevance to lipoxygenase inhibition. J. Agric. Food Chem. 49, 295—302. 

The bitter peptide BPI a 114, isolated by Okai et al.239 > from casein hydrolysates, and delicious tasting peptides from fish proteins, will undoubtedly achieve practical importance in the food industry. 

Essential amino acid distribution in a casein hydrolysate suitable for parenteral injection. Am. J. Pharm., 116, 368 (1944). With D. Bolling. 

Ostrom, K.M., Borschel, M.W., Westcott, J.E., Richardson, K.S., Kerbs, N.F. 2002. Lower calcium absorption in infants fed casein hydrolysate- and soy protein-based infant formulas containing palm olein versus formulas without palm olein. J. Am. College Nutr. 21, 654-659. 

Many workers have studied the influence of enzymatic hydrolysis on the functional properties of various food proteins, and much of this work has recently been reviewed by Richardson (2). However, there seem to be very few reports which quantitatively relate functionality to parameters which characterize the protein hydrolysates per se (e.g. molecular weight). Ricks et al. (3 ) examined the solubility and taste of a number of pure proteins (denatured pepsin, lactoblobulin, a-Sj -, K-, and 8-casein) hydrolysed with... 

They also observed that the bitter taste of the peptides depended on many parameters DH being one of them. It seemed clear from their work that non-bitter hydrolysates could be obtained at high DH-values (above 20%) an observation which is in accordance with the results of Clegg and McMillan (4) who removed the bitter taste of casein hydrolysates by applying an exopeptidase. 

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