Hostname: page-component-78c5997874-v9fdk Total loading time: 0 Render date: 2024-11-19T10:30:41.828Z Has data issue: false hasContentIssue false
  • English
  • Français

Potassium iodate-induced proteolysis in ultra heat treated milk during storage: the role of β-lactoglobulin and plasmin

Published online by Cambridge University Press:  01 June 2009

Mary B. Grufferty  and
Patrick F. Fox
Mary B. Grufferty
Affiliation:
Department of Dairy and Food Chemistry, University College, Cork, Irish Republic,
Get access Rights & Permissions [Opens in a new window]

Summary

The report that addition of KI03 (0·1 mm) to milk before ultra high temperature (UHT) treatment induces extensive proteolysis during subsequent storage at 37 °C was confirmed. None was produced by addition of H202 KMn04 or K2Cr207. The pH optimum for KI03-induced proteolysis was between 7·0 and 8·0 and the temperature optimum 37—45 °C. β-Casein was particularly susceptible and the proteolysis pattern was similar to that caused by indigenous alkaline milk proteinase (MPA, plasmin). Addition of plasmin to milk before UHT treatment (140 °C/10 s) caused slight proteolysis during subsequent storage but addition of 0·1 mm-KI03 and plasmin caused extensive proteolysis which was prevented by addition of soyabean trypsin inhibitor, indicating the probable involvement of plasmin in KI03-induced proteolysis in UHT-treated milk. Equally extensive proteolysis occurred in serum protein-free casein micelle systems (SPFCM), with or without KI03, during storage at 37 °C following UHT treatment, indicating a role for whey proteins in KI03-induced proteolysis. Addition of β-lactoglobulin (β-lg) to a SPFCM system inhibited proteolysis, but extensive proteolysis occurred in a SPFCM system containing both β-lg and KI03. MPA-free Na caseinate (prepared by heating at 140 °C for 7 min) underwent extensive proteolysis when treated with plasmin before UHT treatment; proteolysis was inhibited by addition of °-lg to this system and KI03 reversed the inhibitory effect of β-lg. Plasmin proteolysis of isolated αs1-casein was inhibited by denatured β-lg (90 °C/30 min) at a level of 4 mg/ml but not by native β-lg. When denatured in the presence of KI03, β-lg had a lower free SH content than the control and was less inhibitory for plasmin in proteolysis of isolated αsl-casein. The results show that denatured β-lg inhibits plasmin proteolysis of caseins in UHT milk and that inhibition is prevented by KI03. This inhibition may occur via thiol–disulphide interchange, which is prevented if the SH group of ²-lg is oxidized by KI03, thus permitting the stimulatory effect of KI03 on proteolysis in UHT-treated milk.

Type
Original Articles
Information
Journal of Dairy Research , Volume 53 , Issue 4 , November 1986 , pp. 601 - 613
Copyright
Copyright © Proprietors of Journal of Dairy Research 1986

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Andrews, A. T. 1983 Proteinases in normal bovine milk and their action on caseins. Journal of Dairy Research 50 45–55CrossRefGoogle ScholarPubMed
Andrews, A. T. & Alichanidis, E. 1983 Proteolysis of caseins and the proteose-peptone fraction of bovine milk. Journal of Dairy Research 50 275–290CrossRefGoogle ScholarPubMed
Beeby, R. 1980 The use of fluorescamine at pH 6η0 to follow the action of chymosin on κ-casein and to estimate this protein in milk. New Zealand Journal of Dairy Science and Technology 15 99–108Google Scholar
Chen, J. H. & Ledford, R. A. 1971 Purification and characterization of milk protease. Journal of Dairy Science 54 763Google Scholar
Cogan, T. M. 1977 A review of heat resistant lipases and proteinases and the quality of dairy products. Irish Journal of Food Science and Technology 1 95–105Google Scholar
Cousin, M. A. 1982 Presence and activity of psychrotrophic microorganisms in milk and dairy products: A review. Journal of Food Protection 45 172–207CrossRefGoogle ScholarPubMed
De Rham, O. & Andrews, A. T. 1982 The roles of native milk proteinase and its zymogen during proteolysis in normal bovine milk. Journal of Dairy Research 49 577–585CrossRefGoogle ScholarPubMed
Driessen, F. M. & Van Der Waals, C. B. 1978 Inactivation of native milk proteinase by heat treatment. Netherlands Milk and Dairy Journal 32 245–254Google Scholar
Dulley, J. R. 1972 Bovine milk protease. Journal of Dairy Research 39 1–9CrossRefGoogle ScholarPubMed
Eigel, W. N. 1977 Effect of bovine plasmin on αsl-B and κ-A caseins. Journal of Dairy Science 60 1399–1403CrossRefGoogle ScholarPubMed
Eigel, W. N., Hofmann, C. J., Chibber, B. A. K., Tomich, J. M., Keenan, T. W. & Mertz, E. T. 1979 Plasmin-mediated proteolysis of casein in bovine milk. Proceedings of the National Academy of Sciences of the United States of America 76 2244–2248CrossRefGoogle ScholarPubMed
Ellman, G. L. 1959 Tissue sulfhydryl groups. Archives of Biochemistry and Biophysics 82 70–77CrossRefGoogle ScholarPubMed
Fox, P. F. & Guiney, J. 1972 A procedure for the partial fractionation of the αS-casein complex. Journal of Dairy Research 39 49–53CrossRefGoogle Scholar
Halpaap, I., Reimerdes, E. H. & Klostermeyer, H. 1977 [Milk proteinases. VI. Comparative isolation of plasminogen from bovine blood and a proteinase from cows′ milk]. Milchwissenschaft 32 341–346Google Scholar
Hird, F. J. R. & Yates, J. R. 1961 The oxidation of protein thiol groups by iodate, bromate and persulphate. Biochemical Journal 80, 612–616CrossRefGoogle ScholarPubMed
Humbert, G. & Alais, C. 1979 Review of the progress of Dairy Science: The milk proteinase system. Journal of Dairy Research 46 559–571CrossRefGoogle ScholarPubMed
Jenness, R. & Koops, J. 1962 Preparation and properties of a salt solution which simulates milk ultrafiltrate. Netherlands Milk and Dairy Journal 16 153–164Google Scholar
Kaminogawa, S., Mizobuchi, H. & Yamauchi, K. 1972 Comparison of bovine milk protease with plasmin. Agricultural and Biological Chemistry 36 2163–2167CrossRefGoogle Scholar
Kaminogawa, S. & Yamauchi, K. 1972 Acid protease of bovine milk. Agricultural and Biological Chemistry 36 2351–2356CrossRefGoogle Scholar
Kaminogawa, S., Yamauchi, K., Miyazawa, S. & Koga, Y. 1980 Degradation of casein components by acidprotease of bovine milk. Journal of Dairy Science 63 701–704CrossRefGoogle Scholar
Korycka-Dahl, M., Ribadeau-Dumas, B., Chene, N. & Martal, J. 1983 Plasmin activity in milk. Journal of Dairy Science 66 704–711CrossRefGoogle Scholar
Lyster, R. L. J. 1964 The free and masked sulphydryl groups of heated milk and milk powder and a new method for their determination. Journal of Dairy Research 31 41–51CrossRefGoogle Scholar
Noomen, A. 1975 Proteolytic activity of milk protease in raw and pasteurized cow's milk. Netherlands Milk and Dairy Journal 29 153–161Google Scholar
Reimerdes, E. H. 1983 New aspects of naturally occurring proteases in bovine milk. Journal of Dairy Science 66 1591–1600CrossRefGoogle ScholarPubMed
Richardson, B. C. 1983 The proteinases of bovine milk and the effect of pasteurization on their activity. New Zealand Journal of Dairy Science and Technology 18 233–245Google Scholar
Robbins, K. C., Summaria, L., Hsieh, B. & Shah, R. J. 1967 The peptide chains of human plasmin. Mechanism of activation of human plasminogen to plasmin. Journal of Biological Chemistry 242 2333–2342CrossRefGoogle ScholarPubMed
Sawyer, W. M. 1968 Heat denaturation of bovine β-lactoglobulins and relevance of disulfide aggregation. Journal of Dairy Science 51 323–329CrossRefGoogle Scholar
Sedlak, J. & Lindsay, R. H. 1968 Estimation of total, protein-bound and nonprotein sulfhydryl groups in tissue with Ellman's reagent. Analytical Biochemistry 25 192–205CrossRefGoogle ScholarPubMed
Skudder, P. J. 1981 Effects of adding potassium iodate to milk before UHT treatment. II. Iodate-induced proteolysis during subsequent aseptic storage. Journal of Dairy Research 48 115–122CrossRefGoogle ScholarPubMed
Skudder, P. J., Thomas, E. L., Pavey, J. A. & Perkin, A. G. 1981 Effects of adding potassium iodate to milk before UHT treatment. I. Reduction in the amount of deposit on the heated surfaces. Journal of Dairy Research 48 99–113CrossRefGoogle ScholarPubMed
Snoeren, T. H. M., Van RIEL, J. A. M. & Both, P. 1980 [Some properties of a milk proteinase isolated from UHT milk]. Zuivelzicht 72 42–43Google Scholar
Thompson, M. P., Kiddy, C. A., Johnston, J. O. & Weinberg, R. M. 1964 Genetic polymorphism in caseins of cows′ milk. II. Confirmation of the genetic control of β-casein variation. Journal of Dairy Science 47 378–381CrossRefGoogle Scholar
Visser, S. 1981 Proteolytic enzymes and their action on milk proteins. A review. Netherlands Milk and Dairy Journal 35 65–88Google Scholar