Hostname: page-component-78c5997874-m6dg7 Total loading time: 0 Render date: 2024-11-02T20:52:20.014Z Has data issue: false hasContentIssue false

A fluorimetric method for determination of Pseudomonas fluorescens AR11 lipase in skim milk powder, whey powder and whey protein concentrate

Published online by Cambridge University Press:  01 June 2009

Donald Stead
Affiliation:
*National Institute for Research in Dairying, (University of Reading), Shinfield, Reading, RG2 9 AT, UK

Summary

A method which was developed for assaying the extracellular lipases of psychrotrophic bacteria in milk (Stead, 1983, 1984) and which uses the fluorogenic substrate 4-methylumbelliferyl oleate has been adapted for use with skim milk powder (SMP), whey powder (WP) and whey protein concentrate (WPC). A five-fold increase in the concentration of sodium taurocholate (NaTC), in the mixture of NaTC and cetyltrimethylammonium bromide needed to dissociate lipase from milk proteins, removed the excessive sensitivity of the assay to variations in the concentrations of SMP, WP or WPC incorporated. Commercially available pancreatic lipase provided a suitable standard of lipolytic activity and as little as 1–2 μ could be detected in each assay system.

Type
Original Articles
Copyright
Copyright © Proprietors of Journal of Dairy Research 1984

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

Andersson, R. E. 1980 Microbial lipolysis at low temperatures. Applied and Environmental Microbiology 39 3640CrossRefGoogle ScholarPubMed
Bradley, J. 1981 The ingredients for success. Milk Producer 28 (5) 1618Google Scholar
Cousin, M. A. 1982 Presence and activity of psychrotrophic microorganisms in milk and dairy products: a review. Journal of Food Protection 45 172207CrossRefGoogle ScholarPubMed
Darrington, H. 1981 New products from milk. Food Manufacture 56 (5) 23Google Scholar
Deeth, H. C. & Fitz-Gerald, C. H. 1976 Lipolysis in dairy products: a review. Australian Journal of Dairy Technology 31 5364.Google Scholar
Downey, W. K. 1980 Review of the progress of dairy science: flavour impairment from pre– and postmanufacture lipolysis in milk and dairy products. Journal of Dairy Research 47 237252CrossRefGoogle Scholar
Gilles, J. & Lawrence, R. C. 1982 The manufacture of cheese and other fermented products from recombined milk. International Dairy Federation Bulletin Document 142 111117Google Scholar
Kieseker, F. G. 1982 Recombined evaporated milk. International Dairy Federation Bulletin Document 142 7988Google Scholar
Kishonti, E. 1975 Influence of heat resistant lipases and proteases in psychrotrophic bacteria on product quality. International Dairy Federation Annual Bulletin Document 86 121124Google Scholar
Law, B. A. 1979 Reviews of the progress of dairy science: enzymes of psychrotrophic bacteria and their effects on milk and milk products. Journal of Dairy Research 46 573588CrossRefGoogle Scholar
Mann, E. J. 1980 Utilization of dairy ingredients in meat products. Dairy Industries International 45(11) 17, 19Google Scholar
Mann, E. J. 1981 a Beverages. Dairy Industries International 46 (5) 2526Google Scholar
Mann, E. J. 1981 b Dairy desserts. Dairy Industries International 46 (8) 9, 11Google Scholar
Mann, E. J. 1982 a Whey utilization in foods. Dairy Industries International 47 (2) 2223Google Scholar
Mann, E. J. 1982 b Recombined milks and dairy products. Dairy Industries International 47 (4) 3233Google Scholar
Mann, E. J. 1982 c Ice cream. Dairy Industries International 47 (6) 43, 45Google Scholar
Mann, E. J. 1982d Utilization of dairy ingredients in bakery products. Dairy Industries International 47 (8) 1112Google Scholar
Newstead, D. F. 1982 Recombined sweetened condensed milk. International Dairy Federation Bulletin Document 142 5962Google Scholar
Spieler, R. 1982 Recombination of butter and ice cream. International Dairy Federation Bulletin Document 142 132136Google Scholar
Stead, D. 1983 A fluorimetric method for the determination of Pseudomonas fluorescens AR11 lipase in milk. Journal of Dairy Research 50 491502CrossRefGoogle Scholar
Stead, D. 1984 Evaluation of a fluorimetric assay on the lipases from strains of milk psychrotrophic bacteria. Journal of Dairy Research 51 123130CrossRefGoogle Scholar
Zadow, J. G. 1982 Recombined milks and creams. International Dairy Federation Bulletin Document 142 3343Google Scholar