The determination of plasmin and plasminogen-derived activity in turbid samples from various dairy products using an optimised spectrophotometric method

Summary, in English

A spectrophotometric assay for plasmin and plasminogen-derived activity in dairy products was optimised and extended to determine plasmin and plasminogen-derived activity in turbid samples of dairy products. The method was validated by assessing reproducibility, repeatability, level of detection and recovery of plasmin activity in different sample matrices. Plasmin activity in raw milk was not affected by skimming, but decreased by 30% in pasteurised and homogenised whole milk, leading to an underestimation of plasmin activity. The effects of dissociation of plasmin and caseins by epsilon-aminocaproic acid (EACA) plus NaCl on the plasmin activity were investigated. Comparison of pasteurised milk with a micellar casein solution showed that the dissociation of plasmin and caseins on adding EACA and NaCl decreases interference by caseins, but increases inhibition of plasmin with serum-based inhibitory components. The level of detection and repeatability of this method for plasmin activity analysis were improved compared with previous spectrophotometric assays. (C) 2014 Elsevier Ltd. All rights reserved.

• Author: Valentin M. Rauh; Mette Bakman; Richard Ipsen; Marie Paulsson; Alan L. Kelly; Lotte B. Larsen; Marianne Hammershoj
• Department/s: Department of Food Technology, Engineering and Nutrition
• Publishing year: 2014
• Language: English
• Pages: 74-80
• Publication/Series: International Dairy Journal
• Volume: 38
• Issue: 1
• Links: http://dx.doi.org/10.1016/j.idairyj.2014.03.008
• Document type: Journal article
• Publisher: Elsevier
• Topic: Food Engineering
• Status: Published
• ISBN/ISSN/Other: ISSN: 0958-6946