Novel quality assurance concept for milk products: Characterization of heat resistant lipases

Publication Type

Poster

Authors

Krewinkel, M.; Baur, C.; von Neubeck, M.; Wenning, M.; Kranz, B.; Fischer, L.

Year of publication

2013

Conference name

GVC / Dechema Tagung: Effiziente Verfahren und Anlagen in der Bioverfahrenstechnik und Lebensmittelbiotechnologie

Conference location

Bad Wildungen

Conference date

06.05. - 08.05.2013

<p></p> <p class="Haupttext" style="text-align: justify;"><span style="font-family: 'Arial','sans-serif'; mso-ansi-language: EN-US;">The kind of milk processing is strongly influenced by the microbial and enzymatic quality of raw milk. (Re-)contamination can occur during the milking process and later during the processing in dairy industry. As recognized in our studies, t<span style="mso-bidi-font-style: italic;">he majority of microorganisms found in raw milk belong to the genera <i>Pseudomonas </i>and <i>Acinetobacter</i>. In our studies we found that these psychrotrophic bacteria are capable to secrete lipases. Even if the microorganisms themselves are inactivated securely during general pasteurization or ultra high temperature processes some enzymes can withstand these thermal treatment and are able to remain active in the derived milk products.</span> If milk is spoiled by heat resistant lipases, changes in the manufactured milk product like bitter, rancid and fruity off flavors can occur.</span></p> <p class="Haupttext" style="text-align: justify;"><span style="font-family: 'Arial','sans-serif'; mso-ansi-language: EN-US; mso-bidi-font-style: italic;">Until now there is no quality assurance concept in the dairy industry to examine the enzymatic quality of raw milk before processing it to milk products. The aim of our study is to develop a new, specific detection system for heat resistant lipases and peptidases in raw milk. In this contribution the focus is on lipases. </span></p> <p class="Haupttext" style="text-align: justify;"><span style="font-family: 'Arial','sans-serif'; mso-ansi-language: EN-US;">Up to now, there are only few literature data available about distribution of microorganisms in raw milk and their capability to secrete thermo resistant lipases. Therefore, in a first screening step 1000 from raw milk isolated microorganism were identified and investigated for lipase formation. In a second screening step microorganisms capable to secrete thermo resistant lipases were identified. Out of these microorganisms relevant lipase secreting bacteria were cultivated and the thermo resistant lipases were biochemically characterized. Based on this knowledge it is possible to develop a specific enzyme assay.<span style="mso-bidi-font-style: italic;"></span></span></p>