Growth of Pseudomonas weihenstephanensis, Pseudomonas proteolytica and Pseudomonas sp. in raw milk: Impact of residual heat-stable enzyme activity on stability of UHT milk during shelf-life
| Autor: | Jörg Hinrichs, Manuel Krewinkel, Timo Stressler, Mario von Neubeck, Lutz Fischer, Veronika Achberger, Siegfried Scherer, Mareike Wenning, Melanie Lidolt, Claudia Glück, Marina Stoeckel |
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| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
chemistry.chemical_classification biology Pseudomonas Food spoilage 0402 animal and dairy science food and beverages 04 agricultural and veterinary sciences Raw milk biology.organism_classification Shelf life 040201 dairy & animal science Applied Microbiology and Biotechnology Enzyme assay 03 medical and health sciences Creaming 030104 developmental biology Enzyme chemistry Pseudomonas proteolytica biology.protein Food science Food Science |
| Zdroj: | International Dairy Journal. 59:20-28 |
| ISSN: | 0958-6946 |
| Popis: | One of the reasons for spoilage of UHT milk during shelf-life is the presence of residual proteolytic activity produced from Pseudomonas spp. during storage of raw milk. The aim of this study was to describe the product defects occurring in indirectly heated UHT milk during shelf-life, and to establish a correlation between proteolytic activity and onset of product spoilage. UHT milk was produced from raw milk incubated with different Pseudomonas strains, and examined over four months during storage at 20 °C. Inactivation kinetics of the peptidases were determined. In UHT milk, product defects occurred in the order: bitterness – particles – creaming – sediment – gelation in all the samples containing peptidases (apparent enzyme activity ≥ 0.03 pkat mL −1 ). A linear correlation was found between proteolytic activity and onset of product defects, apart from onset of gelation. |
| Databáze: | OpenAIRE |
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