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  • Pudding Proteomics: Cyclomaltodextrin Glucanotransferase and Microbial Proteases Can Liquefy Extended Shelf Life Dairy Products.

Pudding Proteomics: Cyclomaltodextrin Glucanotransferase and Microbial Proteases Can Liquefy Extended Shelf Life Dairy Products.

Metabolites (2022-03-25)
Kristina J H Kleinwort, Maria Weigand, Lydia Hoffmann, Roxane L Degroote, Richard Dietrich, Erwin Märtlbauer, Stefanie M Hauck, Cornelia A Deeg
ABSTRACT

In recent years, a lack of stability of dairy products with extended shelf life (e.g., yoghurt products, UHT desserts) has occurred, with the corresponding products liquefying significantly after days or weeks. This project aimed to identify the enzymes responsible for the liquefaction of the affected products based on differential proteomic analyses. No evidence was found for the presence of starch-degrading bacteria in the affected products. With zymography and proteome analysis, we detected the cause of liquefaction in a pudding by contamination of its aroma component with an engineered amylolytic enzyme, cyclomaltodextrin glucanotransferase (CGTase) from Thermoanaerobacterium thermosulfurigenes. In addition, we detected contamination with Pseudomonas-derived proteolytic ATP-dependent Clp protease in one pudding batch and proteases in technically used amylases, which degraded β-caseins in another batch. Identification of these agents with liquefying properties in dairy products are useful for adjustment of production protocols and/or composition of additives, and thus shelf life extension.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
α-Amylase from Bacillus sp., liquid
Sigma-Aldrich
α-Amylase from Bacillus amyloliquefaciens, liquid, ≥250 units/g
Sigma-Aldrich
α-Amylase from Aspergillus oryzae, aqueous solution, ≥800 FAU/g