Kleinwort Kristina J H, Weigand Maria, Hoffmann Lydia, Degroote Roxane L, Dietrich Richard, Märtlbauer Erwin, Hauck Stefanie M, Deeg Cornelia A
Department of Veterinary Sciences, LMU Munich, D-82152 Martinsried, Germany.
Department of Veterinary Sciences, LMU Munich, D-85764 Oberschleißheim, Germany.
Metabolites. 2022 Mar 17;12(3):254. doi: 10.3390/metabo12030254.
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 . In addition, we detected contamination with -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.
近年来，出现了保质期延长的乳制品（如酸奶产品、超高温灭菌甜点）稳定性不足的情况，相应产品在数天或数周后会显著液化。该项目旨在通过差异蛋白质组学分析确定导致受影响产品液化的酶。在受影响的产品中未发现存在降解淀粉细菌的证据。通过酶谱分析和蛋白质组分析，我们检测到一款布丁液化的原因是其香气成分被一种工程化的淀粉分解酶环麦芽糊精葡糖基转移酶（CGTase）污染。此外，我们在一批布丁中检测到了源自的依赖ATP的蛋白水解性Clp蛋白酶污染，以及在技术上使用的淀粉酶中检测到蛋白酶污染，后者在另一批产品中降解了β-酪蛋白。识别乳制品中这些具有液化特性的因素，有助于调整生产方案和/或添加剂组成，从而延长保质期。
