A study of commercial β-galactosidase stability under simulated in vitro gastric conditions
¹Latvia University of Life Sciences and Technologies, Faculty of Food Technology, Department of Food Technology, Rīgas iela 22, LV–3004 Jelgava, Latvia
²Latvia University of Life Sciences and Technologies, Faculty of Food Technology, Department of Chemistry, Lielā iela 2, LV–3001 Jelgava, Latvia
*Correspondence: k.zolnere@gmail.com
Abstract:
β-Galactosidase activity in milk may be affected by several factors, such as temperature, pH, milk composition, and metal ions. It is important to note that digestive proteases and gastrointestinal pH can affect enzyme activity during transit through the gastrointestinal tract. For the investigation of commercial β-galactosidase stability in human and animal gastric tracts, human gastrointestinal tract (GIT) models were employed, enabling prediction of enzyme activity under in vivo conditions. The aim of this study was to analyse and compare commercial β-galactosidase stability under simulated in vitro gastric conditions. Commercial enzymes (Ha Lactase 5200 produced by Kluyveromyces lactis and NOLA™Fit5500 produced by Bifidobacterium bifidum expressed in Bacillus licheniformis, Chr. Hansen, Hørsholm, Denmark; GODO-YNL2 produced by Kluyveromyces lactis, Danisco, Copenhagen, Denmark) were used for this study. Commercial enzymes were added to GIT models at 1 and 5 mL L–1. The enzyme activity was assessed as the percentage of lactose hydrolysis by the enzymes from Kluyveromyces lactis and Bacillus licheniformis using HPLC after digestion. β-Galactosidase extracted from yeast (Kluyveromyces lactis) and bacteria (Bacillus licheniformis) was found to be effective as a strategy for improving lactose tolerance.
Key words:
lactose hydrolysis, simulated gastric conditions, β-galactosidase