The effect of αα-lactalbumin and ββ-lactoglobulin hydrolysates on the metabolic activity of Escherichia coli JM103

Publisher Website
Google Scholar
Abstract
Bovine milk proteins α-lactalbumin (α-la) and β-lactoglobulin (β-lg) were hydrolysed with seven different proteolytic enzymes, and the effect of various hydrolysates on a genetically modified luminous Escherichia coli JM103 was tested in vitro with a bioluminescence assay for bacterial growth and metabolism. Undigested proteins did not inhibit the activity of tested E. coli JM103 at a concentration as high as 0·1 g ml−1. At the same concentrations, α-la hydrolysed with pepsin or trypsin and β-lg hydrolysed with alcalase, pepsin or trypsin, showed a lower metabolic activity during the first 8 h of growth. The activity of E. coli JM103 in the presence of 25 mg ml−1α-la or β-lg hydrolysed with pepsin and trypsin was only 21% of the control after incubation for 6 h. The preliminary results indicated that ultrafiltration through 10 kDa and 1 kDa molecular mass cut-off membranes may be used to enrich bacteriostatic properties.