The effect of alpha-lactalbumin and beta-lactoglobulin hydrolysates on the metabolic activity of Escherichia coli JM103.
Bovine milk proteins alpha-lactalbumin (alpha-la) and beta-lactoglobulin (beta-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, alpha-la hydrolysed with pepsin or trypsin and beta-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-1 alpha-la or beta-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.
Pihlanto-Leppälä
A
A
Agricultural Research Centre of Finland, Jokionen. anne.pihlanto-leppala@mtt.fi
Marnila
P
P
Hubert
L
L
Rokka
T
T
Korhonen
H J
HJ
Karp
M
M
D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism*; D006868:Hydrolysis; D007768:Lactalbumin / Q000378:metabolism*; D007782:Lactoglobulins / Q000378:metabolism*; D008163:Luminescent Measurements; D010434:Pepsin A / Q000378:metabolism; D014357:Trypsin / Q000378:metabolism; D014462:Ultrafiltration
D007782:Lactoglobulins; D007768:Lactalbumin; D014357:Trypsin; D010434:Pepsin A