Effect of milk containing streptococcus thermophilus KACC 91147 on blood glucose levels

Abstract

The lactase activities of nine species of lactic acid bacteria were compared using the chromogenic substrate, o-nitrophenyl-beta-D-galactopyranoside. Streptococcus thermophilus KACC 91147 had the highest lactase activity among a total of thirty strains of Lactobacillus and S. thermophilus tested, including commercial strains. S. thermophilus KACC 91147 released 0.30 +/- 0.12 mg/mL of galactose in treated milk A (10(7) CFU/mL) and 6.49 +/- 0.38 mg/mL in treated milk B (109 CFU/ mL milk) over 2 hours. In milk tolerance tests, the blood glucose level (BGL) of 6 volunteers (2 males and 4 females) clinically diagnosed as lactose intolerant increased 3.0 mg/dl after drinking milk A, but a significant (p < 0.05) additional increase of 11.2 +/- 4.18 mg/dl was found after drinking milk B. This result suggests that the addition of S. thermophilus KACC 91147 cells into milk aids the digestion of lactose in milk and ameliorates the symptoms of lactose-intolerant individuals due to the activity of lactase from the lactic streptococci.