In vitro studies were undertaken to evaluate the probiotic potentiality of β-galactosidase-producing isolates as per FAO/WHO (8 ). All eight isolates were subjected to simulated gastric juice and bile tolerance tests. The simulated gastric juice contained 0.3% w/v pepsin and 0.5% w/v NaCl (Himedia Laboratories Pvt, Ltd.), at pH 2 or 4. A total of 1 ml of cell suspension was centrifuged (12,000 x g, 5 min at 5˚C), inoculated into 10 ml of gastric juice with pH 2 or 4, incubated at 37˚C for 3 h and cell viability was measured as colony-forming units (CFU) by plating technique, and the percentage of survival was calculated as follows:
Bile tolerance was determined by inoculating each strain (1% v/v) into MRS broth with 0.3% (w/v) of bile salt (Oxgall; Himedia Laboratories Pvt, Ltd.) and incubated for 3 h at 37˚C. Viability was measured as CFU by plating technique and compared with the control (without bile salt) (13 (link),21 (link)).
Pancreatic enzyme tolerance was calculated according to a study by Rashmi and Gayathri (13 (link)), with slight modifications. Overnight cultures were centrifuged at 6,000 x g (20 min at 5˚C), inoculated into simulated pancreatic juice (SPJ; bile 3 g/l and pancreatin 0.1 g/l, sodium phosphate dibasic heptahydrate 50.81 g/l, and NaCl 8.5 g/l in a KH2PO4 buffer at pH 8.0; Himedia Laboratories Pvt, Ltd.), incubated at 37˚C for 3 h and the percentage of survival was calculated as follows:
Bile tolerance was determined by inoculating each strain (1% v/v) into MRS broth with 0.3% (w/v) of bile salt (Oxgall; Himedia Laboratories Pvt, Ltd.) and incubated for 3 h at 37˚C. Viability was measured as CFU by plating technique and compared with the control (without bile salt) (13 (link),21 (link)).
Pancreatic enzyme tolerance was calculated according to a study by Rashmi and Gayathri (13 (link)), with slight modifications. Overnight cultures were centrifuged at 6,000 x g (20 min at 5˚C), inoculated into simulated pancreatic juice (SPJ; bile 3 g/l and pancreatin 0.1 g/l, sodium phosphate dibasic heptahydrate 50.81 g/l, and NaCl 8.5 g/l in a KH2PO4 buffer at pH 8.0; Himedia Laboratories Pvt, Ltd.), incubated at 37˚C for 3 h and the percentage of survival was calculated as follows:
