2.5. Aggregation activity
2.5.1. Auto-aggregation
Auto-aggregation capabilities were performed by the method of
Del Re et al. [28]. LAB was harvested by centrifugation at 5000g for
15 min. Then, pellets were washed twice with phosphate-buffered
saline PBS, re-suspended in the same buffer and adjusted to
108 CFU/mL. Cell suspension (4 mL) was mixed, and autoaggregation
was monitored during 5 h of incubation at room
temperature.
Every hour, 0.1 mL of the upper suspension was transferred to
another tube with 3.9 mL of PBS, and the absorbance (A) was
measured at 600 nm. The auto-aggregation percentage was
expressed as followed: 1 - (At/A0) 100, where At represents the
absorbance at time t ¼ 1, 2, 3, 4 or 5 h and A0 the absorbance at
t ¼ 0.