β-Lactoglobulin tablets as a suitable vehicle for protection and intestinal delivery of probiotic bacteria

The use of succinylated β-lactoglobulin as a novel functional tablet excipient for the protection of probiotic bacteria against the adverse gastric conditions and their delivery in the intestine was studied. Tablets were produced by direct compression of a dry mixture of Bifidobacterium longum HA-135 and the tested excipient. The results showed that tablets made of native β-lg did not ensure cell survival while grafting carboxylic acid groups on the protein revealed to be an innovative method to create a gastroresistant matrix that could allow the survival of up to 108 CFU and 107 CFU after 1 h and 2 h gastric incubation, respectively. When compared to other polymers, succinylated β-lg promoted the best survival both upon compression and after simulated gastric passage. The proportion of succinylated β-lg in the formulation could be lowered to 60% without modifying the protective ability of the matrix. Additionally, the tablets proved to be stable over a period of 3 months when refrigerated. Succinylated β-lg tablets are an interesting vehicle for the protection of acid-sensitive bacteria during transit in the upper gastro-intestinal tract.