Probiotic dynamics during the fermentation of milk supplemented with seaweed extracts: The effect of milk constituents

Abstract

Dynamics of probiotics Lactobacillus rhamnosus LGG, L. reuteri BioGaia, Bifidobacterium animalis subsp. lactis BB12 and B. longum subsp. longum BB536 were investigated during the fermentation of milk supplemented with extracts of Chondrus crispus (CC), Himanthalia elongata (HE), Laminaria ochroleuca (LO), Palmaria palmata (PP), Porphyra umbilicalis (PU), Ulva lactuca (UL) and Undaria pinnatifida (UP). After 24 h at 37 °C, LGG attained counts above 108 cfu/ml in control milk and in milk with all seaweed extracts while BioGaia only attained that level in milk with CC, HE, PP, PU and UL extracts, B12 in milk with UL and UP extracts, and BB536 in milk with CC, HE, PU and UL extracts. In physiological saline, LGG, BioGaia, BB12 and BB536 were respectively stimulated by 4, 0, 5 and 3 seaweed extracts after 24 h at 37 °C and inhibited by 1, 5, 2 and 0 seaweed extracts. Casein and whey proteins added to physiological saline neutralized inhibition caused by UL extract, increasing probiotic counts by 4–5 log cfu/ml, while lactose and citrate had no significant effect. Milk supplementation with seaweed extracts permitted attaining probiotic counts above 108 cfu/ml at the end of fermentation, a result of practical interest for the dairy industry.