Isothermal degradation kinetics of the probiotic Lactobacillus fermentum by thermogravimetry

Abstract

Lactobacillus fermentum is a probiotic that belongs to the group of lactic acid bacteria and presents high intestinal colonization capacity after oral administration. To maintain its quality during manufacturing to its expiration, the physical and chemical stability of the probiotic remains a major challenge and concern. This work aimed to determine the thermal degradation parameters of the probiotic Lactobacillus fermentum by thermogravimetry (TG), calculated using the Arrhenius mathematical model. The probiotic degradation followed a second-order kinetics, where the rate of its degradation depends on the concentration of two or more reactants, presenting degradation rate constant of 6.23 × 10−10 min−1 at 25 °C and an activation energy of 21,987 cal mol−1. The value corresponding to the simulate shelf life was also obtained. TG is an extremely useful tool, simple and fast to determine the degradation rate parameters of the compounds including pharmaceuticals and nutraceuticals. The shelf life needs to be defined by realist data. This is the first time that was used TG to determine the degradation reaction of probiotics.