Stability of spray-dried synbiotics containing Lactobacillus plantarum DSM 2648 and exopolysaccharide from Pediococcus acidilactici TISTR 2612 and its vivo effectiveness

Abstract

Spray drying is an economical process for dehydrating microorganisms into a powder form
that preserves viability for use at the industrial scale. It is especially applicable for probiotics
and other temperature sensitive functional foods. In this study, the survival and functionality
of synbiotics were evaluated after spray drying. A mixture of stationary phase probiotic culture
(Lactobacillus plantarum DSM 2648) and 2 % (w/v) of exopolysaccharide (EPS) produced
from Pediococcus acidilactici TISTR2612 was spray-dried with outlet air temperature of
70 ±1°C. Results showed a probiotic survival rate decrease from 96.74 % (log 10.04 CFU/g)
after spray-drying to 96.01, 96.00, 93.18 and 92.17 % during room temperature storage in a
desiccator for 1, 2, 3 and 4 weeks, respectively. In simulated gastric juice (pH 2) and in 2 %
of bile salts solution, probiotics survival rates were 97.94 and 91.56 % and EPS hydrolysis
reached 3.26 and 7.23 %, respectively, after incubation at 37 °C for 12 h. In vivo testing of the
impact of synbiotics on reducing colorectal cancer risk showed a significant decrease of
β-glucuronidase bacterial enzyme activity, with 36.56 and 50.55 % reduction in male and
female rats, respectively. Finally, the acute oral toxicity (LD50) testing was performed by
feeding rats with the maximum dose of synbiotics (5 g per kg body weight). No mortality or
organ abnormalities (from necropsy findings) were observed in any of the rats after oral
administration for 15 days. These results suggest that synbiotics could potentially be a safe
functional food for aiding disease prevention in the future.