Effect of pH and water activity on a probiotic and Lactobacillus viability microencapsulated in apple juice and alginate during refrigerated storage

This work aimed to assess the effect of pH [3.0 and 3.6] and water activity [aw; 0.99, 0.97, 0.96, or 0.94] on alginate beads formulated with apple juice on the viability of Lactiplantibacillus plantarum 299v, Limosilactobacillus reuteri NRRLB-14171, Lactobacillus acidophilus NRRLB-4495, or Lacticaseibacillus casei NRRLB-1922 during the encapsulation process and after 7 days of refrigerated storage. In addition, sensory tests of alginate beads formulated with apple juice and L. reuteri were conducted. The aw did not affect Lactobacillus viability, whereas pH had only a slight effect on their survival. Encapsulation yields exceeded 90% across all tested conditions and bacteria. After 7 days of storage at 5 °C, <1 log10 CFU/g was reduced in Lactobacillus counts. Beads formulated with apple juice at pH 3.6 and aw of 0.97 were the best accepted by the panelists.