Influence of protectant for encapsulation by freeze-drying and spray-drying techniques, and packaging environments on the stability of the probiotic Bifidobacterium animalis subsp. lactis strain KMP-H9-01 during storage

Abstract

The process of drying probiotic bacteria to enhance their storage stability is important for the food industry. This study aimed to assess the efficacy of various drying techniques and food-grade protectants in preserving the viability of Bifidobacterium animalis subsp. lactis KMP H9-01 during drying and under prolonged storage conditions. Among the four protectants tested (skim milk, trehalose, sucrose, and maltodextrin), trehalose and skim milk at 5% (w/v) were selected for freeze- and spray-drying, each conducted at different temperatures. This evaluation encompasses survivability and the observation of the shelf life of probiotic powders. The results demonstrated that spray-drying at 160 °C/80 °C, with either skim milk or trehalose as a protectant, yielded the highest viable cell counts (>log 7 CFU/g) even after 6 months of storage at room temperature in the range of 25–30 °C, regardless of the use of vacuum and nonvacuum packaging. Notably, the calculated inactivation rate values (KRT) demonstrated remarkable stability, ranging from 5.36 × 10−2 to 5.82 × 10−2 day−1. Furthermore, the decimal reduction time (DRT) values predicted that a 90% reduction in probiotic cell number would require approximately 1.3 to 1.4 months at room temperature.