Probiotic powders prepared by mixing suspension of Lactobacillus salivarius NRRL B-30514 and spray-dried lactose: Physical and microbiological properties.

Abstract

Preparation of powdered probiotics is important for storage and application. In this work, a novel method to prepare powdered probiotic ingredients was studied by mixing a Lactobacillus salivarius NRRL B-30514 suspension with amorphous spray-dried lactose at suspension: lactose (v:w) ratios (SLR) of 1:5, 1:15, and 1:25. The simple procedure resulted in lactose-probiotics powders (LPPs) with greater probiotic viability initially and during subsequent 6-month storage at a smaller SLR. In LPPs with SLRs of 1:5 and 1:15, X-ray diffraction spectroscopy and scanning electron microscopy results indicated the formation of lactose crystals, and BacLight® assay suggested the significantly lowered membrane integrity of probiotics due to hypertonic pressure of lactose dissolved in excessive water. A viable but non-culturable state of L. salivarius in LPPs may exist based on the BacLight® and CTC reduction assays. The present study may provide a novel approach to prepare powdered probiotic ingredients.