The protective agents (Table 1 ) were purchased from Sigma-Aldrich except d -mannose, d -xylose, d -fructose, d -galactose (Duchefa, Haarlem, The Netherlands), and glycerol, magnesium sulfate heptahydrate (Duksan, Ansan, Korea), and l -fucose (Carbosynth, Newbury, UK), and peptone, skim milk, yeast extract (Difco, Detroit, MI, USA), and taurine (Daejung, Siheung, Korea), and isomaltooligosaccharide, l -rhamnose (WAKO, Osaka, Japan), and d -maltose (YAKURI, Osaka, Japan).
To prepare the cells, S. cerevisiae 88-4 was cultured in YPD broth (1% inoculum) at 30 °C for 18 h, corresponding to approximately 107 CFU/mL. Cells were centrifuged at 3000× g at 4 °C for 15 min and washed with 0.85% NaCl solution. Prior to the experiments, all protective agents were sterilized under UV for 18 h. The concentrations of each protectant were described inTable 1 . Cells were resuspended in 1 mL protective agent solution as the freeze-dried sample, or 1 mL distilled water as a blank. Suspensions were frozen in a deep freezer at −80 °C for 3 h. Subsequently, freeze-drying was conducted under vacuum at 5 Pa for 24 h with a condenser temperature of −51 °C. Freeze-dried cells were immediately used to determine the survival rate. All protective agents were used directly with the yeast pellet.
To prepare the cells, S. cerevisiae 88-4 was cultured in YPD broth (1% inoculum) at 30 °C for 18 h, corresponding to approximately 107 CFU/mL. Cells were centrifuged at 3000× g at 4 °C for 15 min and washed with 0.85% NaCl solution. Prior to the experiments, all protective agents were sterilized under UV for 18 h. The concentrations of each protectant were described in