Related Experiment Video
Updated: Jan 22, 2026

Evaluation of the Storage Stability of Extracellular Vesicles
Published on: May 22, 2019
Comprehensive optimization of composite cryoprotectant for Saccharomyces boulardii during freeze-drying and
Shu Guowei1, Xin Yang1, Chen Li2
1School of Food and Biological Engineering, Shaanxi University of Science and Technology , Xi'an , China.
Abstract:
Saccharomyces boulardii (S. boulardii) is widely adopted in the diarrhea treatment for humans or livestock, so guaranteeing the survival rate of S. boulardii is the critical issue during freeze-drying process. In this study, the survival rate of S. boulardii with composite cryoprotectants during freeze-drying procedure and the subsequent storage were investigated. With the aid of response surface method, the composite cryoprotectants were comprehensively optimized to be lactose of 21.24%, trehalose of 22.00%, and sodium glutamate of 4.00%, contributing to the supreme survival rate of S. boulardii of 64.22 ± 1.35% with the viable cell number of 9.5 ± 0.07 × 109 CFU/g, which was very close to the expected rate of 65.55% with a number of 9.6 × 109 CFU/g. The accelerated storage test demonstrated that the inactivation rate constant of the freeze-dried S. boulardii powder was k-18 = 8.04 × 10-6. In addition, the freeze-dried goat milk powder results exhibited that the inactivation rate constants were k4 = 4.48 × 10-4 and k25 = 9.72 × 10-3 under 4 and 25 °C, respectively. This work provides a composite cryoprotectant formulation that has a good protective effect for the probiotic S. boulardii during freeze-drying process, possessing the potential application prospect in food, medicine, and even feed industry.
Related Concept Videos
Storage
Nuclear Stability
To hold positively charged protons together...
RNA Stability
Freezing Point Depression and Boiling Point Elevation
The boiling point of a liquid is the temperature at which its vapor pressure is equal to ambient atmospheric pressure. Since the vapor pressure of a solution is lowered due to the presence of nonvolatile solutes, it stands to reason that the solution’s boiling point will subsequently be increased. Vapor pressure increases with temperature, and so a solution will require a higher temperature than will pure solvent to achieve any given vapor pressure, including one...
Classifying Matter by Composition
According to its composition, the matter can be classified into two broad categories — pure substances and mixtures.
A pure substance is a form of matter that has a constant composition throughout with uniform properties. For example, any sample of sucrose has the same composition and same physical properties, such as melting point, color, and sweetness, regardless of the source from which it is isolated.
A mixture is composed of two or...
Phase Transitions: Melting and Freezing

