The Effects of Cryoprotectants on the Survival Rate of Saccharomyces cerevisiae in a Freeze-Dried Gelatin Matrix
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Mi-Jung Choi
This study was carried out to determine the effects of cryoprotectants on yeast survival rate. Here, yeast was mixed with the following cryoprotectants: saccharose, hydroxyethylstarch, trehalose, lactose, caboxymethyl cellulose, and ?-carrageenan, and then frozen at -40°C, -30°C, and -18°C, respectively. The freeze-dried gelatin matrices were cut horizontally into 5 mm thick slices from the bottom and their pore sizes were measured. The freezing temperature (-40°C, -30°C, and -18°C) affected the freezing rate, and the partial freezing rate in the matrix was dependent on the distance. The higher the sample distance was from the bottom, the lower the partial freezing rate. We also found that the cryoprotectant concentration affected the freezing rate. Furthermore, the cryoprotectant and freezing rate affected the different survival rates of the yeast. The highest survival rate occurred with saccharose and trehalose, and was obtained by freezing at -40°C, which depended significantly on the concentration of trehalose. The ice dendrite sizes that formed during freezing at -40°C, -30°C, and -18°C showed a direct relationship with the freezing rate and cryoprotectant concentration. In the samples, the maximum primary ice dendrite size was 215.9 ?m at 1%, and the minimum primary ice dendrite size was 145.6 ?m at 5%, from the experiments at -18°C.
©2011 Walter de Gruyter GmbH & Co. KG, Berlin/Boston
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Articles in the same Issue
- Article
- The Effects of Cryoprotectants on the Survival Rate of Saccharomyces cerevisiae in a Freeze-Dried Gelatin Matrix
- Effect of Process Parameters on Quality Properties of Microwave Dried Red Pitaya (Hylocereus costaricensis)
- Sorption Drying of Soybean Seeds with Silica Gel in a Fluidized Bed Dryer
- Optimization of Osmotic Dehydration of Toona Sinensis Leaves Using Response Surface Methodology
- Droplet-Particle Agglomeration of Maltodextrin and Salt in a Small-Scale Spray Dryer
- Heat Pump Drying Kinetics of Spanish Cheese
- Guest Editorial
- Design of Hybrid Drying- Dedusting Unit Processor for Rough Rice Processing
- Fruits & Vegetables Drying Combining Hot Air, DIC Technology and Microwaves
- Diffusion Model for Apple Cubes Atmospheric Freeze-Drying with the Effect of Shrinkage
