科研之友
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摘要
In the present research, an air-suspension fluidized-bed technique for generation of core and shell microcapsules containing probiotic Lactobacillusparacasei cells was evaluated. The air-suspension process was performed in a Wurster coater system with a bottom-spraying atomizer. In the first stage, a solution containing trehalose, maltodextrin, and probiotic cells was spray-coated onto and absorbed by the inert carrier microcrystalline cellulose to produce nonagglomerating dry coated particles with high probiotic cell viability (10 9 colony-forming units [cfu]/g particles). The effect of inlet air temperature, spray flow rate, solids concentration, cell concentration, and encapsulation formulation on survival was investigated. The inlet air temperature had the most pronounced effect; a 15 degrees C increase in inlet air temperature led to a 250-fold decrease in survival percentage. There was no agglomeration of the coated adsorbed particles at spray flow rates of 1 to 3.5 mL/min. Spray-coating was performed with both laboratory-and pilot-scale Wurster systems. Scaling up the equipment from the lab scale to the pilot scale did not affect cell survival percentage. Low solids concentration (%26lt;20%) and low probiotic cell concentration (6%) resulted in a fair survival percentage (35-40). Spraying a solution formulation of trehalose-maltodextrin with dextrose equivalent (DE) 3 at a 1: 1 ratio provided the best protection in terms of cell viability during the spray-coating process as well during storage. Layering with ethylcellulose (ETHOCEL) provided some protection in a low acidic environment (12%); however, the nonuniform coating and cracks detected by scanning electron microscopy (SEM) imaging were the main reasons for the layering%26apos;s relatively poor protection of the cells against humidity, oxygen, and acid environment.
- 出版日期2012
