Experimental investigation and numerical modeling of pilot-scale fluidized-bed drying of yeast: Part A – Drying model development and validation

Soltani, Behdad; McClure, Dale D.; Oveissi, Farshad; Langrish, T.A.G.; Kavanagh, John M.

doi:10.1016/j.fbp.2019.11.008

Cited by 6 publications

(2 citation statements)

References 15 publications

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“…Freeze-drying of the same yeast strain has enabled survival rates up to 42.9% [ 9 ], and fluidized bed drying of Saccharomyces cerevisiae pellets (another strain), without protectants, has enabled survival rates of up to and more than 90% [ 47 , 48 ]. In contrast, only significantly lower survival rates are achieved in the present study.…”

Section: Resultsmentioning

confidence: 99%

Effect of Process Parameters, Protectants and Carrier Materials on the Survival of Yeast Cells during Fluidized Bed Granulation for Tableting

et al. 2023

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The administration of living microorganisms is of special interest, with regard to probiotic microorganisms providing health benefits to the patient. Effective dosage forms require the preservation of microbial viability until administration. Storage stability can be improved by drying, and the tablet is an especially attractive final solid dosage form due to its ease of administration and its good patient compliance. In this study, drying of the yeast Saccharomyces cerevisiae via fluidized bed spray granulation is investigated, as the probiotic Saccharomyces boulardii is a variety of it. Fluidized bed granulation enables faster drying than lyophilization on the one hand and lower temperatures than spray drying on the other hand, which are the two predominantly used techniques for life-sustaining drying of microorganisms. Yeast cell suspensions enriched with protective additives were sprayed onto the carrier particles of common tableting excipients, namely, dicalcium phosphate (DCP), lactose (LAC) and microcrystalline cellulose (MCC). Different protectants, such as mono-, di-, oligo- and polysaccharides, but also skimmed milk powder and one alditol, were tested; as they themselves, or chemically similar molecules, are known from other drying technologies to stabilize biological structures such as cell membranes, and thus, improve survival during dehydration. With the combined use of trehalose and skimmed milk powder, survival rates were 300 times higher than without the use of protective additives. In addition to these formulation aspects, the influence of process parameters such as inlet temperature and spray rate were considered. The granulated products were characterized regarding their particle size distribution, moisture content and the viability of the yeast cells. It has been shown that thermal stress on the microorganisms is especially critical, which can be reduced, for example, by reducing the inlet temperature or increasing the spray rate; however, formulation parameters such as cell concentration also influenced survival. The results were used to specify the influencing factors on the survival of microorganisms during fluidized bed granulation and to derive their linkages. Granules based on the three different carrier materials were tableted and the survival of the microorganisms was evaluated and linked to the tablet tensile strength achieved. Using LAC enabled the highest survival of the microorganisms throughout the considered process chain.

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Section: Resultsmentioning

confidence: 99%

Effect of Process Parameters, Protectants and Carrier Materials on the Survival of Yeast Cells during Fluidized Bed Granulation for Tableting

et al. 2023

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“…Wang, 10 Beigi, 15 and Srinivas 9 presented heat and mass transfer models to describe the phenomena within the dried particles in a batch fluidized bed dryer. Because fluidized bed drying has been developed over many years, many of the corresponding models and related approaches have been employed in various applications 16,29‐31. These thermodynamic models and mass transfer models deeply analyze the drying processes based on heat and mass transfer principles.…”

Section: Data Analysis and Case Studymentioning

confidence: 99%

An improved batch fluidized drying experimental design based on digital sensors and a minicomputer

Cui

Peng

et al. 2021

Engineering Reports

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In most undergraduate programs of chemical engineering in Chinese universities, the batch fluidized bed drying (BFBD) experiment is commonly adopted as a part of the experimental course of chemical engineering unit operation. In those BFBD experiments, the students should dry the material in a dryer, repeatedly sample and measure it outside to get its moisture content. In most cases, each sampling and measuring operation needs more than 5 min. The BFBD drying experiment conducted in that manner cannot obtain adequate, accurate data, making it difficult for the student to perform proper calculation and data analysis. In this article, the authors build a small BFBD prototype equipment and mount a set of digital temperature/humidity sensors. Then they use a Raspberry Pi 3, a kind of mini‐computer, to automatically measure and record the process parameters values online. Aided by those modern information process methods, the data accuracy and amount are all enhanced. Based on the gotten big data set, the student can get much more accurate results and do a more thorough analysis. The data analysis based on the old BFBD equipment is too straightforward and simple because it only needs the mass balance calculations. On the contrary, although the new BFBD equipment adopts an indirect way to measure the drying process, it obtains much more accurate results than before. The students must also apply more theories to get the results, such as mass transmission, the thermal balance, which makes the experiment more comprehensive. That is meaningful and helps to achieve the objectives of the chemical engineering experiments.

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Powders containing microorganisms and enzymes

Ghandi,

Adhikari,

Powell

2024

Handbook of Food Powders

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Experimental investigation and numerical modeling of pilot-scale fluidized-bed drying of yeast: Part A – Drying model development and validation

Cited by 6 publications

References 15 publications

Effect of Process Parameters, Protectants and Carrier Materials on the Survival of Yeast Cells during Fluidized Bed Granulation for Tableting

Effect of Process Parameters, Protectants and Carrier Materials on the Survival of Yeast Cells during Fluidized Bed Granulation for Tableting

An improved batch fluidized drying experimental design based on digital sensors and a minicomputer

Powders containing microorganisms and enzymes

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