scholarly journals Microwave Technology in Freeze-Drying Process

2018 ◽  
Author(s):  
Mohsen Kalantari
Keyword(s):  
Freeze Drying ◽  
Drying Process ◽  
Microwave Technology

Video real-time imaging of artificial membranes during freeze-drying by cryo-electron microscopy

1988 ◽  
Vol 46 ◽  
pp. 16-17
Author(s):  
Alan S. Rudolph ◽  
Ronald R. Price
Keyword(s):  
Real Time ◽  
Self Assembly ◽  
Freeze Drying ◽  
Video Capture ◽  
Drying Process ◽  
Artificial Membranes ◽  
The Past ◽  
Cryo Electron Microscopy ◽  
Spherical Structures ◽  
Capture Techniques

We have employed cryoelectron microscopy to visualize events that occur during the freeze-drying of artificial membranes by employing real time video capture techniques. Artificial membranes or liposomes which are spherical structures within internal aqueous space are stabilized by water which provides the driving force for spontaneous self-assembly of these structures. Previous assays of damage to these structures which are induced by freeze drying reveal that the two principal deleterious events that occur are 1) fusion of liposomes and 2) leakage of contents trapped within the liposome [1]. In the past the only way to access these events was to examine the liposomes following the dehydration event. This technique allows the event to be monitored in real time as the liposomes destabilize and as water is sublimed at cryo temperatures in the vacuum of the microscope. The method by which liposomes are compromised by freeze-drying are largely unknown. This technique has shown that cryo-protectants such as glycerol and carbohydrates are able to maintain liposomal structure throughout the drying process.

scholarly journals Strengthening of Porcine Plasma Protein Superabsorbent Materials through a Solubilization-Freeze-Drying Process

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 772
Author(s):  
Estefanía Álvarez-Castillo ◽  
Carlos Bengoechea ◽  
Antonio Guerrero
Keyword(s):  
Water Uptake ◽  
Plasma Protein ◽  
Freeze Drying ◽  
Meat Industry ◽  
Drying Process ◽  
Uptake Capacity ◽  
Water Uptake Capacity ◽  
Protein Flour ◽  
Hydrophilic Materials ◽  
By Products

The replacement of common acrylic derivatives by biodegradable materials in the formulation of superabsorbent materials would lessen the associated environmental impact. Moreover, the use of by-products or biowastes from the food industry that are usually discarded would promote a desired circular economy. The present study deals with the development of superabsorbent materials based on a by-product from the meat industry, namely plasma protein, focusing on the effects of a freeze-drying stage before blending with glycerol and eventual injection molding. More specifically, this freeze-drying stage is carried out either directly on the protein flour or after its solubilization in deionized water (10% w/w). Superabsorbent materials obtained after this solubilization-freeze-drying process display higher Young’s modulus and tensile strength values, without affecting their water uptake capacity. As greater water uptake is commonly related to poorer mechanical properties, the proposed solubilization-freeze-drying process is a useful strategy for producing strengthened hydrophilic materials.

scholarly journals Studies on the Catalytic Properties of Crude Freeze-Dried Preparations of Yarrowia lipolytica Extracellular Lipases for Geranyl Ester Derivative Synthesis

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 839
Author(s):  
Karina Jasińska ◽  
Bartłomiej Zieniuk ◽  
Dorota Nowak ◽  
Agata Fabiszewska
Keyword(s):  
Freeze Drying ◽  
Antioxidant Properties ◽  
Antibacterial Properties ◽  
Synthetic Activity ◽  
Drying Process ◽  
Enzyme Preparations ◽  
Ester Derivative ◽  
Freeze Dried ◽  
The Impact ◽  
Geranyl Ester

The study aimed to evaluate the impact of selected factors of the freeze-drying process on the hydrolytic and synthetic activity of the extracellular lipases of Y. lipolytica KKP 379 and to attempt the use of the crude enzyme preparation as a biocatalyst in the synthesis of geranyl 4-hydroxyphenylpropanoate. Antioxidant and antibacterial properties of the geranyl ester derivative were also investigated in order to evaluate their usefulness as a novel food additive. The studies confirmed that freeze-drying was an effective method of dehydrating yeast supernatant and allowed for obtaining lyophilizates with low water activity from 0.055 to 0.160. The type and concentration of the additive (2–6% whey protein hydrolyzate, 0.5% and 1% ammonium sulphate) had a significant effect on the hydrolytic activity of enzyme preparations, while the selected variants of drying temperature during the freeze-drying process were not significant (10 °C and 50 °C). Low yield of geranyl 4-hydroxyphenylopropionate was shown when the lyophilized supernatant was used (5.3%), but the yield of ester synthesis increased when the freeze-dried Y. lipolytica yeast biomass was applied (47.9%). The study confirmed the antioxidant properties of the synthesized ester by the DPPH• and CUPRAC methods, as well as higher antibacterial activity against tested bacteria than its precursor with 0.125 mM MIC (minimal inhibitory concentration) against L. monocytogenes.

Choked flow and importance of Mach I in freeze-drying process design

2010 ◽  
Vol 65 (21) ◽  
pp. 5716-5727 ◽  
Author(s):  
Sajal M. Patel ◽  
Swetaprovo Chaudhuri ◽  
Michael J. Pikal
Keyword(s):  
Process Design ◽  
Freeze Drying ◽  
Drying Process ◽  
Choked Flow

Innovative freeze-drying process based on self-heat recuperation technology

2017 ◽  
Vol 168 ◽  
pp. 1244-1250 ◽  
Author(s):  
Kenta Bando ◽  
Yasuki Kansha ◽  
Masanori Ishizuka ◽  
Atsushi Tsutsumi
Keyword(s):  
Freeze Drying ◽  
Drying Process ◽  
Heat Recuperation

scholarly journals Freeze-drying microscopy in mathematical modeling of a biomaterial freeze-drying

2012 ◽  
Vol 48 (2) ◽  
pp. 203-209 ◽  
Author(s):  
Camila Figueiredo Borgognoni ◽  
Joyce da Silva Bevilacqua ◽  
Ronaldo Nogueira de Moraes Pitombo
Keyword(s):  
Mathematical Modeling ◽  
Freeze Drying ◽  
Drying Process ◽  
Critical Temperatures ◽  
Fundamental Properties ◽  
Moving Interface ◽  
Energy Consuming ◽  
Sublimation Rates ◽  
Time And Energy

Transplantation brings hope for many patients. A multidisciplinary approach on this field aims at creating biologically functional tissues to be used as implants and prostheses. The freeze-drying process allows the fundamental properties of these materials to be preserved, making future manipulation and storage easier. Optimizing a freeze-drying cycle is of great importance since it aims at reducing process costs while increasing product quality of this time-and-energy-consuming process. Mathematical modeling comes as a tool to help a better understanding of the process variables behavior and consequently it helps optimization studies. Freeze-drying microscopy is a technique usually applied to determine critical temperatures of liquid formulations. It has been used in this work to determine the sublimation rates of a biological tissue freeze-drying. The sublimation rates were measured from the speed of the moving interface between the dried and the frozen layer under 21.33, 42.66 and 63.99 Pa. The studied variables were used in a theoretical model to simulate various temperature profiles of the freeze-drying process. Good agreement between the experimental and the simulated results was found.

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