Kinetics of atmospheric freeze-drying of apple

2007 ◽  
pp. 159-172 ◽  
Author(s):  
Jan Stawczyk ◽  
Sheng Li ◽  
Dorota Witrowa-Rajchert ◽  
Anna Fabisiak
Keyword(s):  
Freeze Drying ◽  
Kinetics Of

scholarly journals Morphology and Release Kinetics of Protein-Loaded Porous Poly(L-Lactic Acid) Spheres Prepared by Freeze-Drying Technique

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Takashi Sasaki ◽  
Kazuki Tanaka ◽  
Daisuke Morino ◽  
Kensuke Sakurai
Keyword(s):  
Lactic Acid ◽  
Freeze Drying ◽  
Release Kinetics ◽  
Particle Surface ◽  
Spherical Particles ◽  
Freeze Dried ◽  
Model Drug ◽  
Drug Compound ◽  
Kinetics Of ◽  
Step Mechanism

Freeze-drying a biodegradable polymer, poly(L-lactic acid) (PLLA), from 1,4-dioxane solutions provided very porous spherical particles of ca. 3 mm in radius with specific surface area of 8–13 m2 g−1. The surface of the particle was found to be less porous compared with its interior. To apply the freeze-dried PLLA (FDPLLA) to drug delivery system, its morphology and drug releasing kinetics were investigated, bovine serum albumin (BSA) being used as a model drug compound. Immersion of FDPLLA into a BSA aqueous solution gave BSA-loaded FDPLLA, where mass fraction of the adsorbed BSA reached up to 79%. Time-dependent release profile of BSA in water suggested a two-step mechanism: (1) very rapid release of BSA deposited on and near the particle surface, which results in an initial burst, and (2) leaching of BSA from the interior of the particle by the diffusion process. It was suggested that the latter process is largely governed by the surface porosity. The porosity of both the interior and surface was found to decrease remarkably as the concentration of the original PLLA/1,4-dioxane solution increases, C0. Thus, C0 is a key parameter that controls the loading and releasing of BSA.

Freeze Drying Kinetics of Sucrose-NaCl-Protein Aqueous Mixtures

1998 ◽  
Vol 51 (3) ◽  
pp. 905-911 ◽  
Author(s):  
J. M. Saiter ◽  
N. Delahaye ◽  
A. Bardat ◽  
E. Chatenet
Keyword(s):  
Freeze Drying ◽  
Drying Kinetics ◽  
Aqueous Mixtures ◽  
Kinetics Of

Analysis of Freeze-Drying and Rehydration of Açai (Euterpe oleracea Martius)

2015 ◽  
Vol 365 ◽  
pp. 11-16
Author(s):  
R.J. Brandão ◽  
M.M. Prado ◽  
L.G. Marques
Keyword(s):  
Mass Transfer ◽  
Energy Demand ◽  
Freeze Drying ◽  
Moisture Diffusion ◽  
Euterpe Oleracea ◽  
Power Ultrasound ◽  
Ultrasound Waves ◽  
Freeze Dried ◽  
Peleg’S Equation ◽  
Kinetics Of

The freeze-drying rate is essentially low, since it is controlled by internal moisture diffusion. In addition, the application of vacuum and low temperature during the process presents a higher energy demand. Therefore, the search for new strategies to improve water mobility during freeze-drying constitutes a topic of relevant research. The aim of this work was to evaluate the use of power ultrasound to improve freeze-drying characteristics of açai, quantifying the influence of the applied power on both the drying and rehydration kinetics of the material. Açai (Euterpe oleracea Martius) samples were sonicated with two different frequency levels, 20 kHz and 40 kHz, and two sonication times, 3 min and 10 min. Page’s equation considering internal and external resistances to mass transfer provided a good fit of freeze-drying kinetics, while the Peleg’s equation was found to be suitable for describing the rehydration kinetics of freeze-dried açai. Pretreatment of açai with ultrasound waves was not effective. Ultrasound-induced structural disruption in the açai skin hindered the mass transfer during both freeze-drying and rehydration processes.

scholarly journals Effect of Carboxylmethyl Cellulose Coating and Osmotic Dehydration on Freeze Drying Kinetics of Apple Slices

Foods ◽  
2013 ◽  
Vol 2 (2) ◽  
pp. 170-182 ◽  
Author(s):  
Jamshid Rahimi ◽  
Ashutosh Singh ◽  
Peter Adewale ◽  
Akinbode Adedeji ◽  
Michael Ngadi ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Osmotic Dehydration ◽  
Drying Kinetics ◽  
Apple Slices ◽  
Kinetics Of

Influence of structure on freeze‐drying kinetics of instant coffee

2020 ◽  
Vol 92 (9) ◽  
pp. 1332-1332
Author(s):  
P. Levin ◽  
V. Meunier ◽  
S. Palzer ◽  
S. Heinrich
Keyword(s):  
Freeze Drying ◽  
Drying Kinetics ◽  
Instant Coffee ◽  
Kinetics Of

Aerosol survival of Serratia marcescens as a function of oxygen concentration, relative humidity, and time

1974 ◽  
Vol 20 (11) ◽  
pp. 1529-1534 ◽  
Author(s):  
C. S. Cox ◽  
S. J. Gagen ◽  
Jean Baxter
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Relative Humidity ◽  
Serratia Marcescens ◽  
Oxygen Concentration ◽  
Freeze Drying ◽  
Cytoplasmic Membrane ◽  
Cell Wall Synthesis ◽  
Freeze Dried ◽  
Kinetics Of

Previously the kinetics of loss of viability of freeze-dried Serratia marcescens 8UK were determined by Cox and Heckly as a function of oxygen concentration and time. Results are presented here when dehydration is brought about by aerosolization into atmospheres of low relative humidity (RH) rather than by freeze-drying. As for freeze-dried S. marcescens, oxygen was toxic and viable decay followed the same kinetics with respect to oxygen concentration and time. The influence of RH upon viable decay (which was not studied in the previous report) was that above 65% RH oxygen was not toxic but was progressively more toxic as the humidity was further reduced. Kinetic analyses of the results indicate that the site for the toxic action of oxygen lies in the interspace between the cytoplasmic membrane and the cell wall. Such a finding is consistent with other data which suggest that cell division and (or) cell wall synthesis in bacteria are inhibited by oxygen.

scholarly journals Physicochemical and Quality Properties of Dried Courgette Slices: Impact of Vacuum Impregnation and Drying Methods

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4597
Author(s):  
Magdalena Kręcisz ◽  
Bogdan Stępień ◽  
Marta Pasławska ◽  
Jarosław Popłoński ◽  
Kinga Dulak
Keyword(s):  
Water Activity ◽  
Bioactive Compounds ◽  
Logistic Model ◽  
Freeze Drying ◽  
Convective Drying ◽  
Vacuum Impregnation ◽  
Drying Methods ◽  
Drying Time ◽  
Quality Properties ◽  
Kinetics Of

The aim of this study was to determine the effects that the type of impregnating solution and drying method (freeze drying (FD) and vacuum drying (VD) at 45 °C and convective drying (CD) at 50, 60, and 70 °C) had on the physicochemical and quality properties of courgettes. Courgette slices were vacuum-impregnated (6 kPa) in freshly squeezed onion, kale, and onion and kale (50:50) juices with 3% NaCl solution (N). The application of vacuum impregnation (VI) with impregnating solutions from freshly squeezed onions and kale had a beneficial effect on the bioactive values of courgette. The highest contents of quercetin (41.84 μg/g d.m.) and carotenoids (276.04 μg/g d.m.) were found in courgette impregnated with onion juice after freeze drying. The highest values of lutein and zeaxanthin (216.42 μg/g d.m.) were recorded for courgette impregnated with kale juice and convective dried. By analysing the kinetics of convective drying, the best matching of the logistic model was found. Increasing the drying process temperature from 50 to 70 °C reduced the drying time from 15% to 36%, depending on the type of impregnating solution used. Water activity <0.6 was recorded for courgette dried by freezing, vacuum, and convection at 60 and 70 °C. Conclusions: The vacuum impregnation process and the impregnation solutions from freshly squeezed vegetables can be used to develop new snacks with high levels of bioactive compounds. The FD method is the most appropriate considering both the bioactive compounds content and the obtained colour and water activity.

scholarly journals Novel Cellulose Nanofibers/Polyvinyl Alcohol/Polyethyleneimine Nanoparticle for Cu2+ Removal in Water

2021 ◽  
Author(s):  
Rongrong Si ◽  
Chaojun Wu ◽  
Dongmei Yu ◽  
Qijun Ding ◽  
Ronggang Li
Keyword(s):  
Polyvinyl Alcohol ◽  
Freeze Drying ◽  
Removal Rate ◽  
Cellulose Nanofibers ◽  
Drying Method ◽  
Order Model ◽  
Bending Vibration ◽  
Pseudo Second Order ◽  
Kinetics Of ◽  
Structurally Stable

Abstract In this study, environmentally friendly CNF/PVA/PEI nanoparticle was obtained by assembling PEI (polyethyleneimine) into CNF/PVA aerogels, which were prepared by freeze-drying method with the help of glutaraldehyde. FTIR results showed that PEI likely assembled into the CNF/PVA aerogel due to appearances of bending vibration of the CNF/PVA/PEI nanoparticle at 1615cm− 1. BET results further demonstrated that PEI have successfully assembled into aerogel since the specific surface area (22.93m2/g) of CNF/PVA/PEI nanoparticle was lower than that (56.37m2/g) of CNF/PVA aerogel. SEM results also showed that PEI could obviously regulate the morphology of CNF/PVA aerogel. TGA indicated that CNF/PVA/PEI nanoparticle was structurally stable at 216.4°C. The adsorption kinetics of the CNF/PVA/PEI nanoparticle for Cu2+ removal presented good correlations with the Pseudo-second-order model. The adsorption and desorption results showed that the removal rate of 2g/L CNF/PVA/PEI nanoparticle for Cu2+in water could reach more than 93% when the concentration of Cu2+ ranged from 20 to 80mg/L in one hour, and it could still retain more than 80% after 3 cycles.

Kinetics of Atmospheric Freeze-drying of Apple

2006 ◽  
Vol 66 (1-2) ◽  
pp. 159-172 ◽  
Author(s):  
Jan Stawczyk ◽  
Sheng Li ◽  
Dorota Witrowa-Rajchert ◽  
Anna Fabisiak
Keyword(s):  
Freeze Drying ◽  
Kinetics Of
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