Morphological, thermal, and structural aspects of dried and redispersed nanofibrillated cellulose (NFC)

Holzforschung ◽  
2014 ◽  
Vol 68 (6) ◽  
pp. 657-667 ◽  
Author(s):  
Vesna Žepič ◽  
Erika Š. Fabjan ◽  
Marta Kasunič ◽  
Romana C. Korošec ◽  
Aleš Hančič ◽  
...  
Keyword(s):  
Spray Drying ◽  
Network Formation ◽  
Fine Powder ◽  
Nanofibrillated Cellulose ◽  
Freeze Dried ◽  
Drying Treatment ◽  
Dehydration Processes ◽  
Structural Behaviors ◽  
Structural Aspects ◽  
Aggregation Phenomena

Abstract The effects of various drying techniques, such as air, oven, freeze, and spray drying, on the morphological, thermal, and structural behaviors of two different nanofibrillated cellulose (NFC) materials were investigated. Field emission scanning electron microscopy (FE-SEM) observations indicated an interlaced network formation of predominantly in-plane fibrillar orientation for air- and oven-dried samples, while freeze and spray drying resulted in the formation of coarse and fine powder fractions. Comparison of redispersed powders obtained by freeze and spray drying indicated that aggregation phenomena are significantly reduced in freeze-dried specimens. Rheological and sedimentation analysis revealed that the freeze-dried NFC powders are more stable than spray-dried NFC powders when redispersed in water. Aggressive dehydration processes, such as freezing or heating, significantly influence the thermal stability of the dried cellulose samples. On the contrary, the crystallinity properties of dried NFC materials are very similar regardless of the drying treatment.

scholarly journals Effect of spray drying treatment on the optical properties of Mg–Al spinel ceramics

Open Ceramics ◽  
2021 ◽  
Vol 6 ◽  
pp. 100102
Author(s):  
Robin Stocky ◽  
Judith Boehmler ◽  
Sébastien Lemonnier ◽  
Pierre Gibot ◽  
Yannick Lorgouilloux ◽  
...  
Keyword(s):  
Optical Properties ◽  
Spray Drying ◽  
Drying Treatment

scholarly journals The Quality of Red Bell Pepper Subjected to Freeze-Drying Preceded by Traditional and Novel Pretreatment

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 226
Author(s):  
Katarzyna Rybak ◽  
Artur Wiktor ◽  
Dorota Witrowa-Rajchert ◽  
Oleksii Parniakov ◽  
Małgorzata Nowacka
Keyword(s):  
Freeze Drying ◽  
Bell Pepper ◽  
Total Phenolic ◽  
Thermal Methods ◽  
Drying Time ◽  
Freeze Dried ◽  
Dehydration Processes ◽  
Vacuum Freezing ◽  
Better Than

It has been demonstrated previously in the literature that utilization of PEF or a combination of a pulsed electric field (PEF) and ultrasounds (US) can facilitate dehydration processes and improve the quality of dried products even better than the application of thermal methods such as blanching. The aim of the study was to evaluate the quality of red bell pepper subjected to freeze-drying preceded by blanching or PEF or US treatment applied in a single and combined mode. Furthermore, the freeze-drying was preceded by shock freezing or vacuum freezing performed inside the freeze-dryer as a result of pressure drop during the first stage of freeze-drying. All of the analyzed technological variants enhanced the drying kinetics when compared to the intact material. Freeze-dried bell pepper subjected to non-thermal pretreatment exhibited higher vitamin C, total phenolic and carotenoids content than blanched material despite the fact that blanching reduced drying time the most compared to all other analyzed methods.

scholarly journals Comparison between freeze and spray drying to obtain powder Rubrivivax gelatinosus biomass

2013 ◽  
Vol 33 (1) ◽  
pp. 47-51 ◽  
Author(s):  
Edson Francisco do Espírito Santo ◽  
Leandro Kanamaru Franco de Lima ◽  
Ane Pamela Capucci Torres ◽  
Gabriela de Oliveira ◽  
Elisa Helena Giglio Ponsano
Keyword(s):  
Spray Drying ◽  
Freeze Drying ◽  
Bacterial Biomass ◽  
Quality Criterion ◽  
Industrial Effluents ◽  
Product Recovery ◽  
Animal Origin ◽  
Freeze Dried ◽  
Rubrivivax Gelatinosus ◽  
Industry Effluent

The use of colorants in products of animal origin is justified by the improvement in the color of foods since this attribute is considered a quality criterion. These additives can be produced using industrial effluents as substrates and appropriate organisms, such as Rubrivivax gelatinosus. Oxycarotenoids represent a class of carotenes responsible for the pigmentation of animals and vegetables. R. gelatinosus grows in fish industry effluent with the resulting production of a bacterial biomass containing oxycarotenoids. The purpose of this study was to compare the use of two drying processes - spray and freeze drying - to obtain powder biomass in terms of the process parameters (yield, productivity, and product recovery) and the product characteristics (color, proximate composition, and oxycarotenoids). No difference was detected in the yield between these techniques, while productivity was higher using spray drying. Higher product recovery and moisture were achieved with freeze drying, while ash was higher with spray drying. The freeze dried biomass was redder, darker and less saturated than the spray dried biomass. No difference in oxycarotenoids was detected between the biomasses. Although it results in lower recovery rate, spray drying was faster and more productive, and it provided the same yield as freeze drying, which makes it the method of choice for obtaining R. gelatinosus biomass.

scholarly journals Freeze versus Spray Drying for Dry Wild Thyme (Thymus serpyllum L.) Extract Formulations: The Impact of Gelatin as a Coating Material

2021 ◽  
Author(s):  
Aleksandra A. Jovanović ◽  
Steva M. Lević ◽  
Vladimir B. Pavlovic ◽  
Smilja B. Markovic ◽  
Rada V. Pjanovic ◽  
...  
Keyword(s):  
Spray Drying ◽  
Dry Weight ◽  
Drying Process ◽  
Scanning Calorimetry ◽  
Coating Agent ◽  
Microwave Assisted ◽  
Freeze Dried ◽  
Wild Thyme ◽  
The Impact ◽  
Spray Dried

Freeze drying was compared with spray drying regarding feasibility to process wild thyme drug in order to obtain dry formulations at laboratory scale starting from liquid extracts produced by different extraction methods: maceration, heat-, ultrasound-, and microwave-assisted extractions. Higher powder yield (based on the dry weight prior to extraction) was achieved by freeze than spray drying and lower loss of total polyphenol content (TPC) and total flavonoid content (TFC) due to the drying process. Gelatin as a coating agent (5% w/w) provided better TPC recovery by 70% in case of lyophilization and higher powder yield in case of spray drying by diminishing material deposition on the wall of the drying chamber. The resulting gelatin-free and gelatin-containing powders carried polyphenols in amount ~190 and 53-75 mg gallic acid equivalents GAE/g of powder, respectively. Microwave-assisted extract formulation distinguished from others by higher content of polyphenols, proteins and sugars, higher bulk density and lower solubility. The type of the drying process affected mainly position of the gelatin-derived -OH and amide bands in FTIR spectra. Spray dried formulations compared to freeze dried expressed higher thermal stability as confirmed by differential scanning calorimetry analysis and higher diffusion coefficient; the last feature can be associated with the lower specific surface area of irregularly shaped freeze-dried particles (151-223 µm) compared to small microspheres (~8 µm) in spray-dried powder.

Structural Aspects of Dehydration Processes in Rubidium-, Potassium- and Sodium p-Nitrosophenolates

1993 ◽  
Vol 28 (8) ◽  
pp. 1153-1162
Author(s):  
P. Milart ◽  
E. Kapturkiewicz-Kowal ◽  
B. Borzecka-Prokop
Keyword(s):  
Dehydration Processes ◽  
Structural Aspects

COST-FP1105: Properties of PLA films reinforced with unmodified and acetylated freeze dried nanofibrillated cellulose

Holzforschung ◽  
2016 ◽  
Vol 70 (12) ◽  
pp. 1125-1134 ◽  
Author(s):  
Vesna Žepič ◽  
Ida Poljanšek ◽  
Primož Oven ◽  
Matjaž Čop
Keyword(s):  
Heterogeneous System ◽  
Cellulose Nanofibrils ◽  
Composite Films ◽  
Hydrophobic Surface ◽  
Nanofibrillated Cellulose ◽  
Nanocomposite Films ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Elongation At Break ◽  
Freeze Dried

Abstract Freeze dried nanofibrils were acetylated in a heterogeneous system with acetic anhydride, pyridine, and dimethylformamide and the obtained acetylated cellulose nanofibrils (CNFac) were combined with poly(lactic acid) (PLA) to a composite. CNFac with its partially hydrophobic surface showed a good compatibility with PLA resulting in composite films with improved properties. Tensile strength (TS), modulus of elasticity (MOE), and elongation at break (EB) of PLA/CNF increased significantly when 2–5% of CNFac was added to the PLA matrix, while the addition of 10% and higher amounts CNFac decreased the EB at a higher TS and MOE. Mechanical parameters did not improve in the case of unmodified CNF addition. The addition of CNFac maintained transparency and had absorbance values between those of pure PLA film and PLA film with 2% CNF, while films formed with the addition of 5 and 10% of CNF were less transparent. The addition of CNF did not essentially affect the thermal properties of nanocomposite films. The addition of 2–10% of CNFac increased the enthalpy and maximal temperature of cold crystallization as opposed to higher loading of CNFac. The results of differential scanning calorimetry (DSC) coincide with those of the mechanical properties. Tailoring properties of PLA/CNF are only reproducible in case of homogenously distributed CNF within the PLA matrix and by an improved interphase adhesion between PLA and CNFac.

An assay for the measurement of the protein content of cells immobilized in carrageenan

1984 ◽  
Vol 30 (4) ◽  
pp. 475-481 ◽  
Author(s):  
A. Jones ◽  
T. Razniewska ◽  
B. H. Lesser ◽  
R. Siqueira ◽  
D. Berk ◽  
...  
Keyword(s):  
Protein Content ◽  
Immobilized Cells ◽  
Fine Powder ◽  
Cellular Protein ◽  
Cell Protein ◽  
Specific Productivity ◽  
Immobilized Cell ◽  
Freeze Dried ◽  
Lowry Method ◽  
Reproducible Method

A reliable and reproducible method for the estimation of the protein content of fungal cells immobilized in a carrageenan gel is described. The procedure depends upon the acid lability of the polysaccharide gel at 90 °C and on the acetone solubility of accumulated phenolics. Freeze-dried gel beads (2–3 mm) containing entrapped cells of Penicillium urticae were ground to a fine powder and samples of powder (~20 mg) were sequentially extracted with hot 1 N HCl – 0.9% NaCl and acetone. The precipitated residue contained the cell protein, which was then solubilized with 1 N NaOH at 90 °C and quantitated by the Folin–Lowry method. Interferences from both carrageenan and phenols were thus eliminated. The presence of carrageenan (20–25 mg) did not affect the recovery of varying amounts (0–2500 μg) of bovine serum albumin. The recovery of radiolabeled protein from immobilized cells was parallel to that of Folin–Lowry positive material over a range of 0–60 beads (0–60 mg powder). Cycloheximide (0–100 μg/mL) was shown to progressively inhibit the incorporation of L-[U-14C]leucine so that the radioactivity present in the initial HCl–NaCl extract (i.e., [14C]leucine) increased as that in the final NaOH extract (i.e., 14C-labeled protein) decreased. Using this new assay for cell protein, free and immobilized cell cultures were found to exhibit virtually identical kinetics of glucose utilization, growth, and patulin production. In addition to providing a means of comparing the specific productivity of free versus immobilized cell preparations, this assay accurately measures the incorporation of [14C]leucine into cellular protein and could be used as a measure of cell viability.

scholarly journals Characterization of a 23-kDa Protein from the Wood of Cornus sericea, whose Accumulation is Associated with Seasonal Changes in Cold Hardiness

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 647a-647 ◽  
Author(s):  
Eric Sarighausen ◽  
Edward Ashworth
Keyword(s):  
Cell Wall ◽  
Gel Electrophoresis ◽  
Cold Hardiness ◽  
Fine Powder ◽  
Cell Wall Fraction ◽  
Total Proteins ◽  
Predominant Component ◽  
Freeze Dried ◽  
Cornus Sericea ◽  
Tissue Characteristics

Deciduous trees vary in their ability to survive low winter temperatures. Among species studied, two distinct responses to freezing have been described: deep supercooling and extracellular freezing. The tissue characteristics that account for these different responses have not been identified, but it has been proposed that properties of the cell wall distinguish species that supercool from those that do not. Our present objective was to analyze proteins from the cell walls of Cornus sericea, an extremely freeze-tolerant species that does not supercool. Twigs were collected throughout the year. The bark was removed, and the remaining wood was frozen in LN2, freeze dried, and ground into a fine powder. Modifications of published protocols were used for the isolation of total proteins and cell wall proteins. The proteins in the cell wall fraction constituted only a small portion of the total proteins in wood ((<2%). SDS gel electrophoresis established at a single band corresponding to a 23-kDa protein was the predominant component in an extract from twigs in winter. The quantity of 23-kDa protein within the cell wall fraction varied with season. Levels were highest in winter, were reduced in spring, not detectable in summer, and increased in fall. Further analysis, using 2D gel electrophoresis, has shown that the 23-kDa band contains several proteins having similar MW and basic PI These proteins are glycosylated, and a partial amino acid sequence of one protein has been obtained.

scholarly journals Bioavailability of freeze-dried and spray-dried grapefruit juice vitamin C

2018 ◽  
Author(s):  
Nuria Martínez-Navarrete ◽  
María del Mar Camacho ◽  
Marta Igual ◽  
Juan José Martínez-Lahuerta
Keyword(s):  
Vitamin C ◽  
Spray Drying ◽  
Freeze Drying ◽  
Grapefruit Juice ◽  
Serum Vitamin ◽  
Relative Increase ◽  
Freeze Dried ◽  
Quality Product ◽  
High Quality Product ◽  
Powdered Form

An alternative as to offer higher stable and easy handling than fresh fruit is in powdered form, as long as the process used to obtain it ensures a high quality product. The objective of this study was to compare the bioavailability of the vitamin C of a juice prepared from powdered grapefruit obtained by freeze-drying and by spray-drying. A trial was conducted with 11 healthy volunteers. A relative increase of 1,4 – 25,8 % of blood serum vitamin C concentration was quantified after juices intake, with no significant differences (p&gt;0.05) due to the process used to obtain the powder. Keywords: vitamin C; bioavailability in humans; grapefruit powder; freeze-drying; spray-drying.

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