Open-Cellular Alumina Foams with Hierarchical Strut Porosity by Ice Templating: A Thickening Agent Study

Alumina replica foams were manufactured by the Schwartzwalder sponge replication technique and were provided with an additional strut porosity by a freeze-drying/ice-templating step prior to thermal processing. A variety of thickeners in combination with different alumina solid loads in the dispersion used for polyurethane foam template coating were studied. An additional strut porosity as generated by freeze-drying was found to be in the order of ~20%, and the spacings between the strut pores generated by ice-templating were in the range between 20 µm and 32 µm. In spite of the lamellar strut pore structure and a total porosity exceeding 90%, the compressive strength was found to be up to 1.3 MPa. Combining the replica process with freeze-drying proves to be a suitable method to enhance foams with respect to their surface area accessible for active coatings while preserving the advantageous flow properties of the cellular structure. A two-to-threefold object surface-to-object volume ratio of 55 to 77 mm−1 was achieved for samples with 30 vol% solid load compared to 26 mm−1 for non-freeze-dried samples. The freeze-drying technique allows the control of the proportion and properties of the introduced pores in an uncomplicated and predictable way by adjusting the process parameters. Nevertheless, the present article demonstrates that a suitable thickener in the dispersion used for the Schwartzwalder process is inevitable to obtain ceramic foams with sufficient mechanical strength due to the necessarily increased water content of the ceramic dispersion used for foam manufacturing.

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EFFECT OF DRYING TECHNIQUE ON PHYSICAL QUALITY AND ANTI-INFLAMMATORY ACTIVITY OF WILD BETEL LEAVES (Piper sarmentosum Roxb. ex Hunter) EXTRACT

JURNAL ILMU KEFARMASIAN INDONESIA ◽

10.35814/jifi.v16i1.436 ◽

2018 ◽

Vol 16 (1) ◽

pp. 42

Author(s):

Fahleni Fahleni ◽

Yuslia Noviani ◽

Syarifah Ramadhani

Keyword(s):

Water Content ◽

Freeze Drying ◽

Inflammatory Activity ◽

Test Results ◽

Drying Method ◽

Flow Properties ◽

Dry Extract ◽

Freeze Dried ◽

Anti Inflammatory ◽

Dried Extract

Kaduk betel leaves (Piper sarmentosum Roxb. ex. Hunter) contain flavonoids and alkaloids that have anti-inflammatory activity. Processing thick extract into a dry extract is required to determine the appropriate dose and increase the homogeneity. The purpose of tahhis study was to determine the effect of drying method to physical properties of dried powder and its antiinflammatory activity. Thick extract was dried using maltodextrin and lactose as adsorbents with concentrations of extract-adsorbent ratio 1: 1, 1: 2 and 1: 3. Method of drying were freeze drying and adsorbent. The evaluation results based on organoleptic dried powder, water content and flow properties. The water content of dried powder which is dried by freeze drying is smaller than that of the adsorbent. Organoleptic and flow properties of freeze dried powder results were also better. The best dried powder in each method tested its anti-inflammatory activity using BSA. The test results showed that the anti-inflammatory activity of dried extract of freeze drying (extract-maltodextrin 1:3) have higher activity with IC50 551.79 ppm compared to dried extract with adsorbent (extract-maltodextrin 1:3) 598.30 ppm.

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Freeze dried quince (Cydonia oblonga) puree with the addition of different amounts of maltodextrin: physical and powder properties

Proceedings of 21th International Drying Symposium ◽

10.4995/ids2018.2018.7469 ◽

2018 ◽

Author(s):

Hira Yüksel ◽

Özle Ünlüeroğlugil ◽

Gülşah Çalışkan Koç ◽

Safiye Nur Dirim

Keyword(s):

Adverse Effect ◽

Moisture Content ◽

Freeze Drying ◽

Flow Properties ◽

Cydonia Oblonga ◽

Drying Time ◽

Freeze Dried ◽

Drying Behavior ◽

Density Values ◽

Powder Properties

This study aims to determine the drying behavior of quince puree and as an adverse effect powdered sugar added quince puree with the addition of maltodextrin. The addition of powdered sugar increases the drying time and the total amount of energy and the same time slightly decreases the moisture content and water activity values. The color values and the properties on these values changed both with the addition of maltodextrin and powdered sugar. The density values, flow properties and reconstitution properties are significantly affected by the amount of maltodextrin in plain or powdered sugar added samples. Keywords: quince, freeze-drying, maltodextrin, powder properties

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Open-Cell Aluminum Foams by the Sponge Replication Technique

Materials ◽

10.3390/ma12233840 ◽

2019 ◽

Vol 12 (23) ◽

pp. 3840 ◽

Cited By ~ 4

Author(s):

Sutygina ◽

Betke ◽

Scheffler

Keyword(s):

Thermal Conductivity ◽

Aluminum Oxide ◽

Thermal Processing ◽

Total Porosity ◽

Lower Amount ◽

Processing Conditions ◽

Aluminum Foams ◽

Open Cell ◽

Thermally Processed ◽

Replication Technique

Open-cell aluminum foams were manufactured by a sponge replication technique having a total porosity of ~90%. The influence of the thermal processing conditions such as atmosphere and temperature on the cellular structure, phase composition porosity, thermal conductivity, and compressive strength of the foams was studied. It was found that the thermal processing of aluminum foams in Ar at temperatures up to 800 °C led to aluminum foams with a reduced strut porosity, a lower amount of aluminum oxide, a higher thermal conductivity, and a higher compression strength, compared to foams thermally processed in air. These results were explained by the lower amount of aluminum oxide after thermal processing of the foams.

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Scanning Electron Microscopy-cuticular Lesions on the Roundworm Ascaris Suum

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010006756x ◽

1970 ◽

Vol 28 ◽

pp. 114-115

Author(s):

P. A. Madden ◽

W. R. Anderson

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Freeze Drying ◽

Room Temperature ◽

Secondary Electron ◽

Distilled Water ◽

Freeze Dried ◽

Silver Paint ◽

To Come ◽

Scanning Electron

The intestinal roundworm of swine is pinkish in color and about the diameter of a lead pencil. Adult worms, taken from parasitized swine, frequently were observed with macroscopic lesions on their cuticule. Those possessing such lesions were rinsed in distilled water, and cylindrical segments of the affected areas were removed. Some of the segments were fixed in buffered formalin before freeze-drying; others were freeze-dried immediately. Initially, specimens were quenched in liquid freon followed by immersion in liquid nitrogen. They were then placed in ampuoles in a freezer at −45C and sublimated by vacuum until dry. After the specimens appeared dry, the freezer was allowed to come to room temperature slowly while the vacuum was maintained. The dried specimens were attached to metal pegs with conductive silver paint and placed in a vacuum evaporator on a rotating tilting stage. They were then coated by evaporating an alloy of 20% palladium and 80% gold to a thickness of approximately 300 A°. The specimens were examined by secondary electron emmission in a scanning electron microscope.

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Revealing gross three-dimensional structure in the SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100127712 ◽

1987 ◽

Vol 45 ◽

pp. 656-657

Author(s):

Sterling P. Newberry

Keyword(s):

Freeze Drying ◽

Three Dimensional ◽

Dimensional Structure ◽

Small Object ◽

Final Solution ◽

Dimensional Representation ◽

X Ray ◽

Three Dimensional Representation ◽

Freeze Dried ◽

Critical Point Drying

The beautiful three dimensional representation of small object surfaces by the SEM leads one to search for ways to open up the sample and look inside. Could this be the answer to a better microscopy for gross biological 3-D structure? We know from X-Ray microscope images that Freeze Drying and Critical Point Drying give promise of adequately preserving gross structure. Can we slice such preparations open for SEM inspection? In general these preparations crush more readily than they slice. Russell and Dagihlian got around the problem by “deembedding” a section before imaging. This some what defeats the advantages of direct dry preparation, thus we are reluctant to accept it as the final solution to our problem. Alternatively, consider fig 1 wherein a freeze dried onion root has a window cut in its surface by a micromanipulator during observation in the SEM.

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Effect of Freeze Drying and Simulated Gastrointestinal Digestion on Phenolic Metabolites and Antioxidant Property of the Natal Plum (Carissa macrocarpa)

Foods ◽

10.3390/foods10061420 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1420

Author(s):

Faith Seke ◽

Vimbainashe E. Manhivi ◽

Tinotenda Shoko ◽

Retha M. Slabbert ◽

Yasmina Sultanbawa ◽

...

Keyword(s):

Freeze Drying ◽

Array Detector ◽

Gastrointestinal Digestion ◽

Liquid Chromatograph ◽

Antioxidant Power ◽

Intestinal Phase ◽

Glucosidase Activity ◽

Freeze Dried ◽

Small Intestinal ◽

The Impact

Natal plums (Carissa macrocarpa) are a natural source of bioactive compounds, particularly anthocyanins, and can be consumed as a snack. This study characterized the impact of freeze drying and in vitro gastrointestinal digestion on the phenolic profile, antioxidant capacity, and α-glucosidase activity of the Natal plum (Carissa macrocarpa). The phenolic compounds were quantified using high performance liquid chromatography coupled to a diode-array detector HPLC-DAD and an ultra-performance liquid chromatograph (UPLC) with a Waters Acquity photodiode array detector (PDA) coupled to a Synapt G2 quadrupole time-of-flight (QTOF) mass spectrometer. Cyanidin-3-O-β-sambubioside (Cy-3-Sa) and cyanidin-3-O-glucoside (Cy-3-G) were the dominant anthocyanins in the fresh and freeze-dried Natal plum powder. Freeze drying did not affect the concentrations of both cyanidin compounds compared to the fresh fruit. Both cyanidin compounds, ellagic acid, catechin, epicatechin syringic acid, caffeic acid, luteolin, and quercetin O-glycoside from the ingested freeze-dried Natal plum powder was quite stable in the gastric phase compared to the small intestinal phase. Cyanidin-3-O-β-sambubioside from the ingested Natal plum powder showed bioaccessibility of 32.2% compared to cyanidin-3-O-glucoside (16.3%). The degradation of anthocyanins increased the bioaccessibility of gallic acid, protocatechuic acid, coumaric acid, and ferulic acid significantly, in the small intestinal digesta. The ferric reducing antioxidant power (FRAP), 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) activities, and inhibitory effect of α-glucosidase activity decreased in the small intestinal phase. Indigenous fruits or freeze-dried powders with Cy-3-Sa can be a better source of anthocyanin than Cy-3-G due to higher bioaccessibility in the small intestinal phase.

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Process for production of microencapsulated anthocyanin pigments from Rosa pimpinellifolia L. fruits: optimization of aqueous two-phase extraction, microencapsulation by spray and freeze-drying, and storage stability evaluation

International Journal of Food Engineering ◽

10.1515/ijfe-2020-0057 ◽

2020 ◽

Vol 16 (9) ◽

Author(s):

Halil İbrahim Odabaş ◽

Ilkay Koca

Keyword(s):

Freeze Drying ◽

Fold Increase ◽

Drying Methods ◽

Phase Extraction ◽

Extraction Temperature ◽

Two Phase ◽

Freeze Dried ◽

Anthocyanin Pigments ◽

Promising Source ◽

Aqueous Two Phase Extraction

AbstractRosa pimpinellifolia L. fruits (RPF) are promising source of anthocyanin pigments. The objectives of this study were to optimization of the aqueous two-phase extraction (ATPE) process of anthocyanin from RPF and microencapsulation of anthocyanin-rich RPF extract. The optimal ATPE conditions were as follows: 0% HCl, 30% ethanol, 19% ammonium sulfate, and liquid to solid ratio 51.71, 97.71 min, and 30°C extraction temperature. Predicted anthocyanin yield at the optimum conditions was 1578.90 mg cyanidin 3-glucoside equivalent/100 g dry fruit. ATPE resulting in 1.80-fold increase in the purity of anthocyanins when compared to conventional solvent extraction (CSE). The composition of the anthocyanins were determined with HPLC-QTOF-MS. Freeze-drying and spray-drying methods were employed for the production of microencapsulated anthocyanin pigments. The half times of microencapsulated anthocyanins at 4, 25 and 37°C were determined as 12.16, 6.60 and 3.12 months for freeze-dried microcapsules, and 16.50, 9.24 and 4.29 months for spray-dried microcapsules, respectively.

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Preparation and Characterization of Chitosan-Based Scaffolds for Biomedical Applications

Materials Science Forum ◽

10.4028/www.scientific.net/msf.514-516.1005 ◽

2006 ◽

Vol 514-516 ◽

pp. 1005-1009 ◽

Cited By ~ 2

Author(s):

José V. Araújo ◽

J.A. Lopes da Silva ◽

Margarida M. Almeida ◽

Maria Elisabete V. Costa

Keyword(s):

Biomedical Applications ◽

Freeze Drying ◽

Average Pore Size ◽

Composite Scaffolds ◽

Average Pore ◽

Chitosan Matrix ◽

Freeze Dried ◽

Porous Chitosan ◽

Interconnected Structure

Porous chitosan/brushite composite scaffolds were prepared by a freeze-drying technique, starting from brushite suspensions in chitosan solutions. The obtained scaffolds showed a regular macroporous and interconnected structure with brushite particles uniformly distributed in the chitosan matrix. The variation of the brushite concentration affected the microstructure of the final freeze-dried scaffold, in particular, its porosity and its average pore size. The yield strengths of the composite scaffolds could also be improved by the increase of the brushite content.

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

Foods ◽

10.3390/foods10020226 ◽

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.

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Fourier transform infrared spectroscopy coupled with machine learning classification for identification of oxidative damage in freeze-dried heart valves

Scientific Reports ◽

10.1038/s41598-021-91802-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Dejia Liu ◽

Sükrü Caliskan ◽

Bita Rashidfarokhi ◽

Harriëtte Oldenhof ◽

Klaus Jung ◽

...

Keyword(s):

Fourier Transform ◽

Infrared Spectroscopy ◽

Oxidative Damage ◽

Fourier Transform Infrared Spectroscopy ◽

Heart Valve ◽

Freeze Drying ◽

Heart Valves ◽

Fourier Transform Infrared ◽

Freeze Dried ◽

Nbt Staining

AbstractFreeze-drying can be used to ensure off-the-shelf availability of decellularized heart valves for cardiovascular surgery. In this study, decellularized porcine aortic heart valves were analyzed by nitroblue tetrazolium (NBT) staining and Fourier transform infrared spectroscopy (FTIR) to identify oxidative damage during freeze-drying and subsequent storage as well as after treatment with H2O2 and FeCl3. NBT staining revealed that sucrose at a concentration of at least 40% (w/v) is needed to prevent oxidative damage during freeze-drying. Dried specimens that were stored at 4 °C depict little to no oxidative damage during storage for up to 2 months. FTIR analysis shows that fresh control, freeze-dried and stored heart valve specimens cannot be distinguished from one another, whereas H2O2- and FeCl3-treated samples could be distinguished in some tissue section. A feed forward artificial neural network model could accurately classify H2O2 and FeCl3 treated samples. However, fresh control, freeze-dried and stored samples could not be distinguished from one another, which implies that these groups are very similar in terms of their biomolecular fingerprints. Taken together, we conclude that sucrose can minimize oxidative damage caused by freeze-drying, and that subsequent dried storage has little effects on the overall biochemical composition of heart valve scaffolds.

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