On the interaction between 5-hydroxytryptamine and N-acetylneuraminic acid under aqueous conditions

1985 ◽  
Vol 63 (7) ◽  
pp. 757-763 ◽  
Author(s):  
Leslie R. Berry ◽  
Frank V. Puzzuoli ◽  
Mark W. C. Hatton
Keyword(s):  
Freeze Drying ◽  
Gel Filtration ◽  
Fluorescence Emission ◽  
Equimolar Amount ◽  
Resonance Spectroscopy ◽  
Chemical Analyses ◽  
Acetylneuraminic Acid ◽  
Freeze Dried ◽  
Aqueous Conditions ◽  
Comparison Measurements

A complex designated 5-HT–NeuAc was formed between 5-hydroxytryptamine (5-HT) and N-acetylneuraminic acid (NeuAc) under aqueous conditions. Complex formation was encouraged by exposure to light (3000–3800 Å; 1 Å = 0.1 nm) and freeze-drying and the freeze-dried complex was isolated by gel filtration chromatography. Although stable to rechromatography on Bio-Gel P-2 if H2O was the eluent, 5-HT–NeuAc dissociated into the free components when placed in 0.1 M NaCl. Chemical analyses of the isolated complex showed that an equimolar amount of 5-HT and NeuAc was present and that all group functions were intact; these data suggested that the association between 5-HT and NeuAc was noncovalent. Spectrophotometric measurements demonstrated a small increase (approximately 12%) in extinction coefficient (275 nm) and a large increase (340- to 440-fold) in fluorescence emission (340 nm) compared with 5-HT alone. Data obtained from 1H nuclear magnetic resonance spectroscopy (250 MHz) of 5-HT and NeuAc standards compared closely to published reports. In comparison, measurements made with 5-HT-NeuAc showed that all 5-HT protons were slightly deshielded; of the NeuAc protons, slight deshielding of H8 and significant shielding of H3eq, H3ax, and H6 was observed. From these observations, a model describing the association between 5-HT and NeuAc is proposed.

Effect of Freeze-Drying and Cooking on Shrimp Quality

1970 ◽  
Vol 53 (5) ◽  
pp. 899-902 ◽  
Author(s):  
Barbara R Moorhouse ◽  
Harold Salwin
Keyword(s):  
Freeze Drying ◽  
Starting Material ◽  
White Shrimp ◽  
Chemical Analyses ◽  
Decomposition Products ◽  
Organoleptic Quality ◽  
Freeze Dried ◽  
Plate Counts ◽  
Crushed Ice

Abstract Approximately 500 pounds of white shrimp were stored in crushed ice until they decomposed. Portions were withdrawn at intervals and processed. Based on judgments of odor, shrimp that reached a stage of incipient decomposition before processing were rated as passable after they were freeze-dried or cooked. The organoleptic quality of samples that reached a stage of advanced decomposition was also improved by processing, but not to the extent of their being classified as passable. Aerobic plate counts increased during storage but they were reduced significantly by freezedrying or cooking. Although there were changes in composition during storage, the classical chemical tests used were of limited value for assessing the degree of decomposition. Also, many volatile decomposition products were lost during processing. Computing the results of chemical analyses on a moisturefree basis offered distinct advantages. Inasmuch as organoleptic, bacteriological, and chemical tests on the finished products failed to reveal the decomposed condition of the starting material, there is need for additional investigation of methods for that purpose.

EXTRACTION DES ACIDES FULVIQUES D'UN HORIZON SPODIQUE PAR UNE RESINE ECHANGEUSE D'IONS DE TYPE H POSITIF

1971 ◽  
Vol 51 (2) ◽  
pp. 157-164
Author(s):  
G. HUBERT ◽  
A. GONZALEZ
Keyword(s):  
Organic Matter ◽  
Fulvic Acid ◽  
Freeze Drying ◽  
Gel Filtration ◽  
Fulvic Acids ◽  
Ash Content ◽  
Freeze Dried ◽  
Efficient Reagent

A resin in the H+ form (Dowex 50W-X8) was used to extract fulvic acids from a Spodic horizon. This resin has the following advantages in relation to the reagents normally used. It solubilizes organic matter while purifying it and without altering it by oxidation and hydrolysis. Furthermore, since the resin is eliminated completely from the extract, no contaminating ions remain. The soil was agitated in a mixture of water and resin. The extract obtained was filtered, centrifuged, purified by passage through a column of H+ resin and freeze-dried. The alternation of freeze-drying and resolubilization resulted in the coagulation of the silica which was removed by centrifugation. Acid organic matter with very low ash content (1%) was obtained. The fulvic acids extracted by resin and by Na-pyrophosphate were compared. Qualitatively they were practically the same, as evidenced by the similarity of the curves obtained by gel-filtration (Sephadex). Quantitatively the resin, however, was a more efficient reagent. Therefore, it is recommended for the extraction of fulvic acid and organo-mineral complexes.

IMPROVEMENT OF WATER SOLUBILITY AND IN VITRO DISSOLUTION RATE OF DEFLAZACORT BY COMPLEXATION WITH Β-CYCLODEXTRIN THROUGH FREEZE DRYING PROCESS

INDIAN DRUGS ◽  
2020 ◽  
Vol 57 (07) ◽  
pp. 70-73
Author(s):  
Nilesh S Kulkarni ◽  
Pallavi D Gitte ◽  
Manojkumar K Munde ◽  
Shashikant N. Dhole
Keyword(s):  
Dissolution Rate ◽  
Freeze Drying ◽  
Water Solubility ◽  
Water Soluble ◽  
In Vitro Dissolution ◽  
Resonance Spectroscopy ◽  
Cyclodextrin Complex ◽  
Water Soluble Polymer ◽  
Freeze Dried

Deflazacort is a poorly water-soluble drug and is practically insoluble in water. The objective of this study was to improve the solubility of deflazacort by using as solubility enhancer β-cyclodextrin and also to study the effect of the water-soluble polymer PEG 4000 on solubility of the deflazacort:β-cyclodextrin binary system. The inclusion complexes of deflazacort with β-cyclodextrin in 1:1 w/w, 1:2 w/w and 1:3 w/w proportions were prepared by kneading, microwave irradiation and freeze-drying techniques. The in vitro dissolution study showed improved dissolution rate for deflazacort for freeze-dried binary deflazacort: β-cyclodextrin 1:2 w/w complex, as compared to ternary deflazacort:β-cyclodextrin: PEG 6000 1:2 w/w complexes, plain deflazacort, physical mixtures and complexes prepared by kneading and microwave technique. This was confirmed by Fourier transform infrared spectroscopy, differential scanning calorimetry, powder x-ray diffraction study, scanning electron microscopy and 1 H nuclear magnetic resonance spectroscopy study. Thus, deflazacort:β-cyclodextrin complex with improved solubility was successfully developed using freeze drying technique.

scholarly journals COMPARATIVE STUDIES WITH DIFFERENT CYCLODEXTRIN DERIVATIVES IN IMPROVING THE SOLUBILITY AND DISSOLUTION OF SAQUINAVIR

2018 ◽  
Vol 11 (6) ◽  
pp. 509
Author(s):  
Bharani S Sogali ◽  
Vikram Bn ◽  
Ramana Murthy Kv
Keyword(s):  
Drug Release ◽  
Spray Drying ◽  
Comparative Studies ◽  
Freeze Drying ◽  
Dissolution Time ◽  
Resonance Spectroscopy ◽  
Phase Solubility ◽  
Phase Solubility Studies ◽  
Freeze Dried ◽  
Solubility Studies

Objective: The present study was aimed to perform comparative studies with different cyclodextrin (CD) derivatives and to study the effect of different methods of preparation in improving the solubility and dissolution of saquinavir (SQV).Methods: Phase solubility studies were performed with beta CD (βCD), hydroxypropyl βCD, randomly methylated βCD, and sulfobutyl ether βCD (SBE7βCD). Complexes were prepared using physical mixture, coevaporation, kneading, spray drying, and freeze-drying techniques. For complexes prepared by spray drying, process parameters were optimized based on percentage yield. The prepared complexes were characterized using Fourier-transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction studies, nuclear magnetic resonance spectroscopy, and scanning electron microscopy. In vitro drug release study was conducted in phosphate buffer pH 6.8 and mean dissolution time (MDT) was calculated for all freeze-dried complexes.Results: Phase solubility studies showed a linear relationship with an increase in CD concentration and phase diagrams were of AL type. Highest stability constant was observed with SQV-SBE7βCD (8281.28/M). All characterization studies proved complexation. Among four CD derivatives, SQV complexed with SBE7βCD by freeze-drying showed maximum drug release and low MDT of 20.67.Conclusion: Among different CDs, SBE7βCD proved as ideal CD derivative, and among different methods of preparations, freeze-drying method was found to be useful in improving the solubility and dissolution of SQV.

Scanning Electron Microscopy-cuticular Lesions on the Roundworm Ascaris Suum

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.

Revealing gross three-dimensional structure in the SEM

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.

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

Foods ◽  
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.

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

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.

Preparation and Characterization of Chitosan-Based Scaffolds for Biomedical Applications

2006 ◽  
Vol 514-516 ◽  
pp. 1005-1009 ◽  
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.

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.

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