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PubMed2000

Gentamicin encapsulation in PLA/PLGA microspheres in view of treating Brucella infections.

In view of treating intracellular Brucella infections, microspheres made of poly(lactide) (PLA) and poly(lactide-co-glycolide) (PLGA) were developed as delivery system for the cationic and highly hydrophilic antibiotic gentamicin sulphate. Drug microencapsulation by spray drying yielded microspheres with regular morphology, an average particle size of approximately 3 micrometer and encapsulation efficiencies of up to 45%. Different copolymers of similar molecular weights gave varying encapsulation efficiencies and particle size distributions. The encapsulation efficiency generally increased with polymer hydrophilicity, except for the hydrophilic copolymer PLGA50:50H carrying carboxylic end groups. Encapsulation also depended on the pH value of the aqueous drug solution to be encapsulated. Moreover, increasing nominal gentamicin sulphate loading yielded lower efficiencies. For comparison, some formulations were also prepared by a (W(1)/O)W(2)-solvent evaporation method, which yielded lower encapsulation efficiencies, in the order of 13%. Finally, drug bioactivity was found to remain intact after microencapsulation, MS storage and MS incubation in aqueous medium. The results suggest that PLA/PLGA microspheres prepared by spray drying may be an appropriate delivery system for gentamicin sulphate to be used in the treatment of intracellular Brucella infections.

Biocompatible Materials↗
PubMed2001

Pressurized liquid extraction of lipids for the determination of oxysterols in egg-containing food.

Pressurized liquid extraction (PLE, ASE) was compared with the Folch procedure (a solid-liquid extraction with chloroform/methanol 2:1, v/v) for the lipid extraction of egg-containing food; the accuracy of PLE for the quantitative determination of oxysterols in whole egg powder was evaluated. Samples of spray-dried whole egg, an Italian vanilla cake (Pandoro) and egg noodles were used. Two different extraction solvents (chloroform/methanol 2:1, v/v, and hexane/isopropanol 3:2, v/v) were tested at different extraction temperatures and pressures (60 degrees C at 15 MPa, 100 degrees C at 15 MPa, 120 degrees C at 20 MPa). No significant differences in the lipid recovery of the egg powder sample using PLE were found. However, PLE of the vanilla cake and egg noodles with the chloroform/methanol mixture was not selective enough and led to the extraction of a non-lipid fraction, including nitrogen-containing compounds. In the same samples, the pressurized hexane/isopropanol mixture gave a better recovery result, comparable to that obtained using the Folch method. Cholesterol oxidation products of the Folch extract and the pressurized liquid extract of spray dried egg powder (obtained with hexane/isopropanol 3:2, v/v, at 60 degrees C and 15 MPa) were determined by gas chromatography. PLE performed under these conditions is suitable to replace the Folch extraction, because the differences between the two methods tested were not statistically significant. Moreover, PLE shows important advantages, since the analysis time was shortened by a factor of 10, the solvent costs were reduced by 80% and the use of chlorinated solvents was avoided.

Chromatography, Gas↗
PubMedDate not supplied

Microencapsulation of ascorbic acid: effect of process variables on product characteristics.

This study deals with a comparative investigation of the characteristics of ascorbic acid microcapsules prepared by different methods, such as thermal phase separation, melt dispersion, solvent evaporation and spray drying. Scanning electron microscopy (SEM), release tests and size distribution were used for the evaluation of product characteristics. The results show that microencapsulated ascorbic acid could prevent the ascorbic acid colour change, retard its core release rate, and generally mask its acid taste. In the thermal phase separation, molecular weight (Mw) of ethyl cellulose (EC) and the addition of polyisobutylene (PIB) significantly influenced the aggregation and release rate of microcapsules. In the melt dispersion method, spherical particles were prepared by using carnauba. The ascorbic acid release rate was found to be slower in the case of carnauba-encapsulated ascorbic acid than that made by EC using other methods. In the solvent evaporation method, a higher Mw of EC and the addition of plastizer were also found to be important for good encapsulation. In the spray drying method, loss of ascorbic acid was found to be minimum during microencapsulation. Starch and beta-cyclodextrin encapsulated ascorbic acid delayed the degradation of ascorbic acid during storage at 38 degrees C and relative humidity 84.0%.

Antioxidants↗
PubMed1989

Affinity purification of the novel cysteine proteinase papaya proteinase IV, and papain from papaya latex.

A procedure is described for the purification of a previously undetected cysteine proteinase, which we have called papaya proteinase IV, from spray-dried latex of the papaya (Carica papaya) plant. The purification involves affinity chromatography on Gly-Phe-aminoacetonitrile linked to CH-Sepharose 4B, with elution by 2-hydroxyethyl disulphide at pH 4.5. The product thus obtained is a mixture of almost fully active papain and papay proteinase IV, which are then separated by cation-exchange chromatography. A preliminary characterization of papaya proteinase IV showed it to be very similar to chymopapain in both molecular size and charge. However, the new enzyme is immunologically distinct from the previously characterized cysteine proteinases of papaya latex. It also differs in its lack of activity against the synthetic substrates of the other papaya proteinases, in its narrow specificity against protein substrates and its lack of inhibition by chicken cystatin. Papaya proteinase IV is abundant, contributing almost 30% of the protein in spray-dried papaya latex, and contamination of chymopapain preparations with this enzyme may account for some of the previously reported heterogeneity of chymopapain.

Catalysis↗
PubMed2004

Effects of elderberry juice on fasting and postprandial serum lipids and low-density lipoprotein oxidation in healthy volunteers: a randomized, double-blind, placebo-controlled study.

BACKGROUND: In a recent pilot study, the intake of elderberry juice resulted in a significant decrease in serum cholesterol concentrations and an increase in low-density lipoprotein (LDL) stability. This study was designed to verify the preliminary results. OBJECTIVE: We investigated the impact of elderberry juice on cholesterol and triglyceride concentrations as well as antioxidant status in a cohort of young volunteers. DESIGN: Study A: The randomized, placebo-controlled trial for studying the effect of anthocyanes on lipid and antioxidant status, 34 subjects took capsules with 400 mg spray-dried powder containing 10% anthocyanes t.i.d. equivalent to 5 ml elderberry juice for 2 weeks. A subgroup of 14 subjects continued for an additional week to test for resistance to oxidation of LDL. Study B: To investigate the short-term effects on serum lipid concentrations, six subjects took a single dose of 50 ml of elderberry juice (equivalent to 10 capsules) along with a high-fat breakfast. RESULTS: In the placebo-controlled study, there was only a small, statistically not significant change in cholesterol concentrations in the elderberry group (from 199 to 190 mg/dl) compared to the placebo group (from 192 to 196 mg/dl). The resistance to copper-induced oxidation of LDL did not change within 3 weeks. In the single-dose experiment increases in postprandial triglyceride concentrations were not significantly different when the six subjects were investigated with and without elderberry juice. CONCLUSIONS: Elderberry spray-dried extract at a low dose exerts a minor effect on serum lipids and antioxidative capacity. Higher, but nutritionally relevant doses might significantly reduce postprandial serum lipids.

Antioxidants↗
PubMed2006

Improving low water activity and desiccation tolerance of the biocontrol agent Pantoea agglomerans CPA-2 by osmotic treatments.

AIMS: To study the improvement of tolerance to low water activity (aw) and desiccation during spray drying in Pantoea agglomerans cells subjected to mild osmotic stress during growth. METHODS AND RESULTS: The micro-organism was cultured in an unmodified liquid (control) or in aw-modified media, and viability of these cells was evaluated on unstressed (0.995) and 0.96 aw stressed solid media, in order to check total viability and aw stress tolerance respectively. Significant improvements in viability on unmodified medium were observed with cells grown for 24 h in NaCl 0.98 aw, glycerol 0.98 aw and 0.97 aw and for 48 h in NaCl 0.98 aw and 0.97 aw modified media. Both yield improvements and water stress tolerance were achieved with low aw media. Cells grown for 24 h in NaCl 0.98 aw or for 48 h in NaCl 0.98 aw, 0.97 aw and 0.96 aw, glucose 0.97 aw and glycerol 0.97 aw showed improved aw stress tolerance in comparison with control cells. The best results were obtained with NaCl treatments (0.98 aw and 0.97 aw) which also exhibited better survival rates than control cells during spray-drying process and maintained their efficacy against postharvest fungal pathogens in apples and oranges. CONCLUSIONS: NaCl treatments are very appropriate for improving P. agglomerans low aw tolerance obtaining high production levels and maintaining biocontrol efficacy. SIGNIFICANCE AND IMPACT OF THE STUDY: Improving stress tolerance of biocontrol agents could be an efficient way to obtain consistency and maintain efficacy of biological control under practical conditions.

Desiccation↗
PubMed2004

Spherical composite particles of rice starch and microcrystalline cellulose: a new coprocessed excipient for direct compression.

Composite particles of rice starch (RS) and microcrystalline cellulose were fabricated by spray-drying technique to be used as a directly compressible excipient. Two size fractions of microcrystalline cellulose, sieved (MCS) and jet milled (MCJ), having volumetric mean diameter (D50) of 13.61 and 40.51 microm, respectively, were used to form composite particles with RS in various mixing ratios. The composite particles produced were evaluated for their powder and compression properties. Although an increase in the microcrystalline cellulose proportion imparted greater compressibility of the composite particles, the shape of the particles was typically less spherical with rougher surface resulting in a decrease in the degree of flowability. Compressibility of composite particles made from different size fractions of microcrystalline cellulose was not different; however, using MCJ, which had a particle size range close to the size of RS (D50 = 13.57 microm), provided more spherical particles than using MCS. Spherical composite particles between RS and MCJ in the ratio of 7:3 (RS-MCJ-73) were then evaluated for powder properties and compressibility in comparison with some marketed directly compressible diluents. Compressibility of RS-MCJ-73 was greater than commercial spray-dried RS (Eratab), coprocessed lactose and microcrystalline cellulose (Cellactose), and agglomerated lactose (Tablettose), but, as expected, lower than microcrystalline cellulose (Vivapur 101). Flowability index of RS-MCJ-73 appeared to be slightly lower than Eratab but higher than Vivapur 101, Cellactose, and Tablettose. Tablets of RS-MCJ-73 exhibited low friability and good self-disintegrating property. It was concluded that these developed composite particles could be introduced as a new coprocessed direct compression excipient.

Cellulose↗
PubMed2005

How much particle surface corrugation is sufficient to improve aerosol performance of powders?

PURPOSE: The current study aimed to quantify the different degree of particle surface corrugation and correlate it to the aerosol performance of powders. METHODS: Powders of different degree of surface corrugation were prepared by spray drying under varying conditions. The solid-state properties of the powders including particle size, morphology, crystal form, true density, and moisture content were characterized. The degree of surface corrugation was quantified by the surface fractal dimension (Ds) obtained by light scattering. The aerosol performance was studied by dispersing the powders using the Rotahaler at 60 L/min into a multi-stage liquid impinger. Fine particle fraction (FPF) was expressed as the wt% of BSA particles of size < or =5 microm in the aerosol. RESULTS: Four powders of increasing degree of particle surface corrugation were prepared, with Ds ranging from 2.06 for the least corrugated to 2.41 for the most corrugated. The powders had a similar size distribution (VMD 3 microm, span 1.4-1.5) and solid-state properties. Increasing the surface corrugation, Ds, slightly from 2.06 to 2.18 enhanced the FPF significantly from 27% to 41%. This was explained by the reduced area of contacts and increased separation distance between the particles. Further increase of corrugation (Ds > or = 2.18) did not improve FPF. CONCLUSIONS: Powders with varying degrees of corrugation were successfully obtained by spray drying with their surface roughness quantified by fractal analysis. It was shown that only a relatively small degree of surface corrugation was sufficient to accomplish a considerable improvement in the aerosol performance of the powder.

Aerosols↗
PubMed2003

Properties and stability of a liquid crystal form of cyclosporine-the first reported naturally occurring peptide that exists as a thermotropic liquid crystal.

A new solid-state form of cyclosporine produced by spray-drying exhibited characteristics consistent with a liquid crystal. No sharp diffraction peaks were observed by powder X-ray diffraction; however, analysis by both small-angle X-ray diffraction (SAXR) and microscopic under polarized light (PLM) confirmed the existence of two-dimensional ordered liquid crystal. Hot stage microscopy revealed a solid-to-liquid transition, in the range of 118 to 125 degrees C. Moreover, the solid-to-liquid transition showed frequency dependence by dielectric analysis (DEA), and was coincidental with a stepwise heat capacity change measured by differential scanning Calorimetry (DSC). The two-dimensional order was maintained above the solid-to-liquid transition temperature indicated by low-angle diffraction by SAXR and birefringence by PLM. However, birefringence was lost at temperatures above 170 degrees C, indicating the conversion of the liquid crystal into an isotropic liquid. In situ annealing experiments, by DSC, revealed the presence of an endotherm, unexplained by either a phase transition or solvent loss, and it is believed to be the result of a structural rearrangement that has no impact on the macroscopic properties of the material. Spray-dried cyclosporine at room temperature is therefore a frozen thermotropic liquid crystal due to the presence of two-dimensional order and the lack of substantial residual solvent. This is, to our knowledge, the first report of the existence of a thermotropic liquid crystal of a naturally occurring peptide.

Calorimetry, Differential Scanning↗
PubMed2005

Degradation of endogenous and exogenous genes of roundup-ready soybean during food processing.

Roundup-Ready soybeans have been genetically modified to resist the effects of the herbicidal glyphosate and have become the most prevalent transgenic crop in the world. In this work, Roundup-Ready soybeans were used as raw material to study the effects of critical processing procedures such as grinding, cooking, blending, homogenization, sterilization, and spray-drying on the length of DNA fragments of an endogenous gene (lectin) and an exogenous gene (epsps) examined in material from three soybean foods of bean curd, soy milk, and soy powder and from samples taken during their processing. The results showed that various processing procedures caused degradations of both the endogenous and exogenous genes to different degrees. In the grinding procedure, endogenous gene DNA was degraded from 1883 to approximately 836 bp, and exogenous gene DNA was degraded from 1512 to approximately 408 bp. In the blending and squeeze-molding procedures, exogenous gene DNA was also degraded from about 408 to 190 bp, but there was no obvious action on the endogenous gene. After the endogenous and exogenous genes had been degraded to some degree, such as 836 and 408 bp, respectively, they were not evidently affected by cooking procedure at 100 degrees C for 15 min. However, the endogenous gene was further considerably degraded from around 836 to 162 bp in the sterilization procedure at 121 degrees C for 30 s. The effect of the homogenization step on endogenous and exogenous genes was similar to that of the cooking procedure. The coagulation procedure, principally a biochemical reaction, did not greatly affect the exogenous gene but did affect endogenous gene, reducing DNA size from about 836 to 407 bp. Furthermore, the spray-drying procedure, a process of physical shearing, high temperature, and sudden high pressure, distinctly caused degradation of both the lectin and epsps genes, rapidly decreasing the sizes from about 836 to 162 bp for the endogenous gene and from about 408 to 190 bp for the exogenous gene.

3-Phosphoshikimate 1-Carboxyvinyltransferase↗
PubMed1996

Stable formulations of recombinant human growth hormone and interferon-gamma for microencapsulation in biodegradable microspheres.

PURPOSE: The successful development of controlled release formulations for proteins requires that the protein not be denatured during the manufacturing process. The major objective was to develop formulations that stabilize two recombinant human proteins, human growth hormone (rhGH) and interferon-gamma (rhIFN-gamma), at high protein concentrations (> 100 mg/mL) in organic solvents commonly used for microencapsulation, methylene chloride and ethyl acetate. METHODS: Several excipients were screened to obtain the maximum solubility of each protein. These formulations (aqueous, lyophilized, milled, spray dried, or isoelectric precipitate) were then rapidly screened by emulsification in the organic solvent followed by recovery into excess buffer. Additional screening was performed with solid protein that was suspended in the organic solvent and then recovered with excess buffer. The recovery of native protein was determined by native size exclusion chromatography (SEC-HPLC) and circular dichroism (CD). The selected formulations were encapsulated in polylactic-coglycolic acid (PLGA) microspheres by either water-in-oil-in-water (W/O/W) or solid-in-oil-in-water (S/O/W) methods. The initial protein released from the microspheres incubated at physiological conditions was analyzed by SEC-HPLC, CD, and biological assays. RESULTS: The stability of a given formulation in the rapid screening method correlated well with stability during encapsulation in PLGA microspheres. Formulations of rhGH containing Tween 20 or 80 resulted in lower recovery of native protein, while trehalose and mannitol formulations (phosphate buffer, pH 8.0) yielded complete recovery of native rhGH. Other additives such as carboxymethyl cellulose, gelatin, and dextran 70 were not effective stabilizers, and polyethylene glycol provided some stabilization of rhGH. Trehalose/rhGH (1:4 mass ratio) and mannitol/rhGH (1:2 mass ratio) formulations (potassium phosphate buffer, pH 8.0) were lyophilized, reconstituted to 200 and 400 mg/mL rhGH, respectively, and then encapsulated in PLGA microspheres. The protein was released from these microspheres in its native state. Lyophilized formulations of rhGH yielded analogous results indicating the ability of trehalose and mannitol to stabilize the protein. Small solid particles of rhGH generated by spray drying (both air and freeze-drying) formulations containing Tween 20 or PEG were stable in ethyl acetate, but not methylene chloride. Similar results were also obtained with rhIFN-gamma (137 mg/mL in succinate buffer, pH 5.0), where both mannitol and trehalose were observed to stabilize the protein during exposure to the organic solvents resulting in the release of native rhIFN-gamma from PLGA microspheres. CONCLUSIONS: The rapid screening method allowed the development of stable concentrated protein solutions or solid protein formulations that could be successfully encapsulated in PLGA microspheres. The excipients observed to stabilize these proteins function by preferential hydration of the protein, and in the dry state (e.g., trehalose) may stabilize the protein via water substitution yielding a protective coating around the protein surface. Studies of other proteins should provide further insight into this mechanism of protein stabilization during encapsulation.

Chemical Precipitation↗
PubMed2006

Supplementing drinking water with Solutein did not mitigate acute morbidity effects of porcine reproductive and respiratory syndrome virus in nursery pigs.

The objective of this study was to determine whether providing nursery pigs drinking water supplemented with spray-dried animal plasma (Solutein, American Protein Corporation Inc., Ankeny, IA) would reduce the detrimental impact of porcine reproductive and respiratory syndrome virus (PRRSV) infection. Sixty-four pigs were subjected to 1 of 4 treatment combinations (2 x 2 factorial arrangement) of Solutein [0 or 2.5% (wt/wt) in drinking water] and PRRSV (sterile medium or 5 mL of tissue culture infectious dose of high-virulence strain ATCC VR-2385). Pigs were provided the water treatments during a 1-wk period before inoculation as well as during a 2-wk period after inoculation. Growth performance was determined throughout the study, and several indicators of the immunological response to PRRSV and disease pathology were assessed in blood and tissue samples collected from pigs killed 7 or 14 d after inoculation. Before inoculation, pigs provided water supplemented with Solutein tended to eat less (P = 0.08) but tended to gain more BW (P = 0.13) than pigs provided tap water. Thus, Solutein markedly improved G:F (P < 0.01), after accounting for the DM provided by Solutein. Inoculation with PRRSV reduced ADG and ADFI (P < 0.01) irrespective of water treatment; however, the beneficial effects of Solutein on G:F persisted. Infection with PRRSV also reduced (P < 0.009) villus height and crypt depth in cranial, medial, and caudal segments of the small intestine and increased (P < 0.05) lung and spleen weight, the number of leukocytes in lung lavage fluid, and serum concentrations of interferon-gamma and IL-1beta regardless of water treatment. Collectively, these results indicate that supplementing water with spray-dried animal plasma improved feed efficiency but did not afford nursery pigs protection from the effects of PRRSV on growth and certain hematological traits.

Animals↗
PubMed1988

Effect of the drying process on the nutritive value of milk. Part 1. Biochemical composition.

Five different brands of instant dry whole milk that are most commonly used, and freeze dried milk were analyzed for nitrogen, fat, ash and 4 inorganic constituents and compared with human milk. The composition of the milks differed considerably. The protein content varied widely, ranging from 11.6 to 24.5%. Fat content did not differ widely, ranging from 24.9 to 29.5%. Freeze dried milk had the highest fat content (42.6%). Three out of the five brands of dry milk studied were spray dried and the remaining two were roller dried. All milks tested contained considerably more sodium, potassium, calcium and phosphorus solid than human milk, some of them the four fold amount of calcium and phosphorus.

Animals↗
PubMed2006

Environmental stress response in wine lactic acid bacteria: beyond Bacillus subtilis.

Lactic acid bacteria (LAB) constitute a heterogeneous group of bacteria that are traditionally used to produce fermented foods. The industrialization of food transformations has increased the economical importance of LAB, as they play a crucial role in the development of the organoleptic and hygienic quality of fermented products. However, the strains selected for industrial purposes, should tolerate adverse conditions encountered in industrial processes, either during starter handling and storage (freeze-drying, freezing, or spray-drying) or during food processing in which abiotic stresses such as heat, cold, acidity, and high concentration of NaCl or ethanol are common. Wine LAB have to deal with several stresses including an acidic pH, a high alcoholic content, non optimal growth temperatures, and growth-inhibitory compounds such as fatty acids and tannins, originated from yeast and bacteria metabolism. Wine LAB have developed several mechanisms to escape or to tolerate wine conditions. They carry out a malolactic fermentation in this stressful environment. In addition to the regulation of the expression of specific genes, bacteria have evolved adaptive networks to face the challenges of a changing environment and to survive under conditions of stress. The so called Global Regulatory Systems control the simultaneous expression of a large number of genes in response to a variety of environmental stress factors. CIRCE sequences able to bind the HrcA repressor, sigma(B) dependent promoters and CtsR regulatory elements have been observed in several genes identified from wine LAB. Improved knowledge of regulators and a better understanding of LAB stress responses could constitute a basis of comparison with the well known model microorganisms, Escherichia coli and Bacillus subtilis. Moreover, it can provide an important insight into improving current industrial starter strains.

Bacillus subtilis↗
PubMed2003

Bitter melon malt vinegar increases daily energy turnover in rats.

Vinegar is generally believed to be good for health. A mash consisting of 35% ethanolic extract from bitter melon malt vinegar-water (8:50:42) was subjected to further acetate fermentation and the resulting vinegar was converted to dried vinegar powder by spray drying after adsorption on dextrin, which was mixed with a commercial rat chow (CRF-1) in the ratio of 1:19 so as to prepare an experimental diet. Male 12-wk old rats of LETO and OLETF strains were fed this experimental diet in parallel with CRF-1 (control) and examined for respiratory quotient (RQ) and blood or plasma parameters associated with diabetes mellitus. Administration of the experimental diet increased daily food intake as well as daily energy expenditure in both strains. RQ significantly lessened in the vinegar diet-fed group of LETO strain, which was reflected not only in the increased energy consumption from fat but also in the decreased energy consumption from carbohydrate, while no significant difference was observed between both dietary groups of OLETF strain in this respect. The profiles of diurnal energy expenditure in both dietary groups of LETO strain exerted two peaks before lights-on and lights-off. Nevertheless, there was a clear difference between both dietary groups of OLETF strain: interestingly the reproduction of the two peaks became conspicuous in the vinegar diet-fed group despite the lack of such peaks in the control. As a consequence of blood or plasma inspection, it turned out that there was no change in HbA1c but a significant increase in plasma cholesterol in the vinegar diet-fed OLETF rats. From these results, a long-term administration of bitter melon malt vinegar can be expected to suppress a lowering of energy turnover inherent with aging and thereby improve anorexia rather than to bring about a preventive effect against the manifestation of NIDDM.

Acetic Acid↗