ascorbic-acid has been researched along with maltodextrin* in 20 studies
2 trial(s) available for ascorbic-acid and maltodextrin
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Double-blind, placebo-controlled trial comparing effects of supplementation of two micronutrient sprinkles on fatty acid status in Cambodian infants.
Infants in developing countries require early dietary interventions to prevent nutritional deficiencies, above all protein, energy, iron and zinc. To what extent these interventions may affect the fatty acid (FA) status is still unknown.. To examine and compare the effects of 2 micronutrient "sprinkles" supplementations (iron 12.5 mg + folic acid 150 microg, iron/folate and iron 12.5 mg + folic acid 150 microg + zinc 5 mg + vitamins A, C and D3, mineral/micronutrient [MMN]) versus placebo on the FA status of Cambodian infants.. A total of 204 infants age 6 mo and living in Kompong Chhnang Province, Cambodia, were randomly assigned to receive daily supplementation of MMN (n = 68) and iron/folate (n = 68) or placebo (n = 68) for a 12-mo period in powder form as sprinkles. At the end of the intervention period, FAs in the range of 16 to 24 C were determined in blood drops absorbed on a strip collected from 182 subjects, and values among the 3 intervention subgroups and those of 21 Italian 18-mo-old, normal-growing infants as the reference group were compared.. At the end of the supplementation trial, higher levels of the 2 essential FAs (EFAs) (linoleic acid, 18:2n-6, and alpha-linolenic acid, 18:3n-3) were found in the MMN group. No differences occurred for the major longer chain derivatives of both EFAs arachidonic acid (20:4n-6) and docosahexaenoic acid (22:6n-3). In MMN supplemented Cambodians, blood levels of linoleic acid approached those of Italian infants, and in addition their alpha-linolenic acid levels were improved. Cambodian infants, mostly still breast-fed through the second year of life, showed significantly higher levels of long-chain derivatives of both the n-6 and the n-3 series compared with Italians.. Supplementation with iron, folic acid, zinc and vitamins was associated with an increase of linoleic acid and alpha-linolenic acid levels in Cambodian infants versus placebo, without significant changes in the concentrations of their longer chain derivatives, resulting in a FA status closer to Italian counterparts for the essential polyunsaturated FA levels. The iron/folate-treated infants showed no differences compared with the other 2 groups. Studies are needed to differentiate the potential effects of the supplemented micronutrients on the FA status. Topics: alpha-Linolenic Acid; Anemia, Iron-Deficiency; Ascorbic Acid; Cambodia; Child Development; Cholecalciferol; Dietary Supplements; Double-Blind Method; Female; Folic Acid; Fumarates; Gluconates; Humans; Infant; Iron Compounds; Italy; Linoleic Acid; Longitudinal Studies; Male; Micronutrients; Polysaccharides; Vitamin A | 2007 |
Effects of Cassia tora fiber supplement on serum lipids in Korean diabetic patients.
Cassia tora fiber supplement consisting of 2 g of soluble fiber extracted from Cassia semen (C. tora L.), 200 mg of alpha-tocopherol, 500 mg of ascorbic acid, and 300 mg of maltodextrin was formulated in a pack, and given to 15 type II diabetic subjects (seven men and eight women 57.1 +/- 2.9 years old) with instructions to take two packs per day for 2 months. Placebo contained maltodextrin only with a little brown caramel color. Lifestyle factors and dietary intakes of the subjects were not altered during the 2-month period. Serum total cholesterol was moderately (P < .1) decreased in the C. tora group compared with the age- and gender-matched placebo group, as was the ratio of apolipoprotein B to apolipoprotein A1 (P < .1). Levels of serum triglycerides and low-density lipoprotein-cholesterol tended to decrease more in the C. tora-supplemented group than in the placebo group. Serum alpha-tocopherol was increased (P < .01) but lipid peroxides were not significantly lower in the C. tora group. Fasting blood glucose, hemoglobin A1c, blood urea nitrogen, creatinine, and activities of serum aspartate aminotransferase and alanine aminotransferase were not changed by the fiber supplement. We concluded that C. tora supplements can help improve serum lipid status in type II diabetic subjects without serious adverse effects. Topics: alpha-Tocopherol; Apolipoprotein A-I; Apolipoproteins B; Ascorbic Acid; Cassia; Cholesterol, LDL; Diabetes Mellitus, Type 2; Diet; Dietary Fiber; Dietary Supplements; Female; Humans; Korea; Life Style; Lipids; Male; Middle Aged; Placebos; Plant Extracts; Polysaccharides; Thiobarbituric Acid Reactive Substances; Triglycerides | 2005 |
18 other study(ies) available for ascorbic-acid and maltodextrin
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Stability of vitamin C, carotenoids, phenols, and antioxidant capacity of pasteurised orange juice with resistant maltodextrin storage.
Resistant maltodextrin (RMD) was added at increasing concentrations (0%, 2.5%, 5% and 7.5%) before pasteurisation to orange juice to analyse its potential protective effect on the health-related bioactive compounds of pasteurised orange juice throughout its storage time. Samples were characterised in terms of basic physico-chemical properties and bioactive compounds at the beginning of the storage. Higher concentrations of RMD proved to better preserve the bioactive compounds of orange juice, thus obtaining a higher antioxidant capacity (AC). Stability of all samples was determined by measuring the same parameters at days 0, 15, 45, 75, 105, 136 and 170 of storage. °Brix and pH were very stable in all samples along storage, while all bioactive compouds had negative variations. However, RMD addition slightly improved ascorbic acid, vitamin C, total phenols, and total carotenoids retention, improving then its AC. This effect was greater in the 5% RMD-added samples. All bioactive compounds showed a positive Pearson's correlation coefficient with AC. Colour variations were also measured at days 105 and 170. All samples had a positive variation of all colour parameters, being this clearer at day 170. This work enlights the potential functionality of RMD to better preserve the health-related compounds of pasteurised orange juice. Topics: Antioxidants; Ascorbic Acid; Carotenoids; Citrus sinensis; Phenols | 2024 |
Effects of drying methods and maltodextrin on vitamin C and quality of Terminalia ferdinandiana fruit powder, an emerging Australian functional food ingredient.
Terminalia ferdinandiana, common name Kakadu plum (KP), fruit is a valuable source of vitamin C, and its concentration can be used as a quality index of KP products, such as dried fruit powder. The present study investigated the effects of two drying methods (freeze-drying and oven-drying) and the addition of maltodextrin (0-25%) on vitamin C, Maillard products, and overall quality of KP fruit powder.. Freeze-drying was a better dehydration technique than oven-drying in retaining vitamin C, reducing the formation of non-enzymatic browning and oxidation products, and improving powder colour (P < 0.05). Non-enzymatic browning products (furfural and 5-hydroxymethyl furfural) were generated in the oven-dried samples as a function of heating and high water activity. Maltodextrin acted as a vitamin C stabilizer in protecting vitamin C from oxidation, and significantly improved the colour attributes of the final dry products. Incorporation of 10-15% maltodextrin could reduce the percentage loss of vitamin C from 8.1% to 3.4% and 18.9% to 11.4% (compared with the control) during freeze-drying and oven-drying, respectively. Scanning electron micrographs revealed differences in the microstructures of the KP powder processed by the two drying methods with different levels of maltodextrin. Multivariate data analysis (principal component analysis) showed separation between the oven-dried and freeze-dried samples, and also suggested that addition of maltodextrin of 7.5-10% and 10-15% are effective for preserving vitamin C and other quality properties of the freeze- and oven-dried KP powder samples, respectively.. The results obtained are important for the KP industry, including Indigenous enterprises, in selecting the most appropriate drying method for KP fruit in terms of quality and sustainability. © 2021 Society of Chemical Industry. Topics: Ascorbic Acid; Australia; Food Handling; Food Ingredients; Freeze Drying; Fruit; Hot Temperature; Polysaccharides; Powders; Terminalia | 2021 |
Beta-Glucan as Wall Material in Encapsulation of Elderberry (Sambucus nigra) Extract.
The aim of the study was to investigate the potential of using β-glucan as wall material to microencapsulate the elderberry extract. Firstly, the extract was obtained by the water-acetone extraction method to extract mainly anthocyanins from ground dried fruits. The extract was mixed with wall materials: maltodextrin-β-glucan mixture and the control sample as a widely used combination of maltodextrin and arabic gum (92.5:7.5). In the examined samples the content of β-glucan was 0.5, 1, 2 and 3%. Properties of encapsulated extracts of final powders were measured using particle size and morphology, encapsulation efficiency, color measurement, total anthocyanin and ascorbic acid content (TAC and TAAC) methods. Our results indicated that the β-glucan wall material samples had higher process quality compared to control samples. Addition of β-glucan insignificantly decreases encapsulation efficiency. Among powders with β-glucan content, the powder with 1% β-glucan content was characterized by the smallest (24 μm) particle size. The sample with 2% β-glucan content had the highest water solubility and polydispersity index. Due to the encapsulation efficiency, moisture content, and water solubility index, the optimum condition of microencapsulation process for elderberry extract was for samples with 0.5% β-glucan as wall material content. To conclude, due to high molecular weight of β-glucan the higher than 0.5% ratio of β-glucan is not recommended for spray-drying method. However, small quantity of health-beneficial β-glucan could act as potential encapsulation agent in clean label products to replace Arabic gum. Topics: Anthocyanins; Ascorbic Acid; beta-Glucans; Desiccation; Drug Compounding; Fruit; Gum Arabic; Particle Size; Plant Extracts; Polysaccharides; Powders; Sambucus nigra; Solubility; Water | 2019 |
Microencapsulation of extracts of bioactive compounds obtained from acerola (Malpighia emarginata DC) pulp and residue by spray and freeze drying: Chemical, morphological and chemometric characterization.
The acerola pulp and residue extracts were microencapsulated by spray and freeze-drying, using gum arabic and maltodextrin as encapsulating agents. Total anthocyanins, carotenoids (CA), ascorbic acid (AA), phenolic compounds (PC), total flavonoids, antioxidant activity, color, moisture, water activity, solubility, hygroscopicity and microstructure of the powders were analyzed. The acerola residue extract had higher concentrations of bioactive compounds (except for AA) and lower antioxidant activity. The microencapsulated powders by spray and freeze-drying showed good physico-chemical properties. Spray-dried powder has lower microencapsulation efficiency for CA, AA and PC and in general, it presented the best characteristics due to its higher concentration of bioactive compounds (except AA), and antioxidant activity by FRAP and ORAC assays. The spray-dried particles were of spherical shape while the freeze-dried products were of irregular structures. Overall, these results demonstrate the better utility of agro-industrial acerola residue in the form of microparticles of bioactive compounds, retaining good antioxidant activity. Topics: Anthocyanins; Antioxidants; Ascorbic Acid; Carotenoids; Drug Compounding; Flavonoids; Freeze Drying; Gum Arabic; Malpighiaceae; Phenols; Plant Extracts; Polysaccharides; Powders; Solubility | 2018 |
Influence of spray drying conditions on the properties of avocado powder drink.
Consumers are increasingly looking for foods with attractive taste, easy preparation, quick consumption and nutritious. Avocado is a nutritional fruit that presents a preservation challenge to food industry. The development of powder blends using spray drying of avocado as a powdered drink is an attractive option that generates products with high nutritional value and stable. Two avocado formulations were spray dried using a design of experiments to assess the influence of drying conditions on powder blends. Results showed higher drying temperatures in combination with smaller droplets resulted in higher yields, lower residual moisture, lower water activity, and in smaller, less dense particles with color green. The inclusion of maltodextrin proved to be vital in preserving high contents of protein, ascorbic acid, and phenolic compounds at any drying conditions possibly due to hydrogen bonding stabilization of those compounds. Using a scalable and efficient drying process, avocado high nutritional value was maintained. Topics: Ascorbic Acid; Beverages; Color; Desiccation; Fruit; Nutritive Value; Particle Size; Persea; Phenols; Polysaccharides; Powders; Rheology; Temperature; Water | 2018 |
Effects of Spray-Drying Parameters on In Vitro Functional Properties of Camu-Camu (Myrciaria dubia Mc. Vaugh): A Typical Amazonian Fruit.
Camu-camu (Myrciaria dubia) fruit is a rich source of bioactive compounds but its shelf life is rather short. Therefore, this study was aimed to evaluate the effect of inlet air temperature (T) and concentration (C) of maltodextrin and arabic gum on the spray-drying process of commercial camu-camu pulps (São Paulo and Manaus). Moisture, solubility, total phenolics (TP), ascorbic acid (AA), and proanthocyanidins (PAC) contents, and in vitro antioxidant capacity of the powders (FRAP, DPPH, Folin-Ciocalteu's reducing capacity were measured). Arabic gum resulted in better yields (22% to 30%), powder solubility (84% to 90%), and lower losses of analyzed compounds than the powders manufactured with maltodextrin. Overall, inlet air temperature had a lower impact on the responses studied than the concentration of carrier agents. Polynomial equations were generated for AA (R Topics: Antioxidants; Ascorbic Acid; Biphenyl Compounds; Brazil; Commerce; Desiccation; Food Handling; Food Storage; Fruit; Gum Arabic; Humans; Myrtaceae; Phenols; Picrates; Polysaccharides; Proanthocyanidins; Temperature | 2017 |
Maltodextrin/ascorbic acid stimulates wound closure by increasing collagen turnover and TGF-β1 expression in vitro and changing the stage of inflammation from chronic to acute in vivo.
It has been reported that carbohydrates confer physicochemical properties to the wound environment that improves tissue repair. We evaluated in vitro and in vivo wound healing during maltodextrin/ascorbic acid treatment. In a fibroblast monolayer scratch assay, we demonstrated that maltodextrin/ascorbic acid stimulated monolayer repair by increasing collagen turnover coordinately with TGF-β1 expression (rising TGF-β1 and MMP-1 expression, as well as gelatinase activity, while TIMP-1 was diminished), similar to in vivo trends. On the other hand, we observed that venous leg ulcers treated with maltodextrin/ascorbic acid diminished microorganism population and improved wound repair during a 12 week period. When maltodextrin/ascorbic acid treatment was compared with zinc oxide, almost four fold wound closure was evidenced. Tissue architecture and granulation were improved after the carbohydrate treatment also, since patients that received maltodextrin/ascorbic acid showed lower type I collagen fiber levels and increased extracellular alkaline phosphatase activity and blood vessels than those treated with zinc oxide. We hypothesize that maltodextrin/ascorbic acid treatment stimulated tissue repair of chronic wounds by changing the stage of inflammation and modifying collagen turnover directly through fibroblast response. Topics: Administration, Cutaneous; Adult; Aged; Aged, 80 and over; Antioxidants; Ascorbic Acid; Case-Control Studies; Collagen Type III; Drug Combinations; Female; Humans; Longitudinal Studies; Lower Extremity; Male; Middle Aged; Pilot Projects; Polysaccharides; Prospective Studies; Random Allocation; Tissue Inhibitor of Metalloproteinase-1; Transforming Growth Factor beta1; Varicose Ulcer; Wound Healing; Zinc Oxide | 2017 |
Optimisation of phenolic extraction from Averrhoa carambola pomace by response surface methodology and its microencapsulation by spray and freeze drying.
Optimised of the extraction of polyphenol from star fruit (Averrhoa carambola) pomace using response surface methodology was carried out. Two variables viz. temperature (°C) and ethanol concentration (%) with 5 levels (-1.414, -1, 0, +1 and +1.414) were used to design the optimisation model using central composite rotatable design where, -1.414 and +1.414 refer to axial values, -1 and +1 mean factorial points and 0 refers to centre point of the design. The two variables, temperature of 40°C and ethanol concentration of 65% were the optimised conditions for the response variables of total phenolic content, ferric reducing antioxidant capacity and 2,2-diphenyl-1-picrylhydrazyl scavenging activity. The reverse phase-high pressure liquid chromatography chromatogram of the polyphenol extract showed eight phenolic acids and ascorbic acid. The extract was then encapsulated with maltodextrin (⩽ DE 20) by spray and freeze drying methods at three different concentrations. Highest encapsulating efficiency was obtained in freeze dried encapsulates (78-97%). The obtained optimised model could be used for polyphenol extraction from star fruit pomace and microencapsulates can be incorporated in different food systems to enhance their antioxidant property. Topics: Antioxidants; Ascorbic Acid; Averrhoa; Biphenyl Compounds; Chromatography, High Pressure Liquid; Drug Compounding; Ethanol; Ferric Compounds; Food Technology; Freeze Drying; Fruit; Hydrogen-Ion Concentration; Phenols; Picrates; Plant Extracts; Polyphenols; Polysaccharides; Surface Properties; Temperature | 2015 |
[Improving maltodextrin specificity by site-saturation engineering of subsite +1 in cyclodextrin glycosyltransferase from Paenibacillus macerans].
By engineering the subsite +1 of cyclodextrin glycosyltransferase (CGTase) from Paenibacillus macerans, we improved its maltodextrin specificity for 2-O-D-glucopyranosyl-L-ascorbic acid (AA-2G) synthesis. Specifically, we conducted site-saturation mutagenesis on Leu194, Ala230, and His233 in subsite +1 separately and gained 3 mutants L194N (leucine --> asparagine), A230D (alanine --> aspartic acid), and H233E (histidine --> glutamic acid) produced higher AA-2G yield than the wild-type and the other mutant CGTases. Therefore, the 3 mutants L194N, A230D, and H233E were further used to construct the double and triple mutations. Among the 7 obtained combinational mutants, the triple mutant L194N/A230D/H233E produced the highest AA-2G titer of 1.95 g/L, which was increased by 62.5% compared with that produced by the wild-type CGTase. Then, we modeled the reaction kinetics of all the mutants and found a substrate inhibition by high titer of L-AA for the mutants. The optimal temperature, pH, and reaction time of all the mutants were also determined. The structure modeling indicated that the enhanced maltodextrin specificity may be related with the changes of hydrogen bonding interactions between the side chain of residue at the three positions (194, 230 and 233) and the substrate sugars. Topics: Ascorbic Acid; Glucosyltransferases; Hydrogen Bonding; Kinetics; Mutagenesis, Site-Directed; Paenibacillus; Polysaccharides; Protein Engineering; Substrate Specificity; Temperature | 2014 |
Improving maltodextrin specificity for enzymatic synthesis of 2-O-d-glucopyranosyl-l-ascorbic acid by site-saturation engineering of subsite-3 in cyclodextrin glycosyltransferase from Paenibacillus macerans.
In this work, the subsite-3 of cyclodextrin glycosyltransferase (CGTase) from Paenibacillus macerans was engineered to improve maltodextrin specificity for 2-O-d-glucopyranosyl-l-ascorbic acid (AA-2G) synthesis. Specifically, the site-saturation mutagenesis of tyrosine 89, asparagine 94, aspartic acid 196, and aspartic acid 372 in subsite-3 was separately performed, and three mutants Y89F (tyrosine→phenylalanine), N94P (asparagine→proline), and D196Y (aspartic acid→tyrosine) produced higher AA-2G titer than the wild-type and the other mutants. Previously, we found the mutant K47L (lysine→leucine) also had a higher maltodextrin specificity. Therefore, the four mutants K47L, Y89F, N94P, and D196Y were further used to construct the double, triple, and quadruple mutations. Among the 11 combinational mutants, the quadruple mutant K47L/Y89F/N94P/D196Y produced the highest AA-2G titer of 2.23g/L, which was increased by 85.8% compared to that produced by the wild-type CGTase. The reaction kinetics of all the mutants were modeled, and the pH and thermal stabilities of all the mutants were analyzed. The structure modeling indicated that the enhanced maltodextrin specificity may be related with the changes of hydrogen bonding interactions between the side chain of residue at the four positions (47, 89, 94, and 196) and the substrate sugars. Topics: Amino Acid Substitution; Ascorbic Acid; Base Sequence; Enzyme Stability; Glucosyltransferases; Hydrogen-Ion Concentration; Kinetics; Models, Molecular; Mutagenesis, Site-Directed; Mutant Proteins; Paenibacillus; Polysaccharides; Protein Engineering; Substrate Specificity; Temperature | 2013 |
Iterative saturation mutagenesis of -6 subsite residues in cyclodextrin glycosyltransferase from Paenibacillus macerans to improve maltodextrin specificity for 2-O-D-glucopyranosyl-L-ascorbic acid synthesis.
2-O-d-Glucopyranosyl-l-ascorbic acid (AA-2G), a stable l-ascorbic acid derivative, is usually synthesized by cyclodextrin glycosyltransferase (CGTase), which contains nine substrate-binding subsites (from +2 to -7). In this study, iterative saturation mutagenesis (ISM) was performed on the -6 subsite residues (Y167, G179, G180, and N193) in the CGTase from Paenibacillus macerans to improve its specificity for maltodextrin, which is a cheap and easily soluble glycosyl donor for AA-2G synthesis. Site saturation mutagenesis of four sites-Y167, G179, G180, and N193-was first performed and revealed that four mutants-Y167S, G179R, N193R, and G180R-produced AA-2G yields higher than those of other mutant and wild-type CGTases. ISM was then conducted with the best positive mutant as a template. Under optimal conditions, mutant Y167S/G179K/N193R/G180R produced the highest AA-2G titer of 2.12 g/liter, which was 84% higher than that (1.15 g/liter) produced by the wild-type CGTase. Kinetics analysis of AA-2G synthesis using mutant CGTases confirmed the enhanced maltodextrin specificity and showed that compared to the wild-type CGTase, the mutants had no cyclization activity but high hydrolysis and disproportionation activities. A possible mechanism for the enhanced substrate specificity was also analyzed through structure modeling of the mutant and wild-type CGTases. These results indicated that the -6 subsite played crucial roles in the substrate binding and catalytic reactions of CGTase and that the obtained CGTase mutants, especially Y167S/G179K/N193R/G180R, are promising starting points for further development through protein engineering. Topics: Ascorbic Acid; Binding Sites; Glucosyltransferases; Kinetics; Metabolic Engineering; Models, Molecular; Mutagenesis, Site-Directed; Mutant Proteins; Mutation, Missense; Paenibacillus; Polysaccharides; Protein Conformation; Protein Engineering; Substrate Specificity | 2013 |
Site-saturation engineering of lysine 47 in cyclodextrin glycosyltransferase from Paenibacillus macerans to enhance substrate specificity towards maltodextrin for enzymatic synthesis of 2-O-D-glucopyranosyl-L-ascorbic acid (AA-2G).
In this work, the site-saturation engineering of lysine 47 in cyclodextrin glycosyltransferase (CGTase) from Paenibacillus macerans was conducted to improve the specificity of CGTase towards maltodextrin, which can be used as a cheap and easily soluble glycosyl donor for the enzymatic synthesis of 2-O-D-glucopyranosyl-L-ascorbic acid (AA-2G) by CGTase. When using maltodextrin as glycosyl donor, four mutants K47F (lysine→ phenylalanine), K47L (lysine→ leucine), K47V (lysine→ valine) and K47W (lysine→ tryptophan) showed higher AA-2G yield as compared with that produced by the wild-type CGTase. The transformation conditions (temperature, pH and the mass ratio of L-ascorbic acid to maltodextrin) were optimized and the highest titer of AA-2G produced by the mutant K47L could reach 1.97 g/l, which was 64.2% higher than that (1.20 g/l) produced by the wild-type CGTase. The reaction kinetics analysis confirmed the enhanced maltodextrin specificity, and it was also found that compared with the wild-type CGTase, the four mutants had relatively lower cyclization activities and higher disproportionation activities, which was favorable for AA-2G synthesis. The mechanism responsible for the enhanced substrate specificity was further explored by structure modeling and it was indicated that the enhancement of maltodextrin specificity may be due to the short residue chain and the removal of hydrogen bonding interactions between the side chain of residue 47 and the sugar at -3 subsite. Here the obtained mutant CGTases, especially the K47L, has a great potential in the production of AA-2G with maltodextrin as a cheap and easily soluble substrate. Topics: Amino Acid Substitution; Ascorbic Acid; Enzyme Stability; Glucosyltransferases; Hydrogen-Ion Concentration; Kinetics; Lysine; Models, Molecular; Mutagenesis, Site-Directed; Mutant Proteins; Paenibacillus; Polysaccharides; Protein Conformation; Substrate Specificity; Temperature | 2013 |
Systems engineering of tyrosine 195, tyrosine 260, and glutamine 265 in cyclodextrin glycosyltransferase from Paenibacillus macerans to enhance maltodextrin specificity for 2-O-(D)-glucopyranosyl-(L)-ascorbic acid synthesis.
In this work, the site saturation mutagenesis of tyrosine 195, tyrosine 260 and glutamine 265 in the cyclodextrin glycosyltransferase (CGTase) from Paenibacillus macerans was conducted to improve the specificity of CGTase for maltodextrin, which can be used as a cheap and easily soluble glycosyl donor for the synthesis of 2-O-d-glucopyranosyl-l-ascorbic acid (AA-2G). Specifically, the site-saturation mutagenesis of three sites-tyrosine 195, tyrosine 260, and glutamine 265-was performed, and it was found that the resulting mutants (containing the mutations Y195S [tyrosine → serine], Y260R [tyrosine → arginine], and Q265K [glutamine → lysine]) produced higher AA-2G yields than the wild type and the other mutant CGTases when maltodextrin was used as the glycosyl donor. Furthermore, double and triple mutations were introduced, and four mutants (containing Y195S/Y260R, Y195S/Q265K, Y260R/Q265K, and Y260R/Q265K/Y195S) were obtained and evaluated for the capacity to produce AA-2G. The Y260R/Q265K/Y195S triple mutant produced the highest titer of AA-2G at 1.92 g/liter, which was 60% higher than that (1.20 g/liter) produced by the wild-type CGTase. The kinetics analysis of AA-2G synthesis by the mutant CGTases confirmed the enhanced maltodextrin specificity, and it was also found that compared with the wild-type CGTase, all seven mutants had lower cyclization activities and higher hydrolysis and disproportionation activities. Finally, the mechanism responsible for the enhanced substrate specificity was explored by structure modeling, which indicated that the enhancement of maltodextrin specificity may be related to the changes of hydrogen bonding interactions between the side chain of residue at the three positions (195, 260, and 265) and the substrate sugars. This work adds to our understanding of the synthesis of AA-2G and makes the Y260R/Q265K/Y195S mutant a good starting point for further development by protein engineering. Topics: Amino Acid Substitution; Ascorbic Acid; Glucosyltransferases; Kinetics; Mutagenesis, Site-Directed; Mutant Proteins; Paenibacillus; Polysaccharides; Protein Engineering; Substrate Specificity | 2013 |
Effect of protective compounds on the survival, electrolyte leakage, and lipid degradation of freeze-dried Weissella paramesenteroides LC11 during storage.
The effect of cryoprotectants (maltodextrin+glycerol) and cryoprotectants+antioxidant [ascorbic acid and/or butylated hydroxytoluene (BHT)] mixtures on the survival, electrolyte leakage, and lipid degradation of freeze-dried Weissella paramesenteroides LC11 during storage was investigated and compared with that of the control (cells without additives) over a 90-day storage period at 4 or 20 degrees in glass tubes with water activity (a(w)) of 0.23. The survival, electrolyte leakage, and lipid degradation were evaluated through colony counts, electrical conductivity, and thiobarbituric acid reactive substances (TBARS) content, respectively. The fatty acids composition was determined by gas chromatography, in both the total lipid extract and the polar lipid fraction, and compared with that of the control after the 90-day storage period. As the storage proceeded, increases in leakage value and TBARS content, as well as a decrease in viability, were observed. After 90 days of storage, the major fatty acids found in both the total lipid extract and the polar lipid fraction were palmitic (16:0), palmitoleic (16:1), stearic (18:0), oleic (18:1), linoleic (18:2), and linolenic (18:3) acids. The survival, leakage value, TBARS content and 18:2/16:0 or 18:3/16:0 ratio were the greatest for the protected strain held at 4 degrees . Cells with the cryoprotectants+BHT mixture showed the highest percentage of survival and 18:2/16:0 or 18:3/16:0 ratio in both lipid extracts, as well as the lowest leakage value and TBARS content after the 90-day storage period. Drying cells with the cryoprotectants+BHT mixture considerably slowed down polar lipid degradation and loss of membrane integrity, resulting in improved viability during storage. Topics: Antioxidants; Ascorbic Acid; Butylated Hydroxytoluene; Cryoprotective Agents; Electric Conductivity; Electrolytes; Fatty Acids; Freeze Drying; Glycerol; Lactobacillus; Microbial Viability; Oxidation-Reduction; Polysaccharides; Thiobarbituric Acid Reactive Substances; Time Factors | 2009 |
Psychrometry as a methodological tool for optimizing the spray drying process.
Because psychrometry takes into account a great number of variables reflecting the quality of the drying air, it is an interesting tool to improve the control and the optimization of the spray drying process. In this article the authors study the evolution of the psychrometric variables according to the values taken by four inlet parameters (inlet air temperature, liquid flow rate, solid concentration of the spray dried liquid, and nature of the product). The results highlighted the existence of mathematical models making it possible to optimize the process, but also to underline the influence of the nature of the product on the drying mechanism. Topics: Ascorbic Acid; Chemistry, Pharmaceutical; Models, Theoretical; Pharmaceutical Preparations; Polysaccharides; Quality Control; Technology, Pharmaceutical; Temperature; Thermodynamics | 2008 |
New microencapsulation system for ascorbic acid using pea protein concentrate as coat protector.
Microencapsulation is essential to preserve biological activity of ascorbic acid (AA) and pea protein has not been used as a carrier in such processes. This work aimed to produce microparticles by a spray-drying process using pea protein (PPC) as wall material of AA and evaluate the retention of the core by HPLC, overall morphology SEM, size distribution by light scattering and release kinetics. Carboxymethylcellulose (CMC) and blends with maltodextrin (M) were produced for comparative analyses. The yields were compatible with the applied technology and the retention was above 84% for all materials. The PPC microparticles presented irregular and rough surfaces, CMC produced a regular and smooth surface and agglomeration was more intense in microparticles with M. Mean particle diameters were all below 8 microm. The microparticle release rates were lower than those with free AA, being best correlated to the Higuchi kinetic model. These results support the utilization of PPC for microencapsulation of AA. Topics: Aerosols; Antioxidants; Ascorbic Acid; Carboxymethylcellulose Sodium; Chromatography, High Pressure Liquid; Coated Materials, Biocompatible; Drug Compounding; Drug Delivery Systems; Kinetics; Microscopy, Electron, Scanning; Particle Size; Pisum sativum; Polysaccharides; Proteins | 2006 |
Suppressive effect of saturated acyl L-ascorbate on the oxidation of linoleic acid encapsulated with maltodextrin or gum arabic by spray-drying.
6-O-Palmitoyl L-ascorbate was added to linoleic acid at various molar ratios of the ascorbate to the acid, the mixtures were emulsified with a maltodextrin or gum arabic solution, and the emulsions were spray-dried to produce microcapsules. At higher molar ratios, the oil droplets in the emulsions were smaller, and the oxidative stabilities of the encapsulated linoleic acid were higher for both the maltodextrin- and gum arabic-based microcapsules. 6-O-Capryloyl, caproyl, and lauroyl L-ascorbates, which were synthesized through lipase-catalyzed condensation in acetone, were also used for the microencapsulation of linoleic acid. Except for capryloyl L-ascorbate, the addition of a saturated acyl ascorbate, especially caproyl ascorbate, to linoleic acid was effective for preparing oil droplets of small particle diameter and for suppressing the oxidation of the encapsulated linoleic acid. Topics: Acylation; Antioxidants; Ascorbic Acid; Caprylates; Capsules; Decanoic Acids; Drug Stability; Emulsions; Gum Arabic; Lauric Acids; Linoleic Acid; Oxidation-Reduction; Polysaccharides; Solubility; Time Factors | 2002 |
Multidex Gel for use in wound care.
Topics: Ascorbic Acid; Bandages; Gels; Humans; Polysaccharides; Powders; Wound Healing | 1997 |