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1.
Food Chem ; 339: 127875, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32866701

RESUMO

Gluten protein based snacks have been a major concern for allergen, low nutrition and physio-chemical properties. In this study, wheat flour (WF) was replaced with cassava starch (CS) at different levels [10, 20, 30, 40 and 50%(w/w)] to prepare fried snacks. The addition of CS significantly (P < 0.05) increased hardness and pasting properties while gluten network, oil uptake, water holding capacity, and expansion were decreased. Fourier transform infrared spectroscopy revealed that the secondary structure of amide I, α-helix (1650-1660 cm-1), along with amide II region (1540 cm-1) changed when CS was added. Starch-protein complex was identified by X-ray diffraction analysis while no starch-protein-lipid complex was observed. The micrographs from scanning electron microscopy showed that starch-protein matrix was interrupted when ≥40%(w/w) CS was added. Furthermore, in vitro calcium bioavailability was decreased slightly with the addition of CS. The results suggest the feasibility of adding 40% CS as an alternative to WF in snacks.


Assuntos
Digestão , Glutens/química , Manihot/química , Lanches , Triticum/química , Farinha/análise , Dureza , Amido/química , Água/química
2.
J Food Sci ; 85(9): 2832-2842, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32856302

RESUMO

Films were produced using the blown extrusion method from blends made with cassava and pinhão thermoplastic starch, compostable polyester (poly(butylene adipate co-terephthalate, PBAT) and natural extracts (rosemary and green tea). The effect of the incorporation of the extracts and the type of starch added in the film properties were investigated following the mixture design (23 ) approach. Regression models and response surface curves were generated to predict the film properties. The effect of the cold storage (6 °C and 17% of humidity relative, for 60 days) on the film properties was also investigated in order to simulate future applications. All the properties were mainly influenced by the extract type. The incorporation of the extracts decreased the lightness parameter and the films produced with green tea extract were more opaque than those made with rosemary. Starch/rosemary blends were more flexible, while the extract type did not have a significant effect on tensile strength (TS). Film elongation (ELO) ranged from 520% to 719% and might be comparable to some synthetic polymers. The water vapor permeability was improved in approximately 14% with addition of the extracts. The storage conditions, on the one hand, increased the TS, elastic modulus, and opacity of films and, on the other hand, decreased the elongation parameter. The thermal stability of films was not modified by adding extracts or varying the starch type. The results demonstrated that pinhão/cassava/PBAT blends and the natural extracts are a good alternative matrix to produce packagings with adequate mechanical and barrier properties. PRACTICAL APPLICATION: Extruded films produced from cassava or pinhão starch, poly(butylene adipate co-terephthalate) (PBAT) and natural extracts show technological potential to be used as active packaging for food products. Pinhão starch is a great alternative substitute to cassava starch and the incorporation of the commercial compostable polymer (PBAT) is necessary in order to confer suitable mechanical properties to extrusion process. The extrusion blown method, a process widely used by plastic industries, allows the scale-up of bio-based packagings for industrial scale.


Assuntos
Embalagem de Alimentos/instrumentação , Manihot/química , Extratos Vegetais/química , Amido/química , Módulo de Elasticidade , Umidade , Permeabilidade , Ácidos Ftálicos/química , Poliésteres/química , Polímeros/química , Vapor , Resistência à Tração
3.
J Food Sci ; 85(9): 2857-2865, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32812228

RESUMO

The present study was aimed to develop Manihot esculenta and Carrageenan bio-based composite active film functionalized with anise, caraway, and nutmeg essential oils (EOs) and to assess the shelf life of chicken nuggets wrapped with the developed film at refrigeration storage. Overall, the Minimum Inhibitory Concentration (MIC) values of the three EOs ranged from 0.4 to 0.8% v/v of which nutmeg EO was found most effective. Incorporation of EOs in the film resulted in significant (P ˂ 0.05) decrease in tensile strength and water activity while elongation at break was significantly (P ˂ 0.05) increased. No significant (P ˃ 0.05) changes in thickness and Water Vapor Transmission Rate (WVTR) were observed. Based on physicomechanical and sensory evaluation, films incorporated with 0.5, 1, and 1% concentration of anise, nutmeg, and caraway EO were selected. Chicken nuggets overwrapped with aforementioned films were stored aerobically at refrigeration temperature (4 ± 1 °C) to evaluate antimicrobial, antioxidant, and sensory characteristics. The result indicated that pH, peroxide, free fatty acid (FFA), and thiobarbituric acide (TBA) value of treatments were significantly (P ˂ 0.05) lower than controls however significantly (P < 0.05) higher DPPH activity was observed in all treatments. The total plate count, psychrophilic count and, yeast and mold count were also significantly (P ˂ 0.01) lower in treatment groups and were within the permissible limits. The treated samples were well acceptable during whole storage period of 15 days. The application of composite, active edible bio-based film was found proficient in confining product quality attributes throughout storage. PRACTICAL APPLICATION: The majority of films used for packaging of meat and meat products are derived from synthetic "plastic" materials. The demerits associated with plastics have eventually led to explore natural alternatives such as edible films. The composite-active bio-based films have a huge potential to be molded for specific film properties based on requirements of product-specific packaging conditions.


Assuntos
Anti-Infecciosos/farmacologia , Antioxidantes/análise , Filmes Comestíveis , Embalagem de Alimentos/instrumentação , Produtos da Carne/análise , Óleos Voláteis/análise , Polímeros/química , Animais , Antioxidantes/farmacologia , Bactérias/efeitos dos fármacos , Bactérias/crescimento & desenvolvimento , Carragenina/química , Galinhas , Embalagem de Alimentos/métodos , Armazenamento de Alimentos , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Humanos , Manihot/química , Produtos da Carne/microbiologia , Testes de Sensibilidade Microbiana , Óleos Voláteis/farmacologia , Polímeros/síntese química , Refrigeração , Paladar
4.
J Appl Microbiol ; 129(5): 1287-1296, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32330366

RESUMO

AIM: To express amylomaltase from Thermus filiformis (TfAM) in a generally recognized as safe (GRAS) organism and to use the enzyme in starch modification. METHODS AND RESULTS: TfAM was expressed in Saccharomyces cerevisiae, using 2% (w/v) galactose inducer under GAL1 promoter. The enzyme was thermostable with high disproportionation and cyclization activities. The main large-ring cyclodextrin (CD) products were CD24-CD29, with CD26 as maximum at all incubation times. TfAM was used to modify cassava and pea starches, the amylose content decreased 18% and 30%, respectively, when 5% (w/v) starch was treated with 0·5 U TfAM g-1 starch. The increase in short branched chain (DP, degree of polymerization, 1-5) and the broader chain length distribution pattern which extended to the longer chain (DP40) after TfAM treatment were observed. The thermal property was changed, with an increase in retrogradation of starch as suggested by a lower enthalpy. CONCLUSIONS: TfAM was successfully expressed in S. cerevisiae and was used to make starches with new functionality. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report on the expression of AM in the GRAS yeast and the production of a modified starch gel from pea starch to improve the versatility of starch for food use.


Assuntos
Proteínas de Bactérias/metabolismo , Sistema da Enzima Desramificadora do Glicogênio/metabolismo , Saccharomyces cerevisiae/genética , Amido/metabolismo , Thermus/enzimologia , Amilose/metabolismo , Proteínas de Bactérias/genética , Ciclodextrinas/biossíntese , Ciclodextrinas/química , Sistema da Enzima Desramificadora do Glicogênio/genética , Manihot/química , Ervilhas/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Saccharomyces cerevisiae/metabolismo , Temperatura , Thermus/genética
5.
Neurology ; 94(14): e1495-e1501, 2020 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-32127386

RESUMO

OBJECTIVE: To identify the etiology of an outbreak of spastic paraparesis among women and children in the Western Province of Zambia suspected to be konzo. METHODS: We conducted an outbreak investigation of individuals from Mongu District, Western Province, Zambia, who previously developed lower extremity weakness. Cases were classified with the World Health Organization definition of konzo. Active case finding was conducted through door-to-door evaluation in affected villages and sensitization at local health clinics. Demographic, medical, and dietary history was used to identify common exposures in all cases. Urine and blood specimens were taken to evaluate for konzo and alternative etiologies. RESULTS: We identified 32 cases of konzo exclusively affecting children 6 to 14 years of age and predominantly females >14 years of age. Fourteen of 15 (93%) cases ≥15 years of age were female, 11 (73%) of whom were breastfeeding at the time of symptom onset. Cassava was the most commonly consumed food (median [range] 14 [4-21] times per week), while protein-rich foods were consumed <1 time per week for all cases. Of the 30 patients providing urine specimens, median thiocyanate level was 281 (interquartile range 149-522) µmol/L, and 73% of urine samples had thiocyanate levels >136 µmol/L, the 95th percentile of the US population in 2013 to 2014. CONCLUSION: This investigation revealed the first documented cases of konzo in Zambia, occurring in poor communities with diets high in cassava and low in protein, consistent with previous descriptions from neighboring countries.


Assuntos
Paraparesia Espástica/epidemiologia , Adolescente , Fatores Etários , Aleitamento Materno , Criança , Cianetos/análise , Dieta , Surtos de Doenças , Feminino , Humanos , Masculino , Manihot/química , Debilidade Muscular/epidemiologia , Debilidade Muscular/etiologia , Deficiência de Proteína/epidemiologia , Chuva , Estações do Ano , Tiocianatos/urina , Adulto Jovem , Zâmbia/epidemiologia
6.
Trop Anim Health Prod ; 52(4): 2035-2041, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32016880

RESUMO

The principle of the study was to assess the influence of yeast-fermented cassava pulp (YFCP) as a protein supplement on feed intake, nutrient digestibilities, rumen microbial protein synthesis, fermentation end-products, and N-balance in Thai native beef cattle. The experiment was conducted following the 4 × 4 Latin square design using 4 levels of YFCP supplementation (0, 100, 200, and 300 g/head/day) in 3-year-old Thai native beef cattle crossbreds. The response of YFCP supplementation level using rice straw as a roughage source revealed promising results. The rumen ecology parameters including cellulolytic, amylolytic, and proteolytic bacterial population were significantly increased while the protozoal population were reduced, as affected by increasing level of YFCP supplementation (P < 0.05). In parallel with these results, totals VFA, propionate (C3) production in the rumen, and the ratio of C2:C3 were remarkably increased (P < 0.01), while rumen methane production by prediction from VFA was decreased (P < 0.01), as YFCP supplementation increased. Regarding, the nutrient digestibilities, those of OM and CP were remarkably enhanced (P < 0.01), hence increased DM intake. Furthermore, the use of YFCP at high level resulted in the highest N-balance and N retention absorption (P < 0.01). The results indicated that YFCP can be nutritionally enhanced by yeast fermentation, thus is promising to be used as a protein source in ruminant feeding.


Assuntos
Dieta/veterinária , Digestão/efeitos dos fármacos , Comportamento Alimentar/efeitos dos fármacos , Microbioma Gastrointestinal/efeitos dos fármacos , Manihot/química , Nitrogênio/metabolismo , Nutrientes/fisiologia , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal/efeitos dos fármacos , Animais , Bovinos , Suplementos Nutricionais/análise , Digestão/fisiologia , Relação Dose-Resposta a Droga , Feminino , Fermentação , Alimentos e Bebidas Fermentados , Microbioma Gastrointestinal/fisiologia , Masculino , Rúmen/microbiologia , Saccharomyces cerevisiae/metabolismo , Soja
7.
PLoS One ; 15(2): e0228624, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32101546

RESUMO

We report a rapid and accurate quantitative detection method using droplet digital PCR (ddPCR) technology to identify cassava adulteration in starch products. The ddPCR analysis showed that the weight of cassava (M) and cassava-extracted DNA content had a significant linear relationship-the correlation coefficient was R2 = 0.995, and the maximum coefficient of variation of replicates was 7.48%. The DNA content and DNA copy number (C) measured by ddPCR also had a linear relationship with R2 = 0.992; the maximum coefficient of variation of replicates was 8.85%. The range of cassava ddPCR DNA content was 25 ng/µL, and the formula M = (C + 32.409)/350.579 was obtained by converting DNA content into the median signal. The accuracy and application potential of the method were verified using the constructed adulteration model.


Assuntos
Análise de Alimentos/métodos , Contaminação de Alimentos , Manihot/química , Reação em Cadeia da Polimerase/métodos , Amido/química , DNA de Plantas/análise , DNA de Plantas/genética , Análise de Alimentos/normas , Manihot/genética , Reação em Cadeia da Polimerase/normas , Amido/normas
8.
PLoS One ; 15(2): e0228641, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32053630

RESUMO

The use of plant tissue analysis as a tool for attaining low cyanogenic glucoside levels in cassava roots, has hardly been investigated. Just as the quality of crops is improved through the use of plant tissue analysis, the same can probably be done to consistently attain the lowest possible cyanogenic glucoside levels in cassava roots. High levels of cyanogenic glucosides in consumed fresh cassava roots or in their products have the potential of causing cyanide intoxication, hence the need to lower them. An experiment was thus conducted to assess the occurrence of meaningful relationships between plant nutritional status and cyanogenic glucoside production in cassava roots. Total hydrogen cyanide (HCN) levels in cassava roots were used to assess cyanogenic glucoside production. Using NPK fertiliser application to induce changes in plant nutritional status, the main objective of the study was investigated using the following sub-objectives; (1) to determine the effects of increased NPK fertiliser application on cassava root HCN levels; (2) and to show the occurrence of relationships between changes in nutrient levels in plant 'indicator tissue' and HCN levels in cassava roots. The study was a field experiment laid out as a split-plot in a randomized complete block design with three replicates. It was repeated in two consecutive years, with soil nutrient deficiencies only being corrected in the second year. The varieties Salanga, Kalinda, Supa and Kiroba were used in the experiment, while the NPK fertiliser treatments included; a control with no fertiliser applied; a moderate NPK treatment (50 kg N + 10 kg P + 50 kg K /ha); and a high NPK treatment (100 kg N + 25 kg P + 100 kg K /ha). A potassium only treatment (50 kg K/ha) was also included, but mainly for comparison. The root HCN levels of Salanga, Kalinda and Kiroba were significantly influenced by NPK fertiliser application in at least one of the two field experiments, while those of Supa remained uninfluenced. Changes in plant nutritional status in response to fertiliser application were thus shown to influence cyanogenic glucoside production. The results of the multiple linear regression analysis for the first field experiment, generally showed that the root HCN levels of some cassava varieties could have been 'reduced' by decreasing concentrations of nitrogen, potassium and magnesium in plants, or by improving plant calcium concentrations along with NPK fertiliser application. However, in the second field experiment (with corrected soil nutrient deficiencies) the regression analysis generally showed that the root HCN levels of some cassava varieties could have been 'reduced' by improving either one or a combination of the nutrients phosphorous, zinc and potassium in plants along with NPK fertiliser application. Although the results obtained in the two experiments had been contradicting due to slight differences in how they were conducted, the study had nonetheless demonstrated the occurrence of meaningful relationships between plant nutritional status and cyanogenic glucoside production; confirming the possible use of plant tissue analysis in predicting fertiliser needs for the consistent attainment of low cyanogenic glucosides in cassava roots.


Assuntos
Fertilizantes , Glucosídeos/análise , Cianeto de Hidrogênio/análise , Manihot/química , Nitrilos/análise , Raízes de Plantas/química , Agricultura , Produtos Agrícolas/química , Cianetos/análise , Glicosídeos/análise , Concentração de Íons de Hidrogênio , Modelos Lineares , Nitrogênio/análise , Fósforo/análise , Potássio/análise , Solo
9.
Pak J Biol Sci ; 23(3): 271-277, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31944088

RESUMO

BACKGROUND AND OBJECTIVE: Most food industries try to solve the problem of dried food quality by using optimum pre-treatments before subjecting to hot air drying. The edible coating is considerably extended shelf-life of dried foods. The objectives of this research were to investigate the effect of edible coating agents (modified cassava starch and sodium caseinate) on properties of dried Jerusalem artichoke (JA) slices. MATERIALS AND METHODS: Pieces of the sample were coated by dipping in the coating solution for 10 min both for atmospheric coating (AC) and vacuum coating (VC). The weight ratio of the sample to the solution was 1:2. The VC was conducted in a closed desiccator connected to a vacuum pump with a residual pressure of 150 m bar controlled during 10 min of dipping. RESULTS: The coating agents resulted in improvements in product qualities. Browning and shrinkage were reduced significantly (p<0.05). The antioxidant properties were similar between a hot air-dried product and a freeze-dried product. There was no observed benefit of using vacuum pressure rather than atmospheric pressure. Sensory acceptance of coated products was similar to that of an uncoated product. CONCLUSION: The edible coating with modified cassava starch or sodium caseinate was, therefore, an efficient pre-treatment and could be applied with conventional drying to produce healthy fruit and vegetable snacks by using a simple and inexpensive method.


Assuntos
Antioxidantes/química , Dessecação , Filmes Comestíveis , Conservação de Alimentos/métodos , Helianthus , Caseínas/química , Cor , Manipulação de Alimentos/métodos , Manihot/química , Pressão , Amido/química , Vácuo
10.
J Sci Food Agric ; 100(1): 258-267, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31512250

RESUMO

BACKGROUND: Composite gels were individually prepared from 20 g kg-1 myofibrillar protein (MP) imbedded with typical native starch (potato, tapioca, rice or corn starch) in 0.6 mol L-1 NaCl at pH 6.2. The gel strength, water holding capacity, rheological properties and microstructure of the obtained myofibrillar protein-starch composite gels were evaluated. RESULTS: Tapioca starch improved (P < 0.05) gel strength and water holding capacity of MP composite gel at 80 °C. Rheological properties of MP-starch composites differed significantly with the addition of different types of native starch. Additionally, the promoting effect of starch on the storage modulus of the composite gels positively correlated with the gelatinization properties of different typical starch. Environmental scanning electron microscopy showed that the filling effect of starch on the composite gel was related to the pasting temperature and particle size of typical starch, with almost no particles forming at 80 °C. Moreover, the addition of starch changed the relaxation peak area and increased the relaxation time in nuclear magnetic resonance tests, which suggested that starch could improve the water holding capacity of MP-starch composite gels. CONCLUSION: Different typical native starch has varied impacts on the gel strength, water holding capacity, rheological properties and microstructure of MP gels, indicating the potential and feasibility of these typical native starches as an addition agent to modify the textural properties in comminuted meat products. © 2019 Society of Chemical Industry.


Assuntos
Produtos da Carne/análise , Proteínas Musculares/química , Miofibrilas/química , Extratos Vegetais/química , Amido/química , Animais , Aditivos Alimentares/química , Géis/química , Espectroscopia de Ressonância Magnética , Manihot/química , Oryza/química , Reologia , Solanum tuberosum/química , Suínos , Zea mays/química
11.
Int J Biol Macromol ; 142: 846-854, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31622700

RESUMO

The green composite cassava starch films were prepared using stearic acid modified microcrystalline cellulose (M-MCC)/nanocellulose (M-NCC) as strength agent, which shows good mechanical and hydrophobic properties and is a candidate for food package in this work. Microcrystalline cellulose (MCC) was prepared with 98% phosphoric acid hydrolysis and mechanical stirring at 600 r/min and nanocellulose (NCC) was prepared with 65% sulfuric acid hydrolysis. After using stearic acid to modify MCC and NCC, the casting method was used to prepare the M-MCC/cassava starch composite films and M-NCC/cassava starch films. Physical, mechanical, hydrophobic and thermal properties were characterized using SEM, electronic universal testing machine, contact angle meter and TGA. The results showed that: M-MCC and M-NCC can lead to the enhancement of mechanical and hydrophobic properties of composite films; 0.5% M-MCC and 1.5% M-NCC had the highest enhancement effect on mechanical properties, leading the tensile strength of cassava starch film increased by 484.5% and 327.7% respectively; As to hydrophobic property, when 2% M-MCC and 0.5% M-NCC added, the hydrophobicity of the film increased by 65.0% and 30.3% respectively. Overall, the enhancement effect of M-MCC was better than M-NCC. But when M-MCC/M-NCC was added, the thermal stability of films reduced.


Assuntos
Celulose/química , Manihot/química , Nanoestruturas/química , Amido/química , Ácidos Esteáricos/química , Módulo de Elasticidade , Embalagem de Alimentos/métodos , Hidrólise , Interações Hidrofóbicas e Hidrofílicas , Membranas Artificiais , Permeabilidade , Ácidos Fosfóricos/química , Ácidos Sulfúricos/química , Temperatura , Resistência à Tração
12.
Int J Biol Macromol ; 144: 289-295, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31838069

RESUMO

The present study was intended to prepare and optimize the mucoadhesive buccal patch of gambier leaf extract using chitosan (CH) and tapioca starch (TS) composite as the polymer complexes. The patch formulation was designed based on 22 factorial design in order to optimize the composition of CH and TS. The physical and chemical characteristics of the prepared patches, including mass and thickness uniformity, folding endurance, surface pH, swelling index, percent of elongation, and mucoadhesive time were successfully evaluated. Based on statistical analysis, the optimum concentration of CH and TS was 900 mg and 300 mg, respectively, with desirability percent of 0.968. The characterization of the optimum patch showed that the variability coefficient of the mass and thickness uniformity was 0.4805 ± 0.1887% and 0.9716 ± 1.2026%, surface pH of the patch was 6, folding endurance >300 times, elongation percent was 53.333 ± 0.1082%, and mucoadhesive time was 320 ± 1.1547 min. The catechin content, as the active agent of the gambier leaf extract, was 92.1667 ± 0.3626%, and the FT-IR characterization indicated that there are no chemical interactions between each patch component.


Assuntos
Catequina/química , Quitosana/química , Gengivite/terapia , Manihot/química , Amido/química , Uncaria/química , Concentração de Íons de Hidrogênio , Extratos Vegetais/química , Folhas de Planta/química , Polímeros/química , Adesivo Transdérmico
13.
Carbohydr Polym ; 229: 115449, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31826526

RESUMO

In this study, the effect and mechanism of myofibrillar protein (MP) gelation influenced by the hydration characteristic of three polysaccharides were studied through puncture test, paraffin section, SEM and Raman spectroscopy. The gel strength and water holding capability reflect that MP gelation only significantly improves until modified starch (MS) addition beyond 1.0%. The MS granule improves MP gel property through simply physical swelling effect. At gelatinization temperature, MS absorbs the moisture nearby to compress the MP three-dimensional networks, but the swelling effect is limited. The insoluble dietary fiber (IDF) improves MP gelation property through moisture stability. The IDF addition could lessen the appearance of moisture channel in MP gel networks and promote the interaction of hydrophobic groups. The MP gelation with 2.0% IDF addition has the highest gel strength (279 g) and water holding capability (91.87%). The konjac glucomannan (KG) (>1.0%) could degrade gel property of MP gelation through interpenetrate structure, because the KG hydrogel hinders the aggregation of the MP gel networks. In conclusion, the IDF, which has strong water-holding capability at room temperature and distribute individually, is the best polysaccharides-based fat replacement in low-fat restructured products.


Assuntos
Fibras na Dieta , Hidrogéis/química , Mananas/química , Proteínas Musculares/metabolismo , Miofibrilas/química , Amido/química , Animais , Substitutos da Gordura/química , Manihot/química , Proteínas Musculares/química , Conformação Proteica/efeitos dos fármacos , Estrutura Secundária de Proteína/efeitos dos fármacos , Saccharum/química , Suínos
14.
Int J Biol Macromol ; 143: 136-142, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31805331

RESUMO

In this study tapioca starch nanoparticles (SNPs) were prepared by nanoprecipitation with acetone and nanoprecipitation-sonication treatments. The prepared SNPs were characterized by dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR). The results revealed that application of ultrasound not only increased the yield but also decreased the acetone consumption. Electron micrographs indicate that all SNPs were spherical in shape while having different particle size. Samples prepared using 3 g starch by sonication treatment had relatively similar particle size as those prepared using 1 g starch with no sonication. The increase in starch concentration, increased the particle size of samples and the samples with the highest concentration of starch had the largest particle size. The crystalline structure of native starch was destroyed by nanoprecipitation and sonication. The lowest sample crystallinity was realized for SNPs prepared by nanoprecipitation and sonication of 1 g starch. The DSC data showed that the thermal properties of SNPs were lower than those of native starch. The FT-IR spectroscopy exhibited slight changes between native starch and SNPs.


Assuntos
Precipitação Fracionada , Manihot/química , Nanopartículas/química , Sonicação , Amido/química , Fenômenos Químicos , Nanopartículas/ultraestrutura , Tamanho da Partícula , Análise Espectral
15.
Chem Commun (Camb) ; 55(100): 15137-15140, 2019 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-31789333

RESUMO

A fluorescent probe (TPA-BTD-MT) was designed to monitor cyanide ions (CN-) with a "turn-on" response, changing from "turn-off" behavior due to the structural change. TPA-BTD-MT exhibited high selectivity for sensing CN- in several food samples and was successfully used for imaging CN- in living cells and animals with strong "turn-on" fluorescence.


Assuntos
Cianetos/análise , Corantes Fluorescentes/química , Análise de Alimentos/métodos , Imagem Óptica , Compostos de Anilina/química , Animais , Linhagem Celular Tumoral , Limite de Detecção , Manihot/química , Manihot/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Microscopia de Fluorescência , Teoria Quântica , Solanum tuberosum/química , Solanum tuberosum/metabolismo
16.
Ars pharm ; 60(4): 205-211, oct.-dic. 2019. tab
Artigo em Inglês | IBECS | ID: ibc-188483

RESUMO

Objectives: The physicochemical characteristics of bran of cassava starch flour and bran of cassava flour (viz. organoleptic characteristics, pH value, moisture content, total ashes, lipid, protein, starch and fiber contents) and biopharmacotechnical parameters (viz. granulometry, flow capacity, angle at rest, outflow time and apparent density) were evaluated aiming at assessing their potential use as tablet excipients. Methodos: Three tablet formulations of venlafaxine hydrochloride were proposed, having as excipients bran of cassava flour, bran of cassava starch flour and Starch 1500(R). The tablets were produced using two different pressures (98 ± 5 MPa and 32 ± 6 Mpa) and their mechanical (hardness and friability) and dissol-ubility characteristics were evaluated. Results and Conclusions: The tablets produced with both cassava flours, using higher pressures, presented similar physicochemical characteristics to those obtained with the excipient Starch1500(R), thus indicating that cassava flours possess the potential to be used as disintegrating agents in tablets


Objetivos: Se evaluaron características físico-químicas del salvado de harina y del salvado de la fécula de mandioca (características organolépticas, pH, humedad, cenizas totales y contenido de lípidos, proteínas, almidones y fibras) y biofarmacotécnicas (granulometría, capacidad de flujo, ángulo en reposo, tiempo de salida y densidad aparente) con el objetivo de evaluar el uso de estos residuos como excipientes para comprimidos. Métodos: Se propusieron tres formulaciones en comprimidos de venlafaxina teniendo como excipientes salvado de harina de mandioca, salvado de fécula de mandioca y Starch 1500 (R). Las pastillas se produjeron utilizando dos presiones diferentes (98 ± 5 MPa y 32 ± 6 Mpa). Las características mecánicas (dureza y friabilidad) y de disolución de los comprimidos se evaluaron. Resultados y Conclusiones: Los comprimidos producidos con ambos salvados de mandioca, utilizando las presiones más elevadas, presentaron características físico-químicas similares a las obtenidas con el excipiente Starch1500(R), indicando que las harinas de mandioca poseen potencial para ser utilizadas como agentes desintegrantes en comprimidos


Assuntos
Excipientes Farmacêuticos , Comprimidos/farmacologia , Manihot/química , Comprimidos/normas , Físico-Química/métodos , Absorção Fisico-Química/efeitos dos fármacos
17.
J Microbiol Biotechnol ; 30(8): 1227-1234, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31581383

RESUMO

In this study, yeast cell immobilization was carried out in a packed bed reactor (PBR) to investigate the effects of the volumetric capacity of carriers as well as the different fermentation modes on fuel ethanol production. An optimal volumetric capacity of 10 g/l was found to obtain a high cell concentration. The productivity of immobilized cell fermentation was 16% higher than that of suspended-cell fermentation in batch and it reached a higher value of 4.28 g/l/h in repeated batches. Additionally, using this method, the ethanol yield (95.88%) was found to be higher than that of other tested methods due to low concentrations of residual sugars and free cells. Continuous ethanol production using four bioreactors showed a higher productivity (9.57 g/l/h) and yield (96.96%) with an ethanol concentration of 104.65 g/l obtained from 219.42 g/l of initial total sugar at a dilution rate of 0.092 h-1. Furthermore, we reversed the substrate-feed flow directions in the in-series bioreactors to keep the cells at their highest activity and to extend the length of continuous fermentation. Our study demonstrates an effective method of ethanol production with a new immobilized approach, and that by switching the flow directions, traditional continuous fermentation can be greatly improved, which could have practical and broad implications in industrial applications.


Assuntos
Reatores Biológicos/microbiologia , Etanol/metabolismo , Manihot/química , Saccharomyces cerevisiae/metabolismo , Células Imobilizadas , Estudos de Viabilidade , Fermentação , Microbiologia Industrial , Saccharomyces cerevisiae/ultraestrutura
18.
J Mol Model ; 25(9): 295, 2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31478108

RESUMO

Cyanogenesis is an enzyme-promoted cleavage of ß-cyanoglucosides; the release of hydrogen cyanide is believed to produce food poisoning by consumption of certain crops as Cassava (Manihot esculenta Crantz). The production of hydrogen cyanide by some disruption of the plant wall is related to the content of two ß-cyanoglucosides (linamarin and lotaustralin) which are stored within the tuber. Some features about the mechanistic bases of these transformations have been published; nevertheless, there are still questions about the exact mechanism, such as the feasibility of a difference in the kinetics of cyanogenesis between both cyanoglucosides. In this work, we have performed a theoretical analysis using DFT and QTAIM theoretical frameworks to propose a feasible mechanism of the observed first step of the enzyme-catalyzed rupture of these glucosides; our results led us to explain the observed difference between linamarin and lotaustralin. Meanwhile, DFT studies suggest that there are no differences between local reactivity indexes of both glucosides; QTAIM topological analysis suggests two important intramolecular interactions which we found to fix the glucoside in such a way that suggests the linamarin as a more reactive system towards a nucleophilic attack, thus explaining the readiness to liberate hydrogen cyanide.


Assuntos
Glucosídeos/química , Cianeto de Hidrogênio/química , Manihot/química , Nitrilos/química , Biocatálise , Biotransformação , Glucosídeos/metabolismo , Cianeto de Hidrogênio/metabolismo , Cinética , Manihot/enzimologia , Estrutura Molecular , Nitrilos/metabolismo , Tubérculos/química , Tubérculos/enzimologia , Teoria Quântica , Termodinâmica
19.
Int J Biol Macromol ; 141: 713-720, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31494157

RESUMO

In this study, biodegradable films were produced from cassava starch modified by ozone at different levels. The films were produced by casting technique using native and ozonated cassava starch, glycerol as the plasticizer, and water as the solvent. Films were characterized in term of their mechanical, barrier and functional properties, morphology, crystallinity, colour, and opacity. The morphology of the ozonated films was more homogeneous in comparison to the films produced with the non-modified starch and enhanced properties were achieved. Films produced with ozonated cassava starch presented higher tensile strength, Young's modulus and lower elongation. The water vapour permeation and the oxygen permeation were increased by increasing the ozonation time. Moreover, ozone processing resulted in films with a more hydrophilic surface and lower solubility after 24 h. Possible explanations and applications were discussed. In conclusion, the ozone processing showed to be a good alternative for starch based packaging production.


Assuntos
Manihot/química , Ozônio/química , Amido/química , Cor , Fenômenos Mecânicos , Amido/metabolismo
20.
Int J Biol Macromol ; 139: 1151-1161, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31419552

RESUMO

Cassava bagasse, a high-fiber coproduct of cassava starch processing, was used to produce lignocellulose nanofibers (LCNF) to apply as reinforcement in cassava starch films. LCNF-reinforced cast starch films were evaluated for changes in structural, thermal and mechanical properties and compared with control films reinforced with commercial grade nanoclay (Nclay). Five different types of cassava starch cast-films were produced: no-reinforcement control, two LCNF-reinforced, and two Nclay-reinforced, each at 0.65 and 1.3% w w-1. The LCNF morphology showed the characteristic microscopic structure of lignocellulose nanofibers, with an aspect ratio > 85 and average diameter of 4.5 nm. All reinforced films were transparent and had a good distribution of the nanoparticles within. The opacity values reduced for the films with all nanoreinforcements, compared to control. The permeability to water vapor reduced with reinforcements, with lower values for the films tested with LCNF 0.65 and Nclay 1.3. Thermal stability improved with 1.3% of LCNF and both concentrations of Nclay. Tensile stress for films increased and elongation at break value decreased with both types of nanoreinforcements.


Assuntos
Celulose/química , Lignina/química , Manihot/química , Fenômenos Mecânicos , Nanofibras/química , Amido/química , Embalagem de Alimentos , Teste de Materiais , Temperatura , Resistência à Tração
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