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1.
Food Chem ; 324: 126858, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32353656

RESUMO

Wheat flour noodles are sometimes fortified with ß-glucan for nutritional value, but this can decrease eating quality. The contributions of ß-glucan and starch molecular fine structure to physicochemical properties of wholemeal oat flour and to the texture of oat-fortified white salted noodles were investigated here. Hardness of oat-fortified noodles was controlled by the longer amylopectin chains (DP ≥ 26) and amount of longer amylose chains (DP ≥ 1000). Higher levels of ß-glucan, in the range from 3.1 to 5.2%, result in increased noodle hardness. Pasting viscosities of wholemeal oat flour positively correlate with the hardness of oat-fortified noodles. The swelling power of oat flour is not correlated with either pasting viscosities of oat flour or noodle hardness. Longer amylopectin chains and the amount of longer amylose chains both control the pasting viscosities of oat flour, which in turn affect noodle texture. This provides new means, based on starch and ß-glucan molecular structure, to choose oats with optimal starch structure and ß-glucan content for targeted oat-fortified noodle quality.


Assuntos
Avena/metabolismo , Amido/química , Triticum/metabolismo , beta-Glucanas/química , Amilopectina/química , Amilose/química , Farinha/análise , Dureza , Viscosidade
2.
Food Chem ; 324: 126863, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32353657

RESUMO

In this study, 95 accessions of proso millet (Panicum miliaceum L.) were characterized for starch physicochemical properties, including apparent amylose content (AAC), gel textural properties, Rapid Visco Analyzer (RVA) pasting viscosity properties, thermal and retrogradation properties. Based on genotypic data, the genetic diversity and inter-relationship of these starch traits were analyzed. Diverse starch quality was found, for example, AAC ranged from 0 to 32.3%, gelatinization temperature (GT) varied from 71.5 to 79.0 ℃, and RVA profile showed distinct patterns among proso millet of different AAC types. Interestingly, high AAC proso millet usually had GT lower than that of low AAC proso millet, which is different from the findings in rice starch. Many starch traits were significantly correlated and most of the 18 tested traits could be classified as either AAC-related traits or GT-related traits. In summary, the information presented here will be useful for further development of proso millet products.


Assuntos
Panicum/química , Amido/química , Amilose/análise , Análise por Conglomerados , Géis/química , Genótipo , Oryza/química , Oryza/metabolismo , Panicum/genética , Panicum/metabolismo , Análise de Componente Principal , Amido/análise , Temperatura , Viscosidade
3.
Curr Opin Plant Biol ; 55: 109-117, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32428846

RESUMO

The traditional view of starch metabolism has focused on the multiplicity of enzymes and enzyme isoforms contributing to the production of the constituent polymers, amylopectin and amylose. However, knowledge of these enzymes has not provided a full insight into many aspects of starch biosynthesis. This enzyme-centered view has recently been augmented by the discovery and characterization of novel proteins with proposed regulatory, scaffolding, and interactive roles. This begins to reveal an unprecedented level of complexity beyond mere glucan biosynthesis, enabling us to envisage how starch granules are initiated and grow into specific forms, allowing it to serve biological roles beyond just carbohydrate storage. This review focuses on very recent findings in this vibrant field, highlighting the evolutionary novelty.


Assuntos
Enzima Ramificadora de 1,4-alfa-Glucana/genética , Amilopectina , Amilose , Evolução Biológica , Metabolismo dos Carboidratos , Amido
4.
J Chromatogr A ; 1621: 461053, 2020 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-32276857

RESUMO

The chromatographic properties of a new coated amylose tris(3-chloro-5-methylphenylcarbamate) were evaluated in supercritical fluid chromatography for the separation of enantiomers of chiral 1-aryl-5-aryl-pyrrolidin-2-one derivatives, potential anticancer agents, and some commercial drugs. The mobile phase consisted of CO2-modifier mixtures with 30% of either methanol or ethanol, the flow rate was 3 mL/min. The column oven temperature was 40 °C and the outlet pressure was 15 MPa, in order to limit the compressibility of the CO2, thus limiting density variation along the column. The obtained results were then compared to those observed toward 3 other stationary phases: the coated amylose tris(3,5-dimethylphenylcarbamate), the immobilized amylose tris(3,5-dimethylphenylcarbamate) and the coated amylose tris(5-chloro-2-methylphenylcarbamate). It was shown that the new coated amylose tris(3-chloro-5-methylphenylcarbamate) was the most retentive column whatever the studied compounds, particularly for thalidomide and omeprazole with retention factors up to 73.3 and 29.5for the second enantiomer, respectively. Concerning the enantioselectivity, even most of the compounds are separated on all the four columns, the coated amylose tris(3-chloro-5-methylphenylcarbamate) allows the best resolution for most of the ten studied analytes (except omeprazole for which the resolution values are equal to 7.8 and 9.7 on the coated amylose tris(3-chloro-5-methylphenylcarbamate) and amylose tris(3,5-dimethylphenylcarbamate), respectively). Acting in complementary ways, the two chlorinated stationary phases permitted the complete separation of enantiomers of nine compounds out of the ten.


Assuntos
Amilose/análogos & derivados , Cromatografia com Fluido Supercrítico/métodos , Amilose/química , Antineoplásicos/análise , Antineoplásicos/isolamento & purificação , Carbamatos/química , Preparações Farmacêuticas/análise , Preparações Farmacêuticas/isolamento & purificação , Fenilcarbamatos/química , Pirrolidinonas/análise , Pirrolidinonas/isolamento & purificação , Dióxido de Silício/química , Estereoisomerismo
5.
PLoS One ; 15(4): e0232164, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32330189

RESUMO

Maize (Zea mays L) is one of main nutrients sources for humans and animals worldwide. In Africa, storage of maize ensures food resources availability throughout the year. However, it often suffers losses exceeding 20% due to insects such as the larger grain borer, Prostephanus truncatus (Horn) (Coleoptera; Bostrichidae), major pest of stored maize in the tropical countries. This study aims to select resistant varieties to reduce maize storage losses and explain the physicochemical parameters role in grains susceptibility. In the first study, maize grains were artificially infested under no-choice method with insects. Susceptibility parameters such as weight loss, grain damage, number of emerged insects, median development time and susceptibility index varied significantly through maize varieties. Dobie susceptibility index (SI) was assessed as a major indicator of resistance. The most resistant varieties were Early-Thaï, DMR-ES and Tzee-Yellow. Conversely, Synth-9243, Obatampa and Synth-C varieties were susceptible. SWAN, Across-Pool and Tzee-White were classified as moderately resistant varieties. The insect reproductive potential was significantly different in the nine maize varieties and Early-Thaï, DMR-ES and Tzee-Yellow varieties were the least favourable host. To assess the relationship between grains physicochemical characteristics and varietal susceptibility, moisture, total phenolics, palmitic acid, proteins, amylose, density and grain hardness were evaluated according to standardized methods. Palmitic acid, SI, insects emerged and grain damage were significantly and positively correlated with each other, and negatively correlated with grains hardness, phenolics and amylose contents. Maize susceptibility index was significantly and negatively correlated to amylose, and phenolics contents and positively correlated to palmitic acid content. This study identified three resistant maize varieties to P. tuncatus and revealed that the major factors involved in this resistance were hardness, phenolic and amylose contents of grains.


Assuntos
Besouros/patogenicidade , Zea mays/crescimento & desenvolvimento , Zea mays/parasitologia , África , Amilose/metabolismo , Animais , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , Ácido Palmítico/metabolismo , Fenol/metabolismo , Estruturas Vegetais/crescimento & desenvolvimento , Estruturas Vegetais/metabolismo , Estruturas Vegetais/parasitologia , Zea mays/metabolismo
6.
Food Chem ; 318: 126489, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32135425

RESUMO

In the present study, starches isolated from heat-moisture treated (HMT) adlay seeds were characterized with hierarchical structures and digestibility to understand the relationships in structural and digestible behaviors of starches in a HMT starch-based food system. The results indicated that HMT not only caused the disorganizations of hierarchical structures, but also promoted the molecular rearrangements and reassembly of starch chains to form a new ordered molecular aggregation architecture (i.e., highly ordered molecular structure, amylose-lipids complexes and thicker crystalline lamella). And the reinforced molecular interactions between starch molecules during HMT occurred to form more densely ordered structure, thus reducing the digestibility and digestion rate coefficients (k) of adlay starch. Particularly, HMT applied directly in adlay seeds with 30% moisture content displayed the highest resistant starch level (20.6%) and lowest k (2.74 × 10-3 min-1). Thus, the results are useful to realize the desired regulation of starch digestibility in adlay products following HMT.


Assuntos
Amilose/química , Coix/química , Lipídeos/química , Estrutura Molecular , Amido/química , Digestão , Temperatura Alta , Microscopia Eletrônica de Varredura , Sementes/química , Amido/ultraestrutura , Água/química
7.
Food Chem ; 318: 126490, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32146307

RESUMO

This study examined the contribution of amylose to the organization of each starch fraction in recrystallized starch. Amylosucrase (AS)-modified waxy potato starches with different branch chain lengths were completely solubilized with amylose (3:1 ratio) and recrystallized at 4 °C for 48 h. The content of rapidly digestible starch and resistant starch (RS) showed linear change with degree of AS modification, while slowly digestible starch (SDS) did not. The changes in structural characteristics were tracked according to serial removal of each fraction. Results from iodine binding property, branch chain length, X-ray diffraction, and thermal property analysis indicated that branch chain length of amylopectin determined the length of the amylose-amylopectin double helix and the mobility of amylose and that formation of SDS or RS could be induced by controlling the length of amylopectin chains. These findings could be used for production of customized starches with specific digestive properties for health benefits.


Assuntos
Amilopectina/química , Amilose/química , Glucosiltransferases/química , Solanum tuberosum/química , Amido/química , Cristalização , Digestão , Estrutura Molecular , Difração de Raios X
8.
J Chromatogr A ; 1621: 461054, 2020 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-32204880

RESUMO

The enantioselective separation of newly prepared, pharmacologically significant isopulegol-based ß-amino lactones and ß-amino amides has been studied by carrying out high-performance liquid chromatography on diverse amylose and cellulose tris-(phenylcarbamate)-based chiral stationary phases (CSPs) in n-hexane/alcohol/diethylamine or n-heptane/alcohol/ diethylamine mobile phase systems. For the elucidation of mechanistic details of the chiral recognition, seven polysaccharide-based CSPs were employed under normal-phase conditions. The effect of the nature of selector backbone (amylose or cellulose) and the position of substituents of the tris-(phenylcarbamate) moiety was evaluated. Due to the complex structure and solvation state of polysaccharide-based selectors and the resulting enantioselective interaction sites, the chromatographic conditions (e.g., the nature and content of alcohol modifier) were found to exert a strong influence on the chiral recognition process, resulting in a particular elution order of the resolved enantiomers. Since no prediction can be made for the observed enantiomeric resolution, special attention has been paid to the identification of the elution sequences. The comparison between the effectiveness of covalently immobilized and coated polysaccharide phases allows the conclusion that, in several cases, the application of coated phases can be more advantageous. However, in general, the immobilized phases may be preferred due to their increased robustness. Thermodynamic parameters derived from the temperature-dependence of the selectivity revealed enthalpically-driven separations in most cases, but unusual temperature behavior was also observed.


Assuntos
Amilose/análogos & derivados , Celulose/análogos & derivados , Cromatografia Líquida de Alta Pressão/métodos , Monoterpenos Cicloexânicos/química , Amidas/química , Amidas/isolamento & purificação , Amilose/química , Celulose/química , Lactonas/química , Lactonas/isolamento & purificação , Fenilcarbamatos , Estereoisomerismo , Temperatura , Termodinâmica
9.
Food Chem ; 320: 126609, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32222658

RESUMO

Bread crumb firming is largely determined by the properties of gluten and starch, and the transformations they undergo during bread making and storage. Amylose (AM) and amylopectin (AP) functionality in fresh and stored bread was investigated with NMR relaxometry. Bread was prepared from flours containing normal and atypical starches, e.g., flour from wheat line 5-5, with or without the inclusion of Bacillus stearothermophilus α-amylase. Initial crumb firmness increased with higher levels of AM or shorter AM chains. Both less extended AM and gluten networks and too rigid AM networks led to low crumb resilience. AP retrogradation during storage increased when crumb contained more AP or longer AP branch chains. Shorter AP branch chains, which were present at higher levels in 5-5 than in regular bread, were less prone to retrogradation, thereby limiting gluten network dehydration due to gluten to starch moisture migration. Correspondingly, crumb firming in 5-5 bread was restricted.


Assuntos
Amilopectina/química , Amilose/química , Pão/análise , Armazenamento de Alimentos , Amilopectina/metabolismo , Amilose/metabolismo , Proteínas de Bactérias , Farinha/análise , Geobacillus stearothermophilus/enzimologia , Glutens/química , Espectroscopia de Ressonância Magnética , Amido/química , Triticum/química , Água , alfa-Amilases/metabolismo
10.
PLoS One ; 15(3): e0230600, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32210447

RESUMO

Rice-crab culture is the characteristic rice ecological breeding model used in the Panjin area of Liaohe River Basin, China, and it can improve the ecological environment and create increased economic benefits. From a food perspective, both rice yield and quality, which are closely related to the fertilization mode, should be considered. However, the effect of different fertilization modes on rice quality has not been comprehensively investigated in this co-culture system. This study investigated the effects of three fertilization modes(FP1, FP2, and OPT) divided according to different fertilization types and methods on rice yield and quality, and set up a non-fertilized control group. In the rice-crab culture system, FP2 used fewer fertilizers and had a lower economic cost, and the yield was only slightly less than that of OPT(highest yield) but there was no statistical difference. FP2 elicited the best appearance quality and better cooking and eating quality among all treatment modes. Compared with CK, three fertilization modes significantly increased the protein content in rice and decreased the amylose content, which would lead to the deterioration of rice eating quality. However FP2 had the least protein increase and the least amylose reduction. There was no significant change in crude fat and starch content. Therefore, the FP2 fertilization mode was the best choice for the rice-crab culture system, as it significantly improved rice yield and increased rice quality at a relatively low cost.


Assuntos
Braquiúros/fisiologia , Produção Agrícola/métodos , Fertilização/fisiologia , Oryza/crescimento & desenvolvimento , Amilose/metabolismo , Animais , Culinária , Valor Nutritivo , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Paladar
11.
Food Chem ; 318: 126477, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32126465

RESUMO

Water-extractable arabinoxylan (WEAX) could effectively improve the cereal food quality, while its regulatory effect on wheat starch properties has yet to be well-understood. This study selected the WEAX with different molecular weight (Mw) but same branched degree, and comparatively investigated their effects on the gelatinization and retrogradation behavior of wheat starch. The decreased degree of swelling power, solubility and peak viscosity suggested that low Mw WEAX (L-WEAX) could hinder starch gelatinization more evidently compared with high Mw WEAX (H-WEAX), due to the pronounced inhibition effect on amylose leaching and amylose-lipid complex formation. L-WEAX suppressed the recrystallization of amylose and thus the short-term retrogradation. However, H-WEAX mainly retarded the recrystallization of amylopectin, exerting a more significant inhibition effect on the long-term retrogradation. This study could provide a theoretical basis for enhancing the quality and extending the shelf life of starchy foods by selecting the optimum structure of WEAX.


Assuntos
Amido/química , Triticum/química , Xilanos/isolamento & purificação , Amilopectina/química , Amilose/química , Varredura Diferencial de Calorimetria , Cristalização , Gelatina/química , Microscopia Confocal , Peso Molecular , Viscosidade , Água/química , Difração de Raios X , Xilanos/química , alfa-Amilases/química , alfa-Amilases/metabolismo
12.
Food Chem ; 316: 126263, 2020 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-32045812

RESUMO

In this study, starch was isolated from 13 genotypes of 12 Lycoris species, and the morphology, granule size distribution and physicochemical properties, including apparent amylose content (AAC), Rapid Visco Analyzer (RVA) pasting properties, textural properties, thermal and retrogradation properties were characterized. The majority of starch granules of the 13 Lycoris genotypes were oval in shape, and granule size followed a normal distribution with a mean diameter of 20-30 µm. Contrary to previously published findings, the XRD results revealed that lycoris starches had either C-type or CA-type crystallinity. All lycoris starches showed high AAC varying from 25.6% to 32.7%, and low gelatinization temperature (GT) ranging from 58.8 to 69.7℃. Inter-relationships among 18 starch quality traits were analyzed based on correlation analysis. The present study provides information on lycoris starch characteristics which should serve as a useful guide for later studies on lycoris starch utilization in food and non-food industries.


Assuntos
Lycoris/química , Amido/química , Amilose/química , Fenômenos Químicos , Genótipo , Lycoris/genética , Amido/isolamento & purificação , Temperatura
13.
Food Chem ; 316: 126036, 2020 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-32062574

RESUMO

Amylopectin internal part refers to the part between the reducing end and the outmost branches. The importance of amylopectin internal structure affecting starch gelatinization and retrogradation as well as enzyme susceptibility of retrograded starch was explored. A total of 13 different starches from a range of plants were used. Great variations in the structure and properties of these starches were obtained. Longer lengths of internal chain segments (e.g., total internal chain length) and more long internal chains (e.g., B3-chains) of amylopectins were related to more ordered physical structure in native and retrograded starches. More clustered A-chains contributed to more ordered physical structure in the starches. The more ordered structure was reflected by a higher thermal stability and melting enthalpy changes of the starches. It was also related to a higher resistance to enzyme hydrolysis of the retrograded starches.


Assuntos
Amilopectina/química , Amilose/química , Gelatina/química , Glucana 1,4-alfa-Glucosidase/metabolismo , beta-Amilase/metabolismo , Amilopectina/metabolismo , Amilose/metabolismo , Hidrólise , Estrutura Molecular , Termodinâmica
14.
Food Chem ; 315: 126245, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32004980

RESUMO

Our objective was to investigate the correlation between processing conditions and structural properties of lotus seed starch-lecithin complexes by dynamic high-pressure homogenization and explore the formation mechanism. The complexes formed with 5% lecithin at 90 MPa had the highest complex index among samples, thus protecting the integrity of the particles. The complexes inhibited the degradation of amylopectin and retrogradation of amylose, and displayed different V6II-, V6I- and A-type crystalline patterns. Additionally, the double helix structure was enhanced with increasing pressure, and the addition of lecithin contributed to the formation of single-helix amylose-lecithin complexes. These complexes prevented the single helix structure of starch to further form double helix structures, as demonstrated by visual correlation analysis. Moreover, a formation mechanism was established, and lotus seed starch-lecithin complexes with V6I-type crystalline were formed under appropriate conditions, but a homogenization pressure either too low or too high was not conducive to complex formation.


Assuntos
Manipulação de Alimentos/métodos , Lecitinas/química , Lotus/química , Amido/química , Amilopectina/química , Amilose/química , Cromatografia em Gel , Espectroscopia de Ressonância Magnética , Microscopia Eletrônica de Varredura , Pressão , Espalhamento a Baixo Ângulo , Sementes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
15.
Food Chem ; 315: 126241, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32014667

RESUMO

Chemical modification with octenyl succinic anhydride (OSA) helps to control the physicochemical and thermal properties of isolated starches. The main objective, herein, was to partially characterize modified starches from Dominico-Harton plantain and FHIA 21 planted in Colombia. The highest degree of substitution was found in FHIA 21 (0.020) starch with 3% OSA and 4-h reaction at room temperature. The grain morphology was not affected, but small changes on the surface were evident. Both modified starches reported absorption bands in the IR at 1566 and 1738 cm-1, proper for these types of starch derivatives. The hexagonal and monoclinic structures of starch were altered through chemical modification. In the bending curves, a drastic decrease in the viscosity of the modified starches was observed with respect to the native one. The gelatinization temperatures of the modified starches were similar to those of the isolated starches.


Assuntos
Plantago/química , Amido/química , Amilose/análise , Colômbia , Microscopia Eletrônica de Varredura , Plantago/crescimento & desenvolvimento , Amido/análogos & derivados , Anidridos Succínicos/química , Viscosidade , Difração de Raios X
16.
Carbohydr Polym ; 230: 115656, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31887861

RESUMO

How various isoforms of rice-starch biosynthesis enzymes interact during amylose and amylopectin synthesis is explored. The chain-length distributions of amylopectin and amylose from 95 varieties with different environmental and genetic backgrounds were obtained using size- exclusion chromatography, and fitted with biosynthesis-derived models based on isoforms of starch synthase (SSI-SSIV), starch branching enzyme (SBE, including SBEI and SBEII) and granule-bound starch synthase (GBSS) that are involved in amylose and amylopectin synthesis. It is usually thought that these are synthesized by separate enzymes. However, the amount of longer amylopectin chains correlated with that of shorter amylose chains, indicating that GBSS, SBE and SS affect both amylose and amylopectin synthesis. Further, the activity of GBSS in amylose correlated with that of SS in amylopectin. This new understanding of which enzymes are suggested by the statistics to be involved in both amylose and amylopectin synthesis could help rice breeders develop cereals with targeted properties.


Assuntos
Amilopectina/biossíntese , Amilose/biossíntese , Endosperma/metabolismo , Oryza/metabolismo , Enzima Ramificadora de 1,4-alfa-Glucana/química , Grão Comestível/metabolismo , Proteínas de Plantas/química , Sintase do Amido/química
17.
Carbohydr Polym ; 230: 115712, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31887937

RESUMO

The low solubility, gel strength and shear resistance of waxy rice limit utility in large-scale and widespread food applications. Herein, functional properties of waxy rice starch (WRS) have been improved through sequential branching enzyme (BE) and glucoamylase (GA) treatment with wheat amylose (WA), rice amylose (RA) and corn amylose (CA) as the substrate. The results suggest that, compared to the BE treatment, the sequential GA→BE treatment significantly improves the WRS properties. Among the three substrates, WA appears to be suited highly for the WRS through the GA→BE treatment. GABE-WRS/WA had the highest content of α-1,6-glucosidic linkages, increased number of short chains, shortest average chain length, increased crystallinity, enhanced solubility, paste clarity and swelling power, elevated gelatinization temperature and enthalpy, increased viscosity, strongest gels, and highest shear-resistance. Overall, the sequential GA→BE treatment appears to be suitable to modify the functional properties of waxy rice starch toward developing more palatable and large-scale food products.


Assuntos
Amilose/química , Oryza/metabolismo , Amido/química , Enzima Ramificadora de 1,4-alfa-Glucana/química , Géis , Glucana 1,4-alfa-Glucosidase/química , Solubilidade , Viscosidade
18.
Carbohydr Polym ; 230: 115666, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31887946

RESUMO

Amylose-fatty (C12-C16) ammonium salt inclusion complexes are effective antimicrobial polymers causing growth inhibition of microbes at concentrations as low as 40 µg/mL of the complex (2 µg/mL active cationic ligand). The complex was more effective at controlling microbes than the uncomplexed ligand. The complexes were found to be particularly effective at inhibiting the growth of fungi, yeast, gram (+) bacteria, and algae; its performance was affected by pH. The complexes were not hemolytic at concentrations up to 2000 µg/mL. These agents were determined to be surface active polymers and their antimicrobial mode of action may involve cell membrane thinning or disruption, causing moderate leakage. Increased ligand concentration provided increased antimicrobial activity. Solutions of amylose complexes were found to be stable, retaining their antimicrobial efficacy after autoclaving, or after storage at room temperature for 6 months. Antimicrobial amylose complexes were produced using readily available inexpensive materials via an easily scalable process.


Assuntos
Compostos de Amônio , Amilose , Antibacterianos , Antifúngicos , Ácidos Graxos , Nanopartículas/química , Compostos de Amônio/química , Compostos de Amônio/farmacologia , Amilose/química , Amilose/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Antifúngicos/química , Antifúngicos/farmacologia , Bactérias/efeitos dos fármacos , Ácidos Graxos/química , Ácidos Graxos/farmacologia , Fungos/efeitos dos fármacos
19.
Sci China Life Sci ; 63(2): 228-238, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31919631

RESUMO

The palea and lemma are floral organ structures unique to grasses; these structures form the hull and directly affect grain size and quality. However, the molecular mechanisms controlling the development of the hull are not well understood. In this study, we characterized the rice (Oryza sativa) abnormal flower and grain1 (afg1) mutant, a new allele of OsMADS6. Similar to previously characterized osmads6 alleles, in the afg1 floret, the palea lost its marginal region and acquired the lemma identity. However, in contrast to other osmads6 alleles, the afg1 mutant showed altered grain size and grain quality, with decreased total starch and amylose contents, and increased protein and soluble sugar contents. The analysis of transcriptional activity suggested that AFG1 is a transcriptional activator and may affect grain size by regulating the expression levels of several genes related to cell expansion and proliferation in the afg1 mutant. These results revealed that AFG1 plays an important role in determining palea identity and affecting grain yield and quality in rice.


Assuntos
Grão Comestível/genética , Flores/genética , Proteínas de Domínio MADS/genética , Oryza/genética , Proteínas de Plantas/genética , Alelos , Sequência de Aminoácidos , Amilose/genética , Mapeamento Cromossômico , Clonagem Molecular , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Proteínas de Domínio MADS/metabolismo , Mutação/genética , Oryza/crescimento & desenvolvimento , Fenótipo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Amido/genética , Açúcares/metabolismo , Transcrição Genética
20.
Carbohydr Polym ; 230: 115611, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31887905

RESUMO

Porous starch is attractive by providing high surface area for many applications. In this study amyloglucosidase (AMG) and maltogenic α-amylase (MA) were investigated in direct comparison to elucidate potential effects in producing porous starch using high amylose rice starch as a substrate. Both enzymes generated pores at the surface as illustrated by Scanning Electron Microscopy (SEM). The enzyme-treated granules had higher relative crystallinity as deduced from Wide Angle X-ray Scattering (WAXS). MA treatment increased the number of short amylopectin chains and decreased the molecular weight with extended incubation time. The MA-treated starch had higher solubility whereas swelling capacity, amylose content, peak viscosity, final viscosity, breakdown and setback of both treatments were decreased compared to the control. Enzymatic treatments produced starch with delayed gelatinization temperature and increased the enthalpy. The results demonstrate that porous rice starch can provide different functionalities depending on the enzyme mechanisms, extending the range of applications.


Assuntos
Amilose/química , Glucana 1,4-alfa-Glucosidase/metabolismo , Oryza/química , alfa-Amilases/metabolismo , Biocatálise , Interações Hidrofóbicas e Hidrofílicas , Maltose/química , Porosidade , Viscosidade
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