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1.
Food Chem ; 307: 125543, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31634760

RESUMO

Phosphate fertilisation affects the growth, development and quality of Tartary buckwheat. In this study, the effect of different phosphorus levels, including 0, 15, 75, and 135 kg/ha (non-, low-, medium-, and high-phosphorus levels, respectively), on the characteristics of starch from Tartary buckwheat were investigated in 2015 and 2017. With increased phosphorus level, the median diameter of starch granules and the apparent amylose content initially decreased and then increased. All starch samples showed the features of A-type X-ray diffraction patterns. Starches under medium-phosphorus treatment showed higher relative crystallinity than those under non-phosphorus treatment, as well as the highest solubility, gelatinisation enthalpy and transmittance among all starches. Starches under low-phosphorus treatment exhibited higher pasting properties than those under non-phosphorus treatment. This research revealed that phosphorus treatments and year significantly affected the physicochemical properties of Tartary buckwheat starch, and can provide information for the applications of starch in the food and non-food industries.


Assuntos
Fagopyrum/química , Fertilizantes , Fosfatos/farmacologia , Amido/química , Amilose/química , Fenômenos Químicos , Fagopyrum/efeitos dos fármacos , Solubilidade
2.
Food Chem ; 303: 125344, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31446363

RESUMO

The effect of annealing on structure and physicochemical properties of four different waxy starches were investigated to understand the mechanism of annealing in the absence of amylose. Granule morphology, X-ray pattern, molecular order, and gelatinization enthalpy remained unchanged upon annealing. Relative crystallinity of waxy corn starch increased from 42.4 to 46.1% on annealing, while it remained unchanged in other starches. Annealing increased the gelatinization temperatures, while it decreased the temperature range. Waxy potato starch showed the highest increase in To, where it was 8.1 °C after 72 h of annealing. Viscosity profiles were only slightly affected by the annealing treatment. Susceptibility towards amylolysis increased in waxy corn and waxy barley, while it decreased in waxy potato and waxy rice. This study demonstrated that even in the absence of amylose, annealing caused changes in the structure and properties, however, the extents of these changes varied depending on the botanical origin.


Assuntos
Fenômenos Químicos , Amido/química , Ceras/química , Amilopectina/química , Amilose/química , Oryza/química , Solanum tuberosum/química , Temperatura Ambiente , Viscosidade , Zea mays/química
3.
Food Chem ; 311: 126011, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31862571

RESUMO

Variations in fine structure of pigmented sweet potato starches and their relationships with starch functional properties were explored in this study. The amylose content (18.63-20.45%), XAM1 (308-387) and hAP2 (0.723-0.810) and hAM2 (0.134-0.167) significantly differed (P < 0.05), while other structural parameters had small variations. The average chain length of amylopectin ranged in degree of polymerization (DP) from 23.3 to 24.7. The proportions of fa, fb1, fb2 and fb3 were 21.88-27.18%, 45.45-50.81%, 11.87-13.29% and 14.02-16.96%, respectively, with significant (P < 0.05) differences among these samples. Pearson correlation analysis indicated that fine structures of both amylose and amylopectin had significant impacts on pasting, gelatinization, and textural properties. XAM2, fa, fb1, XAM2 and fa/fb1 were significantly correlated with pasting parameters, while fa and fa/fb1 were negatively correlated with thermal parameters. XAM1 and hAP2 were negatively correlated with texture. These results may provide an overview of structure-function correlations for sweet potato starches.


Assuntos
Ipomoea batatas/metabolismo , Amido/química , Amilopectina/química , Amilose/química , Cromatografia em Gel , Temperatura Ambiente
4.
Carbohydr Polym ; 228: 115350, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31635721

RESUMO

The digestibility properties and structural changes of retrograded starch (RS3) induced by ultrasonic treatment (UT) were investigated. The digestion profiles showed that UT increased the slowly digestible starch (SDS) or resistant starch (RS) of RS3 as an effective green process, corresponding to a change in hydrolysis kinetic parameters (equilibrium starch hydrolysis percentage and kinetic constant). SEM analysis showed that ultrasound led to breakage of RS3 particles followed by cracking, reorientation and crystallization. Differences in amylose content, granule size, and ζ-potential were found for native RS3 and ultrasound-treated RS3 (UT-RS3). UT decreased the relative crystallinity and gelatinization enthalpy but enhanced short-range order of RS3 based on the results of XRD, DSC, and FT-IR, respectively. Surprisingly, diffractive peaks at 13°and 20° (V-type crystalline structure) and a new exothermic peak were also observed for UT-RS3. The outcome was believed to open new pathways for regulating the digestibility properties of RS3 by UT and development of low glycemic response food.


Assuntos
Manipulação de Alimentos/métodos , Plantas Comestíveis/química , Amido/química , Amido/metabolismo , Amilose/química , Digestão , Liofilização/métodos , Hidrólise , Cinética , Ondas Ultrassônicas , Zea mays/metabolismo
5.
J Agric Food Chem ; 67(49): 13728-13736, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31617357

RESUMO

A slow fermentation rate of dietary fiber could result in a steady metabolite production release and even distribution in the entire colon, increasing the likelihood of meeting the energy requirements of the distal colon. In the present study, we modulated the fermentation rate in an in vitro human fecal fermentation model by applying chemical cross-linking modification to a type 2 resistant starch [i.e., high-amylose maize starch (HAMS)]. Cross-linking modification decreased the gas production (an indicator of the fermentation rate) of HAMS throughout the whole fermentation progress. The butyrate production rate of cross-linked starches decreased gradually with the increase of the cross-linking degree. Certain beneficial gut microbiota such as genera of Blautia and Clostridiales members were remarkably promoted by starches with low and medium cross-linking degrees, whereas HAMS with a high cross-linking degree obviously promoted the abundance of Bacteroides uniformis and Ruminococcus bromii. This finding reveals that cross-linking modification effectively controls the fermentation rate and highlights the modulation metabolite profiles and gut microbiota composition through chemical modification.


Assuntos
Amilose/química , Fezes/microbiologia , Microbioma Gastrointestinal , Zea mays/metabolismo , Amilose/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Ácidos Graxos Voláteis/metabolismo , Feminino , Fermentação , Humanos , Intestino Grosso/metabolismo , Intestino Grosso/microbiologia , Masculino , Zea mays/química
6.
Carbohydr Polym ; 224: 115185, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31472846

RESUMO

Starch branching enzymes (SBEs) play a major role in determining starch molecular structure in cereal endosperm. This study investigates how SBEIIs contribute to the chain-length distributions (CLDs) of both amylopectin and amylose, obtained by enzymatic debranching of native starch. Wheat starches with low (37%) to high (93%) amylose content were obtained through altering SBEII in planta. Multiple components were detected in both amylose and amylopectin CLDs. Model fitting of these CLDs reveals a quantitative association between the enzyme activities in amylopectin and amylose. SBEIIa modifies shorter branches (degree of polymerization DP ≲ 12) in amylopectin and longer amylose chains with a CLD peak at ˜3000 DP. SBEIIb acts on longer branches (DP≲ 32) in amylopectin, while its effect on amylose fine structure is not significant. Using both the amylose and amylopectin models to analyze the CLD reveals connections between amylose and amylopectin in wheat starch biosynthesis.


Assuntos
Amilopectina/química , Amilose/química , Sistema da Enzima Desramificadora do Glicogênio/metabolismo , Amido/química , Amido/metabolismo , Triticum/metabolismo , Amilopectina/biossíntese , Amilose/biossíntese , Polimerização , Triticum/enzimologia
7.
J Chromatogr A ; 1606: 460425, 2019 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-31471135

RESUMO

In the present study separation of enantiomers of some chiral neutral and weakly acidic analytes was investigated on the chiral stationary phase (CSP) made by covalent immobilization of amylose tris(3-chloro-5-methylphenylcarbamate) onto silica in nano-liquid chromatography (nano-LC) and capillary electrochromatography (CEC) in acetonitrile and aqueous acetonitrile. Few comparisons were made also between the enantioseparations in nano-LC and high-performance liquid chromatography (HPLC) with the chiral column of 4.6 × 250 mm dimension. Slightly better separation of enantiomers was observed in HPLC mode compared to nano-LC mode. It was shown that in the capillary columns packed with the CSP containing about 20% (w/w) of a covalently immobilized neutral chiral selector, amylose tris(3-chloro-5-methylphenylcarbamate), sufficient electroosmotic flow has been generated and enantioseparations with reasonable analysis time were performed also in CEC mode. It was shown once again that CEC offers a clear advantage over nano-LC from the viewpoint of plate numbers and peak resolution.


Assuntos
Amilose/análogos & derivados , Amilose/química , Eletrocromatografia Capilar/métodos , Cromatografia Líquida/métodos , Nanopartículas/química , Fenilcarbamatos/química , Dióxido de Silício/química , Cromatografia Líquida de Alta Pressão/métodos , Estereoisomerismo
8.
J Chem Theory Comput ; 15(11): 6203-6212, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31560849

RESUMO

The inherent flexibility and conformational heterogeneity of a carbohydrate pose a challenge for its modeling and sampling by the existing classical force field. This work quantitatively assesses the quality of four popular carbohydrate force fields (CHARMM36, GLYCAM06, OPLS-AA, GROMOS53A6CARBO_R) against their ability to accurately model the conformational landscape of a dodecamer of single-stranded amylose, the key constituent of starch. While past NMR and X-ray studies have hinted at evidence of a helical structure of amylose and its spontaneous helix-coil transition, it remains to be seen how existing force fields fare against modeling its structural transition. Toward this end, we perform a multimicrosecond long extensive molecular dynamics simulation of dodecamer of a single-stranded amylose chain in explicit water in each of the four force fields and assess these force fields' ability to model relative structural transitions via analyzing the radius of gyration, glycosidic linkage orientation, and pyranose ring puckering of the amylose. In particular, the simulations show that while GLYCAM06 and CHARMM36 force fields predict a significant helix-coil transition in the amylose, GROMOS53A6CARBO_R and OPLS-AA majorly favor extended conformation. The Markov State Model (MSM), built using the simulation trajectories, for each force field, provides a comparative quantification of the population of key macrostates of amylose and elucidates an underlying network of pathways of their mutual interconversion. The macrostates obtained from MSM revealed that metastable helixlike and semicoil intermediate conformations are more probable for CHARMM36, whereas elongated or helixlike conformations are more probable in OPLS-AA and GROMOS53A6CARBO_R. GLYCAM06 showed significant probability for both helix and coil conformations along with intermediate conformations. We find that the differences in the conformations across force fields are governed by differences in the kinetics of glycosidic linkages and pyranose ring pucker conformers. All four force fields share one common point that the majority of α(1 → 4) glycosidic linkages preferred syn conformation, which is found to be energetically more favorable than anti. However, except for GROMOS53A6CARBO_R, all other force fields predicted non-negligible minor anti conformation. The multimicrosecond long simulations on the single-chain amylose, in combination with MSM, described here, suggest that sampling of α(1 → 4) linked oligosacharides on microsecond time scales enable quantitative predictions of helix-coil, glycosidic linkage, and pyranose ring exchange kinetics. These exchange kinetics have otherwise remained inaccessible to quantification by experiments or nanosecond time scale simulations which might have hindered the comparison of the possibility of helix-coil exchange across different force fields on equal footing.


Assuntos
Amilose/química , Simulação de Dinâmica Molecular , Amilose/metabolismo , Cinética , Cadeias de Markov , Conformação Molecular , Oligossacarídeos/química , Oligossacarídeos/metabolismo
9.
Food Chem Toxicol ; 133: 110731, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31369851

RESUMO

The effect of chitosan (CS) on the in vitro digestibility and molecular structural properties of lotus seed starch (LS), and the correlation matrix was studied. The addition of CS could delay the hydrolysis of LS due to a increased level of slowly digestible starch (SDS). LS-CS blends exhibited lower pasting viscosity, greater amylose content and higher ordered structure than LS alone. A significant correlation was found between the digestibility and molecular structural properties of LS-CS blends. Rapidly digestible starch content was positively correlated with viscosity and full width at half-maximum height (FWHH) at 480 cm-1; whereas, SDS content was negatively correlated with setback and FWHH. Moreover, CS concentration was positively related to absorbances at 1047 and 1035 cm-1and amylose content. The results indicated that the addition of CS could be beneficial to the formation of an ordered molecular structure in LS-CS blends and decreased digestibility in vitro.


Assuntos
Amilose/química , Quitosana/química , Amilose/análise , Calefação , Hidrólise/efeitos dos fármacos , Lotus/química , Estrutura Molecular , Sementes/química , Viscosidade
10.
J Photochem Photobiol B ; 198: 111589, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31437761

RESUMO

Glucose is a natural chemical compound and is one of the most abundant organic molecules in nature. Plants and algae are able to produce it from water and carbon dioxide during photosynthesis, using energy of photons coming from the sun. It is very important in life processes because, in energy metabolism, Glucose is the most important source of energy in all organisms. As energy reservoir it is partially stored as a polymer, in plants mainly as starch and amylopectin and in animals as glycogen. Moreover it is used as cellulose, the most abundant carbohydrate, to strengthen plants and algae cell walls. In this paper we study the Delayed Luminescence from Glucose and its polymers, Amylose and Cellulose, composed by chains of glucose connected by different bond, as well as Glucose water solution, in order to acquire new knowledge on the mechanisms responsible for this phenomenon and check the possibility to give in-depth analysis of possible collective states present in Glucose-based structures. The phenomenon of DL in biological systems is not a byproduct, as one can naively expect. Instead, it is a property and necessity of the condensed matter, which can be also used as a tool to study the latter. It is a manifestation of the physical and biochemical processes in the system, on one hand side, and, on the other hand side, of its structural properties, in particular, of the presence and type of crystal-like structure, resulting in specific energy spectrum and electron transitions, as will be presented below. We show that the quantum yield and time trends of the Delayed Luminescence depend on the structure of systems under study. Significant differences in Delayed Luminescence parameters from cellulose before and after imbibition have been observed, indicating that Delayed Luminescence could be used to discriminate between various structures and follow the formation or demolition of them. The experimental results qualitatively agree with the soliton mechanism of the Delayed luminescence.


Assuntos
Glucanos/química , Espectrometria de Fluorescência , Amilose/química , Animais , Celulose/química , Cinética , Camundongos
11.
Ultrason Sonochem ; 59: 104710, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31421611

RESUMO

High-amylose starch is in great demand in the food industry due to its unique functional properties but has very limited source. In this study, high-amylose starch was successfully extracted from Radix Puerariae using ultrasound extraction. The effects of ultrasound intensity (15.29, 20.38, 22.93, 24.46 and 25.38 kW/m2) and frequency (20 and 45 kHz) on extraction kinetics, and chemical compositions, crystallinity, in vitro digestion behaviour and gelling properties of starches were investigated. It was shown that with the increasing intensity, the extraction rate and content of amylose increased, but for starch the extraction rate increased initially until reached a plateau at an intensity of 24.46 kW/m2. With the increasing low-frequency, the extraction rate and content of amylose increased, but the extraction rate of starch decreased. Based on statistical tests, the Logistic model was found to fit well to the extraction kinetics of amylose, and the Peleg model fit well to that of starch. The extraction yield of starch was not significantly affected by ultrasound conditions. The obtained starch has a high-purity with a content of more than 99% dry basis and an unchanged crystallinity. Moreover, the increased amylose content resulted in an increase of the content of slowly digestible starch, resistant starch, and gelling hardness. This study demonstrates that high-amylose starch can be obtained using ultrasound extraction from Radix Puerariae at high-intensity low-frequency.


Assuntos
Amilose/química , Fracionamento Químico/métodos , Pueraria/química , Amido/química , Amido/isolamento & purificação , Ondas Ultrassônicas , Digestão , Cinética , Amido/metabolismo
12.
Chirality ; 31(10): 855-864, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31423667

RESUMO

As an important intermediate of prostaglandins and entecavir, optically pure Corey lactone diol (CLD) has great value in the pharmaceutical industry. In this work, the enantioseparation of (±)-CLD was evaluated using high-performance liquid (HPLC) and supercritical fluid chromatography (SFC). In HPLC, the separations of CLD enantiomers on polysaccharide-based chiral stationary phases with both normal phase and polar organic phase were screened. And the conditions for the enantioseparation were optimized in HPLC and SFC, including the selection of mobile phase, temperature, back-pressure, and other conditions. More important, it was found that the chiral resolutions were greatly enhanced by the increase of the coating amount of ADMPC (amylose tris-(3,5-dimethylphenylcarbamate)) under both HPLC and SFC conditions, which can lead to the increase of the productivity and the decrease of the solvent consumption. The preparations of optically pure CLD were evaluated on a semi-preparative (2 × 25 cm) column packed with 30% ADMPC-coated CSP under HPLC and SFC conditions. Preparative performances in terms of kkd are 1.536 kg racemate/kg CSP/day and 1.248 kg racemate/kg CSP/day in HPLC and SFC, respectively.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Cromatografia com Fluido Supercrítico/métodos , Lactonas/química , Lactonas/isolamento & purificação , Amilose/análogos & derivados , Amilose/química , Fenilcarbamatos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Estereoisomerismo , Temperatura Ambiente
13.
Carbohydr Polym ; 223: 115069, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31426996

RESUMO

Resistant starch (RS) acylated with propionate groups is of particular interest in terms of their capacity to deliver specific short-chain fatty acids (SCFAs) to the colon with health benefits. In the present study, we fabricated propionylated high-amylose maize starches with different degrees of substitution (DS), and monitored the in vitro human fecal fermentation profiles. Propionylated modification did not change the slow gas production properties of high-amylose maize starch throughout the whole fermentation period. The final concentration of propionate (13.68-21.10 mM) produced by propionylated starch fermentation enhanced gradually with increase of DS value, resulting from the release of introduced propionyl groups. Certain beneficial gut microbiota such as Roseburia, and Blautia were obviously promoted, suggesting that propionylated starch could regulate the composition of gut microbiota. The results may facilitate the design and manufacture of functional food products with the aim of improving colonic health.


Assuntos
Amilose/metabolismo , Fezes/microbiologia , Fermentação , Microbioma Gastrointestinal/fisiologia , Propionatos/metabolismo , Zea mays/química , Adulto , Amilose/química , Bactérias/metabolismo , Butiratos/metabolismo , Humanos , Estrutura Molecular , Propionatos/química , Adulto Jovem
14.
Analyst ; 144(15): 4694-4701, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31268436

RESUMO

The development of facile and sensitive miRNA quantitative detection methods is a central challenge for the early diagnosis of miRNA-related diseases. Herein, we propose a strategy for a liposome-encoded magnetic bead-based DNA toehold-mediated DNA circuit for the simple and sensitive detection of miRNA based on a toehold-mediated circular strand displacement reaction (TCSDR) coupled with a personal glucometer (PGM ). In this strategy, a glucoamylase-encapsulated liposomes (GELs)-encoded magnetic bead (GELs-MB) probe is designed to integrate target binding, magnetic separation, and signal response. Upon sensing the target miRNA-21, a GELs-MB probe-based toehold-mediated circular strand displacement reaction (TCSDR) was initiated with the help of fuel-DNA, constructing a DNA circuit system, and realizing target recycling amplification and the disassembly of the liposomes. The disassembled liposomes were finally removed via magnetic separation, and the encapsulated glucoamylase was liberated to catalyze amylose hydrolysis with multiple turnovers to glucose for a PGM readout. Benefiting from target recycling amplification initiated by the toehold-mediated DNA circuit and the liposome multiple-label amplification, a small quantity of target miRNA-21 can be transformed into a large glucose signal. The strategy realized the quantification of miRNA-21 down to a level of 0.7 fM without enzymatic amplification or precise instrumentation. Moreover, the high-density GELs-MB probe allows the sensitive detection of miRNA-21 to be accomplished within 1.5 h. Furthermore, this strategy exhibits the advantages of specificity and simplicity, since a toehold-mediated strand displacement reaction, magnetic separation and portable PGM were used. Importantly, this strategy has been demonstrated to allow the high-confidence quantification of miRNA. Therefore, with the advantages of low cost, ease of use, portability, and sensitivity, the reported method holds great potential for the early diagnosis of miRNA-related diseases.


Assuntos
Sondas de DNA/química , DNA/química , Lipossomos/química , MicroRNAs/análise , Amilose/química , Linhagem Celular Tumoral , Técnicas de Química Analítica/métodos , DNA/genética , Sondas de DNA/genética , Glucana 1,4-alfa-Glucosidase/química , Glucose/análise , Glucose/síntese química , Humanos , Limite de Detecção , Fenômenos Magnéticos , MicroRNAs/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Hibridização de Ácido Nucleico
15.
Plant Foods Hum Nutr ; 74(3): 446-447, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31273640

RESUMO

Cookies are one of the most consumed bakery products and the formulation could be modified to consider them as a functional food. The high amylose maize starch (HAMS) is considered as resistant starch (RS) type 2. The objective of this work was to assess the starch fractions, texture, sensory properties and acceptability of wheat flour cookies added with HAMS at different percentages. Adding 15% of HAMS into the formulation increased the amount of RS from 2.3 to 12.8%. In sensory analysis, children and adults showed a good acceptability of cookies since the addition of HAMS did not result in significant changes in flavor or color. Cookies made with HAMS could be considered as functional foods since they had an acceptable texture and low caloric content.


Assuntos
Amilose/química , Compostos Fitoquímicos/análise , Amido/química , Triticum/química , Zea mays/química , Adulto , Criança , Digestão , Farinha/análise , Alimento Funcional , Humanos , Paladar
16.
Molecules ; 24(13)2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31269663

RESUMO

This study aimed to obtain a second-generation snack by extrusion from the by-product of rice milling enriched with amaranth. The raw material used was amaranth flour (AF), rice starch (NS) and modified rice starch (MS), which were evaluated by the analysis of substitution degree (SD), differential scanning calorimetry (DSC), viscosity (RVA), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The snacks were expanded by extrusion and microwave oven, as a reference method. The samples were evaluated in hardness (D), expansion index (EI), apparent density (DAP), and protein content (P). Afterward, the optimized samples were evaluated by scanning electron microscopy (SEM) and resistant starch (RS). During the thermal characterization, a clear trend in the decrement in gelatinization temperatures was observed (78.35 to 63.90 °C in NS and MS respectively). The curves obtained in RVA analyses showed typical behavior of native (6.35 Pa.s) and extruded starches (2.88 Pa.s), with a significant decrease in viscosity peak. Through the analysis of FT-IR, the introduction of the functional acetyl group (stretching at a wavelength of 1735 cm-1) was corroborated. Snack samples results showed a maximum hardness in MS, with a value of 121 N, and the NS (100%) presented the highest EI value (1.41). The lowest DAP values were obtained for the MS (0.48 g/cm3, 100%) and AF (0.49 g/cm3, 100%) samples. P increased to a higher concentration of AF. In the optimum formulation, the SEM image showed that the expanded microwave sample increased the porosity and obtained an RS value of 8.2%. The formulation obtained in the present study presents high characteristics to be used in the development of a healthy snack.


Assuntos
Amaranthus/química , Oryza/química , Lanches , Amido/química , Acetilação , Amilose/química , Cor , Cristalização , Dureza , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Temperatura Ambiente , Viscosidade , Difração de Raios X
17.
Food Chem ; 298: 125015, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260956

RESUMO

The effect of microwave irradiation-retrogradation (MIR) treatment on the physicochemical properties and in vitro digestibility of corn starch (A-type crystallinity), potato starch (B-type) and chestnut starch (C-type) were evaluated. After MIR treatment, the amount of resistant starch (RS) increased and rapid digestible starch (RDS) decreased along with the retrogradation time in all three starches. The degree of retrogradation (DR) of starch was significantly positive correlated with amylose and RS content. All three starches subjected to MIR treatment exhibited a B-type crystalline structure. With the increase in retrogradation time, starch granules became more orderly. The DR was significantly positively correlated with relative crystallinity of X-ray pattern, To, ΔH of thermal properties, and the Fourier transform infrared ratio of 1047/1022 cm-1 of starch. The results indicated that MIR treatment is a good industrial method for preparing low digestive starch and retrogradation time is an important parameter for the process.


Assuntos
Amilose/efeitos da radiação , Amido/efeitos da radiação , Amilose/química , Fenômenos Químicos/efeitos da radiação , Cristalização , Micro-Ondas , Espectroscopia de Infravermelho com Transformada de Fourier , Amido/química , Difração de Raios X
18.
Int J Biol Macromol ; 138: 441-449, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31302126

RESUMO

Starches isolated from pumpkin fruits, lentil and quinoa seeds were used to prepare edible films. Physicochemical, thermal and mechanical properties of films were determined and compared with potato-based starch (PS) film. It was found that botanical origin of starch has a crucial effect on the films properties. The much lower solubility and higher swelling capacity compared to PS film exhibited lentil and pumpkin starch-based films, respectively. All of the films exhibited significantly higher water vapor permeability compared to PS one. Tensile strength and elongation at break of the films varied between 8.98 and 13.85 MPa, and 3.35 to 4.44%, respectively. All of the films acted as a solid-like materials with prevalently elastic behavior and exhibited endothermic peaks in DSC measurement in the range of 249-281 °C, referred to the melting of films. This study demonstrated that starches from non-conventional sources are good alternative to conventional to develop edible films.


Assuntos
Chenopodium quinoa/química , Cucurbita/química , Lens (Planta)/química , Amido/química , Amilose/química , Varredura Diferencial de Calorimetria , Fenômenos Químicos , Fenômenos Mecânicos , Permeabilidade , Vapor
19.
Int J Biol Macromol ; 138: 819-830, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31351959

RESUMO

The effects of dielectric barrier discharge (DBD) plasma treatment on physicochemical and digestion properties of Tartary buckwheat (TBS), sorghum (SS), wheat (WS) and quinoa (QS) starches were investigated. Plasma treatment resulted in higher solubility and lower swelling capacity of the starch samples studied. Through XRD and FTIR analyses, the relative crystallinity of starch was increased by DBD plasma, while the crystalline type remained unchanged. It was observed from SEM that more fissures and holes appeared for TBS and SS granules, and granule aggregation occurred for WS and QS caused by plasma treatment, both of which made digestion enzymes more accessible to the four starches. In addition, a marked increase in gelatinization temperature and significant reduction in viscosity of plasma treated starches were found. Interestingly, the increased enzyme accessibility and decreased viscosity of starch were consistent with the enhanced starch digestibility that was suggested by the increased RDS content, digestion rate and digestion velocity constant. Therefore, the DBD plasma treatment on starch may be not in favor of postprandial blood sugar control, but it is suggested to be applied in some industrial processes that need acceleration in starch hydrolyzation, such as bioethanol production, brewing and food fermentation.


Assuntos
Fenômenos Químicos , Gases em Plasma/química , Amido/química , Amilose/química , Digestão , Hidrólise , Análise Espectral , Termogravimetria
20.
Carbohydr Polym ; 222: 115000, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31320061

RESUMO

The effects of pullulanase debranching on the properties of maize starch (waxy, normal and high amylose)-glycerol monolaurate (GML) complexes were studied. Pullulanase pretreatment produced more starch chains with favourable lengths (DP ≥ 25) to encourage inclusion complex formation. The debranched starch showed higher amylose content (from 11.2 to 58.6%) than the native starch (from 0.68 to 53.4%). The V-type characteristic diffraction peaks (7.5°, 13.1° and 20.2° 2θ) became more obvious after the starch received the debranching treatment. Thermal properties indicated that the melting enthalpy of the debranched starch-GML complexes (from 6.45 to 10.13 J/g) was higher than those of the untreated complexes (from 0 to 8.91 J/g). The swelling power values and degree of hydrolysis of the starches decreased with the increase in amylose content. In vitro digestibility analysis suggested that the hydrolysis of the starch-GML samples was further restricted by applying the debranching treatment to the starch.


Assuntos
Amilose/química , Glicosídeo Hidrolases/química , Lauratos/química , Monoglicerídeos/química , Zea mays/química , Temperatura Alta , Hidrólise , Estrutura Molecular
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