Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 5.353
Filtrar
1.
Molecules ; 26(13)2021 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-34209649

RESUMO

The aim of the study was to assess the influence of replacing wheat flour with hazelnuts or walnuts, in various amounts, on the thermal and rheological properties of the obtained systems. The research material were systems in which wheat flour was replaced with ground hazelnuts (H) or walnuts (W) in the amount of 5%, 10%, and 15%. The parameters of the thermodynamic gelatinization characteristics were determined by the differential scanning calorimetry method. In addition, the pasting characteristics were determined with the use of a viscosity analyzer and the viscoelastic properties were assessed. Sweep frequency and creep and recovery tests were used to assess the viscoelastic properties of the tested gels. It was found that replacing wheat flour with nuts increased the values of gelatinization temperature, gelatinization, and retrogradation enthalpy, and the degree of retrogradation. The highest viscosity was characteristic of the control sample (2039 mPa·s), and the lowest for the paste with 15% addition of walnuts (1120 mPa·s). Replacing the flour with nuts resulted in a very visible reduction in the viscosity of such systems. In addition, gels based on the systems with the addition of H and W were weak gels (tan δ = G″/G' > 0.1), and the values of G' and G″ parameters decreased with the increased share of nuts in the systems. Creep and recovery analysis indicated that the systems in which wheat flour was replaced with hazelnuts were less susceptible to deformation compared to the systems with the addition of W.


Assuntos
Farinha , Juglans/química , Nozes/química , Triticum/química , Reologia
2.
Food Chem ; 362: 130170, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34091164

RESUMO

Impact of globulin addition on the functional and protein structural properties of dough and cooked noodles were investigated. The underlying mechanism was explored through analyzing the interaction between globulin and gluten by using SDS-PAGE, size exclusion chromatography, free sulfhydryl/disulfide bond analysis, laser scanning confocal microscopy and Fourier transform infrared spectroscopy. Results showed that the stiffness/hardness and maximum resistance of dough and cooked noodles were both increased when globulin addition was 1.5% or higher. Besides, extensibility of cooked noodles was also improved when the addition up to 3.0%. The addition of globulin facilitated weakening the S-S bonds in the gluten network and cross-linked with SDS-soluble gluten mainly through non-covalent interactions, especially hydrophobic interactions. Meanwhile, a more rigid protein network structure was observed. Additionally, following cooking, globulin addition accelerated the aggregation of protein molecules. When the addition reached 3%, the protein conformation was transformed from ß-sheets and random coils to ß-turns.


Assuntos
Farinha , Globulinas/química , Triticum/química , Cromatografia em Gel , Culinária , Dissulfetos/química , Eletroforese em Gel de Poliacrilamida , Farinha/análise , Qualidade dos Alimentos , Glutens/química , Dureza , Interações Hidrofóbicas e Hidrofílicas , Microscopia Confocal , Proteínas de Vegetais Comestíveis/química , Reologia , Espectroscopia de Infravermelho com Transformada de Fourier
3.
Int J Biol Macromol ; 182: 2108-2116, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34087299

RESUMO

To improve the performance of wheat straw/polylactic acid (WS/PLA) composites, four different silane coupling agents were used for constructing compatible interfaces and then examined by scanning electron microscopy, Fourier transform-infrared spectroscopy, X-ray diffractometry and thermogravimetric analysis. The blending and tensile strengths of silane-modified composites were effectively enhanced, with KH-570-modified composite exhibiting the best blending and tensile strengths. Water resistance analysis of silane-modified composites was reduced and contact angles larger, indicating that water resistance performance of this composite had been effectively improved. The KH-570-modified composite exhibited the best water resistance performance. Strain scanning showed that, in the linear viscoelastic region, the storage modulus (G') of modified composite was larger than that of unmodified composites. Frequency scanning showed that the G' and complex viscosity (η*) of modified composites were greater than those of unmodified composites. From strain analysis and frequency scanning, the modified performance of the silane agent was observed to effectively improve composite interfacial compatibility, with KH-570-modified composite exhibiting the best effect. XRD analysis showed that silane coupling agent modification improved the crystallinity of composites with the improvement of KH-570 the best. And the thermal stability of silane-modified composites was improved and the thermal stability of KH-570-modified composite the best.


Assuntos
Poliésteres/química , Silanos/química , Triticum/química , Reologia , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Resistência à Tração , Termogravimetria , Água/química , Difração de Raios X
4.
Food Chem ; 362: 130135, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34077856

RESUMO

Health benefits of whole wheat products are partially attributed by their unique phenolic compounds. This study investigated effect of simulated gastrointestinal digestion and probiotic fermentation on releasing of phenolic acids from whole wheat foods (bread, cookie, and pasta). Kinetics results showed that more phenolic acids were released within the first hour of gastric and intestinal digestions compared to the prolonged digestion. Lactobacillus rhamnosus GG, a common probiotic strain, released additional phenolic acids from the digestive residues during fermentation. Simulated digestion released more soluble trans-ferulic acid than chemical extraction in breads (17.69 to 102.71 µg/g), cookie (15.81 to 54.43 µg/g), and pasta (4.88 to 28.39 µg/g). Phenolic acid composition of whole wheat products appeared to be better estimated by digestion methods than the chemical extraction method. The unique insoluble-bound nature and fermentability of wheat phenolic acids may lead to a mechanistic understanding of whole grain consumption for potential colorectal cancer prevention.


Assuntos
Hidroxibenzoatos/farmacocinética , Probióticos/farmacocinética , Triticum/química , Grãos Integrais/química , Pão/análise , Ácidos Cumáricos/farmacocinética , Digestão , Fermentação , Humanos , Fenóis/análise
5.
Food Chem ; 362: 130203, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34091172

RESUMO

In the crumb of fresh white wheat bread, starch is fully gelatinized. Its molecular and three-dimensional structure are major factors limiting the rate of its digestion. The aim of this study was to in situ modify starch during bread making with starch-modifying enzymes (maltogenic amylase and amylomaltase) and to investigate the impact thereof on bread characteristics, starch retrogradation and digestibility. Maltogenic amylase treatment increased the relative content of short amylopectin chains (degree of polymerization ≤ 8). This resulted in lower starch retrogradation and crumb firmness upon storage, and reduced extent (up to 18%) of in vitro starch digestion for fresh and stored breads. Amylomaltase only modestly shortened amylose chains and had no measurable impact on amylopectin structure. Modification with this enzyme led to slower bread crumb firming but did not influence starch digestibility.


Assuntos
Pão , Sistema da Enzima Desramificadora do Glicogênio/química , Glicosídeo Hidrolases/química , Amido/farmacocinética , Triticum , Amilopectina/química , Amilopectina/metabolismo , Amilose/química , Liofilização , Sistema da Enzima Desramificadora do Glicogênio/metabolismo , Glicosídeo Hidrolases/metabolismo , Amido/química , Triticum/química
6.
J Food Sci ; 86(7): 3176-3187, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34176121

RESUMO

A hapten of metsulfuron-methyl was successfully designed and synthesized from 2-methylester-phenylsulfonamide and succinic anhydride, and the polyclonal antibody against metsulfuron-methyl was prepared by immunization procedure with the hapten-bovine serum albumin conjugate. A stable and sensitive direct competitive enzyme-linked immunosorbent assay (dcELISA) method had been developed under the optimal conditions. The sensitivity (IC50 ) was 37.03 ± 1.87 µg/L, and the detection line (IC15 ) was 1.57 ± 0.11 µg/L. Rice, wheat, oat, flaxseed, milk, and water were chosen to study the recovery test and the recovery rates were 83.11%-117.44% . The matrix effect was eliminated by a simple dilution of the sample extracts. The results from dcELISA were well agreement with the results from HPLC-MS. It was indicated that the developed method had good accuracy and stability. It could be applied for the detection of metsulfuron-methyl residues. It was worth mentioning that the antibody could recognize metsulfuron-methyl and tribenuron-methyl with cross-reactivities of 100% and 49.72%, respectively. In order to understand the cross-reactivity, molecular modeling including molecular alignment and electrostatic potential surfaces were introduced. It was found that the special group of metsulfuron-methyl played an important role, especially on C3 position of the phenyl group. PRACTICAL APPLICATION: A stable, sensitive, and low-cost dc ELISA method had been developed with good accuracy and applied in the determination of metsulfuron-methyl in foods. Molecular simulation was introduced to understand the specificity between the antibody and the analyst. It was a good method to study the cross-reactivity between the antibody and the analyst or analogue.


Assuntos
Sulfonatos de Arila/análise , Sulfonatos de Arila/química , Ensaio de Imunoadsorção Enzimática/métodos , Análise de Alimentos/métodos , Anticorpos/imunologia , Sulfonatos de Arila/imunologia , Oryza/química , Triticum/química
7.
Food Chem ; 362: 130188, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34090046

RESUMO

This study investigates the evolution of the distributions of whole molecular size and of chain length of granular wheat starches (37 ~ 93% amylose content), subjected to in vitro fermentation with a porcine faecal inoculum or digestion with pancreatic enzymes. The results showed that the molecular structures of high-amylose starch (HAS) unfermented residues largely remained unchanged during the fermentation process, while wild-type starch (37% amylose content) showed a preferential degradation of the amylopectin fraction. In contrast, under simulated digestion conditions, the undigested residues of HAS showed structural changes, including a decrease in amylose content, a shift of amylose peak position towards lower degrees of polymerisation, and an enzyme-resistant fraction. These changes of starch structure are likely to be dependent on the different starch-degrading enzyme activities present in pancreatic vs. microbial systems. Molecular changes in response to fermentation metabolism revealed by size-exclusion chromatography can help understand the microbial utilization of resistant starch.


Assuntos
Amilose/química , Amido/química , Amido/farmacocinética , Triticum/química , Amilopectina/química , Amilopectina/metabolismo , Amilopectina/farmacocinética , Animais , Digestão , Fezes/microbiologia , Fermentação , Estrutura Molecular , Polimerização , Amido/isolamento & purificação , Suínos
8.
Food Chem ; 362: 130221, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34098436

RESUMO

Exopolysaccharides (EPS) were produced by four newly isolated lactic acid bacteria strains, then further extracted, separated and characterised under standardised conditions. Using a sucrose carbon source, these LAB strains belonging to Weissella confusa/cibaria produced EPS with a dextran high molecular weight fraction. The obtained yields of EPS ranged from 3.2 g/L to 47.1 g/L and outstandingly high yields were obtained using Weissella confusa/cibaria 3MI3 isolated from spontaneous spelt sourdough. After purification the influence of EPS-dextran of molar mass 3,244,000 g/mol on resistant starch formation in wheat starch pastes and pasted samples after temperature-cycled storage was examined. Size exclusion chromatography with post-column derivatisation revealed that a 1.5% share of EPS dextran limited formation of high molar mass resistant starch in starch pastes during storage. This work provides new insight on hindering resistant starch formation by using EPS, which could be efficiently produced in sourdough, thus improving the properties of sourdough bread.


Assuntos
Polissacarídeos Bacterianos/química , Polissacarídeos Bacterianos/isolamento & purificação , Amido/química , Triticum , Weissella/metabolismo , Pão/análise , Fracionamento Químico , Fermentação , Armazenamento de Alimentos , Amido Resistente , Sacarose/metabolismo , Triticum/química , Triticum/microbiologia , Weissella/química , Weissella/isolamento & purificação
9.
Food Chem ; 361: 130058, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34082391

RESUMO

To improve the quality of vegetarian meatloaves (VMs) made from textured wheat protein, the effects of different treatments (Vacuum, ultrasound and vacuum ultrasound) were compared in terms of texture, moisture distribution, microstructure and chemical bonding interactions. After vacuum, ultrasonic, and vacuum ultrasonic treatments, the hardness of VMs increased by 78%, 66%, 176% respectively. Scanning electron microscopy (SEM) showed that surface of VMs was smoother and the structure was tighter after vacuum ultrasonic treatment. In addition, magnetic resonance imaging (MRI) analysis showed that the moisture in VMs was evenly distributed after vacuum ultrasonic treatment. According to the optical maps observed by spectrofluorimetry and Fourier transform infrared spectroscopy (FT-IR), the fluorescence value and relative content of ß-sheet increased after vacuum ultrasonic treatment. Furthermore, the protein was cross-linked and hydrophobic interactions increased after vacuum ultrasonic treatment. Results showed that texture of VMs after vacuum ultrasonic treatment was closer to that of beef patties.


Assuntos
Manipulação de Alimentos , Proteínas de Grãos/química , Triticum/química , Dieta Vegetariana , Dureza , Interações Hidrofóbicas e Hidrofílicas , Imageamento por Ressonância Magnética , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Ondas Ultrassônicas , Vácuo
10.
Food Chem ; 358: 129826, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33933964

RESUMO

Previous studies reported higher antioxidant and mineral micronutrient concentrations in organic compared to conventional wheat flour, but the reasons are poorly understood. Here we report results from a long-term, factorial field experiment designed to assess effects of variety choice, supplementary irrigation and contrasting fertilization regimes used in organic and conventional production on the nutritional quality and yield of spelt wheat grown in a semi-arid environment. Long-straw (Oberkulmer, Rubiota, ZOR) varieties had 10-40% higher grain Cu, Fe, Mn and Zn concentrations, while the modern, short straw variety Filderstolz had 15-38% higher grain antioxidant activity. Supplementary irrigation and the use of manure instead of mineral NPK as fertilizer had no substantial effect on the nutritional composition of spelt grain, but increased grain yields by ~ 150 and ~ 18% respectively. Overall, this suggests that breeding/variety selection is the most promising approach to improve the nutritional quality of spelt grain in semi-arid production environments.


Assuntos
Fertilizantes , Valor Nutritivo , Triticum/química , Triticum/crescimento & desenvolvimento , Irrigação Agrícola/métodos , Antioxidantes/análise , Farinha/análise , Grécia , Esterco , Micronutrientes/análise , Minerais/análise , Especificidade da Espécie
11.
Food Chem ; 358: 129895, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33933957

RESUMO

The effects of three phosphate salts (PS) on the secondary structure, microstructure of gluten, rheological properties of dough and water status of noodles were investigated to determine the mechanisms underlying the changes in the quality of noodles. Changes in the secondary structure detected were the increased number of ß-sheet and decreased number of random coil structures. PS reduced the content of free sulfhydryl (SH) and increased the content of disulfide (SS) bonds. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis indicated that the band density of the high molecular regions of the gluten was reduced. The results showed that adding PS induced a more compact microstructure and improved the G' and G'' values of the dough. After adding PS, the water-solids interaction in noodles was enhanced by the decreased water mobility. It was concluded that PS promoted the water holding capacity of the noodles and strengthened the gluten network.


Assuntos
Farinha , Glutens/química , Fosfatos/química , Triticum , Dissulfetos/química , Farinha/análise , Qualidade dos Alimentos , Estrutura Secundária de Proteína , Reologia , Sais/química , Triticum/química , Água
12.
Food Chem ; 358: 129850, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33940291

RESUMO

Aegilops geniculata, a relative of common wheat, has many useful traits for the improvements of wheat varieties. The wheat-Ae. geniculata disomic addition lines (DALs) carrying prior traits need to be characterized for wheat varieties improvement. We currently found that CS-1Ug (Chinese Spring-Ae. geniculata 1Ug DAL) possessed improved dough rheological properties than CS (Chinese Spring) did, and investigated the reasons of those rheological changes in dough. The results showed that CS-1Ug carries a novel high-molecular-weight glutenin subunit (HMW-GS), a substitute for Dx2 from CS, which led to the changes in the relative proportion of individual HMW-GS in total HMW-GSs. Changes in gluten composition improved the stability and elasticity of dough by promoting the accumulation of unextractable polymeric protein, and optimizing the micro-structure of the gluten. The current study provides basic information on CS-1Ug used as a potential resource for future wheat quality breeding.


Assuntos
Aegilops/genética , Glutens/química , Triticum/química , Cromossomos de Plantas , Farinha , Glutens/genética , Peso Molecular , Melhoramento Vegetal , Proteínas de Plantas/química , Reologia , Sementes/química , Triticum/crescimento & desenvolvimento
13.
Food Chem ; 359: 129847, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-33964656

RESUMO

Surface-enhanced Raman spectroscopy (SERS) and deep learning network were adopted to develop a detection method for deoxynivalenol (DON) residues in Fusarium head blight (FHB)-infected wheat kernels. First, the liquid-liquid interface self-extraction was conducted for the rapid separation of DON in samples. Then, the gold nanorods modified with sodium citrate (Cit-AuNRs) were prepared as substrate for a gigantic enhancement of SERS signal. Results showed that the spectral characteristic peaks for DON residues of 99.5-0.5 mg/L were discernible with the relative standard deviation of 4.2%, with the limit of detection of 0.11 mg/L. Meanwhile, the fully convolutional network for the spectra of matrix input form was developed and obtained the optimal quantitative performance, with a root-mean-square error of prediction of 4.41 mg/L and coefficient of determination of prediction of 0.9827. Thus, the proposed method provides a simple, sensitive, and intelligent detection for DON in FHB-infected wheat kernels.


Assuntos
Fusarium/fisiologia , Ouro/química , Nanotubos/química , Citrato de Sódio/química , Análise Espectral Raman/métodos , Tricotecenos/análise , Triticum/química , Extração Líquido-Líquido , Doenças das Plantas/microbiologia , Tricotecenos/isolamento & purificação , Triticum/microbiologia
14.
BMC Plant Biol ; 21(1): 212, 2021 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-33975563

RESUMO

BACKGROUND: Anemia is thought to affect up to 1.6 billion people worldwide. One of the major contributors to low iron (Fe) absorption is a higher proportion of cereals compared to meats and pulse crops in people's diets. This has now become a problem in both the developed and developing world, as a result of both modern food choice and food availability. Bread wheat accounts for 20 % of the calories consumed by humans and is an important source of protein, vitamins and minerals meaning it could be a major vehicle for bringing more bioavailable Fe into the diet. RESULTS: To investigate whether breeding for higher concentrations of Fe in wheat grains could help increase Fe absorption, a multiparent advanced generation intercross (MAGIC) population, encompassing more than 80 % of UK wheat polymorphism, was grown over two seasons in the UK. The population was phenotyped for both Fe concentration and Fe bioavailability using an established Caco-2 cell bioassay. It was found that increasing Fe concentrations in the grains was not correlated with higher Fe bioavailability and that the underlying genetic regions controlling grain Fe concentrations do not co-localise with increased Fe absorption. Furthermore, we show that phytate concentrations do not correlate with Fe bioavailability in our wheat population and thus phytate-binding is insufficient to explain the lack of correlation between Fe bioavailability and Fe concentrations in the wheat grain. Finally, we observed no (Fe bioavailability) or low (Fe concentration) correlation between years for these traits, confirming that both are under strong environmental influence. CONCLUSIONS: This suggests that breeders will have to select not only for Fe concentrations directly in grains, but also increased bioavailability. However the use of numerous controls and replicated trials limits the practicality of adoption of screening by Caco-2 cells by many breeders.


Assuntos
Disponibilidade Biológica , Grão Comestível/química , Ferro na Dieta/análise , Ferro na Dieta/metabolismo , Triticum/química , Triticum/genética , Triticum/metabolismo , Produtos Agrícolas/química , Produtos Agrícolas/genética , Produtos Agrícolas/metabolismo , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Variação Genética , Genótipo , Melhoramento Vegetal , Reino Unido
15.
Int J Biol Macromol ; 183: 1200-1209, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-33961879

RESUMO

Promising strategies to stabilize gelatin or collagen include glutaraldehyde-based chemical cross-linking or dehydrothermal treatment at different temperatures (120-180 °C). However, these procedures require 24-48 h for complete cross-linking to occur. The present study aims to evaluate the role of wheat gluten on enhancing thermal cross-linking of silica-nanohydroxyapatite (nanoHA)-gelatin composite scaffolds within a shorter period (2 h). Changes in properties were evaluated by varying the ratio of gelatin and gluten in silica-nanoHA matrix (60 wt% ceramic: 40 wt% polymer). The results showed that the scaffolds cross-linked at 170 °C were stable in phosphate-buffered saline for 21 days. It was crystalline and porous in nature. However, the scaffolds with high weight percentage of wheat gluten were brittle, while those with low gluten degraded fast in vitro. The mesenchymal stem cells could adhere, proliferate and differentiate into osteogenic lineage on wheat gluten-containing scaffolds for 21 days (mainly medium concentration). The scaffold also supported new bone formation in critical-sized rat calvarial defect, showing its osteoconductive and osteointegrative nature. In short, this study showed the potential of wheat gluten on improving thermal cross-linking within a shorter period and its suitability to use as a biomimetic bone graft for bone tissue engineering.


Assuntos
Durapatita/farmacologia , Gelatina/química , Glutens/química , Osteogênese/efeitos dos fármacos , Triticum/química , Animais , Regeneração Óssea/efeitos dos fármacos , Células Cultivadas , Reagentes para Ligações Cruzadas/química , Durapatita/química , Masculino , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Porosidade , Ratos , Tecidos Suporte
16.
J Food Sci ; 86(6): 2387-2397, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34018189

RESUMO

Gelation properties of myofibrillar protein (MP)/wheat gluten (WG) induced by glutamine transaminase (TGase) were studied. Results showed that the inclusion of transglutaminase increased the gel strength, water-holding capacity (WHC), and nonfreezable water (Wnf) of MP/WG mixture. Circular dichroism (CD) analysis showed that the ß-sheet and random coil content of the MP/WG treated with TGase addition increased by 12.1% and 3.7%, while the α-helix and ß-turn content decreased by 14.2% and 1.8%. Rheological measurements showed that TGase induced higher energy storage modulus value during the MP/WG gel heating-cooling cycle. the hydrogen bond and hydrophobic interaction content of the MP/WG gels increased by 80 and 120 ug/L, and the disulfide bond decreased by 200 ug/L, with TGase addition was increased from 0 to 120 U/g protein. Scanning electron microscope (SEM) showed that MP/WG gel with TGase had uniform and dense network structure. PRACTICAL APPLICATION: The properties of myofibrillar/wheat gluten gel induced by TGase crosslinking was studied. The gel structure and water holding capacity of MP/WG were improved by the cross-linking of TGase. The study of the gel properties of MP/WG induced by TGase crosslinking also can provide a theoretical basis for analyzing the effect of TGase on the application of gluten protein in complex meat emulsion system.


Assuntos
Géis/química , Glutens/química , Miofibrilas/metabolismo , Reologia , Transglutaminases/farmacologia , Triticum/química , Glutens/efeitos dos fármacos , Glutens/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Miofibrilas/efeitos dos fármacos , Triticum/efeitos dos fármacos , Triticum/metabolismo
17.
J Food Sci ; 86(6): 2421-2433, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34028019

RESUMO

Effects of vacuum degrees (0.00, 0.02, 0.04, 0.06, 0.08 MPa) on water distribution state, tensile properties, stress relaxation properties, and viscoelasticity of dough, as well as the effects of mixing speed (50, 70, 90 rpm/min) and water content (40%, 45%, 50%) under optimum vacuum degree were studied. The results showed that the proper vacuum degree (0.06 MPa) could promote the full contact between flour and water and improved the water-holding capacity of the dough. Meanwhile, the dough had stronger tensile strength, the best viscoelasticity and the ability to recover from external deformation more quickly. Under the vacuum of 0.06 MPa, with the increasing of mixing speed, the response to the external force of dough increased first and then decreased. Adding more water reduced the strength of dough, weakened the response to external forces, and led to a significant decrease in tensile resistance and tensile area of the dough, as well as a decrease in viscoelasticity (p < 0.05). The proper vacuum mixing allowed the preparation of dough to require more water and less energy. PRACTICAL APPLICATION: In the processing of wheat flour products, vacuum mixing is considered to be beneficial to the quality of noodles and breads. As the intermediate of these products, the dough is of great significance for the monitoring of its rheological characteristics. In this study, a moderate vacuum degree led to a significant improvement in the rheological properties of the dough, and the processing performance was the best. Under the optimal vacuum degree, the influence of mixing speed and water amount cannot be ignored. Vacuum mixing is an efficient dough preparation method, which can produce certain economic benefits.


Assuntos
Pão/análise , Farinha/análise , Manipulação de Alimentos/métodos , Reologia , Triticum/química , Água/química , Fenômenos Mecânicos , Vácuo , Viscosidade
18.
Int J Biol Macromol ; 183: 481-489, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-33933544

RESUMO

In this study, the effect of microwave-ultrasound or/and toughening treatment on the physicochemical, structural properties, and in vitro digestibility of A- and B-type granules isolated from wheat starch were investigated. From the SEM, microwave-ultrasound and toughening treatment (MU-T) led to the appearance of irregular and disrupted structure significantly and an increment in the resistant starch content of A- and B-type granule. Furthermore, the MU-T starch possessed the lowest swelling power, light transmittance, and gelatinization temperature range (Tc -To) and the highest ΔH. After MU-T, the relative crystallinity (RC) of X-ray pattern, Fourier transform infrared ratio of 1047/1022 cm-1, and the content of double helix and single helix of 13C CP/MAS NMR had increased significantly. In particular, there was a difference in the content of RS and SDS between A-starch granules and B-starch granules as well as their changes after modification (from 69.305% to 82.93 for A-starch and form 74.97% to 88.17 for B-starch, respectively), which was a similar trend with RC and helix content. This study indicated that, for both A-type granule and B-type granule starches, microwave-ultrasound and toughening treated samples had unique properties compared to singly modified starches.


Assuntos
Amilose/metabolismo , Digestão , Manipulação de Alimentos , Micro-Ondas , Amido Resistente/metabolismo , Triticum/enzimologia , Ultrassom , Amilose/química , Configuração de Carboidratos , Hidrólise , Amido Resistente/análise , Triticum/química
19.
Nature ; 594(7861): 71-76, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34012114

RESUMO

Micronutrient deficiencies (MNDs) remain widespread among people in sub-Saharan Africa1-5, where access to sufficient food from plant and animal sources that is rich in micronutrients (vitamins and minerals) is limited due to socioeconomic and geographical reasons4-6. Here we report the micronutrient composition (calcium, iron, selenium and zinc) of staple cereal grains for most of the cereal production areas in Ethiopia and Malawi. We show that there is geospatial variation in the composition of micronutrients that is nutritionally important at subnational scales. Soil and environmental covariates of grain micronutrient concentrations included soil pH, soil organic matter, temperature, rainfall and topography, which were specific to micronutrient and crop type. For rural households consuming locally sourced food-including many smallholder farming communities-the location of residence can be the largest influencing factor in determining the dietary intake of micronutrients from cereals. Positive relationships between the concentration of selenium in grain and biomarkers of selenium dietary status occur in both countries. Surveillance of MNDs on the basis of biomarkers of status and dietary intakes from national- and regional-scale food-composition data1-7 could be improved using subnational data on the composition of grain micronutrients. Beyond dietary diversification, interventions to alleviate MNDs, such as food fortification8,9 and biofortification to increase the micronutrient concentrations in crops10,11, should account for geographical effects that can be larger in magnitude than intervention outcomes.


Assuntos
Grão Comestível/química , Nutrientes/análise , Valor Nutritivo , Agricultura , Cálcio/análise , Dieta/estatística & dados numéricos , Etiópia , Humanos , Ferro/análise , Malaui , Micronutrientes/análise , Selênio/análise , Inquéritos e Questionários , Triticum/química , Zinco/análise
20.
Int J Biol Macromol ; 183: 463-472, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-33932417

RESUMO

Two alcohol soluble glutenins (ASGLUs) were extracted from gluten and further separated by column chromatography. The ASGLUs with Mw lower than 20,000 (ASGLU 1) and Mw higher than 70,000 (ASGLU 2) show the total amino acid contents of 86.71 g/100 g and 62.847 g/100 g respectively. Both of them are rich in Glu (45.574% and 43.224%) and Pro (15.447% and 16.370%) while poor in cys-s, met and lys (less than 1%). When wheat amylopectin/amylose retrogrades with those ASGLUs, the retrogradation rate of amylopectin with ASGLU 1 enhances significantly. UV-Vis, X-ray diffraction, FT-IR, DSC, CD and solid 13C NMR suggest that the double helixes of amylopectin short-chain branching are unwound during gelatinization. The hydrogen bonds of ASGLU 1 between amide and carbonyl oxygen are destroyed, meanwhile, ß-sheets are unfolded. During retrogradation, ASGLU 1 with less steric hindrance gets into the crevice of amylopectin and combines with the short-chain branching by hydrogen bond. The retrogradation dynamics show that the nucleation type of amylopectin-ASGLU 1 changes from instantaneous to rod-like growth during the process of retrogradation. ß-sheet of ASGLU 1 changes to ß-turn and random conformations at the meantime. The results provide a key targeting to control retrogradation of dough.


Assuntos
Amilopectina/química , Amilose/química , Etanol/química , Glutens/química , Solventes/química , Triticum/química , Configuração de Carboidratos , Ligação de Hidrogênio , Cinética , Peso Molecular , Conformação Proteica em Folha beta , Desdobramento de Proteína , Solubilidade , Relação Estrutura-Atividade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...