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1.
Food Chem ; 339: 127853, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32829247

RESUMO

The correlation between potato components and Maillard reaction derivative harmful products (MRDHPs) formation during heat-processing was assessed in nine commercial potato varieties in China. Principal component analysis (PCA) combined with canonical correlation analysis (CCA) approach was performed to explore their relationships. The variables contributing most to the PCA results were extracted for CCA, and the results indicated that several amino acids, including lysine, tryptophan, alanine, phenylalanine, aspartate, and glutamate, have significant impacts on acrylamide and ß-carboline heterocyclic amine formation. Moreover, 5-O-caffeoylquinic acid, 3-O-caffeoylquinic acid, α-solanine, and α-chaconine were also important factors associated with acrylamide and ß-carboline heterocyclic amine formation. Optimally using raw potato varieties based on the impacts of these factors can help control MRDHP formation during thermal processing. For the first time, such approach was applied, which may be a useful tool for discovering the correlation of food components and MRDHPs.


Assuntos
Produtos Finais de Glicação Avançada/análise , Solanum tuberosum/química , Acrilamida/análise , Acrilamida/química , Aminas/análise , Aminas/química , Carbolinas/química , Cromatografia Líquida de Alta Pressão , Reação de Maillard , Análise de Componente Principal , Solanum tuberosum/metabolismo , Espectrometria de Massas em Tandem
2.
Food Chem ; 333: 127480, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32688306

RESUMO

Acrylamide (AA) is a toxic industrial chemical but is also found in heated potato foods such as French fries due to the Maillard reaction between amino acids and reducing sugars. However, high-temperature cooking is often required for flavoring, browning, and sterilizing of raw ingredients. Imidazole dipeptides, such as carnosine (ß-alanyl-l-histidine, CAR) and anserine (ß-alanyl-Nπ-methyl-l-histidine, ANS), are present in high concentrations in meat and are known to scavenge radical species and toxic aldehydes. Here, we investigated the reaction between CAR/ANS and AA under several conditions expected to detoxify AA by cooking with meat. The reaction products were characterized by LC-ESI-MS/MS as CAR/ANS-AA adducts at the N-terminus, and His-Nτ/Nπ. The reactivity of CAR sites toward AA were in the order N-terminus > Nτ > Nπ. A selective LC-ESI-SRM/MS method was also developed and confirmed the formation of CAR/ANS-AA adducts during pan frying of minced potato and chicken breast.


Assuntos
Acrilamida/química , Anserina/química , Carnosina/química , Galinhas , Culinária , Acrilamida/toxicidade , Animais , Carne/análise , Espectrometria de Massas em Tandem
3.
Food Chem ; 332: 127434, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32645669

RESUMO

The baking in N2 and CO2 atmosphere decreased by 50% the acrylamide, while this level was 99% in SO2. The highest acrylamide content was detected in the control sample as 39.03 µg/kg. Additionally, the lowest HMF content was determined in S-bread as 14.85 mg/kg. The baking atmosphere has a significant impact on L* and a* colour values of bread. The highest L* value was measured in S-bread as 71.2, whereas it was the lowest in the control sample as 49.1. According to the Pearson results, acrylamide showed a negative correlation between L* value. However, no correlation was detected between colour values and HMF. Acrylamide had a positive correlation with flavour, although it did not affect the taste features of bread. No correlation between HMF and sensory properties was determined. The result of the study suggested that inert or inhibitor baking atmosphere may help prevent the Maillard reactions in bakery products.


Assuntos
Acrilamida/química , Pão/análise , Culinária/métodos , Furaldeído/análogos & derivados , Farinha/análise , Furaldeído/química , Temperatura Alta , Humanos , Reação de Maillard , Paladar , Triticum/química
4.
Food Chem ; 328: 127117, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32474240

RESUMO

This study was aimed to reduce the concentrations of benzopyrene (BaP) and acrylamide (ACR) in roasted coffee beans by corona discharge plasma jet (CDPJ). The initial concentrations of BaP and ACR in roasted beans were decreased by 53.6% and 32.0%, respectively, following CDPJ (powered by 20 kV DC/1.5 A) treatment for 60 min. The levels of total solid, total acid, chlorogenic acid, caffeine, trigonelline, and pH were insignificantly changed upon CDPJ treatment compared to controls. However, the concentration of total phenolic content and Agtron color values were altered significantly. The treatment of beans did not alter descriptive sensory properties of the corresponding coffee brews, except aroma and aftertaste characteristics. As the treatment time increased from 15 to 60 min, scores for aroma profiles in PCA plot were shifted from right to left, although overlapping was observed between 15- and 30-min-treated samples. Additionally, none of the treated samples were discriminated from the control by electronic tongue.


Assuntos
Acrilamida/química , Benzopirenos/química , Café/química , Alcaloides/análise , Fenômenos Bioquímicos , Cafeína/análise , Ácido Clorogênico/análise , Culinária , Nariz Eletrônico , Temperatura Alta
5.
Food Chem ; 329: 127171, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32502745

RESUMO

The inhibition effects of glutathione (GSH) on acrylamide (AA) in the asparagine/glucose model systems and cookies were investigated. The formation of AA was significantly inhibited by GSH addition in the model systems. The decreasing levels of AA were in the range of 38-86%, 57-82%, and 3-41% at 120, 140, and 160 °C, respectively. In addition, the presence of GSH in cookies also inhibited the AA formation, but with no corresponding relationship between the GSH level and the inhibition ratio. The addition of 0.05 g/kg GSH in cookie dough resulted in the decreasing of AA by 48%, some improvement in cookie lightness, but no influence on cookie texture. Kinetic analysis showed that the application of GSH not only inhibited the formation of AA but also improved the elimination of AA. In the summary, GSH could be a potential inhibitor to reduce the AA formation in food during the heating process.


Assuntos
Acrilamida/química , Asparagina/química , Culinária , Glucose/química , Glutationa/química , Acrilamida/metabolismo , Asparagina/metabolismo , Indústria de Processamento de Alimentos , Glucose/metabolismo , Glutationa/metabolismo , Cinética
6.
Nat Methods ; 17(6): 609-613, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32424271

RESUMO

We developed entangled link-augmented stretchable tissue-hydrogel (ELAST), a technology that transforms tissues into elastic hydrogels to enhance macromolecular accessibility and mechanical stability simultaneously. ELASTicized tissues are highly stretchable and compressible, which enables reversible shape transformation and faster delivery of probes into intact tissue specimens via mechanical thinning. This universal platform may facilitate rapid and scalable molecular phenotyping of large-scale biological systems, such as human organs.


Assuntos
Hidrogéis/química , Coloração e Rotulagem/métodos , Engenharia Tecidual/métodos , Acrilamida/química , Animais , Fenômenos Biomecânicos , Materiais Biomiméticos/química , Bioimpressão , Córtex Cerebral/química , Reagentes para Ligações Cruzadas/química , Módulo de Elasticidade , Hipocampo/química , Humanos , Teste de Materiais , Camundongos , Estresse Mecânico , Resistência à Tração
7.
Food Chem ; 318: 126467, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32145542

RESUMO

This study aims to investigate in depth the mechanism of acrylamide formation in coffee during roasting. For this purpose, a comprehensive kinetic model including the elementary steps for acrylamide formation was proposed. The changes in sucrose, reducing sugars, free amino acids, asparagine, acrylamide, 3-deoxyglucosone, methylglyoxal, glyoxal, and 5-hydroxymethylfurfural were monitored in coffee during roasting at 200, 220 and 240 °C. Dominant pathways of complex reactions leading to acrylamide were unravelled by means of multiresponse kinetic modelling approach. The results of the model indicated that sucrose degrades into glucose and a reactive fructofuranosyl cation. Interestingly, glucose takes part mostly in the formation of intermediates, glyoxal and especially 3-deoxyglucosone rather than acrylamide formation. On the other hand, fructofuranosyl cation contributed mostly to the formation of 5-hydroxymethylfurfural which was found to be the most important intermediate precursor of acrylamide formed in coffee during roasting.


Assuntos
Acrilamida/química , Café/química , Furaldeído/análogos & derivados , Aminoácidos/química , Desoxiglucose/análogos & derivados , Desoxiglucose/química , Indústria de Processamento de Alimentos/métodos , Furaldeído/química , Glucose/química , Glioxal/química , Temperatura Alta , Cinética , Aldeído Pirúvico/química , Sacarose/química
8.
Food Chem ; 320: 126601, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32208180

RESUMO

Acrylamide (AA) formation during coffee roasting happens rapidly, reaching a peak value within the first minutes of roasting followed by a fast decrease to reach an asymptote at approximately 200 µg/kg. Today, the mechanisms by which AA is reduced during roasting remain unclear. In this research, the fate of AA during roasting followed by drip brewed-like extraction was studied using 14C-radiolabeled (14C-AA) and 13C-labeled (13C3-AA) materials. Results showed that 28% of the spiked 14C-AA was lost during the roasting process, presumably by degradation to volatile compounds and 25% was non-extractable; therefore, appeared bound to the matrix. About 50% of initial AA went into the water extract, either unchanged or transformed by conjugation/binding. The release of bound acrylamide was further evidenced by increasing levels of 13C3-AA over prolonged roasting times. In addition, the absence of 14C activity in the hexane extracts suggested acrylamide not to bind to any lipophilic material.


Assuntos
Acrilamida/química , Café/química , Manipulação de Alimentos , Acrilamida/análise , Radioisótopos de Carbono , Temperatura Alta
9.
Ecotoxicol Environ Saf ; 195: 110522, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32220794

RESUMO

Superabsorbent polymers (SAPs) are most often used in hygienic goods or in the agricultural sector but the range of their application is much broader, including the utilization in advanced building materials. Although SAPs were studied widely during the last decades, the data related to the interactions between the natural environment and various organisms occurring on their surface are still lacking. In addition, SAPs can create a variable gel-forming matter in the presence of water but standard ecotoxicological bioassays are mostly not suitable for testing such type of materials. In this study, the SAPs potential for reducing/supporting unwanted indoor microorganism settlement was analyzed by biological methods under controlled laboratory conditions. Three commonly used SAPs (Cabloc CT, Creasorb SIS, Hydropam) were exposed to selected organisms representing green algae (Hematococcus pluvialis), cyanobacteria (Nostoc sp.), yeasts (Saccharomyces cerevisiae), wood-destroying fungi (Gleophyllium trabeum), and aerial molds. The obtained results indicated that Hydropam provided favorable conditions for Hematococcus pluvialis, Nostoc sp., and Saccharomyces cerevisiae. All three tested SAPs inhibited, both with and without nutrient addition, the growth of Gleophyllium trabeum and aerial molds.


Assuntos
Acrilamida/química , Clorófitas/crescimento & desenvolvimento , Materiais de Construção/microbiologia , Nostoc/crescimento & desenvolvimento , Polímeros/química , Saccharomyces cerevisiae/crescimento & desenvolvimento , Humanos , Nostoc/isolamento & purificação , Saccharomyces cerevisiae/isolamento & purificação , Água/química
10.
Food Funct ; 11(2): 1489-1497, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-31989150

RESUMO

Children are one of the most exposed groups to dietary acrylamide with 'potato fried products' that account for up to half the total exposure to this contaminant. Acrylamide was measured in French fries prepared in 31 primary school canteens randomly recruited from different Spanish regions. The mean content was 329 µg kg-1 (from <20 to 4000 µg kg-1). French fries prepared from frozen par-fried potatoes reported a lower acrylamide content than those from fresh potatoes, 229 and 460 µg kg-1, respectively. Only 15.7% of samples were above the benchmark levels established by the EU Regulation 2017/2158 (500 µg kg-1). Significant differences were found according to the color of toasted (2274 µg kg-1), dark-golden (463 µg kg-1), golden (134 µg kg-1) and light-golden (52 µg kg-1) French fries. All the samples that were golden and light-golden showed acrylamide content below the threshold. The chromatic parameter a* was used as a rough classification of the French fries according to the benchmark level. Both educational initiatives intended for food operators and managerial-technical criteria that include the code of frying practices at public food service establishments should consider the golden color as the target for the end-point of frying. Acrylamide exposure will be reduced and, therefore, the risk linked to French fries consumption. This fact is especially relevant in establishments that prepare food for schoolchildren and would help to provide healthier diets, not only from a nutritional point of view but also from the reduction of chemical contaminants.


Assuntos
Acrilamida/química , Manipulação de Alimentos , Refeições , Instituições Acadêmicas , Solanum tuberosum/química , Criança , Humanos , Espanha
11.
Carbohydr Polym ; 230: 115661, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31887893

RESUMO

This study indicated tailoring efficient polymer-enzyme bioconjugates with superb stability and activity for practical utilization of cellulase enzyme in hydrolyzing lignocellulosic biomass. To this goal, a dual crosslinking (DC) strategy was presented to synthesize novel 3D networks of carboxymethyl cellulose grafted copolymers of 2-acrylamido-2methyl propane sulfonate and acrylamide (CMC-g-poly(AMPS-co-AAm)) hydrogels. Graphene oxide (GO) nano-sheets were utilized as nano-filler and physical cross-linker making H-bondings between polymeric chains to prepare GO@CMC-g-poly(AMPS-co-AAm) networks. The GO content effects on the performance of as-synthesized architectures in conjugation to a model enzyme (PersiCel1) were examined. PersiCel1 immobilization on the GO reinforced hydrogels resulted in noticeable retaining near 60 % of its maximum activity at 90 °C, along with the remarkable enhancement of its specific activity and storage stability. Compared with the free PersiCel1, the immobilized enzyme on the GO containing hydrogels showed 154.8 % increase in conversion of alkalin-treated sugar beet pulp, while the PersiCel1/neat-Hydrogel indicated an increment of 66.7 %, under the same conditions.


Assuntos
Celulase/química , Enzimas Imobilizadas/química , Lignina/química , Acrilamida/química , Acrilamidas/química , Alcanossulfonatos/química , Carboximetilcelulose Sódica/química , Grafite/química , Hidrogéis/química , Hidrólise
12.
Spectrochim Acta A Mol Biomol Spectrosc ; 227: 117699, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31685423

RESUMO

In this work, 3-Phenyl-N-[4-(10,15,20-triphenyl-porphyrin-5-yl)-phenyl]- acrylamide (TPPCA) was synthesized for the determination of metronidazole (MTZ). It was found that the type of fluorescence quenching was static quenching determined by Stern-Volmer plot and UV absorption spectroscopy, and thermodynamic related parameters were also obtained. Furthermore, the corresponding measurement conditions: the acidity of the system, the type of surfactant, the concentration of TPPCA and the sequence of reagent addition were optimized. Under the optimal experimental conditions, the linear range of MTZ was determined to be 0.01-0.20 µg mL-1, and the limit of detection (LOD) was 0.004 µg mL-1. Importantly, this report provides a simple, fast, and sensitive probe for the determination of MTZ in pharmaceutical practice.


Assuntos
Acrilamida/química , Cetrimônio/química , Emulsões/química , Metronidazol/análise , Sondas Moleculares/química , Ácidos/química , Acrilamida/síntese química , Calibragem , Concentração de Íons de Hidrogênio , Cinética , Limite de Detecção , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Tensoativos/química , Termodinâmica , Fatores de Tempo
13.
Appl Microbiol Biotechnol ; 104(1): 365-375, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31768610

RESUMO

Microbially induced CaCO3 precipitation (MICP) can give concrete self-healing properties. MICP agents are typically bacterial endospores which are coated into shelled granules, infused into expanded clay, or embedded into superabsorbent polymer (SAP). When small cracks appear in the cured concrete, the encapsulation is broken and the metabolic CO2 production from the germinated bacteria causes healing of the cracks by precipitation of CaCO3. Such systems are being tested empirically at large scales, but survival of endospores through preparation and application, as well as germination and growth kinetics of the germinated vegetative cells, remains poorly resolved. We encapsulated endospores of Bacillus subtilis and Bacillus alkalinitrilicus in crosslinked acrylamide-based SAP and quantified their germination, growth, and, in the case of B. alkalinitrilicus, CaCO3 precipitation potential. The endospores survived crosslinking and desiccation inside the polymer matrix. Microcalorimetry and microscopy showed that ~ 80% of the encapsulated endospores of both strains readily germinated after rehydration of freeze-dried SAP. Germinated cells grew into dense colonies of cells inside the SAP, and those of B. alkalinitrilicus calcified with up to 0.3 g CaCO3 produced per g desiccated SAP when incubated aerobically. Measurements by planar optodes indicated that the precipitation rates were inherently oxygen limited due to diffusional constraints, rather than limited by electron donor or Ca2+ availability. Such oxygen limitation will limit MICP in all water-saturated and oxygen-dependent systems, and MICP agents based on anaerobic bacteria, e.g., nitrate reducers, should be developed to broaden the applicability of bioactive self-healing concretes to wet and waterlogged environments.


Assuntos
Bacillus subtilis/metabolismo , Bacillus/metabolismo , Carbonato de Cálcio/metabolismo , Precipitação Química , Polímeros/química , Acrilamida/química , Bacillus/crescimento & desenvolvimento , Bacillus subtilis/crescimento & desenvolvimento , Bactérias Aeróbias/crescimento & desenvolvimento , Bactérias Aeróbias/metabolismo , Fenômenos Bioquímicos , Dióxido de Carbono/metabolismo , Oxigênio/metabolismo , Esporos Bacterianos/metabolismo , Água/metabolismo
14.
Genome Res ; 30(1): 49-61, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31727682

RESUMO

We show the use of 5'-Acrydite oligonucleotides to copolymerize single-cell DNA or RNA into balls of acrylamide gel (BAGs). Combining this step with split-and-pool techniques for creating barcodes yields a method with advantages in cost and scalability, depth of coverage, ease of operation, minimal cross-contamination, and efficient use of samples. We perform DNA copy number profiling on mixtures of cell lines, nuclei from frozen prostate tumors, and biopsy washes. As applied to RNA, the method has high capture efficiency of transcripts and sufficient consistency to clearly distinguish the expression patterns of cell lines and individual nuclei from neurons dissected from the mouse brain. By using varietal tags (UMIs) to achieve sequence error correction, we show extremely low levels of cross-contamination by tracking source-specific SNVs. The method is readily modifiable, and we will discuss its adaptability and diverse applications.


Assuntos
Acrilamida , Ácidos Nucleicos , Análise de Célula Única/métodos , Acrilamida/química , DNA , Contaminação por DNA , Variações do Número de Cópias de DNA , Dosagem de Genes , Perfilação da Expressão Gênica/métodos , Perfilação da Expressão Gênica/normas , Biblioteca Gênica , Humanos , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologia , Ácidos Nucleicos/química , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Análise de Sequência com Séries de Oligonucleotídeos/normas , Polimerização , RNA , Análise de Célula Única/normas
15.
Bioprocess Biosyst Eng ; 43(3): 457-471, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31705314

RESUMO

Acrylamidase produced by Cupriavidus oxalaticus ICTDB921 was recovered directly from the fermentation broth by ammonium sulfate (40-50%) precipitation and then stabilized by cross-linking with glutaraldehyde. The optimum conditions for the preparation of cross-linked enzyme aggregates of acrylamidase (acrylamidase-CLEAs) were using 60 mM glutaraldehyde for 10 min at 35 °C and initial broth pH of 7.0. Acrylamidase-CLEAs were characterized by SDS-PAGE, FTIR, particle size analyzer and SEM. Cross-linking shifted the optimal temperature and pH from 70 to 50 °C and 5-7 to 6-8, respectively. It also altered the secondary structure fractions, pH and thermal stability along with the kinetic constants, Km and Vmax, respectively. A complete degradation of acrylamide ~ 1.75 g/L in industrial wastewater was achieved after 60 min in a batch process under optimum operating conditions, and the kinetics was best represented by Edward model (R2 = 0.70). Acrylamidase-CLEAs retained ~ 40% of its initial activity after three cycles for both pure acrylamide and industrial wastewater, and were stable for 15 days at 4 °C, retaining ~ 25% of its original activity.


Assuntos
Acrilamida/química , Amidoidrolases , Proteínas de Bactérias , Cupriavidus/enzimologia , Amidoidrolases/química , Amidoidrolases/isolamento & purificação , Proteínas de Bactérias/química , Proteínas de Bactérias/isolamento & purificação , Estabilidade Enzimática
16.
J Sci Food Agric ; 100(3): 1213-1219, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31680253

RESUMO

BACKGROUND: In this article the relationship between lipophilic grape seed proanthocyanidin (LGSP) and acrylamide formation in potato-based products was investigated. The acrylamide, reducing sugar, asparagine, and 3-aminopropionamide contents were determined by high-performance liquid chromatography mass spectrometry (HPLC-MS). Sensory evaluation was used to evaluate the quality of the products. RESULTS: The results showed that LGSP presented greater inhibition effect on the acrylamide formation than the commonly used commercial antioxidants. Furthermore, 81.5% and 84.7% of acrylamide was reduced in potato crisps and French fries after adding 0.1% and 0.05% LGSP (w/w) in palm oil, respectively. When the concentrations of LGSP were less than 0.1%, there was no significant difference between LGSP-treated samples and control sample for sensory evaluation. CONCLUSION: Thus, LGSP is effective in reducing the level of acrylamide and maintaining the reasonable sensory attributes of potato fried foods. The results indicate that LGSP may be used as a potential additive for reducing acrylamide formation in fried foods. © 2019 Society of Chemical Industry.


Assuntos
Acrilamida/química , Aditivos Alimentares/química , Extrato de Sementes de Uva/química , Proantocianidinas/química , Culinária , Temperatura Alta , Humanos , Oxirredução , Lanches , Solanum tuberosum/química , Paladar
17.
ChemSusChem ; 13(4): 663-667, 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-31802645

RESUMO

The solid-solid (immobilized cellulase-insoluble cellulose) phase cellulose hydrolysis reaction is significant in cellulosic biomass conversion processes but hindered because of its low efficiency. Herein, a smart temperature-pH dual-responsive material (D-N-N material) was prepared to be used as a carrier for cellulase recovery. This D-N-N material could undergo reversible and switchable transitions between solution, hydrogel, and solid phases. The following results were demonstrated: 1) the hydrolytic degree of this strategy could be as high as that of free cellulase in buffer solution; 2) the cellulase could be encapsulated into the D-N-N hydrogel without significant leaching and most of the cellulase activity was retained after recycling for at least 10 batches; and 3) more than 95 % of the glucose inside the hydrogel could be extracted during the hydrogel-solid transition within 1 h, which can assist in the high-efficiency separation of cellulase from glucose. The results suggested that this strategy provides a feasible platform for efficient cellulose hydrolysis and could be applied to other bio-derived reactions.


Assuntos
Celulase/química , Celulose/química , Enzimas Imobilizadas/química , Hidrogéis/química , Polímeros/química , Acrilamida/química , Celulase/metabolismo , Celulose/metabolismo , Enzimas Imobilizadas/metabolismo , Glucose/química , Glucose/metabolismo , Concentração de Íons de Hidrogênio , Hidrólise , Transição de Fase , Temperatura
18.
Food Chem ; 307: 125548, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31654949

RESUMO

Due to their high content of ß-glucan, the consumption of oat products can contribute to a healthy diet. Roasting may improve sensory properties but could also affect the nutritional value of oat products. Therefore, the aim of the present study was to analyse the impact of different roasting conditions (140-180 °C, approx. 20 min) on sensory quality, health-related compounds (e.g. acrylamide, ß-glucan) and viscosities of oat kernels and flakes. Roasting resulted in oat flakes with improved sensory properties. Acrylamide formation increased with higher roasting temperatures in kernels, thin and thick flakes. Contents of fat, protein, starch and ß-glucan were not affected by roasting, whereas dietary fibre fractions were marginally modulated. Viscosities were significantly reduced with increasing roasting temperatures. The results indicate that roasting up to 160 °C is a processing technique with potential to generate oat products with improved sensory quality and favourable nutritional composition.


Assuntos
Avena/química , Acrilamida/química , Avena/metabolismo , Fibras na Dieta , Saúde , Temperatura Alta , Amido/química , Amido/metabolismo , Viscosidade , beta-Glucanas/química , beta-Glucanas/metabolismo
19.
Chemosphere ; 239: 124736, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31494326

RESUMO

In this work, a novel process involving the preparation of nanochitosan-grafted flocculants (CPAM-g-NCS) to treat low turbid and salmonella suspensions simultaneously was introduced. Nanotechnology was employed to enhance the adsorption-adhesion and sterilization abilities of dual-functional flocculants. The monomers of chitosan, acrylamide, methacryloyl ethyl trimethyl ammonium chloride, and sodium tripolyphosphate were utilized for flocculants copolymerization. Then, using fourier-transform infrared spectroscopy, nuclear magnetic resonance hydrogen spectrum, and thermogravimetric and differential scanning calorimetry analysis, the successful synthesis of CPAM-g-NCS was verified. Scanning electron microscopy and size analysis suggested that nanostructured flocculants with irregular morphology and nanocolloids of 60.44 nm were formed. CPAM-g-NCS was applied to treat a series of simulated low turbid and salmonella suspensions. The simulation results showed that the minimum residual turbidity of 1.97 NTU and optical density of 0.16 (initial 0.89) can be achieved at dosages of 2.5 and 8.75 mg L-1, respectively, which were superior to conventional organics flocculants. Mechanistic studies suggested that the excellent adsorption property, and large numbers of quaternary ammonium and amino groups of nanoflocculants contributed to the superior flocculation and antibacterial performance of CPAM-g-NCS.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Nanoestruturas/química , Purificação da Água/métodos , Acrilamida/química , Varredura Diferencial de Calorimetria , Quitosana/química , Floculação , Espectroscopia de Ressonância Magnética , Metacrilatos/química , Microscopia Eletrônica de Varredura , Polimerização , Salmonella typhimurium/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier , Suspensões , Termogravimetria , Microbiologia da Água
20.
Chemosphere ; 240: 124866, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31546191

RESUMO

Three series of co-graft cationic starch (St)-based flocculants with distinct structural characteristics, namely, charge density (CD), graft-chain length (L), and graft-chain distribution (N), were successfully synthesized through graft copolymerization of [(2-methacryloyloxyethyl) trimethyl ammonium chloride] and acrylamide. These St-based flocculants with different molecular structures were used to flocculate various kaolin suspensions with different initial turbidities and a sodium humate (NaHA) aqueous solution. The experimental results indicated that CD contributed to flocculation evidently, whereas average L and its N were insignificant in experimentally measured ranges. On the basis of phenomenological theory, a second-order polynomial equation was used to further quantitatively analyze the effects of the three structural factors on the flocculation performance of these St-based flocculants, which were fully consistent with the experimental results. Besides, the optimal dose and its corresponding removal rate could be predicted exactly, and the flocculation mechanisms were discussed in detail according to the established models. With the combination of floc properties and zeta potentials, the flocculation mechanisms of these St-based flocculants for flocculation of kaolin suspensions and NaHA aqueous solution were mainly ascribed to charge patching and simple charge neutralization, respectively. These results improve the understanding of the structure-activity relationship of these graft St-based flocculants, which is of significant guidance for the utilization and design of novel flocculants.


Assuntos
Acrilamida/química , Substâncias Húmicas , Metacrilatos/química , Amido/química , Floculação , Caulim/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Polímeros , Espectroscopia de Infravermelho com Transformada de Fourier , Relação Estrutura-Atividade , Purificação da Água/métodos
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