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1.
Food Chem ; 358: 129819, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33933974

RESUMO

The formation mechanism of furan has been studied extensively in model systems, however, furan formation in real foods are complex and far from being fully understood. In this study, the effects of acid-regulating agent (citric acid), sugar addition (glucose, fructose and sucrose) and thickening agents (xanthan gum, κ-carrageenan and pectin) on furan levels in strawberry jams were studied; meanwhile the formation pathway of furan in canned strawberry jam was proposed by carbon module labeling (CAMOLA) technique. Our results suggested low pH promoted furan formation in strawberry jam. Besides, fructose produces more furans than sucrose and glucose, and the addition of xanthan gum reduced furan levels significantly. The kinetic data showed that ascorbic and dehydroascorbic acid degradation followed first-order kinetics while rate of furan formation followed zero-order kinetics. This study presented the possibility of mitigating furan formation in canned strawberry jams by optimization of processing parameters and addition of xanthan gum.


Assuntos
Indústria de Processamento de Alimentos/métodos , Fragaria/química , Furanos/química , Carragenina/química , Ácido Cítrico/química , Ácido Desidroascórbico/química , Frutose/química , Frutas/química , Glucose/química , Cinética , Pectinas/química , Polissacarídeos Bacterianos/química , Sacarose/química
2.
J Food Sci ; 86(5): 1946-1962, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33844286

RESUMO

Specific heat capacity ( C P ) is regarded as a fundamental parameter for the design, operation, and optimization of the heat transfer equipment widely used in the food industry. Using the calorimetric ASTM E1269-11 standard procedure, the C P -temperature ( C P ( T ) ) curves of fruit juice model systems prepared at different mass fractions of fructose/glucose/sucrose/citric acid/pectin and water were measured. Thus, experimental data of C P for solid samples in crystalline and amorphous states from -80 °C up to the melting temperature range and for aqueous samples from -80 to 110 °C were generated. In the tested temperature interval, the C P of crystalline, amorphous, and aqueous samples were found to be in the ranges of 0.037 ± 0.020 to 5.61 ± 0.04; 0.061 ± 0.004 to 3.12 ± 0.19, and 0.363 ± 0.05 to 3.24 ± 0.14 kJ/kg °C, respectively. Also, a generalized empirical equation based on the type and concentration of components was developed to predict the C P ( T ) curves of the studied samples. The proposed equation exhibited a low error sum of squares (SSE <  57.3) and a high coefficient of determination (R2 > 0.927). An analysis of variance (ANOVA) was performed with a confidence level of 95% (p < 0.05). The C P ( T ) curves were influenced by temperature, thermal transitions, water, solid types, and compound interactions. Glucose was one of the solids that most significantly influenced the C P values of samples. PRACTICAL APPLICATION: The experimental specific heat capacity data and empirical equation proposed in this study are relevant to the design, evaluation, and optimization of heat transfer equipment involved in many foods and biochemical industrial processes such as cryopreservation, frozen storage, freezing, chilling, drying, and the cooking of hard candies.


Assuntos
Varredura Diferencial de Calorimetria/métodos , Frutose/química , Sucos de Frutas e Vegetais/análise , Glucose/química , Temperatura Alta , Sacarose/química , Água/química , Temperatura
3.
Molecules ; 26(8)2021 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-33924652

RESUMO

The immune system plays an important role in maintaining body homeostasis. Recent studies on the immune-enhancing effects of ginseng saponins have revealed more diverse mechanisms of action. Maillard reaction that occurs during the manufacturing processes of red ginseng produces a large amount of Amadori rearrangement compounds (ARCs), such as arginyl-fructose (AF). The antioxidant and anti-hyperglycemic effects of AF have been reported. However, the possible immune enhancing effects of non-saponin ginseng compounds, such as AF, have not been investigated. In this study the effects of AF and AF-enriched natural product (Ginofos, GF) on proliferation of normal mouse splenocytes were evaluated in vitro and male BALB/c mice models. The proliferation of splenocytes treated with mitogens (concanavalin A, lipopolysaccharide) were further increased by addition of AF (p < 0.01) or GF (p < 0.01), in a dose dependent manner. After the 10 days of oral administration of compounds, changes in weights of spleen and thymus, serum immunoglobulin, and expression of cytokines were measured as biomarkers of immune-enhancing potential in male BALB/c mice model. The AF or GF treated groups had higher weights of the thymus (0.94 ± 0.25 and 0.86 ± 0.18, p < 0.05, respectively) than that of cyclophosphamide treated group (0.59 ± 0.18). This result indicates that AF or AF-enriched extract (GF) increased humoral immunity against CY-induced immunosuppression. In addition, immunoglobulin contents and expression of cytokines including IgM (p < 0.01), IgG (p < 0.05), IL-2 (p < 0.01), IL-4 (p < 0.01), IL-6 (p < 0.01), and IFN-γ (p < 0.05) were also significantly increased by supplementation of AF or GF. These results indicate that AF has immune enhancing effects by activation of adaptive immunity via increase of expression of immunoglobulins and cytokines such as IgM, IgG, IL-2, IL-4, IL-6 and thereby proliferating the weight of thymus. Our findings provide a pharmacological rationale for AF-enriched natural products such as ginseng and red ginseng that can possibly have immune-enhancement potential and should be further evaluated.


Assuntos
Imunidade Adaptativa/fisiologia , Panax/química , Animais , Arginina/análogos & derivados , Arginina/química , Frutose/análogos & derivados , Frutose/química , Imunoglobulina G/química , Imunoglobulina M/química , Interleucina-2/química , Interleucina-4/química , Interleucina-6/química , Reação de Maillard , Masculino , Camundongos , Camundongos Endogâmicos BALB C
4.
Food Chem ; 352: 129430, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-33691211

RESUMO

The present work reports the development of a novel electrochemical sensor for the selective detection of fructose. The sensor was developed through electropolymerization of a molecularly imprinted polymer film on a reduced graphene oxide modified electrode. The modified electrode was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy, atomic force microscopy and RAMAN spectroscopy. Through the application of the modified electrode, the recognition of fructose molecules occurred in a concentration range of 1.0 × 10-14 to 1.0 × 10-11 mol L-1, under a Langmuir adsorption isothermal model. The sensitivity and limits of detection and quantification obtained for the sensor were 9.9 × 107 A L mol-1, 3.2 × 10-15 mol L-1 and 1.1 × 10-14 mol L-1, respectively. The analytical method used for the detection of fructose presented good reproducibility, stability and accuracy, and was successfully applied for the quantification of this sugar in orange, apple and grape juices.


Assuntos
Eletroquímica/instrumentação , Análise de Alimentos/instrumentação , Frutose/análise , Sucos de Frutas e Vegetais/análise , Grafite/química , Polímeros Molecularmente Impressos/química , Eletrodos , Frutose/química , Limite de Detecção , Polímeros Molecularmente Impressos/síntese química , Reprodutibilidade dos Testes
5.
Am J Physiol Gastrointest Liver Physiol ; 320(4): G644-G657, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33533318

RESUMO

Colorectal hypersensitivity and sensitization of both mechanosensitive and mechanically insensitive afferents develop after intracolonic instillation of 2,4,6-trinitrobenzenesulfonic acid (TNBS) in the mouse, a model of postinfectious irritable bowel syndrome. In mice in which ∼80% of extrinsic colorectal afferents were labeled genetically using the promotor for vesicular glutamate transporter type 2 (VGLUT2), we systematically quantified the morphology of VGLUT2-positive axons in mouse colorectum 7-28 days following intracolonic TNBS treatment. After removal, the colorectum was distended (20 mmHg), fixed with paraformaldehyde, and optically cleared to image VGLUT2-positive axons throughout the colorectal wall thickness. We conducted vector path tracing of individual axons to allow systematic quantification of nerve fiber density and shape. Abundant VGLUT2-positive nerve fibers were present in most layers of the colorectum, except the serosal and longitudinal muscular layers. A small percentage of VGLUT2-positive myenteric plexus neurons was also detected. Intracolonic TNBS treatment significantly reduced the number of VGLUT2-positive nerve fibers in submucosal, myenteric plexus, and mucosal layers at day 7 post-TNBS, which mostly recovered by day 28. We also found that almost all fibers in the submucosa were meandering and curvy, with ∼10% showing pronounced curviness (quantified by the linearity index). TNBS treatment resulted in a significant reduction of the proportions of pronounced curvy fibers in the rectal region at 28 days post-TNBS. Altogether, the present morphological study reveals profound changes in the distribution of VGLUT2-positive fibers in mouse colorectum undergoing TNBS-induced colitis and draws attention to curvy fibers in the submucosa with potential roles in visceral nociception.NEW & NOTEWORTHY We conducted genetic labeling and optical clearing to visualize extrinsic sensory nerve fibers in whole-mount colorectum, which revealed widespread presence of axons in the submucosal layer. Remarkably, axons in the submucosa were meandering and curvy, in contrast to axons in other layers generally aligned with the basal tissues. Intracolonic TNBS treatment led to pronounced changes of nerve fiber density and curviness, suggesting nerve fiber morphologies as potentially contributing factors to sensory sensitization.


Assuntos
Colite/patologia , Colo/inervação , Frutose/química , Gânglios Espinais/patologia , Glicerol/análogos & derivados , Reto/inervação , Células Receptoras Sensoriais/patologia , Soluções/química , Fixação de Tecidos , Ácido Trinitrobenzenossulfônico , Proteína Vesicular 2 de Transporte de Glutamato/metabolismo , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Channelrhodopsins/genética , Channelrhodopsins/metabolismo , Colite/induzido quimicamente , Colite/metabolismo , Modelos Animais de Doenças , Gânglios Espinais/metabolismo , Glicerol/química , Imuno-Histoquímica , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microscopia Confocal , Células Receptoras Sensoriais/metabolismo , Proteína Vesicular 2 de Transporte de Glutamato/genética
6.
Carbohydr Polym ; 255: 117384, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33436213

RESUMO

Prebiotics are known for their ability to modulate the composition of the human microbiome and mediate health-promoting benefits. Endo-levanases, which hydrolyze levan into short-chain FOS, could be used for the production of levan-based prebiotics. The novel endo-levanase (LevB2286) from Azotobacter chroococcum DSM 2286, combines an exceptionally high specific activity with advantageous hydrolytic properties. Starting from levan isolated from Timothy grass, LevB2286 produced FOS ranging from DP 2 - 8. In contrast to endo-levanases described in the literature, LevB2286 formed minor amounts of fructose and levanbiose, even with greatly extended incubation. The combined activity of LevB2286 and the levansucrase LevS1417 from Gluconobacter japonicus LMG 1417 led to a one-step synthesis of levan-type FOS from sucrose. 387.4 ± 17.3 g L-1 FOS were produced within 48 h by the production strategy based on crude cell extract of recombinant Escherichia coli expressing levS1417 and levB2286 simultaneously.


Assuntos
Azotobacter/enzimologia , Proteínas de Bactérias/metabolismo , Gluconobacter/enzimologia , Glicosídeo Hidrolases/metabolismo , Hexosiltransferases/metabolismo , Oligossacarídeos/biossíntese , Prebióticos/análise , Azotobacter/genética , Proteínas de Bactérias/genética , Dissacarídeos/química , Dissacarídeos/metabolismo , Escherichia coli/enzimologia , Escherichia coli/genética , Frutanos/química , Frutanos/metabolismo , Frutose/química , Frutose/metabolismo , Expressão Gênica , Gluconobacter/genética , Glicosídeo Hidrolases/genética , Hexosiltransferases/genética , Humanos , Hidrólise , Oligossacarídeos/química , Phleum/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Sacarose/química , Sacarose/metabolismo
7.
J Sci Food Agric ; 101(2): 693-702, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32700446

RESUMO

BACKGROUND: This study developed a feasible catalytic method for d-allulose syrup production using a fusion enzyme, either in free or immobilized form, through hydrolysis of inulin extracted from Jerusalem artichoke tubers. RESULTS: d-Allulose 3-epimerase (DAE) was actively expressed in secretory form by fusing with the extracellular exo-inulinase CSCA in Escherichia coli BL21 (DE3). The best linker ligating the two enzymes was a flexible peptide containing 12 residues (GSAGSAAGSGEF). At 55 °C and pH 8.0, and as with the addition of 1 mmol L-1 Mn2+ , the CSCA-linkerE-DAE fusion enzyme obtained through high cell-density cultivation displayed a maximal exo-inulinase activity of 21.8 U mg-1 and resulted in a yield of 6.3 g L-1 d-allulose and 39.2 g L-1 d-fructose using 60 g L-1 inulin as the raw material. Catechol-modified alginate with titanium ions (Alg(Ti)PDA) was found to be a promising immobilization material for the fusion enzyme. After conversion for 8 days, the Alg(Ti)PDA-immobilized CSCA-linkerE-DAE (8 U g-1 ) completed 24 reaction cycles and retained over 80% of its original activity. Each reaction obtained an average of 19.8 g L-1 d-allulose and 32.7 g L-1 D-fructose from 60 g L-1 inulin. CONCLUSION: This study shed light on a feasible and cost-effective approach for the production of syrup containing d-allulose and D-fructose with inulin as the raw material via the use of a CSCA and DAE fusion enzyme. This syrup is of added value as a functional sweetener. © 2020 Society of Chemical Industry.


Assuntos
Frutose/química , Glicosídeo Hidrolases/química , Inulina/química , Racemases e Epimerases/química , Proteínas Recombinantes de Fusão/química , Biocatálise , Enzimas Imobilizadas/química , Enzimas Imobilizadas/genética , Enzimas Imobilizadas/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Tecnologia de Alimentos/economia , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Inulina/genética , Inulina/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo
8.
J Oleo Sci ; 69(10): 1281-1285, 2020 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-32908100

RESUMO

In this study two different strategy were followed to obtain a D-fructose-oleic acid ester. One of the strategies has been well established enzymatic synthesis of an ester bond. The other strategy excluded the biocatalyst and only used a mixture of two organic solvents as the reaction media, 2-methyl-2-butanol / dimethyl sulfoxide or tert-butanol / dimethyl sulfoxide for the production of D-fructose-oleic acid ester. Ester products obtained were characterised by using FT-IR, NMR, by MS. Product yield was also assessed by HPLC. Results of structural analyses and yield measurement indicated that two approaches produced almost identical ester products.


Assuntos
Dimetil Sulfóxido/química , Ésteres/síntese química , Frutose/síntese química , Ácido Oleico/síntese química , Pentanóis/química , terc-Butil Álcool/química , Animais , Biocatálise , Células Cultivadas , Cromatografia Líquida de Alta Pressão , Esterificação , Ésteres/química , Ésteres/toxicidade , Frutose/química , Frutose/toxicidade , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Ácido Oleico/química , Ácido Oleico/toxicidade , Espectroscopia de Infravermelho com Transformada de Fourier
9.
J Breath Res ; 14(4): 041002, 2020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32663815

RESUMO

Fructose intake is associated with increased consumption of processed foods, specifically in the context of nutritional supplements. To assess gastrointestinal symptoms and hydrogen production after the ingestion of a fructose solution in runners, healthy and sick persons. Hydrogen test (H2 test) was performed after the intake a solution with 50 g fructose along with the application of a questionnaire to evaluate the gastrointestinal symptoms during the H2 test in three groups: Athletes group (AG); control group (CG) with healthy subjects; and non-alcoholic fatty liver disease group (NAFLDG). Statistical analysis was performed with analysis of variance at a p < 0.05 significance level. The AG was the largest H2 producer followed by the CG with significant difference between the AG and NAFLDG (p ≤ 0.05). Most participants remained asymptomatic, but the strongest correlation was the symptom of bloating GC (R = 0.625), eructation in NAFLD (R = 0.481) and diarrhea in CG (R = 0.345) and AG (R = 0.338) The result of the present study suggests the production of hydrogen by the colon following the administration of fructose is higher in athletes compared with healthy individuals and persons with NAFLD, showing that fructose intake may be an interesting point of dietary management, especially in elite professionals.


Assuntos
Frutose/química , Hidrogênio/química , Intestinos/fisiopatologia , Hepatopatia Gordurosa não Alcoólica/fisiopatologia , Corrida/fisiologia , Adulto , Feminino , Humanos , Masculino
10.
Macromol Rapid Commun ; 41(15): e2000213, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32583943

RESUMO

Dynamic covalent bonds are established upon molecular recognition of sugar derivatives by boronic acid molecules. These reversible links can be used in a cross-linking method to fabricate polymer-based responsive nanosystems. Herein, the design of the first dynamic nanogels made entirely of polysaccharides (PS) is reported. Based on PS chains alternately modified with phenyl boronic acid groups and sugar moieties, these colloids self-assemble in physiological conditions and combine the biocompatible nature of their PS backbone with the reconfiguration capacities of their cross-linking chemistry. These dynamic nanogels are easily prepared, stable for a long time, pH responsive, and efficiently internalized by cancer cells.


Assuntos
Portadores de Fármacos/química , Nanogéis/química , Polissacarídeos/química , Ácidos Borônicos/química , Transferência Ressonante de Energia de Fluorescência , Frutose/química , Células HEK293 , Humanos , Maltose/química , Microscopia Eletrônica de Transmissão , Nanogéis/toxicidade , Nanogéis/ultraestrutura , Polímeros/química , Polissacarídeos/toxicidade
11.
Food Chem ; 329: 127085, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32512390

RESUMO

The refractive index is a basic optical property of materials. This study explores the effect of ethanol, glycerol, tartaric acid and glucose/fructose on the refractive index in model aqueous solutions and in dry white wines. Various model aqueous solutions consisting of these components were prepared and the refractive index was measured at 20 °C and each component was studied both alone and in mixtures with the others. The refractive index of white dry wines samples was also measured. A linear regression analysis was performed and linear multi-dependence equations were derived. The resulting regression models had a coefficient of determination over 97.3%. Glucose/fructose was found to have the greatest effect on the refractive index, followed by tartaric acid and glycerol while ethanol had the smallest effect. The knowledge of the correlation of the concentration of each wine component to the refractive index can be of value for the estimation of fermentation kinetics.


Assuntos
Etanol/química , Frutose/química , Glucose/química , Glicerol/química , Tartaratos/química , Água/química , Vinho/análise , Refratometria
12.
Food Chem ; 330: 127170, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32531633

RESUMO

With the increasing concerns on food safety, foodborne toxicants, particularly advanced glycation end products (AGEs) have drawn large attention ascribing to their central role in the pathogenic process of diabetic complications. In this study, the antiglycative ability and action mechanism of 10 dried flowers were measured in fructose/glucose-BSA model with apple flower as the most effective one, probably through trapping reactive carbonyl species. Furthermore, apple flower was added in cookies to evaluate its antiglycative effect and data suggested that the fortification of cookies with apple flower powders significantly inhibited the formation of methylglyoxal and fluorescent AGEs. Moreover, sensory evaluation data showed that 2.5% (w/w) apple flower-fortified cookies had the highest acceptance. The active component in apple flower was further identified as phlorizin by chromatographic analysis. Our results highlighted the health benefits of consuming apple flower fortified foods which might possibly be developed into functional foods especially for diabetic patients.


Assuntos
Frutose/química , Glucose/química , Produtos Finais de Glicação Avançada/química , Malus/química , Animais , Flores/química , Aldeído Pirúvico/química , Soroalbumina Bovina/química
13.
Int J Nanomedicine ; 15: 513-519, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32099353

RESUMO

Background: In recent years, numerous bacteria have become resistant to conventional antibiotics. Fortunately, an increasing body of research indicates that through the addition of specific metabolites (like sugars), the antibacterial activity of certain drugs can be enhanced. A new type of self-assembled nano-peptide amphiphile (SANPA) was designed in this study to treat antibiotic-resistant bacterial infections and to reduce the use of antibiotics. Methods: Here, SANPAs were self-assembled into nanorod structures with a diameter of ca. 10.5 nm at concentrations greater than the critical micelle concentration (CMC) of 44.67 µM. Both Gram-positive and Gram-negative bacteria were treated with SANPAs with fructose supplementation. Results: After a 30-min fructose pre-incubation, SANPAs reduced bacteria growth relative to non-fructose treatments at all concentrations. Cytotoxicity assays indicated that the presence of fructose seemed to slightly ameliorate the cytotoxic effect of the treatment on model human fetal osteoblasts (or bone-forming cells) and human dermal fibroblasts. Conclusion: We demonstrated here that SANPAs-like nanomaterials have a promising potential to treat antibiotic-resistant bacteria, especially when added to fructose, potentially limiting their associated infections.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Frutose/farmacologia , Peptídeos/química , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Células Cultivadas , Escherichia coli/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Frutose/química , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Humanos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Nanoestruturas/química , Peptídeos/farmacologia
14.
Molecules ; 25(1)2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31935857

RESUMO

Polyphenols play an important role in the sensorial and health-promoting properties of fruits and vegetables and display varying structure-dependent stability during processing and shelf-life. The current work aimed to increase the fundamental understanding of the link between the stability of polyphenols as a function of their structure, presence of ascorbic acid and fructose and total antioxidant capacity (TAC), using a multi-component model system. Polyphenol extract, used as the multi-component model system, was obtained from freeze-dried, high polyphenol content strawberry (Fragaria × ananassa 'Nerina') and twenty-one compounds were identified using high-performance liquid chromatography-mass spectrometry (HPLC-MS). The TAC and the first-order degradation kinetics were obtained, linking the polyphenol stability to its chemical structure, with and without the presence of fructose and ascorbic acid. The TAC (measured by oxygen radical absorption capacity (ORAC) and ferric reducing antioxidant potential (FRAP) assays) was not dramatically affected by storage temperatures and formulation, while polyphenol stability was significantly and structure dependently affected by temperature and the presence of ascorbic acid and fructose. Anthocyanins and phenolic acids were more unstable in the presence of ascorbic acid, while flavonol stability was enhanced by its presence. Shelf life study performed at 37 °C revealed significantly higher stability of purified polyphenols vs. the stability of the same polyphenols in the strawberry extract (multi-component system).


Assuntos
Antioxidantes/química , Antioxidantes/farmacologia , Ácido Ascórbico/química , Frutose/química , Polifenóis/química , Polifenóis/farmacologia , Antioxidantes/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Estabilidade de Medicamentos , Fragaria/química , Frutas/química , Fenóis/análise , Fenóis/química , Compostos Fitoquímicos/análise , Compostos Fitoquímicos/química , Polifenóis/isolamento & purificação , Temperatura
15.
J Sci Food Agric ; 100(4): 1524-1531, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31769029

RESUMO

BACKGROUND: In recent years, cold-pressed oils have become more and more popular with consumers. However, their oxidative stability is low. Improving the oxidative stability of cold-pressed oils will increase their shelf life. Maillard reaction products (MRPs) have been shown to promote the oxidative stability of lipids. In this study, products from the Maillard reaction of reducing sugars and sesame enzymatically hydrolyzed protein (SEHP) were added to cold-pressed sesame oils to improve their oxidative stability. RESULTS: Three types of MRPs from reducing sugars (xylose, fructose, and glucose) and SEHP were prepared. Xylose-SEHP MRPs prepared under optimum conditions had the highest antioxidant activities among the three. The optimum conditions for xylose-SEHP were as follows: reaction temperature, 130 °C; reaction time, 180 min; pH, 6.5; and sugar/protein ratio, 10:1. The addition of xylose-SEHP MRPs at a level of 20 g kg-1 could significantly improve the oxidative stability of cold-pressed sesame oil. Besides, the addition of MRPs reduced the loss of tocopherol. The interaction of MRPs with endogenous antioxidants in the sesame oil (sesamol and tocopherol) was proved by comparison with lard. There was a synergistic increase in antioxidant activity for the combination of MRPs and sesamol and the combination of MRPs and tocopherol. CONCLUSIONS: The results provide evidence that adding certain MRPs can improve the oxidative stability of cold-pressed sesame oil. © 2019 Society of Chemical Industry.


Assuntos
Manipulação de Alimentos/métodos , Frutose/química , Glucose/química , Produtos Finais de Glicação Avançada/química , Proteínas de Plantas/química , Óleo de Gergelim/química , Sesamum/química , Xilose/química , Aditivos Alimentares/química , Reação de Maillard , Oxirredução
16.
Food Chem ; 305: 125459, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31520919

RESUMO

In this study the elemental compositions of melanoidin formed at 160 °C from d-glucose (Glc) and l-alanine (Ala) as well as from fructosylalanine - the corresponding Amadori rearrangement product - were compared. Specific chemical bonds were probed by FTIR spectroscopy. This approach tackles the different chemical pathways for melanoidin formation via the Amadori rearrangement in contrast to the reaction from Glc/Ala. Melanoidins formed from fructosylalanine contain about twice as much nitrogen and therefore amino acid as compared to melanoidin from Glc/Ala and exhibit higher absorption in the UV/Vis. Consequently, melanoidins formed from Glc/Ala contain more sugar degradation products with lower absorption due to a smaller size of the conjugated double bond network.


Assuntos
Alanina/análogos & derivados , Alanina/química , Frutose/análogos & derivados , Frutose/química , Glucose/química , Polímeros/química , Frutose/síntese química , Espectroscopia de Ressonância Magnética , Reação de Maillard , Polímeros/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman
17.
Carbohydr Polym ; 228: 115373, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31635735

RESUMO

Type of sugar and gelling agents used in confectionery formulations have vital importance since they directly influence physicochemical properties during storage. In this study, the effect of a non-caloric rare sugar, D-allulose (formerly called D-psicose) on the starch based confectionery gels were investigated in the presence and absence of soy protein isolate (SPI) using different experimental techniques for 28 days. For characterization of the formulized gel systems, common techniques were used (SEM, DSC, XRD, moisture content, water activity, hardness and color). Time Domain Nuclear Magnetic Resonance (TD-NMR) technique was also employed to explain dynamics in the systems. Sugar type was found to be a very significant factor affecting gel characteristics and retrogradation. Results showed that D-allulose containing formulations were less prone to retrogradation and showed smaller changes upon storage by supporting presence of better gel network. According to X-ray results, sucrose containing formulations were more susceptible to crystallization. T2 relaxation spectra obtained from NMR experiments showed that number of distinct peaks reduced with the addition of SPI while relaxation times of peaks changed when different type of sugar.


Assuntos
Doces , Armazenamento de Alimentos , Frutose/química , Géis/química , Proteínas de Soja/química , Amido/química , Dureza , Água/química
18.
Molecules ; 24(24)2019 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-31861157

RESUMO

5-Acetoxymethyl-2-furfural (AMF) was prepared from D-fructose via 1,6-diacetylfructose (DAF) through a simple two-step reaction pathway. Immobilized enzyme (Novozym 435) was found to be the best enzymatic catalyst for the trans-esterification step (yielding 94.6% DAF). In the dehydration step, while soluble H2SO4 was found to be the best acidic catalyst (yielding 86.6% AMF), we opted to utilize heterogeneous cation exchange resin (Amberlyst 15) together with recyclable industrial solvents (1,4-dioxane) for a more sustainable AMF synthesis procedure. Although the total yield of AMF was a little lower, both the enzyme and the solid acid catalyst could be recycled for five cycles without a significant loss of activity, which has a major contribution to the cost-efficient aspect of the entire process.


Assuntos
Resinas de Troca de Cátion/química , Enzimas Imobilizadas , Frutose/química , Furaldeído/química , Lipase/química , Catálise , Desidratação , Esterificação , Solventes/química
19.
Anal Bioanal Chem ; 411(30): 7967-7979, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31754770

RESUMO

Naturally occurring fructosamines are of high clinical significance due to their potential use in diabetes mellitus monitoring (quantification of fructosylated hemoglobin, HbA1c) or for the investigation of their reactivity in consecutive reactions and harmfulness towards the organism. Here we report the specific synthesis of the fructosylated dipeptide L-valyl-L-histidine (Fru-Val-His) and fructosylated L-valine (Fru-Val). Both are basic tools for the development and validation of enzymatic HbA1c assays. The two fructosamine derivatives were synthesized via a protected glucosone intermediate which was coupled to the primary amine of Val or Val-His, performing a reductive amination reaction. Overall yields starting from fructose were 36% and 34% for Fru-Val and Fru-Val-His, respectively. Both compounds were achieved in purities > 90%. A HILIC-ESI-MS/MS method was developed for routine analysis of the synthesized fructosamines, including starting materials and intermediates. The presented method provides a well-defined and efficient synthesis protocol with purification steps and characterization of the desired products. The functionality of the fructosylated dipeptide has been thoroughly tested in an enzymatic HbA1c assay, showing its concentration-dependent oxidative degradation by fructosyl-peptide oxidases (FPOX). Graphical abstract.


Assuntos
Diabetes Mellitus/diagnóstico , Frutose/química , Hemoglobina A Glicada/análise , Histidina/química , Cetoses/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Espectrometria de Massas em Tandem/métodos , Valina/química , Ensaios Enzimáticos , Humanos
20.
Appl Microbiol Biotechnol ; 103(21-22): 8753-8761, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31637494

RESUMO

D-Mannose is an epimer of glucose at the C-2 position and exists in nature as a component of mannan. It has 60 and 86% sweetness than that of sucrose and D-glucose, respectively. Because of its low-calorie and nontoxic features, D-mannose is used widely in food, medicine, cosmetic, and food-additive industries. Besides, it exhibits many physiologic benefits on health: immune system, diabetes mellitus, intestinal diseases, and urinary tract infections. It is used as a starting material to synthesize immunostimulatory agents, anti-tumor agents, vitamins, and D-mannitol. However, D-mannose production using chemical synthesis and plant extraction cannot meet the requirements of the industry. This article presents recent research on the biological production of D-mannose. The physiologic benefits and applications of D-mannose are summarized. Besides, different D-mannose-producing enzymes from various sources are discussed in detail with regard to their biochemical characteristics, catalytic efficiency, and reaction kinetics for D-mannose production. Furthermore, attempts to use enzymatic conversion to produce D-mannose are reviewed.


Assuntos
Bactérias/enzimologia , Bactérias/metabolismo , Reatores Biológicos/microbiologia , Manose/metabolismo , Aldose-Cetose Isomerases/metabolismo , Proteínas de Bactérias/metabolismo , Carboidratos Epimerases/metabolismo , Frutose/química , Glucose/química , Plantas/química
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