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1.
Carbohydr Polym ; 328: 121701, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38220338

RESUMO

To illustrate the action mechanism of screw speed on the performance of starch-based straws during the extrusion process, starch-based straws at different screw speeds were prepared using a twin-screw extruder and the structures and characteristics were compared. The results indicated that as screw speeds improved from 3 Hz to 13 Hz, the A chain of amylopectin increased from 25.47 % to 28.87 %, and the B3 chain decreased from 6.34 % to 3.47 %. The absorption peak of hydroxyl group shifted from 3296 cm-1 to 3280 cm-1. The relative crystallinity reduced from 13.49 % to 9.89 % and the gelatinization enthalpy decreased from 3.5 J/g to 0.2 J/g. The performance of starch straws did not increase linearly with increasing screw speeds. The starch straw produced at screw speed of 7 Hz had the largest amylose content, the highest gelatinization temperature, the minimum bending strength, and the lowest water absorption rate in hot water (80 °C). Screw speed had a remarkable impact on the mechanical strength, toughness and hydrophobicity of starch-based straws. This study revealed the mechanism of screw speed on the mechanical strength and water resistance of starch straws in the thermoplastic extrusion process and created the theoretical basis for the industrial production of starch-based straws.


Assuntos
Amilopectina , Amido , Amido/química , Amilopectina/química , Temperatura Alta , Amilose/química , Água/química
2.
Polymers (Basel) ; 15(24)2023 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-38139921

RESUMO

The aim of the present study was to investigate highly efficient alkyl ketene dimer (AKD) emulsions to improve the hydrophobicity of cellulose paper. AKD emulsions stabilized by guar gel were obtained; the guar gel was prepared by hydrogen bond cross-linking sodium tetraborate and guar gum. The cross-linking was confirmed by combining FTIR and SEM. The effect of guar gel on the performance of the AKD emulsions was also studied by testing AKD emulsions stabilized by different guar gel concentrations. The results showed that with increasing guar gel concentration, the stability of the AKD emulsions improved, the droplet diameter decreased, and the hydrophobicity and water resistance of the sized packaging paper were gradually enhanced. Through SEM, the guar gel film covering the AKD emulsion droplet surface and the three-dimensional structure in the aqueous dispersion phase were assessed. This study constructed a scientific and efficient preparation method for AKD emulsions and provided a new method for the application of carbohydrate polymer gels which may avoid the adverse effect of surfactant on paper sizing and environmental problems caused by surfactant bioaccumulation.

3.
Int J Biol Macromol ; 253(Pt 6): 127140, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37778579

RESUMO

In order to investigate the effects of different crosslinking agents on physicochemical properties and adsorption properties of porous starch. Native corn starch was hydrolyzed by maltase and crosslinked with different crosslinking agents. Sodium trimetaphosphate crosslinked porous starch (STMP-MPS), malic acid cross-linked porous starch (MA-MPS) and citric acid cross-linked porous starch (CA-MPS) were prepared. After crosslinking, MA-MPS and CA-MPS showed a new CO stretching absorption peak at 1738 cm-1, and the crosslinking degree was much higher than that of STMP-MPS. The surface area of MA-MPS was 36 % higher than that of STMP-MPS. Compared with the average pore size of 12.43 nm of STMP-MPS, CA-MPS (14.02 nm) and MA-MPS (14.79 nm) were increased more significantly. The degradation temperature of MA-MPS and CA-MPS was increased by the introduction of ester bond, which indicates that the organic acid cross-linking strengthens the starch granules and hence more energy is required for disruption. Compared with STMP-MPS, the water absorption of MA-MPS and CA-MPS increased by 64 % and 32 %, respectively. Furthermore, the adsorption capacity of MA-MPS to essential oil was the strongest, about 4 times that of STMP-MPS. Overall, it is feasible to modify porous starch by crosslinking reaction to improve its heat resistance and adsorption properties.


Assuntos
Amilases , Amido , Amido/química , Adsorção , Zea mays/metabolismo , Compostos Orgânicos
4.
Carbohydr Polym ; 321: 121297, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37739530

RESUMO

To study the relationship between the number of hydroxyl groups of polyols and the plasticizing effect, the effects of different polyols including ethylene glycol, glycerol, erythritol, xylitol and sorbitol on the structure and properties of corn starch straws were analyzed and compared. The results showed that the addition of plasticizer significantly improved the performance of starch straws, which greatly improved the mechanical properties, water absorption rate (WAR) and thermal stability. However, there was no linear relationship between the plasticizing effect on starch straws and the number of hydroxyl groups in plasticizers. Fourier transform infrared (FTIR) results showed that erythritol formed the strongest intermolecular interaction with starch. Starch straws with erythritol (S-ERY) had the highest bending force (Fb = 25.78 N) and the lowest WAR. Starch straws with glycerol (S-GLY) showed the lowest relative crystallinity (RC = 12.87 %) and the highest temperature of the maximum degradation (Tdmax = 302.1 °C). In addition, after storing for 180 days, S-GLY showed higher modulus of elasticity in bending (Eb = 4.26 N/cm) and a uniform surface.


Assuntos
Eritritol , Glicerol , Elasticidade , Radical Hidroxila , Plastificantes , Amido , Água
5.
Int J Biol Macromol ; 242(Pt 4): 124914, 2023 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-37217055

RESUMO

Sorbitol as a plasticizer is easily crystallized from starch film, resulting in the reduction in plasticizing effect. To improve the plasticizing performance of sorbitol in starch films, mannitol, an acyclic hexahydroxy sugar alcohol, was used to cooperate with sorbitol. The effects of different ratios of mannitol (M) to sorbitol (S) as a plasticizer on mechanical properties, thermal properties, water resistance and surface roughness of sweet potato starch films were investigated. The results showed that the surface roughness of starch film with M:S (60:40) was the smallest. The number of hydrogen bonds between plasticizer and starch molecule was proportional to the mannitol content starch film. With the decrease of mannitol contents, the tensile strength of starch films gradually decreased except for M:S (60:40). Moreover, the transverse relaxation time value of starch film with M:S (100:0) was the lowest, indicating that it had the lowest degree of freedom of water molecules. Starch film with M:S (60:40) is the most effective in delaying the retrogradation of starch film. This study offered a new theoretical basis that different ratios of mannitol to sorbitol improve different performances of starch films.


Assuntos
Ipomoea batatas , Amido , Amido/química , Sorbitol/química , Manitol , Plastificantes/química , Resistência à Tração , Água/química
6.
Int J Biol Macromol ; 239: 124211, 2023 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-37001779

RESUMO

Starch/polyvinyl alcohol (PVA) degradable straws with different PVA contents were prepared by the twin-screw extrusion method. The results showed that the starch/PVA straws with 40 % PVA (PS4) had the highest dispersion uniformity of starch and PVA to achieve the best compatibility, and the compatibility size was below the micron level. Molecular interactions between starch and 40 % polyvinyl alcohol reached the highest due to the highest strength of hydrogen bonds, hence resulting in the highest texture densities. Consequently, the largest compatibility and molecular interactions significantly improved the mechanical properties and water resistance of PS4. Compared to the starch/PVA straw with 0 % PVA (PS0), swelling volume of PS4 decreased by 45.5 % (4 °C) and 65.2 % (70 °C), respectively. After soaking, the diameter strength increased by 540.1 % (4 °C, 1 h) and 638.7 % (70 °C, 15 min), respectively. Water absorption decreased by 45.3 % (4 °C, 30 min) and 27.6 % (70 °C, 30 min).


Assuntos
Álcool de Polivinil , Amido , Álcool de Polivinil/química , Amido/química , Água/química
7.
Int J Biol Macromol ; 174: 110-119, 2021 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-33515569

RESUMO

To obtain porous starch granules with higher absorption capacities, three types of enzyme combinations were adopted to modify wheat and maize starches: (1) sequential α-amylase (AA) â†’ glucoamylase (GA); (2) sequential branching enzyme (BE) â†’ GA; and (3) sequential AA→BE→GA. The results indicated that AA→BE→GA treatment had a most optimal influence on porous starches. Compared to AA→GA and BE→GA, the mesopores in wheat starch granules treated with AA→BE→GA decreased by 52.82 and 48.70%, respectively. Conversely, the macropores increased by 216.68 and 138.18%, respectively. While for maize starch, the percentages of mesopores and macropores hardly changed after three enzyme combinations. Comparing the three enzyme treatments showed that pore volume (0.005 and 0.007 cm3/g) and pore size (36.35 and 26.54 nm) were largest in the AA→BE→GA treated wheat and maize starches, respectively. Compared to the AA→GA and BE→GA, the adsorption capacities for oil, dye and heavy metal ions, wheat starch treated with AA→BE→GA increased by 46.61 and 242.33%, and 44.52 and 134.41%, and 28.83 and 271.72%, respectively. Correspondingly, that of maize starch increased by 29.71 and 133.29%, and 42.92 and 79.93%, and 28.16 and 161.43%, respectively. These results may provide a new and valuable enzyme combination for optimising porous starch granules with higher absorption capacities.


Assuntos
Adsorção/fisiologia , Amido/química , Triticum/química , Zea mays/química , Enzima Ramificadora de 1,4-alfa-Glucana/química , Enzima Ramificadora de 1,4-alfa-Glucana/metabolismo , Amilases/química , Amilose/química , Glucana 1,4-alfa-Glucosidase/química , Glucana 1,4-alfa-Glucosidase/metabolismo , Hidrólise , Porosidade , Temperatura , Água/química , alfa-Amilases/química , alfa-Amilases/metabolismo
8.
Int J Biol Macromol ; 164: 1758-1765, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32763394

RESUMO

To explore an effective enzyme combination instead of a common enzyme method, sequential α-amylase and glucoamylase, a method of sequential glycosyltransferase and branching enzyme was chosen to compare the macroscopic features, structure characteristics, porosity characteristics and adsorption quantity of potato, corn, wheat and sweet potato starches. The results indicated that after enzyme treatment, the relative crystallinity of potato, corn, wheat and sweet potato starches increased. Moreover, amylose levels decreased, while pore size and volume, and specific surface area increased after sequential glycosyltransferase and branching enzyme. In terms of pore size, sequential α-amylase and glucoamylase produced abundant mesopores (2-50 nm), whereas sequential glycosyltransferase and branching enzyme developed much more macropores (>50 nm). The adsorption quantities of the starch obtained with sequential glycosyltransferase and branching enzyme were about 2 folds higher than that of the starch obtained with sequential α-amylase and glucoamylase. Therefore, the sequential glycosyltransferase and branching enzyme may be an ideal method to create porous starch as a desirable green adsorbent for industries.


Assuntos
Glucana 1,4-alfa-Glucosidase/química , Amido/química , alfa-Amilases/química , Adsorção/fisiologia , Glucana 1,4-alfa-Glucosidase/metabolismo , Hidrólise , Ipomoea batatas/química , Porosidade , Solanum tuberosum/química , Triticum/química , Água/química , Zea mays/química , alfa-Amilases/metabolismo
9.
Foods ; 9(2)2020 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-31979146

RESUMO

Lunasin, a bioactive peptide, was originally found in soybeans, and it has exhibited multiple biological functions. On the basis of previous studies, salt stress was found able to induce changes in many polypeptides and translatable mRNA levels in plants. Salt stress was applied to soybean germination, with water treatment as a control group, to evaluate the effects of salt stimulation on lunasin accumulation and activity during soybean germination. Lunasin content gradually increased in the control group during germination, reached the highest level after six hours of imbibition, and then slowly decreased. Under salt exposure, lunasin content showed a similar trend to that of the control group. The lunasin content in salt-treated soybean was significantly higher than that in the control group. Lunasin peptide was purified from soybean after six hours of imbibition and it was then used for function evaluation. Purified lunasin from salt-stress-germinated soybean (6 h-LSGS) exhibited stronger antioxidant activity than lunasin from water-treatment-germinated soybean (6 h-LWGS) and soybean seed without imbibition (DRY). The 6 h-LSGS presented anti-inflammatory activity on LPS-induced macrophage cells (p < 0.05) by suppressing the release of nitric oxide (NO) and proinflammatory cytokines, including IL-1 and IL-6. The gene expression of NOS, IL-1, IL-6, and TNF-α was significantly inhibited by 6 h-LSGS. Further, 6 h-LSGS exhibited superior antiproliferation activity on human breast-cancer cells MDA-MB-231 when compared to 6 h-LWGS and DRY. Overall, this study offers a feasible elicitation strategy for enhancing lunasin accumulation and its properties in soybean for possible use in functional food.

10.
Artigo em Inglês | MEDLINE | ID: mdl-28825988

RESUMO

Capsaicin was extracted from capsicum oleoresin using an aqueous two-phase system (ATPS) composed of an ethylene oxide-propylene oxide (EOPO) copolymer, salt and ethanol. Capsaicin was concentrated in the top polymer-rich phase. To determine the optimal conditions, the partitioning of capsaicin in the ATPS was investigated, considering a single-factor experiment including the salt concentration, polymer concentration, buffer pH, ethanol concentration, sample loading and extraction duration. Response surface methodology was applied to investigate the effects of the polymer concentration, buffer pH and sample loading on capsaicin partitioning. A capsaicin yield of 95.5% was obtained using the optimal extraction system, which consisted of 16.3% UCON 50-HB-5100/10% K2HPO4/1% ethanol, a buffer pH of 4.35 and 0.24g of capsicum oleoresin. Capsaicin was purified from the capsaicinoid extract using a two-step macroporous adsorption resin (MAR) method. After purification using non-polar MAR ADS-17, the recovery and purity of capsaicin were 83.7% and 50.3%, respectively. After purification using weakly polar MAR AB-8, the recovery and purity of capsaicin were 88.0% and 85.1%, respectively.


Assuntos
Capsaicina/análise , Capsaicina/isolamento & purificação , Capsicum/química , Fracionamento Químico/métodos , Extratos Vegetais/química , Capsaicina/química , Cromatografia Líquida de Alta Pressão , Compostos de Epóxi/química , Etanol , Óxido de Etileno/química
11.
Appl Biochem Biotechnol ; 175(2): 1018-34, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25355002

RESUMO

Capsaicin was preparatively separated and purified from capsicum oleoresin with a new method combined with aqueous two-phase extraction (ATPE) and chromatography. Screening experiments of ATPE systems containing salts and hydrophilic alcohols showed that potassium carbonate/ethanol system was the most suitable system for capsaicin recovery among the systems considered. Response surface methodology was used to determine an optimized aqueous two-phase system for the extraction of capsaicin from capsaicin oleoresin. In a 20 % (w/w) ethanol/22.3 % (w/w) potassium carbonate system, 85.4 % of the capsaicin was recovered in the top ethanol-rich phase while most oil and capsanthin ester were removed in the interphase. The capsaicinoid extract was then subjected to two chromatographic steps using D101 macroporous resin and inexpensive SKP-10-4300 reverse-phase resin first applied for the purification of capsaicin. After simple optimization of loading/elution conditions for D101 macroporous resin chromatography and SKP-10-4300 reverse-phase resin chromatography, the purities of capsaicin were improved from 7 to 85 %. In the two chromatography processes, the recoveries of capsaicin were 93 and 80 % respectively; the productivities of capsaicin were 1.86 and 4.2 (g capsaicin/L resin) per day respectively. It is worth mentioning that a by-product of capsaicin production was also obtained with a high purity (90 %).


Assuntos
Capsaicina/isolamento & purificação , Capsicum/química , Fracionamento Químico/métodos , Cromatografia de Fase Reversa , Extratos Vegetais/química , Água/química , Adsorção , Soluções Tampão , Capsaicina/química , Carbonatos/química , Etanol/química , Concentração de Íons de Hidrogênio , Porosidade , Potássio/química , Resinas Sintéticas/química , Cloreto de Sódio/química
12.
Artigo em Inglês | MEDLINE | ID: mdl-24657412

RESUMO

In this study, a two-step process combining aqueous two-phase extraction (ATPE) with chromatography was developed for extraction and purification of alliin from garlic powder. The partition coefficient and yield value of alliin in different types of aqueous two-phase system (ATPS) were compared and response surface methodology (RSM) was used for analyzing and optimizing the extraction process. The optimal extraction conditions of 19% (w/w) (NH4)2SO4, 20% (w/w) 1-prpanol, at 30°C, pH 2.35 with 8.54% (w/w) NaCl was chosen based on the higher yield. Compared to the results obtained with the conventional extraction method, this method had an evident advantage on yield (20.4mg/g versus the original yield of 15.0mg/g) and the concentration of alliin in extract solution by ATPE was close to three times of that with conventional extraction. The purification of alliin was carried out with the ammonium form of sulfonic acid cation-exchange resins 001×7. Sample solution with alliin concentration of 1mg/mL was passed through resins and the desorption of alliin was accomplished by water at the flow velocity of 0.5mL/min, 1.5mL/min, respectively. The purity and recovery of alliin after purification were 80% and 76%, respectively.


Assuntos
Cromatografia por Troca Iônica/métodos , Cisteína/análogos & derivados , Alho/química , Extração Líquido-Líquido/métodos , Adsorção , Cisteína/análise , Cisteína/isolamento & purificação , Análise de Regressão , Reprodutibilidade dos Testes , Cloreto de Sódio
13.
Inflammation ; 37(2): 443-50, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24146106

RESUMO

Obesity, characterized as a state of low-level inflammation, is a powerful determinant influencing the development of insulin resistance and progression to type 2 diabetes. The purpose of the present study was to investigate the anti-inflammatory activity of fucoxanthin in experimental high-fat-diet-induced obesity in mice and antioxidant activity in PC12 cells under oxidative stress situation. The anti-inflammatory potential of fucoxanthin in the regulation of maleic dialdehyde (MDA), polymorphonuclear cells (PMNs), interleukin-1ß (IL-1ß), inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), and cyclooxygenase-2 (COX-2) was determined by ELISA. Fucoxanthin significantly inhibited obesity-induced upregulation of the production of IL-1ß, TNF-α, iNOS, and COX-2. Moreover, fucoxanthin suppressed MDA and infiltration of PMNs. The protective effects were associated with lack of hypertrophy and crown-like structures in mammary gland. At the same time, fucoxanthin showed an advantage of antioxidant activity in PC12 cells under oxidative stress situation. These results suggest that supplementation of fucoxanthin is a promising strategy for blocking macrophage-mediated inflammation and inflammation-induced obesity and its associated complications.


Assuntos
Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Gorduras na Dieta , Inflamação/tratamento farmacológico , Obesidade/tratamento farmacológico , Estresse Oxidativo/efeitos dos fármacos , Xantofilas/farmacologia , Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo/imunologia , Tecido Adiposo/metabolismo , Animais , Ciclo-Oxigenase 2/metabolismo , Modelos Animais de Doenças , Inflamação/etiologia , Inflamação/imunologia , Inflamação/metabolismo , Mediadores da Inflamação/metabolismo , Interleucina-1beta/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/metabolismo , Malondialdeído/metabolismo , Camundongos , Óxido Nítrico Sintase Tipo II/metabolismo , Obesidade/etiologia , Obesidade/imunologia , Obesidade/metabolismo , Células PC12 , Ratos , Fatores de Tempo , Fator de Necrose Tumoral alfa/metabolismo
14.
Acta Biochim Biophys Sin (Shanghai) ; 37(10): 709-12, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16215639

RESUMO

Heterogeneous expression of multiple genes in the nucleus of transgenic plants requires the introduction of an individual gene and the subsequent backcross to reconstitute multi-subunit proteins or metabolic pathways. In order to accomplish the expression of multiple genes in a single transformation event, we inserted both large and small subunits of allophycocyanin gene (apcA and apcB) into Chlamydomonas reinhardtii chloroplast expression vector, resulting in papc-S. The constructed vector was then introduced into the chloroplast of C. reinhardtii by micro-particle bombardment. Polymerase chain reaction and Southern blot analysis revealed that the two genes had integrated into the chloroplast genome. Western blot and enzyme-linked immunosorbent assay showed that the two genes from the prokaryotic cyanobacteria could be correctly expressed in the chloroplasts of C. reinhardtii. The expressed foreign protein in transformants accounted for about 2%-3% of total soluble proteins. These findings pave the way to the reconstitution of multi-subunit proteins or metabolic pathways in transgenic C. reinhardtii chloroplasts in a single transformation event.


Assuntos
Chlamydomonas reinhardtii/genética , Chlamydomonas reinhardtii/metabolismo , Cloroplastos/genética , Cloroplastos/metabolismo , Ficocianina/genética , Transformação Genética/genética , Animais , Southern Blotting , Western Blotting , DNA de Algas/genética , Vetores Genéticos
15.
J Microbiol ; 43(4): 361-5, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16145551

RESUMO

In this study, we chronicle the establishment of a novel transformation system for the unicellular marine green alga, Dunaliella salina. We introduced the CaMV35S promoter-GUS construct into D. salina with a PDS1000/He micro-particle bombardment system. Forty eight h after transformation, via histochemical staining, we observed the transient expression of GUS in D. salina cells which had been bombarded under rupture-disc pressures of 450 psi and 900 psi. We observed no GUS activity in either the negative or the blank controls. Our findings indicated that the micro-particle bombardment method constituted a feasible approach to the genetic transformation of D. salina. We also conducted tests of the cells' sensitivity to seven antibiotics and one herbicide, and our results suggested that 20 microg/ml of Basta could inhibit cell growth completely. The bar gene, which encodes for phosphinothricin acetyltransferase and confers herbicide tolerance, was introduced into the cells via the above established method. The results of PCR and PCR-Southern blot analyses indicated that the gene was successfully integrated into the genome of the transformants.


Assuntos
Clorófitas/crescimento & desenvolvimento , Clorófitas/genética , Glucuronidase/genética , Transformação Genética/fisiologia , Aminobutiratos/farmacologia , Antibacterianos/farmacologia , Biolística , Reatores Biológicos , Southern Blotting , Clorófitas/efeitos dos fármacos , Clorófitas/metabolismo , DNA de Plantas/química , DNA de Plantas/genética , Glucuronidase/química , Glucuronidase/metabolismo , Testes de Sensibilidade Microbiana , Plasmídeos/genética , Reação em Cadeia da Polimerase
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