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1.
Bioresour Technol ; 291: 121894, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31387839

RESUMO

Microalgae accumulate starch and lipid as storage metabolites under nutrient depletion, which can be used as sustainable feedstock for biorefinery. Omics analysis coupled with enzymatic and genetic verifications uncovered a partial picture of pathways and important enzymes or regulators related to starch and lipid biosynthesis as well as the carbon partitioning between them under nutrient depletion conditions. Depletion of macronutrients (N, P, and S) resulted in considerable enhancement of starch and/or lipid content in microalgae, but the accompanying declined photosynthesis hampered the achievements of high concentrations. This review summarized the current knowledge on the pathways and the committed steps as well as their carbon allocation involved in starch and lipid biosynthesis, and focused on the manipulation of different nutrients and the alleviation of oxidative stress for enhanced storage metabolites production. The biological and engineering approaches to cope with the conflict between biomass production and storage metabolites accumulation are proposed.


Assuntos
Metabolismo dos Lipídeos , Microalgas/metabolismo , Nutrientes , Amido/metabolismo , Biomassa , Lipídeos
2.
J Agric Food Chem ; 67(31): 8617-8625, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31293160

RESUMO

Inhibiting starch digestion can effectively control postprandial blood sugar level. In this study, the in vitro digestion differences among the mixtures of five polyphenols (i.e., procyanidins [PAs], catechin [CA], tannic acid [TA], rutin [RU], and quercetin [QU]) and starch were analyzed through an in vitro simulation test of starch digestion. The interaction characteristics of these five polyphenols with α-amylase and α-glucosidase were investigated in terms of the inhibition effect, dynamics, fluorescence quenching, and circular dichroism (CD). The results revealed that the rapidly digestible starch (RDS) contents decreased, while the resistant starch (RS) contents increased. All five polyphenols inhibited the α-amylase activity through the noncompetitive approach but inhibited the α-glucosidase activity through the competitive approach. Five polyphenols combined with α-amylase spontaneously by using the hydrophobic effect. The interaction of PAs and QU with α-glucosidase were recognized as van der Waals forces and H bonding, whereas CA and TA interacted with α-glucosidase through the hydrophobic effect. All five polyphenols can cause conformational changes in enzymes.


Assuntos
Extratos Vegetais/química , Polifenóis/química , Amido/química , Animais , Digestão , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Cinética , Modelos Biológicos , Extratos Vegetais/metabolismo , Polifenóis/metabolismo , Amido/metabolismo , Suínos , Leveduras/enzimologia , alfa-Amilases/química , alfa-Amilases/metabolismo , alfa-Glucosidases/química , alfa-Glucosidases/metabolismo
3.
J Agric Food Chem ; 67(30): 8419-8424, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31267740

RESUMO

Increasing the dietary fiber of staple foods such as bread is an attractive way to promote healthy eating in a large part of the population, where dietary fiber consumption is reportedly below the recommended values. However, many consumers prefer white breads, which are typically low in dietary fiber. In this work, white bread was made from two wheat cultivars with differing fiber contents. The resulting breads showed similar quality parameters (volume, specific volume, firmness, inner structure characteristics) with any differences maintained below 7%. Bread digestibility was evaluated using a novel dynamic in vitro digestion model. Reduced digestion rates of 30% were estimated for the high-fiber white bread compared to that in the control. Overall, this work demonstrates the potential to produce healthy, high-fiber white breads that are acceptable to consumers, with a reduced rate of starch digestion, by exploiting a genetic variation in the dietary fiber content of wheat cultivars.


Assuntos
Fibras na Dieta/metabolismo , Triticum/metabolismo , Pão/análise , Fibras na Dieta/análise , Digestão , Farinha/análise , Humanos , Cinética , Amido/química , Amido/metabolismo , Triticum/química
4.
Bioresour Technol ; 289: 121699, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31323726

RESUMO

In this work, we propose a Mixed Integer Nonlinear Programming (MINLP) model to determine the optimal design of a poly(hydroxyalkanoate)s (PHAs) production plant configuration. The superstructure based optimization model considers different carbon sources as raw material: glycerol (crude and purified), corn starch, cassava starch, sugarcane sucrose and sugarcane molasses. The PHA extraction section includes four alternatives: the use of enzyme, solvent, surfactant-NaOCl or surfactant-chelate. Model constraints include detailed capital cost for equipment, mass and energy balances, product specifications and operating bounds on process units. The resulting MINLP model maximizes the project net present value (NPV) as objective function and it is implemented in an equation oriented environment. Optimization results show the sugarcane-enzyme option as the most promising alternative (NPV = 75.01 million USD) for PHAs production with an energy consumption of 22.56 MJ/kg PHA and a production cost of 3.02 USD/kg PHA. Furthermore, an economic sensitivity analysis is performed.


Assuntos
Poli-Hidroxialcanoatos/biossíntese , Carbono/metabolismo , Glicerol/metabolismo , Melaço , Amido/metabolismo
5.
Food Chem ; 297: 124885, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253299

RESUMO

Certain food properties (ex.: pH, polyphenolic composition) can inhibitdigestive amylases and thereby slow down starch digestion. Our aim was twofold. (1) To determine the impact of21 beverages and condiments (coffees, teas, wines, vinegars and lemon juice)on salivary and pancreatic amylolysis: inhibition ranged from 10% to 100%in our experimental conditions. (2) To investigate the effect of one black tea and lemon juice (selected for their strong inhibitory capacity) on starch hydrolysis during dynamicoro-gastro-intestinal digestion of bread. Compared to water (control), the effect of black tea was limited to a ≈20% reduction of released oligosaccharides during the intestinal phase. Lemon juice had a remarkable effect, completely interrupting gastric amylolysis by salivary amylase via a preliminary acidification of gastric contents. These results provide a strong biochemical rationale for the development of dietary strategies to improve the glycaemic impact of starch-rich meals which could be tested in vivo.


Assuntos
Amilases/metabolismo , Camellia sinensis/química , Sucos de Frutas e Vegetais/análise , Amido/metabolismo , Chá/química , Amilases/antagonistas & inibidores , Pão/análise , Camellia sinensis/metabolismo , Humanos , Hidrólise , Pâncreas/enzimologia , Saliva/enzimologia , Chá/metabolismo
6.
Food Chem ; 295: 138-146, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174742

RESUMO

This study investigates the impact of different gelatinization characteristics of small and large barley starch granules on their enzymatic hydrolysis and sugar production during mashing. Therefore, a barley malt suspension was consecutively incubated at 45, 62, 72 and 78 °C to monitor starch behavior and enzymatic starch hydrolysis and sugar production. The combination of microscopic and rapid visco analyses showed that small starch granules persisted longer in the system and were present non-gelatinized at temperatures higher than 62 °C. HPAEC-PAD analysis showed that 8% of the total amount of starch, predominantly small granules, gelatinized at temperatures between 62 °C and 78 °C. Due to their delayed gelatinization in this system, their enzymatic hydrolysis yielded relatively more dextrins compared to what was observed for large granules. It was concluded that small granules should be taken into account when optimizing enzymatic hydrolysis of barley starch, like in brewing, distilling or bio-ethanol production.


Assuntos
Hordeum/metabolismo , Amido/química , Açúcares/metabolismo , Varredura Diferencial de Calorimetria , Dextrinas/metabolismo , Enzimas/metabolismo , Hidrólise , Tamanho da Partícula , Amido/metabolismo , Temperatura Ambiente , Viscosidade
7.
Food Chem ; 295: 147-155, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174743

RESUMO

Influence of different pre-treatments (Ultra-sonication, heat-moisture treatment (HMT) and acid hydrolysis) on the functional properties, in vitro binding capacity and structural properties of succinylated foxtail millet starch were investigated. The degree of substitution was found to be higher in the succinylated starch pretreated by sonication (USFS-0.39). Pre-treatment of succinylated starch by citric acid (ASFS) had markedly increased the resistant starch content. In vitro studies have confirmed that USFS exhibited the highest cholesterol binding capacity at both pH 2.0 (1.86 mg/g) and pH 7.0 (3.12 mg/g) owing to the chemical bonding and entrapment of cholesterol molecules in the starch matrix. FT-IR had confirmed the cross-linking of succinic anhydride as indicated by the presence of a new peak at 1724 cm-1. This study concludes that prior treatment of succinylated starch by ultra-sonication is an efficient way to improve the resistant starch content and principally in vitro cholesterol and bile acid/salts binding ability.


Assuntos
Setaria (Planta)/metabolismo , Amido/química , Anidridos Succínicos/química , Amilose/análise , Colesterol/química , Colesterol/metabolismo , Ácido Cítrico/química , Hidrólise , Estrutura Molecular , Sonicação , Espectroscopia de Infravermelho com Transformada de Fourier , Amido/metabolismo
8.
Food Chem ; 295: 646-652, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174808

RESUMO

The effect of Clitoria ternatea flower (CTE) incorporated into cooked rice using domestic cooking methods on starch digestibility was determined. The incorporation of 1.25% and 2.5% (w/v) CTE caused a reduction in the starch digestibility of cooked rice using an electric rice cooker. In addition, there was significant alteration on the starch digestibility of cooked rice incorporated with 2.5% CTE using a microwave oven. Moreover, CTE significantly reduced the level of rapidly digestible starch and increased the level of undigested starch in cooked rice using an electric rice cooker. In the textural characteristics, the hardness of cooked rice with CTE remained unchanged, whereas a reduction in stickiness of cooked rice with CTE was observed. The sensory evaluation of cooked rice with CTE given by panelists demonstrated a good overall acceptability. Overall, the results show that CTE is a useful ingredient to incorporate with cooked rice for reduction of starch digestibility.


Assuntos
Culinária/métodos , Oryza/química , Ervilhas/metabolismo , Amido/metabolismo , Paladar , Antocianinas/análise , Flores/metabolismo , Fenóis/análise , Limiar Sensorial , Amido/química
9.
Food Chem ; 295: 484-492, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174785

RESUMO

The eating and cooking quality (ECQ) of stored rice grains is significantly affected by ageing, but the molecular mechanisms for this are not well understood. In the present study, changes of starch hierarchical structures and thermal properties of starch were investigated for rices with up to 12 months storage. For the first time, it was seen that storage resulted in molecular degradation of starch. This mainly involved shorter amylose chains and around (1 → 6)-α glycosidic branching points of amylopectin, which altered the crystalline structure. This resulted in lower gelatinization temperatures and enthalpy but higher crystalline heterogeneity. The ageing effect was varietally-dependent. The information obtained from this study offers improved molecular-level understanding of the effects of ageing process on rice cooking and eating qualities.


Assuntos
Armazenamento de Alimentos , Oryza/química , Amido/química , Amilopectina/química , Amilopectina/metabolismo , Amilose/química , Amilose/metabolismo , Cromatografia em Gel , Culinária , Gelatina/química , Gelatina/metabolismo , Microscopia Eletrônica de Varredura , Estrutura Molecular , Oryza/metabolismo , Espalhamento a Baixo Ângulo , Sementes/química , Amido/metabolismo , Fatores de Tempo , Difração de Raios X
10.
Bioresour Technol ; 289: 121686, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31238290

RESUMO

Chlorella kessleri accumulates triacylglycerol usable for biodiesel-fuel production to >20% dry cell weight in three days when cultured in three-fold diluted seawater, which imposes the combinatory stress of hyperosmosis and nutrients limitation. The quantitative behavior of major C-compounds, and related-gene expression patterns were investigated in Chlorella cells stressed with hyperosmosis, nutrients limitation, or their combination, to elucidate the C-metabolism for economical seawater-based triacylglycerol accumulation. Combinatory-stress cells showed repressed protein synthesis with initially accumulated starch being degraded later, the C-metabolic flow thereby being diverted to fatty acid and subsequent triacylglycerol accumulation. This C-flow diversion was induced by cooperative actions of nutrients-limitation and hyperosmosis. Semi-quantitative PCR analysis implied positive rewiring of the diverted C-flow into triacylglycerol in combinatory-stress cells through upregulation of gene expression concerning fatty acid and triacylglycerol synthesis, and starch synthesis and degradation. The information of regulatory C-metabolism will help reinforce the seawater-based triacylglycerol accumulation ability in algae including Chlorella.


Assuntos
Carbono/metabolismo , Chlorella/metabolismo , Triglicerídeos/biossíntese , Biocombustíveis , Ácidos Graxos/metabolismo , Água do Mar , Amido/metabolismo
11.
Food Chem ; 297: 124997, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253298

RESUMO

The present study evaluated the thermal properties of sponge cake batters with different functional ingredients, and the effects of their adding on starch gelatinization. Samples of sponge cake batter: with wheat flour (control batter), with a reduced quantity of wheat flour and addition of functional ingredients (sponge cake batter with 50% einkorn wholemeal flour, sponge cake batter with 20% Jerusalem artichoke powder, sponge cake batter with 35% cocoa husk powder) were investigated. Using the method of differential scanning calorimetry (DSC) the starch gelatinization temperature intervals (°C) and energies of the different batters during baking were evaluated. Based on the experimental results, it could be concluded that the addition of functional ingredients in the cake batter retard the starch gelatinization. The gelatinization occurs at higher temperature and with higher energy consumption. The retarding effect of the functional ingredients is related to the water binding capacity and the presence of dietary fiber.


Assuntos
Pão/análise , Amido/química , Cacau/química , Cacau/metabolismo , Varredura Diferencial de Calorimetria , Culinária , Fibras na Dieta/análise , Farinha/análise , Helianthus/química , Helianthus/metabolismo , Microscopia Eletrônica de Varredura , Amido/metabolismo , Termogravimetria , Temperatura de Transição , Triticum/química , Triticum/metabolismo , Água/química
12.
Food Chem ; 297: 124990, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253323

RESUMO

Use of banana flours as functional ingredients is growing due to their nutritional benefits derived from phenolics and dietary fiber. However, the effect oven-drying, freeze-drying and extrusion on the phenolic compounds or starch digestibility is not understood. In this work, phenolic acids (gallic acid, caffeic acid), flavan-3-ols (epicatechin, catechin) and flavonols (quercetin-3-O-glucoside and myricetin) were quantified in banana flour processed by different methods. Epicatechin, the most abundant phenolic in all flours (up to 1.93 mg/100 g), was significantly reduced during thermal processing (oven-drying and extrusion). Meanwhile, phenolic acids and flavonols were found to be more thermally stable. Thus, oven-drying and extrusion generally improved the extractability of phenolic acids and flavonols. Freeze-drying resulted in native flours with significantly higher insoluble dietary fiber (up to 43.3%), although the digestible starch fraction was digested more rapidly than the oven-dried counterpart.


Assuntos
Farinha/análise , Musa/metabolismo , Fenóis/química , Amido/metabolismo , Antioxidantes , Cromatografia Líquida de Alta Pressão , Dessecação , Fibras na Dieta/análise , Flavonóis/análise , Flavonóis/química , Liofilização , Hidroxibenzoatos/análise , Hidroxibenzoatos/química , Cinética , Espectrometria de Massas , Fenóis/análise
13.
Food Chem ; 297: 124992, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253327

RESUMO

Complex starch is gaining research attention due to its unique physicochemical and functional properties. In this study, the effects of green tea polyphenols on the properties and digestion of lotus seed starch under high hydrostatic pressure were investigated. The particle size, swelling power, solubility, crystallization, morphology and thermal properties of lotus seed starch were affected by green tea polyphenols. These may be due to the formation of non-inclusive complexes between lotus seed starch and green tea polyphenols. The morphology and green tea polyphenols distribution of the complexes were determined by scanning electron microscopy and confocal laser scanning microscopy. In addition, slow digestion properties of starch were realized under a dynamic in vitro rat stomach-duodenum model and the erosion of granules by amylase gradually decreased by scanning electron microscopy. Furthermore, green tea polyphenols were shown to be able to form V-type inclusion complex with amylose via high hydrostatic pressure.


Assuntos
Lotus/metabolismo , Polifenóis/química , Amido/química , Chá/química , Animais , Varredura Diferencial de Calorimetria , Cristalização , Pressão Hidrostática , Lotus/química , Modelos Biológicos , Tamanho da Partícula , Ratos , Sementes/química , Sementes/metabolismo , Solubilidade , Amido/metabolismo , Chá/metabolismo
14.
J Anim Sci ; 97(7): 2952-2964, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31074782

RESUMO

Two experiments were conducted to determine the DE and ME as well as the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of CP and AA in corn fed to growing pigs. All corn was yellow dent corn collected from different areas in China. In Exp. 1, 60 crossbred barrows (Duroc × Landrace × Yorkshire; 40.7 ± 3.5 kg BW) were randomly allotted to 1 of 10 diets to determine the DE and ME of corns. Diets were formulated to contain 96.8% of 1 of the 10 corn samples and 3.2% of other microingredients. In Exp. 2, 11 crossbred barrows (Duroc × Landrace × Yorkshire; 30.5 ± 2.3 kg) fitted with a T-cannula at the distal ileum were assigned to a 6 × 11 Youden square design with 6 periods and 11 diets. Diets included a N-free diet based on cornstarch and sucrose and 10 test diets formulated with 96.6% 1 of the 10 corns as the sole source of AA. Chromic oxide (0.3%) was added to each diet as an indigestible marker for calculating the AA digestibility. On a DM basis, the starch, ether extract (EE), CP, NDF, and ADF contents of corns averaged 74.05% (69.98 to 78.59%), 3.83% (2.04 to 4.73%), 9.63% (7.74 to 10.43%), 10.80% (10.27 to 11.46%), and 2.27% (2.03 to 2.57%), respectively. The CV of EE, CP, and ADF was 22.59, 8.22, and 8.21%, respectively. The DE and ME of corns averaged 4,087 and 3,981 kcal/kg, respectively, and ranged from 3,999 to 4,161 kcal/kg and from 3,898 to 4,067 kcal/kg, respectively. The DE and ME values were positively correlated (P < 0.05) with the EE content. Optimal prediction equations of ME were ME = 940.35 + (0.72 × DE) + (21.88 × EE) (R2 = 0.94) or ME = 1,051.50 + (0.82 × DE) - (282.05 × ash) (R2 = 0.99). In Exp. 2, significant differences (P < 0.05) were observed in the SID of Arg, His, Phe, Ala, Pro, Cys, and Tyr. The SID of Lys (average 73.79%), Met (average 87.32%), and Thr (average 80.06%) ranged from 61.45 to 78.47%, from 74.09 to 90.91%, and from 79.19 to 85.79%, respectively. The standardized ileal digestible Met was positively correlated (P < 0.01) with the Met and CP contents. The obtained prediction equations were standardized ileal digestible Met = 31.34 + (3.43 × CP) + (116.04 × Met) and standardized ileal digestible Met = 104.92 + (294.71 × Met) - (7.03 × NDF). In conclusion, sources had an effect on the energy values and ileal digestibility of most AA in corn. The ME can be predicted by the DE combined with either the EE or ash content. The AA concentrations and SID of AA in corn varied largely.


Assuntos
Aminoácidos/metabolismo , Ração Animal/análise , Metabolismo Energético , Suínos/fisiologia , Zea mays/metabolismo , Animais , China , Cor , Dieta/veterinária , Digestão , Íleo/metabolismo , Masculino , Amido/metabolismo
15.
J Dairy Sci ; 102(7): 6088-6108, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31056327

RESUMO

The objective of this study was to determine whether the partial replacement of barley starch with lactose (fed as dried whey permeate; DWP) affects N utilization, whole-body urea kinetics, and production in dairy cows. Eight lactating Holstein cows were used in a replicated 4 × 4 Latin square design with 28-d periods. Four cows in one Latin square were ruminally cannulated and used to determine dietary effects on whole-body urea kinetics and N utilization. Cows were fed a barley-based diet that contained 3.6% (dry matter basis) total sugar (TSG; designated control), or diets that contained 6.6, 9.6, or 12.6% TSG. Dietary TSG content was increased by the replacement of barley grain with DWP (83% lactose). Diets were isonitrogenous (∼17.3% crude protein), and starch contents of the control, 6.6, 9.6, and 12.6% TSG diets were 24.3, 22.2, 21.2, and 19.1%, respectively. Whole-body urea kinetics were measured using 4-d infusions of [15N15N]-urea with concurrent total collections of feces and urine. Dry matter intake (mean = 26.7 kg/d), milk yield (mean = 34.9 kg/d), and milk protein and fat contents were unaffected by diet. Ruminal ammonia-N concentration decreased linearly as TSG content increased, whereas ruminal butyrate concentration increased linearly as TSG content increased. Urinary excretion of total N and urea-N changed quadratically, whereas urinary excretion of total N (% of N intake) tended to change quadratically as TSG content increased. Fecal N excretion linearly increased as TSG content increased. A quadratic response was observed for total N excretion as TSG content increased. Milk N and retained N were not affected by diet. As TSG content increased, we observed quadratic responses in the omasal flow of fluid-associated and total bacterial nonammonia N, endogenous production of urea-N, urea-N recycled to the gastrointestinal tract, and urea-N returned to the ornithine cycle. Dietary TSG content did not affect the anabolic utilization of recycled urea-N or the proportion of recycled urea-N that was used for bacterial growth. Our results indicate that feeding DWP did not influence dry matter intake, milk yield, or milk composition. Feeding DWP decreased ruminal ammonia-N concentration, but this did not result in positive responses in milk protein secretion or N balance. The quadratic response in omasal flow of total bacterial nonammonia N indicated that including TSG beyond 9.6% of diet dry matter might depress ruminal microbial protein synthesis.


Assuntos
Ração Animal , Bovinos/metabolismo , Hordeum , Lactose/administração & dosagem , Nitrogênio/metabolismo , Omaso/metabolismo , Ureia/metabolismo , Amônia/metabolismo , Ração Animal/análise , Animais , Nitrogênio da Ureia Sanguínea , Indústria de Laticínios , Dieta/veterinária , Feminino , Lactação , Lactose/metabolismo , Leite , Proteínas do Leite/metabolismo , Nutrientes/metabolismo , Amido/administração & dosagem , Amido/metabolismo
16.
Food Chem ; 294: 96-103, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126511

RESUMO

In consideration of health benefits, more digestible vinasses were investigated, which are associated with the use of different raw cereals and fermented leavens. In an in vitro digestibility test, milled long-grain glutinous rice vinasse with Taibai rice leaven showed a slow glucose-controlled release potential, which contained 37.08% slowly digestible starch, after complete vinasse consumption. The crystalline structure, thermal properties and morphology of vinasse starches were analysed. The relatively long amylopectin chains, which originated from the starch structure present in raw rice and the higher glucoamylase activity of the fermented leaven, partly explained the slower digestion of vinasse. By the optimization of the type of fermented leaven used and the starch structure of the raw rice in fermentation, the rate of vinasse starch digestion could be controlled, resulting in improved nutritional value. The results of this study are important for designing healthy vinasse products by controlling starch structures and digestion rates.


Assuntos
Oryza/metabolismo , Amido/análise , Varredura Diferencial de Calorimetria , Cromatografia em Gel , Microscopia Eletrônica de Varredura , Amido/metabolismo
17.
Food Chem ; 294: 248-259, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126460

RESUMO

In this study, ultrasound was used to modulate the molecular structure of retrograded starch (RS3) responsible for the digestion properties, and the relationships among the ultrasonic power, molecular structure, and RS3 digestibility were revealed. Results revealed that the morphological characteristics of RS3 changed after ultrasonic treatment, and high power resulted in more compact block-shape structure. The results of particle size analysis, Fourier transform infrared spectroscopy, and X-ray diffraction showed that ultrasound decreased the long-range orders but increased the median particle size, short-range orders, and V-type polymorph of ultrasound-treated RS3. A decreased (double helix of amylopectin) and an increased (single helix of V-amylose) enthalpy change were observed by differential scanning calorimeter. Digestion profiles showed that some fractions of rapidly-digestible starch were converted into slowly-digestible starch and/or resistant starch. This study provides a potential approach to regulate the digestion of starch-rich foods with desired digestibility through ultrasonic treatment.


Assuntos
Amido/química , Amilopectina/química , Amilopectina/metabolismo , Amilose/química , Varredura Diferencial de Calorimetria , Conformação Molecular , Tamanho da Partícula , Solubilidade , Sonicação , Espectroscopia de Infravermelho com Transformada de Fourier , Amido/metabolismo , Difração de Raios X , alfa-Amilases/metabolismo
18.
Food Chem ; 294: 378-383, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126477

RESUMO

The quality of starchy foods is highly correlated with their amylose content. After boiling or roasting, the amylose content in cooked chestnut starch decreased to 16.6-26.8%, which was significantly lower than that of raw chestnut starch (26.6-28.1%). After cooking, the pasting temperature and peak time increased, while the breakdown, peak viscosity, final viscosity and setback of starches decreased. The amylose content showed a negative correlation with the pasting characteristics of the starch gel of cooked chestnut. The amylose content negatively affected the springiness and chewiness of starch gel, and positively correlated with its cohesiveness and stringiness. The freeze-thaw stability of starch from cooked chestnut was lower than that of raw chestnut. The amylose content was negatively correlated with freeze-thaw stability and positively correlated with the solubility of starch. The results demonstrated that amylose plays an important role in the pasting and gel texture properties of starch during cooking.


Assuntos
Amilose/química , Fagaceae/química , Amido/química , Amilose/metabolismo , Fagaceae/metabolismo , Congelamento , Géis/química , Nozes/química , Nozes/metabolismo , Solubilidade , Amido/metabolismo , Temperatura Ambiente , Viscosidade
19.
Plant Sci ; 283: 407-415, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31128711

RESUMO

Starch content and composition are major determinants of yield and quality in maize. In recent years, the major genes for starch metabolism have been cloned in this species. However, the role of transcription factors in regulating the starch metabolism pathway remains unclear. The ZmbZIP22 gene encodes a bZIP transcription factor. In our study, plants overexpressing ZmbZIP22 showed reductions in the size of starch granules, the size and weight of seeds, reduced amylose content, and alterations in the chemical structure of starch granules. Also, overexpression of ZmbZIP22 resulted in increases in the contents of soluble sugars and reducing sugars in transgenic rice and maize. ZmbZIP22 promotes the transcription of starch metabolism genes by binding to their promoters. Screening by yeast one-hybrid assays indicated a possible interaction between ZmbZIP22 and the promoters of eight key starch enzyme genes. Collectively, our results indicated that ZmbZIP22 functions as a negative regulator of starch synthesis, and suggest that this occurs through the regulation of key sugar and starch metabolism genes in maize.


Assuntos
Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Endosperma/metabolismo , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Amido/metabolismo , Zea mays/metabolismo , Amilose/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/genética , Southern Blotting , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Análise de Sequência de DNA , Transcriptoma , Técnicas do Sistema de Duplo-Híbrido , Zea mays/genética
20.
Food Chem ; 289: 103-111, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30955591

RESUMO

The effect of three combinations of bioprocessing methods by lactic acid fermentation, cell wall hydrolyzing enzymes and phytase on the biochemical (protein, fat, carbohydrate composition) and technofunctional properties (protein solubility, emulsifying and foaming properties) of wheat bran protein isolates were evaluated. The bioprocessing increased the protein (up to 80%) and fat content (up to 22.8%) in the isolates due to the degradation of starch and soluble pentosans. Additional proteins, globulin 3A and 3C, chitinase, ß-amylase and LMW glutenins, were identified from the electrophoretic pattern of the protein isolate bioprocessed with added enzymes. Generally, the bioprocessed protein isolate had lower protein solubility and stronger net charge in pH below 7, when compared to the protein isolate made without bioprocessing. The emulsifying properties of the protein isolates were not affected by bioprocessing. However, the foaming stability of the protein isolates was nearly doubled by bioprocessing with cell wall hydrolyzing enzymes and phytase.


Assuntos
Fibras na Dieta/metabolismo , Proteínas de Plantas/química , Quitinases/química , Quitinases/isolamento & purificação , Quitinases/metabolismo , Eletroforese em Gel de Poliacrilamida , Hidrólise , Proteínas de Plantas/isolamento & purificação , Proteínas de Plantas/metabolismo , Estabilidade Proteica , Solubilidade , Amido/metabolismo , beta-Amilase/química , beta-Amilase/isolamento & purificação , beta-Amilase/metabolismo
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