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1.
Int J Biol Macromol ; 265(Pt 2): 131009, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38513905

RESUMEN

Annona montana mucilage (AMM) is a novel mucilage with unique but limited information. This study investigated the effects of AMM addition on the pasting and rheological properties of wheat starch (WS), corn starch (CS), water caltrop starch (WCS), and lotus rhizome starch (LRS). The addition of AMM generally increased the pasting temperature and peak viscosity, but reduced the setback value of all starches to varying degrees, and the initiation of viscosity-increase for cereal starch/AMM systems during pasting occurred at lower temperatures, accompanied with a distinctive two-stage swelling process as well as lower peak and final hot paste viscosity at 50 °C. AMM significantly increased the pseudoplasticity and entanglement of the systems to varying degrees (LRS > WS > WCS > CS). Under a constant shear rate of 50 s-1, the consistency level was found to fall in honey-like for cereal starch/AMM groups, and honey-like to extremely thick levels for WCS and LRS/AMM groups. Except for the WCS/AMM systems, the storage and loss modulus as well as tan increased with increasing AMM concentration. Short-term retrogradation of starch at 4 °C was pronouncedly retarded by the addition of AMM for WS, CS and WCS groups, but was less affected for LRS group.


Asunto(s)
Annona , Lotus , Lythraceae , Zea mays , Triticum , Montana , Rizoma , Almidón , Polisacáridos , Viscosidad
2.
Foods ; 12(19)2023 Sep 25.
Artículo en Inglés | MEDLINE | ID: mdl-37835205

RESUMEN

The effects of treatment time of continuous annealing (ANN) and cycle numbers of cycled ANN on the structural, physicochemical, and digestive properties of water caltrop starch were studied under 70% moisture at 65 °C. It was found that continuous and cycled ANN have no significant effects on the morphology of starch granules. However, the relative crystallinity and content of resistant starch increased pronouncedly, possibly due to crystalline perfection, which also led to the rise in gelatinization temperature and the narrowed gelatinization temperature range of starch. The treatment time in continuous ANN generally showed a pronounced effect on the rheological properties of water caltrop starch. During pasting, the breakdown viscosity and setback viscosity of all treatment decreased, implying that ANN modified starch was less susceptible to the condition in heating and continuous shearing, and less likely to cause short-term retrogradation. In contrast, peak viscosity decreased with increasing treatment time of continuous ANN, indicating crystalline perfection restricted the swelling of starch granules and viscosity development during pasting process, which was consistent with the results of steady and dynamic rheological evaluation. All ANN-modified samples showed pseudoplastic behavior with weak gel viscoelastic characteristic. Under a total annealing time of 96 h, the pasting and rheological properties of water caltrop starch were essentially less affected by annealing cycle numbers. However, multistage ANN showed stronger resistance to enzyme hydrolysis.

3.
Molecules ; 27(3)2022 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-35163877

RESUMEN

The structural and functional properties of Citrus grandis Osbeck (CGO) seed mucilage by different extraction practices, including conventional citrate buffer, ultrasonic-assisted (UAE), enzymatic-assisted extraction (EAE) with cellulase or Celluclast® 1.5 L and various ultrasonic-assisted enzymatic extraction (UAEE) procedures were investigated. It was found that CGO seed from agricultural and processing byproducts is an excellent new source of high methoxyl pectin with quite high intrinsic viscosity (about 108.64 dL/g) and molecular weight (about 1.9 × 106) as compared with other pectin sources. UAEE with Celluclast® 1.5 L enhanced the extraction yield most pronouncedly (about 2.3 times). Moreover, the monosaccharide composition of CGO seed mucilage is least affected by EAE with Celluclast® 1.5 L. In contrast, EAE with cellulase dramatically reduces the galacturonic acid (GalA) content to less than 60 molar%, and increases the glucose (Glc) content pronouncedly (to about 40 molar%), which may be considered as an adverse effect in terms of pectin purity. Though extraction procedures involved with ultrasound and cellulolytic enzymes generally show a decrease in GalA contents, weight average molar mass and intrinsic viscosity, EAE with Celluclast® 1.5 L is least affected, followed by UAE and UAEE with Celluclast® 1.5 L. These features can be leveraged in favor of diversified applications.


Asunto(s)
Celulasa/metabolismo , Citrus/química , Citrus/metabolismo , Ácidos Hexurónicos/metabolismo , Extractos Vegetales/aislamiento & purificación , Semillas/química , Semillas/metabolismo , Ondas Ultrasónicas , Citrus/efectos de la radiación , Semillas/efectos de la radiación
4.
Molecules ; 26(16)2021 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-34443559

RESUMEN

The influence of hydrothermal treatments on the structural properties and digestibility of water caltrop starch was investigated. Scanning electron microscopy (SEM) showed some small dents on the surface of starch granules for samples treated with heat moisture treatment (HMT), but not for samples treated with annealing (ANN) which generally showed smoother surfaces. The gelatinization temperature of starch was generally increased by hydrothermal treatments, accompanied by a trend of decreasing breakdown viscosity. These results implied the improvement of thermal and shearing stability, particularly for HMT in comparison to ANN. After being cooked, the native and ANN-modified water caltrop starch granules were essentially burst or destroyed. On the other hand, the margin of starch granules modified by HMT and dual hydrothermal treatments remained clear with some channels inside the starch granules. X-ray diffraction revealed that the crystalline pattern of water caltrop starch changed from the CA-type to the A-type and the relative crystallinity reduced with increasing moisture levels of HMT. Results of ANN-modified water caltrop starch were mostly similar to those of the native one. Moreover, water caltrop starch modified with HMT20 and dual modification contained a pronouncedly higher resistant starch content. These results suggested that HMT, ANN, and dual modification effectively modified the functional properties of water caltrop starch.

5.
Foods ; 10(8)2021 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-34441465

RESUMEN

This study focused on the effect of cycled heat-moisture treatment (cHMT) on the in vitro digestibility, rheological, and physicochemical properties of water caltrop starch. The amylose content increased significantly by cHMT, whereas damaged starch content decreased only in the groups with more than two cycles applications. cHMT generally increased the weight-average molecular weight, except for single cycle treatment which showed the reverse result. In thermal properties, the onset temperature (T0), peak temperature (Tp), and conclusion temperature (Tc) increased, while the enthalpy needed to complete the gelatinization was lowered by cHMT. Water caltrop starch paste showed less shear-thinning behavior with cHMT. Meanwhile, the viscosity and tendency to form strong gel were enfeebled with modification. cHMT significantly changed predicted glycemic index (pGI) value, especially in samples that underwent the most cycles of treatment, which showed the lowest pGI compared to native and other treatment. These results suggested that cHMT water caltrop starch was effectively modified and showed diversified properties.

6.
Molecules ; 26(14)2021 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-34299614

RESUMEN

Heat-moisture treatment (HMT) changed the morphology and the degree of molecular ordering in lotus rhizome (Nelumbo nucifera Gaertn.) starch granules slightly, leading to some detectable cavities or holes near hilum, weaker birefringence and granule agglomeration, accompanied with modified XRD pattern from C- to A-type starch and lower relative crystallinity, particularly for high moisture HMT modification. In contrast, annealing (ANN) showed less impact on granule morphology, XRD pattern and relative crystallinity. All hydrothermal treatment decreased the resistant starch (from about 27.7-35.4% to 2.7-20%), increased the damage starch (from about 0.5-1.6% to 2.4-23.6%) and modified the functional and pasting properties of lotus rhizome starch pronouncedly. An increase in gelatinization temperature but a decrease in transition enthalpy occurred after hydrothermal modification, particularly for hydrothermal modification involved with HMT. HMT-modified starch also showed higher pasting temperature, less pronounced peak viscosity, leading to less significant thixotropic behavior and retrogradation during pasting-gelation process. However, single ANN treatment imparts a higher tendency of retrogradation as compared to native starch. For dual hydrothermally modified samples, the functional properties generally resembled to the behavior of single HMT-modified samples, indicating the pre- or post-ANN modification had less impact on the properties HMT modified lotus rhizome starch.


Asunto(s)
Lotus/química , Almidón Resistente/análisis , Rizoma/química , Cristalización , Calor , Humedad , Viscosidad
7.
Animals (Basel) ; 11(6)2021 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-34200930

RESUMEN

Past immunological studies in broilers focused on juveniles within the rapid pre-slaughter growth period and may not reflect adult immune responses, particularly in breeders managed with chronic feed restriction (R). The study aimed to assess innate immune cell functions in respect to R vs. ad libitum (Ad) feed intake in breeder hens with and without dietary 25-hydroxycholecalciferol (25-OH-D3) supplementation. Ad-feed intake consistently suppressed IL-1ß secretion, respiratory burst, and cell livability in peripheral heterophils and/or monocytes along the feeding trial from the age of 51 to 68 weeks. Supplemental 25-OH-D3 repressed IL-1ß secretion and respiratory burst of both cells mostly in R-hens, but promoted monocyte phagocytosis, chemotaxis, and bacterial killing activity in Ad-hens in accompany with relieved hyperglycemia, hyperlipidemia, and systemic inflammation. Overnight cultures with leukocytes from R-hens confirmed the differential effects of 25-OH-D3 to rescue immune functions altered by glucose and/or palmitic acid exposure. Studies with specific inhibitors further manifested the operative mechanisms via glucolipotoxicity in a cell type- and function-dependent manner. The results concluded no predominant changes between R- vs. Ad-feed intake on leukocyte defense against pathogens despite some differential differences, but supplemental 25-OH-D3 exerts more pronounced effects in Ad-hens.

8.
Int J Mol Sci ; 21(21)2020 Nov 08.
Artículo en Inglés | MEDLINE | ID: mdl-33171670

RESUMEN

Broiler breeder hens with efficient feed conversion rate under restricted feed intake (R-hens) or allowed unlimited access to feed (Ad-hens) progressed with cardiac functional failure and suffered early sudden death. A supplement of 69 µg 25-hydroxycholecalciferol (25-OH-D3)/kg feed improved heart health and rescued livability in both R- and Ad-hens throughout laying stage (26-60 wks). Improvements occurred through cardiac hypertrophic remodeling, reduced arrhythmias, and pathological cues. Here, we further demonstrated consistently decreased circulating and cardiac IL-6 and IL-1ß levels in conjunction with reduced cardiac chemoattraction and leukocyte infiltration by 25-OH-D3 in Ad-hens and in R-hens at later time points (35 and 47 wks) (p < 0.05). Supplemental 25-OH-D3 also ameliorated cardiac fibrosis, endoplasmic reticulum (ER) stress, and autophagy, mostly in Ad-hens, as both collagen content and expression of COL3A1, as well as CCAAT box binding enhancer homologous protein (CHOP) and activating transcription factor 6 (ATF6), were consistently decreased, and suppression of microtubule-associated protein 1 light Chain 3 beta (LC3B) and Sequestosome 1 (SQSTM1) was rescued at 35 and 47 wks (p < 0.05). Vitamin D receptor-NF-κB signaling was shown to mediate these beneficial effects. The present results demonstrate that ER stress and autophagic processes along the sequence from inflammation to fibrotic changes contribute to pathological cardiac remodeling and functional compromise by Ad-feed intake. 25-OH-D3 is an effective anti-inflammatory and anti-fibrotic supplement to ameliorate cardiac pathogenesis in broiler breeder hens.


Asunto(s)
Calcifediol/administración & dosificación , Suplementos Dietéticos , Inflamación/veterinaria , Miocardio/patología , Enfermedades de las Aves de Corral/dietoterapia , Alimentación Animal/análisis , Animales , Autofagia , Proteínas Aviares/sangre , Proteínas Aviares/metabolismo , Cardiomegalia/sangre , Cardiomegalia/dietoterapia , Cardiomegalia/veterinaria , Quimiotaxis de Leucocito , Pollos , Estrés del Retículo Endoplásmico , Femenino , Fibrosis , Inflamación/sangre , Inflamación/dietoterapia , Interleucina-1beta/sangre , Interleucina-6/sangre , FN-kappa B/metabolismo , Enfermedades de las Aves de Corral/sangre , Receptores de Calcitriol/metabolismo
9.
Poult Sci ; 99(7): 3363-3373, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32616230

RESUMEN

A supplement of 69 µg 25-hydroxycholecalciferol (25-OH-D3)/kg feed suppressed the mortality in feed-restricted broiler breeder hens and in hens allowed ad libitum feed intake (Ad-hens) in a feeding trial from age 26 to 60 wk. Outcomes for the mechanisms found that 25-OH-D3 relieved systemic hypoxia, pathological cardiac remodeling and arrhythmias, and hepatopathology to improve hens' livability. In the study, we further evaluated the effect of 25-OH-D3 on blood pressure and vascular remodeling relative to cardiac pathogenesis of sudden death (SD). Ad libitum feed intake increased mechanical loading and contributed to maladaptive cardiac hypertrophy as evidenced by consistently elevated peripheral arterial blood pressure in Ad-hens before SD (P < 0.05). In planned longitudinal measurements, Ad-hens also showed higher right ventricle systolic pressure and right ventricle diastolic pressure (RVDP) (P < 0.05). Supplemental 25-OH-D3 relieved peripheral hypertension and prevented time-dependent increases of RVDP in Ad-hens through the renin-angiotensin system and circulating nitric oxide availability and by regulating vascular remodeling including elastin/collagen ratio and smooth muscle cell proliferation in the pulmonary artery for improved elasticity/stiffness (P < 0.05). The antihypertensive effect via the renin-angiotensin system and nitric oxide regulation in respect to heart rate and arrhythmias by 25-OH-D3 were further confirmed in 51 week-old feed-restricted broiler breeder hens challenged with salt loading for 5 wk. Despite feed restriction, the most feed-efficient hens of feed-restricted groups also exhibited cardiac pathological hypertrophy, in conjunction with higher right ventricle systolic pressure, RVDP, plasma nitric oxide levels, and more dramatic arterial remodeling (P < 0.05). These results suggest that peripheral and pulmonary hypertension are the key drivers of SD and that 25-OH-D3 is an effective antihypertensive supplement to alleviate cardiac pathogenesis and improve livability in broiler breeder hens.


Asunto(s)
Presión Sanguínea/efectos de los fármacos , Calcifediol/metabolismo , Remodelación Vascular/efectos de los fármacos , Vitaminas/metabolismo , Alimentación Animal/análisis , Animales , Calcifediol/administración & dosificación , Pollos , Dieta/veterinaria , Suplementos Dietéticos/análisis , Distribución Aleatoria , Vitaminas/administración & dosificación
10.
Animals (Basel) ; 9(10)2019 Oct 08.
Artículo en Inglés | MEDLINE | ID: mdl-31597394

RESUMEN

A supplement of 69 µg 25-hydroxycholecalciferol (25-OH-D3)/kg feed increased livability in feed restricted (R-hens) broiler breeder hens by 9.9% and by 65.6% in hens allowed ad libitum feed intake (Ad-hens) in a feeding trial from age 26-60 weeks. Hens with higher bodyweight and/or adiposity suffered sudden death (SD) earlier in conjunction with compromised heart rhythms and over-ventilation. In the study with the same flock of hens, we demonstrate that 25-OH-D3 improved hen's livability and heart health by ameliorating systemic hypoxia, acidosis, and cardiac pathological hypertrophy through calcineurin-NFAT4c signaling and MHC- expression in association with reduced plasma triacylglycerol and hepatic steatosis and fibrosis (p < 0.05). In contrast to live hens sampled at 29, 35, and 47 weeks, SD hens exhibited severe cardiac hypertrophy that was either progressive (Ad-groups) or stable (R-groups). Actual and relative liver weights in SD hens from any group declined as the study progressed. Heart weight correlated significantly to total and relative liver weights in SD-hens of both R- and Ad-groups. In contrast to normal counterparts sampled at 35 and 47 weeks, R-hens exhibiting cardiac hypertrophy experienced severe hypoxia and acidosis, with increased bodyweight, absolute and relative weights of liver and heart, hepatic and plasma triacylglycerol content, and cardiac arrhythmia (p < 0.05). The present results demonstrate that pathological cardiac hypertrophy and functional failure are causative factors of SD and this pathogenic progression is accelerated by hepatopathology, particularly during the early age. Increased feed efficiency with rapid gains in BW and fat increase hens' risk for hypoxia, irreversible cardiac hypertrophy, and arrhythmias that cause functional compromise and SD. Additional supplementation of 69 mg/kg feed of 25-OH-D3 to the basal diet is effective to ameliorate cardiac pathogenesis and prevent SD in broiler breeder hens.

11.
J Biosci Bioeng ; 127(6): 738-743, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-30639118

RESUMEN

Some bioactive properties of p-coumaric acid and fucose-rich polysaccharide in skin health have been studied, including melanogenesis inhibition of the phenolic acid and growth inhibitory effects of the polysaccharide on melanoma. The dermatological benefits of bird's nest fern extracts (BNFE), containing both substantial fucose-rich polysaccharide and p-coumaric acid, like promoting collagen production and growth of fibroblast cell and further improving the elasticity and dryness of human skins have been demonstrated in our previous study. Besides, the anti-melanization effects of various BNFE on B16-F10 melanoma and human skin were first studied here. The promising extracts revealed that the main phenolic acid, p-coumaric acid, in BNFE resulted in suppression against tyrosinase activity from melanogenesis. The inhibitory kinetics on the diphenolase activity indicated that AE40 was a noncompetitive inhibitor of mushroom tyrosinase. On the other hand, the fucose-rich mucilage of BNFE showed pronouncedly suppressing effect on B16-F10 melanoma viability. Clinical trial was performed by recruiting 46 female volunteers and the results indicated that the lotions with 1% of BNFE was non-irritant and reduced effectively the pigmentation on human skin after 7-14 days of continuous application. It was suggested that the fucose-rich mucilage and p-coumaric acid in BNFE may have potential for nutricosmetics and phytotherapy applications as a natural hypopigmenting agent.


Asunto(s)
Helechos/enzimología , Melaninas/biosíntesis , Melanoma Experimental/metabolismo , Monofenol Monooxigenasa/antagonistas & inhibidores , Extractos Vegetales/farmacología , Piel/efectos de los fármacos , Piel/metabolismo , Inhibidores Enzimáticos/farmacología , Femenino , Humanos , Cinética , Pigmentación/efectos de los fármacos
12.
Nat Prod Res ; 33(5): 736-741, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29161888

RESUMEN

p-coumaric acid and fucose-rich polysaccharide have been studied for many bio-functions in skin including cutaneous protection from oxidative damage and antiageing, respectively, as well as wound healing. The physiological activities of various bird's nest fern extracts (BNFE), containing considerable fucose-rich mucilage and p-coumaric acid, on fibroblast and human skin were first investigated. BNFE with higher polysaccharide content generally contributed to a better moisture holding capability. Furthermore, BNFE showed pronouncedly enhancing effect on collagen production and growth of fibroblast (NIH-3T3), clinical trial results revealed that the emulsions with 1% BNFE showed good moisturising effect and improved the elasticity of human skins effectively. The potential of BNFE for cosmetics and medical applications such as natural moisturiser, antiageing and wound repairing was possibly related to the fucose-rich mucilage and various phenolic compounds including p-coumaric acid in BNFE.


Asunto(s)
Ácidos Cumáricos/farmacología , Extractos Vegetales/farmacología , Mucílago de Planta/farmacología , Piel/efectos de los fármacos , Tracheophyta/química , Administración Cutánea , Adolescente , Adulto , Animales , Ácidos Cumáricos/aislamiento & purificación , Elasticidad , Emulsiones , Femenino , Fibroblastos/efectos de los fármacos , Humanos , Ratones , Células 3T3 NIH , Fitoquímicos/aislamiento & purificación , Fitoquímicos/farmacología , Hojas de la Planta/química , Mucílago de Planta/aislamiento & purificación , Pigmentación de la Piel , Taiwán , Adulto Joven
13.
Int J Biol Macromol ; 124: 346-353, 2019 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-30465842

RESUMEN

Enzyme-assisted extraction (EAE) possesses the advantages of being environmentally friendly and easily operated owing to relatively mild reaction conditions. Thus, mucilage from Asplenium australasicum was extracted with xylanase, glucanase and simultaneous application of both enzymatic preparations then investigated for their physicochemical properties. It was observed that compared to the control, the yield of mucilage increased significantly by EAE (from 3.64% to 6.04-6.86%), while the average molecular weight also increased slightly. SEM results showed that enzymes can erode the raw material which contributed to the higher extraction efficiency of polysaccharide. Furthermore, EAE modified the monosaccharide composition profile of A. australasicum mucilage considerably, especially there was a significant increase in glucose and galacturonic acid content. Although the FT-IR fingerprint did not change pronouncedly due to the action of the enzymes, but the degree of polysaccharide branching seemed to be more complicated, thus significantly reducing the intrinsic viscosity and water holding capacity of mucilage.


Asunto(s)
Glicósido Hidrolasas/química , Mucílago de Planta/química , Polisacáridos/química , Tracheophyta/química , Glucosa/química , Ácidos Hexurónicos/química , Peso Molecular , Polisacáridos/aislamiento & purificación , Semillas/química , Espectroscopía Infrarroja por Transformada de Fourier , Viscosidad , Agua/química
14.
Carbohydr Polym ; 134: 222-9, 2015 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-26428119

RESUMEN

The effects of hsian-tsao gum (HG) addition on the physical properties, antioxidant activities and structure of casein (CAS) film have been investigated. It has been observed that HG addition provided CAS film with better mechanical properties and resistant to moisture, stronger barrier properties against light and higher antioxidant activities than pure CAS film. Fourier transformation infrared (FTIR) data indicated that hydrogen bonding interactions and Maillard reactions occurred between CAS and HG, giving rise to a more compact structure than CAS film. The results of X-ray diffraction and differential scanning calorimetry (DSC) indicated that CAS and HG were compatible, and addition of HG destroyed the original crystalline domains of CAS film, and the blend films exhibited higher glass transition temperatures than CAS film. Moreover, nuclear magnetic resonance (NMR) analysis showed that HG addition significantly changed the mobility of water molecule in CAS film. Especially, ratio of the high mobility water of CAS/HG films significantly decreased as compared to CAS film.


Asunto(s)
Antioxidantes/química , Caseínas/química , Medicamentos Herbarios Chinos/química , Antioxidantes/farmacología , Compuestos de Bifenilo/química , Rastreo Diferencial de Calorimetría , Caseínas/farmacología , Medicamentos Herbarios Chinos/farmacología , Enlace de Hidrógeno , Espectroscopía de Resonancia Magnética , Oxidación-Reducción/efectos de los fármacos , Permeabilidad , Picratos/química , Espectroscopía Infrarroja por Transformada de Fourier , Vapor/análisis , Agua/química , Difracción de Rayos X
15.
Int J Food Microbiol ; 139(1-2): 23-30, 2010 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-20138382

RESUMEN

The antimicrobial activities of edible coatings based on a tapioca starch/decolorized hsian-tsao leaf gum (dHG) matrix with various green tea extracts (GTEs) were evaluated. Its effect on the shelf-life extension of fruit-based salads, romaine hearts, and pork slices were investigated as well. Three types of GTEs from hot water (80 degrees C) (W), 40% (E4) and 80% (E8) ethanol were prepared. It was found that all GTEs showed pronounced inhibition on Gram positive bacteria in agar media, including Staphylococcus aureus BCRC 10781, Bacillus cereus BCRC 11778 and Listeria monocytogenes BCRC 14848, but not on Gram negative bacteria, such as Escherichia coli DH10beta and Salmonella enteria BCRC 10747. The antimicrobial activities increased with increasing GTEs concentration (1, 2 and 5%), but did not differentiate significantly in terms of the effect of extraction solvents. When various GTEs (1%) were added to an edible coating formulation based on 1.35% tapioca starch +0.15% dHG +0.225% glycerol, pronounced antimicrobial activity on Gram positive bacteria was also observed as evaluated by using cylinder diffusion and antimicrobial migration tests. It was believed that the active compounds in green tea extracts could leave the coating matrix and migrate to increase the non-growth area. When being sprayed on various real food models, all tapioca starch/dHG coatings containing GTEs could successfully reduce the aerobic counting and growth of yeasts/molds by 1 to 2 log cycles in fruit-based salads, as compared to the control sample. Furthermore, during refrigerated storage of romaine hearts and pork slices for 48h, tapioca starch/dHG coatings with E4 extracts demonstrated pronounced antimicrobial activity against Gram positive bacteria (4-6 log cycles reduction), followed by W extracts and E8 extracts in a decreasing order. Such results implied the high efficacy of antimicrobial migration of tapioca starch/dHG coatings containing GTEs and their application potentials on foods.


Asunto(s)
Antiinfecciosos/farmacología , Bacterias/efectos de los fármacos , Camellia sinensis/química , Medicamentos Herbarios Chinos , Microbiología de Alimentos , Conservación de Alimentos/métodos , Manihot , Extractos Vegetales/farmacología , Animales , Manipulación de Alimentos , Frutas/microbiología , Hongos/efectos de los fármacos , Lactuca/microbiología , Carne/microbiología , Pruebas de Sensibilidad Microbiana , Extractos Vegetales/química , Hojas de la Planta , Resinas de Plantas , Almidón , Porcinos , Levaduras/efectos de los fármacos
16.
J Agric Food Chem ; 56(17): 8121-9, 2008 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-18698793

RESUMEN

Two major superoxide dismutases (SODs; SODs I and II) were found in the crude enzyme extract of wheat seedlings after heat treatment, ammonium sulfate fractionation, anionic exchange chromatography, and gel permeation chromatography. The purification fold for SODs I and II were 154 and 98, and the yields were 11 and 2.4%, respectively. SOD I was further characterized. It was found that SOD I from wheat seedlings is a homodimer, with a subunit molecular mass of 23 kDa. Isoelectric focusing electrophoresis (IEF) and zymogram staining results indicated that the isoelectric point of SOD I is 3.95. It belongs to the MnSOD category due to the fact that it was insensitive to KCN or hydrogen peroxide inhibitor. This MnSOD from wheat seedlings was found to be stable over pH 7-9, with an optimum pH of 8, but was sensitive to extreme pH, particularly to acidic pH. It was stable over a wide range of temperatures (5-50 degrees C). Thermal inactivation of wheat seedling MnSOD followed first-order reaction kinetics, and the temperature dependence of rate constants was in agreement with the Arrhenius equation. The activation energy for thermal inactivation of wheat seedling MnSOD in the temperature range of 50-70 degrees C was found to be 150 kJ/mol. HgCl2 and SDS at a concentration of 1.0 mM significantly inhibited enzyme activity. Chemical modification agents, including diethyl pyrocarbonate (2.5 mM) and Woodward's reagent K (50 mM), significantly inhibited the activity of wheat seedling SOD, implying that imidazole groups from histidine and carboxyl groups from aspartic acid and glutamic acid are probably located at or near the active site of the enzyme.


Asunto(s)
Plantones/enzimología , Superóxido Dismutasa/aislamiento & purificación , Triticum/enzimología , Dimerización , Inhibidores Enzimáticos/farmacología , Estabilidad de Enzimas , Calor , Concentración de Iones de Hidrógeno , Focalización Isoeléctrica , Peso Molecular , Superóxido Dismutasa/química , Superóxido Dismutasa/metabolismo
17.
J Agric Food Chem ; 54(22): 8611-6, 2006 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-17061841

RESUMEN

The crude enzyme extract of wheat grass was heated at 60 degrees C for 30 min, followed by ammonium sulfate fractionation and isoelectric chromatofocusing on Polybuffer exchanger (PBE 94) for purification. The purified peroxidase was then characterized for its catalytic characteristics. It was found that AgNO3 at a concentration of 0.25 mM and MnSO4 and EDTA at concentrations of 5 mM significantly inhibited the activity of wheat grass peroxidase. However, KCl, NaCl, CuCl2, CaCl2, ZnCl2, and MgCl2 at concentrations of 5.0 mM and HgCl2 at a concentration of 0.25 mM enhanced enzyme activity. Chemical modification significantly influenced the activity of wheat grass peroxidase. Particularly, N-bromosuccinimide (5 mM) inhibited 16% of the enzyme activity, whereas N-acetylimidazole (2.5 mM), diethyl pyrocarbonate (2.5 mM), and phenylmethanesulfonyl fluoride (2.5 mM) enhanced by 18-29% of the enzyme activity. Such results implied that tryptophan, histidine, tyrosine, and serine residues are related to enzyme activity. The pH optima for wheat grass peroxidase to catalyze the oxidation of o-phenylenediamine (OPD), catechol, pyrogallol, and guaiacol were 5.0, 4.5, 6.5, and 5.0, respectively. The apparent Km values for OPD, catechol, pyrogallol, and guaiacol were 2.9, 18.2, 2.5, and 3.8 mM, respectively. Under optimal reaction conditions, wheat grass peroxidase catalyzed the oxidation of OPD (an aromatic amine substrate) 3-11 times more rapidly than guaiacol, catechol, and pyrogallol (phenolic substrates containing one to three hydroxy groups in the benzene ring).


Asunto(s)
Peroxidasas/metabolismo , Tampones (Química) , Catálisis , Hidrógeno/química , Hidrógeno/metabolismo , Concentración de Iones de Hidrógeno , Iones/química , Metales/química , Metales/farmacología , Estructura Molecular , Hojas de la Planta/enzimología , Sales (Química)/farmacología , Especificidad por Sustrato
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