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1.
The inhibitory effects of phlorotannins isolated from Ishige okamurae on cholinesterase (acetylcholinesterase and butyrylcholinesterase) were evaluated. The methanolic (MeOH) extract and ethyl acetate (EtOAc) soluble fraction obtained from I. okamurae exhibited inhibitory effects against cholinesterase. Repeated column chromatography of the EtOAc fraction of I. okamurae resulted in the isolation of three phlorotannins. Their structures were elucidated on the basis of spectroscopic techniques (1D and 2D NMR) and characterized as phloroglucinol (1), 6,6′-bieckol (2) and diphlorethohydroxycarmalol (3), respectively. Among these, compound 2 exhibited inhibitory activity against acetylcholinesterase (AChE), with IC50 of 46.42 ± 1.19 μM. Compound 3 showed a moderate butyrylcholinesterase (BChE) inhibitory activity with IC50 value of 110.83 ± 1.15 μM. Compound 2 displayed noncompetative type inhibition against AChE when analyzed by Lineweaver–Burk plots of the inhibition kinetics. Thus, we suggest that compound 2 and I. okamurae, serve as a potential AChE inhibitors that could be used as potential functional food ingredients or nutraceuticals for preventing Alzheimer’s disease.  相似文献   

2.
The total polyphenol and flavonoids in leaves of Morus alba var. alba, Morus alba var. rosa and Morus rubra were determined and identification of their components was carried out. The total content of phenolics varied between 345.20 and 631.53 mg gallic acid equivalents (GAE)/100 g dry weight (DW) basis. The total amount of flavonoids ranged between 193.87 and 398.33 mg rutin equivalents (RE)/100 g DW. Thirteen compounds were isolated by chromatography, and their structures determined to be mainly flavonol glycosides and phenolic acids. Three novel components were identified as kaempferol-7-O-glucoside, quercetin-3-O-β-glucoside-7-O-α-rhamnoside and quercetin-3-O-rhamnoside-7-O-glucoside, for the first time from mulberry leaves. Others known compounds were also identified.  相似文献   

3.
The dichloromethane extract and ethyl acetate soluble fraction of Kaempferia parviflora showed antimutagenicity and α-glucosidase inhibitory activity. 7-Methoxyflavones were the major constituents of both extracts and demonstrated antimutagenic activity. In particular, 5,7-dimethoxyflavone (IC50 = 0.40 nmol/plate), 5,3′-dihydroxy-3,7,4′-trimethoxyflavone (0.40 nmol/plate), 3,5,7-trimethoxyflavone (0.42 nmol/plate) and 5-hydroxy-7-methoxyflavone (0.47 nmol/plate) showed potent antimutagenic activity. The results of structure–activity relationship studies suggest that methylation of the 5-hydroxy group enhanced activity. On the other hand, increasing the number of methoxy groups on the B ring caused a reduction in activity. In the case of an α-glucosidase inhibitory effect, 5,7,3′,4′-tetramethoxyflavone exhibited the highest activity (IC50 = 20.4 μM), followed by 5,7,4′-trimethoxyflavone (54.3 μM) and 3,5,7,3′,4′-pentamethoxyflavone (64.3 μM). The results suggest that the α-glucosidase inhibitory activity was enhanced by the methoxy groups at the 5-, 3′- and 4′-position and was reduced by the methoxy group at the 3-position.  相似文献   

4.
An experimental setup based on a 23-full factorial, central composite design was implemented with the aim to optimising recovery of polyphenols from onion solid wastes (OSW). In order to allow for the establishment of a sustainable process, reusable and non-toxic solutions composed of water/ethanol/citric acid were employed as extracting media. The factors considered were (i) the pH of the medium, (ii) the extraction time and (iii) the ethanol concentration. The model obtained produced a satisfactory fitting of the experimental data with regard to total polyphenol extraction (R2 = 0.97, p = 0.0025) and the reducing power of the extracts (R2 = 0.97, p = 0.0033), but not with the antiradical activity (R2 = 0.89, p = 0.0592). The 2nd order polynomial equations obtained after elaboration of the experimental data indicated that all parameters considered were significant in respect with the efficiency of total polyphenol recovery. The highest total polyphenol yield was theoretically predicted to be 9342 ± 1435 mg gallic acid equivalents per 100 g dry weight, under optimal conditions (60% EtOH, pH 2 and 4.2 h). Liquid chromatography-electrospray ionisation mass spectrometry of the optimally obtained extract revealed that the principal phytochemicals recovered were quercetin 3,4′-diglucoside, quercetin 4′-glucoside and quercetin. Simple linear regression analysis between the total polyphenol and the antiradical activity of the OSW extracts showed that there was no correlation in a statistically significant manner, as opposed to reducing power.Industrial relevanceThe recovery of value-added substances from agri-food industrial wastes is an issue with importance pertaining to both the reduction of the waste load released to the environment, and the development of novel, natural food additives with functional properties. Up to date, the examinations pertaining to the clarification of factors that can affect extractability were based on rather unilateral assessment, while it is generally accepted that the retrieval depends on several parameters, which render the phenomenon a particular complexity. In this view, the implementation of factorial design with respect to investigating in parallel several factors pertaining to efficient polyphenol recovery becomes imminent. Thus the establishment of models on such a sound experimental basis is expected to provide a reliable background for more costand resource-effective processes, with a potential direct industrial applicability.  相似文献   

5.
In this work, NIR and MIR spectroscopy was investigated and compared for predicting passion fruit ripening parameters as sugars, organic acids and carotenoids. Spectra of 56 samples of the lyophilized passion fruit were collected using an integrating sphere in NIR range and attenuated total reflectance accessory in MIR range. Individual sugars (sucrose, glucose and fructose), organic acids (malic and citric acids) and carotenoids (β-carotene) contents were determined by reference methods. Spectral and reference data were analyzed by principal component analysis. Partial least square regression (PLSR) was used to establish calibration models. MIR technique was better than the NIR technique for glucose (R2v = 0.942), fructose (R2v = 0.855), sucrose (R2v = 0.818), total sugar (R2v = 0.914) and citric acid (R2v = 0.913) content determination. On the other hand, NIR was superior for total acids (R2v = 0.903) content determination. For malic acid and β-carotene contents both methods were unsatisfactory due to low concentrations of these constituents in the passion fruits.  相似文献   

6.
Flavonoids are important constituents of the human diet. One source for flavonols, a major subclass of the flavonoids, is onion. It contains high amounts of quercetin glycosides, primarily quercetin-3,4′-di-O-glucoside (QDG) and quercetin-4′-O-monoglucoside (Q-4′-MG). Due to their high reactivity flavonols are susceptible to thermal degradation as used in food processing. Especially boiling and roasting influence the flavonoid content of food products. Quercetin and several of its glycosides may serve as substrates for human gut bacteria. For example, Eubacterium ramulus and Flavonifractor plautii are capable of cleaving the aglycone quercetin to form 3,4-dihydroxyphenylacetic acid (DHPAA) and phloroglucinol which to some extent can be degraded further. The aim of this study was to find out whether E. ramulus and F. plautii are also capable of degrading Q-4′-MG and QDG by and to investigate the influence of a thermal treatment (roasting) of the onion glucosides on the subsequent microbial degradation. In this study, E. ramulus was capable of degrading Q-4′-MG and QDG, while F. plautii was not. Roasting of QDG at 180 °C for 5 min led to the formation of quercetin with Q-4′-MG and quercetin-3-O-monoglucoside (Q-3-MG) as intermediates. Roasting accelerated the microbial degradation of Q-4′-MG and QDG. In the case of F. plautii, microbial degradation was induced by quercetin which was formed during roasting and is a preferred substrate of this organism.  相似文献   

7.
《Food chemistry》2004,87(2):269-274
Photon emission from tea (610–670 nm) in the H2O2/KHCO3/MeCHO system and the utility of the photon detection system in tea evaluation were investigated. Photon intensity of tea depended on manufacturing method as follows: green tea (1202 ± SD 173.51 cd/m2) > oolong tea (834 ± SD 237.44 cd/m2) > black tea (222 ± SD 87.65 cd/m2). Photon intensity corresponded with polyphenol content (r2=0.8810) rather than catechin content (r2=0.7759) and showed a high correlation with chemopreventive activities against H2O2 (r2=0.7516), O2 (r2=0.7998) and DPPH radical (r2=0.7516). Photon intensity from green tea leaves at each manufacturing process step gave the same decreasing curve as DPPH radical scavenging activity. Chemiluminescence of tea, which gives information on the polyphenol content and chemopreventive potential, is a useful technique for tea evaluation.  相似文献   

8.
Black (aerated) and green (unaerated) tea products, processed from 10 green and 18 purple leaf coloured cultivars of Kenyan origin, and two tea products, from the Japanese cultivars, Yabukita and Yutakamidori, were assayed for total polyphenols (TP) content, individual catechin profiles and in vitro antioxidant capacity (AA). In addition, the phenolic content of the tea products was determined using the Folin–Ciocalteu phenol reagent. Catechin fractions were identified using reverse phase high performance liquid chromatography (HPLC) with a binary gradient elution system.The AA% of the tea products was determined using a 2,2′-diphenyl picrylhydrazyl (DPPH) radical assay method. The results showed that TPs, catechin profiles and antioxidant activities were significantly (p ? 0.05) higher in unaerated than in aerated teas. Tea products from the purple leaf coloured tea cultivars had levels of TPs, total catechin (TC) and antioxidant activities similar to those from the green leaf coloured cultivars, except for teas from the Japanese cultivars that were very low in the assayed parameters. Caffeine content was significantly (p ? 0.05) lower in products from the purple leaf coloured cultivars than in those from the green leaf coloured tea cultivars. Antioxidant activity (%) was higher in tea products from the Kenyan germplasm than in those from the Japanese cultivars. Antioxidant potency of tea products was significantly (r = 0.7897, p ? 0.01) influenced by the total anthocyanin content of the purple leaf coloured cultivars. Cyanidin-3-O-glucoside was the anthocyanin most highly correlated with AA% (r = 0.8437, p ? 0.01 in unaerated tea). Total catechins in the unaerated products from the green leaf coloured tea cultivars were also significantly correlated with antioxidant capacity (r = 0.8187, p ? 0.01). Results from this study suggest that the antioxidant potency of teas is dependent on the predominant flavonoid compound, the type of tea cultivar and the processing method.  相似文献   

9.
Regime (direction, amount, rate, and pattern) of change in aroma active compounds was quantified as a function of four pulsed electric field (PEF) treatment times, three fruits, and 10 physical and eight sensory properties using the best-fit multiple linear regression (MLR) models. The PEF treatment times did not deteriorate 94% of the sensory properties and 70% of the physical properties and significantly change 57% of a total of 73 aroma active compounds detected for sour cherry juice, and apricot and peach nectars. The best performing MLR models belonged to 1-methyl-4-prop-1-en-2-ylcyclohexene as a function of fruit type, treatment time, and titratable acidity (= 49 mg/L; Radj2 = 95.7%; Rcv2 = 94.9%) and to 2-[(2S,5S)-5-ethenyl-5-methyloxolan-2-yl]propan-2-ol as a function of fruit type, and treatment time (SE = 157 mg/L; Radj2 = 98.2%; Rcv2 = 98.0%), respectively (n = 48; p < 0.001).Industrial relevancePulsed electric field (PEF) is one of the leading nonthermal food technologies especiallyfor processing of high acid low viscosity foods with satisfactory quality and microbial inactivation. It was shown in this study that PEF with different treatment times can successfully be applied in the pasteurization of sour cherry juice, and apricot and peach nectars with minimum loss of aroma active compounds and sensory and physical properties. Both PEF processing conditions and results can be used as a guide to determine PEF processing parameters for industrial scale processing of juices/nectars.  相似文献   

10.
The amount of ice nuclei formed during the pressure release is important for the final formation and development of ice crystals in pressure shift freezing (PSF) frozen products. In this study, a high-pressure (HP) calorimeter was used to evaluate the ratio of ice crystals instantaneously formed by rapid depressurization during PSF of pure water and pork muscle tissue. Experiments were carried out initial pressure levels of 62, 115, 157 and 199 MPa, with corresponding phase change temperatures of −5, −10, −15 and −20 °C, respectively (slightly higher than phase change point of water–ice I). The ice crystal ratio was determined based on calorimetric peak measured and heat balance. The evaluated regression relationship between observed ice crystal ratio (Rice in %) and pressure (P, MPa) was Rice–water = 0.115P + 0.00013P2 (R2 = 0.96, n = 9) for pure water, and Rice–pork = 0.080P + 0.00012P2 (R2 = 0.95, n = 11) for pork muscle. Compared to other methods, the calorimetric evaluation does not require any of the pressure-related properties of the test sample. HP calorimetry can thus be used to evaluate ice crystal ratio for PSF of foods even though their pressure related properties may be unknown.  相似文献   

11.
Lactulose has been successfully synthesized by dual-enzymatic method in organic-aqueous two-phase media using lactose and fructose as the raw materials. Cyclohexane–buffer system C6H12:buffer = 95:5 (v/v) was employed as the organic-aqueous media for the reaction. The dual-enzymatic system was consisted of immobilized lactase (IL) and immobilized glucose isomerase (IGI). Immobilized lactase was prepared by cross-linking the free lactase into Fe3O4-chitosan magnetic microspheres. The main enzymatic reaction parameters were investigated, including reaction temperature (T), pH value and reaction time (t). Under the optimum reaction conditions, i.e., lactose 0.8 g mL?1, fructose 0.1 g mL?1, IL 0.1 g mL?1, IGI 0.05 g mL?1, T = 30 °C, pH = 8.0 and t = 2 h, the obtained highest lactulose yield was approximately 151 g L?1 and the corresponding productivity was 75.5 g L?1 h?1. Experimental results indicated that the organic-aqueous media can significantly promoted the transglycosidation activity of lactase and therefore improve the lactulose yield. The possible reaction mechanism of the synthesis of lactulose using IL and IGI in two-phase system was also proposed.  相似文献   

12.
Watercress (Nasturtium officinale) colour changes due to blanching by heat and a combined treatment of heat/ultrasound (thermosonication) were studied in the temperature range of 82.5 to 92.5 °C. The application of thermosonication was intended to enable less severe blanching treatments and, therefore, improve the quality of the blanched product. The thermosonication blanching processes promoted changes of the green colour (an parameter) at a higher rate (P < 0.05), when compared with the heat blanching processes. No significant differences (P > 0.05) were detected between heat and thermosonication blanching processes in terms of the colour parameters Ln, bn and TCD changes. In both treatments, a fractional first order model fitted well the experimental data for Ln, an and bn (RH2 = 0.99; RTs2 = 0.99) and TCD (RH2 = 0.92; RTs2 = 0.96) colour parameters.The chlorophylls content showed no significant differences (P > 0.05) between thermally treated and thermosonicated watercress samples.The present findings will help to evaluate the effectiveness of thermosonication as a novel process to replace the classical heat treatment.Industrial relevanceConventional blanching commonly results in severe losses or destruction of nutrients due to process intensity and extended process times. Consequently, the attempts to use the synergistic effects of heat and ultrasound (at least) for enzyme inactivation are of high relevance. The results, although not conclusive, indicate, that they may aid optimization of blanching processes.  相似文献   

13.
In this study, the effect of α and β-cyclodextrin on cyanidin-3-O-glucoside color was investigated by UV–visible absorption techniques. The equilibrium and kinetic constants of the network of chemical reactions taking place in cyanidin-3-O-glucoside were also studied in water at 25 °C by UV–visible absorption techniques. The results showed that the addition of β-cyclodextrin resulted in the fading of anthocyanin solution, and this fading effect was greater at higher pH. This anti-copigmentation effect is caused by the selective inclusion and stabilization of the anthocyanin colorless forms into the β-cyclodextrin cavity. Oppositely, no changes were observed in the cyanidin-3-O-glucoside absorption spectra with the addition of α-cyclodextrin.Direct pH jump, from thermally equilibrated solutions at pH = 1.0 (flavylium cation, AH+), shows three kinetic processes: formation of the base A, hydration reaction to form the hemiketal B and the chalcone cistrans isomerization (Cc–Ct). The results obtained clearly indicated that the equilibrium and kinetic constants of the network of chemical reactions taking place in cyanidin-3-O-glucoside were affected by the presence of β-cyclodextrin. Molecular inclusion in the β-cyclodextrin cavity resulted in the increase of the isomerization observed rate constant (kobs) at pH 5.3 and in the increase of the hydration equilibrium constant Kh which is in agreement with the fading of the anthocyanin solution. For the macrocycle α-cyclodextrin, no significant changes were observed on the equilibrium and kinetic constants, which suggests that the inclusion of cyanidin-3-glucoside in the α-cyclodextrin's cavity is not favored.  相似文献   

14.
This research was the first to investigate nutritional components, including soluble phenolics (isoflavones and anthocyanins), protein, oil, and fatty acid as well as antioxidant activities in different coloured seed coat soybeans (yellow, black, brown, and green) for two crop years. The soluble phenolics differed significantly with cultivars, crop years, and seed coat colours, while protein, oil, and fatty acid exhibited only slight variations. Especially, malonylgenistin and cyanidin-3-O-glucoside compositions had the most remarkable variations. Green soybeans had the highest average isoflavone content (3079.42 μg/g), followed by yellow (2393.41 μg/g), and black soybeans (2373.97 μg/g), with brown soybeans showing the lowest value (1821.82 μg/g). Anthocyanins showed only in black soybeans, with the average contents of the primary anthocyanins, cyanidin-3-O-glucoside, delphinidine-3-O-glucoside, and petunidin-3-O-glucoside, quantified at 11.046, 1.971, and 0.557 mg/g, respectively. Additionally, Nogchae of green soybean and Geomjeongkong 2 of black soybean may be recommended as potential cultivars owing to the highest average isoflavone (4411.10 μg/g) and anthocyanin (21.537 mg/g) contents. The scavenging activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radicals also differed remarkably, depending upon isoflavone and anthocyanin contents, with black soybeans exhibiting the highest antioxidant effects.  相似文献   

15.
《Meat science》2009,81(4):1205-1211
The influence of ageing and cooking on the Raman spectrum of porcine longissimus dorsi was investigated. The rich information contained in the Raman spectrum was highlighted, with numerous changes attributed to changes in the environment and conformations of the myofibrillar proteins.Predictions equations for shear force and cooking loss were developed from the Raman spectra of both raw and cooked pork. Good correlations and standard errors of prediction were obtained for both WB shear force and cooking loss, with the raw and the cooked samples showing almost identical results R2 = 0.77, root mean standard error of prediction (RMSEP)% of mean = 12% for shear force; R2 = 0.71, RMSEP% of mean = 10% for cooking loss. The Raman spectra were also able to predict the extent of cooking that occurred within the pork (R2val = 0.94, RMSEP% of range = 5.5%).Raman spectroscopy has considerable potential as a method for non-destructive and rapid determination of pork quality parameters such as tenderness. Raman spectroscopy may provide a means of determining changes during cooking and the extent to which foods have been cooked.  相似文献   

16.
Infrared spectroscopy was used for multivariate determination of linoleic (LA) and linolenic (ALA) acids in yellow and brown flax seed samples, using partial least square regression (PLSR). The models were developed by correlating near-(NIR) and mid-infrared (MIR) spectroscopic signals with the acid content determined by GC-FID. For the flax seed samples, the best models for both, LA (R2 = 0.90, Standard Error of Prediction (SEP) = 1.61) and ALA (R2 = 0.86, SEP = 0.63) were obtained by processing the NIR spectral data. For samples of flax seed flours, the best models for prediction of the ALA (R2 = 0.99, SEP = 1.21) and LA content (R2 = 0.88, SEP = 0.76) were developed by processing the NIR and MIR spectral region, respectively. This report demonstrates that NIR and MIR spectroscopies are efficient techniques for the determination and quantification of LA and ALA in flax seed and flax seed flours.  相似文献   

17.
Anthocyanins are ubiquitous plant pigments. They are hydrophilic, and have high tinctorial value hence, used as natural food colorant. The main aim of this study was characterization of Santalum album L. berries for its pigment content, nutritionally important phytoconstituents and functional attributes. Major pigment identified was cyanidin-3-glucoside (0.21% FW) as confirmed by spectral characteristics including LC–MS. Nutrients such as total carbohydrates (8.5), proteins (5.8), free amino acids (0.8 g), oil (1.5 g), ascorbic acid (1.5 μg), tocopherols (0.3 mg) and niacin (5.2 mg) per 100 g berries were determined along with total soluble solids (13.4°Brix) and phenols (3.1 mg GAE/g). Reducing power and DPPH· scavenging assays showed highest activity in methanol extract, which also efficiently protected bleaching of β-carotene (EC50 285 μg/mL) in β-carotene–linoleate model. Pigment rich crude extract was not toxic to HepG2 cells during 24 h exposure, whereas cyanidin-3-glucoside was cytotoxic (IC50 0.1 μg/mL).  相似文献   

18.
The influence of product position in a row of three similar snacks with varying calorie contents was examined in a sample of 120 students (equal numbers of males and females). Three equally sized, real cereal snack bars were arranged on a vendor’s tray in three identical boxes. Two conditions were used. In the control condition, the three boxes of snack bars were positioned from left to right in ascending order of calorie content (apple/lowest calorie content = left position; apple-chocolate/high calorie content = middle position; coco-chocolate/highest calorie content = right position). In the experimental condition (nudged group), the left and middle box positions were exchanged (apple-chocolate/high calorie content = left position; apple/lowest calorie content = middle position; and coco-chocolate/highest calorie content = right position). There was a significant effect of position on participants’ snack bar selections (χ2(2) = 14.953, p = 0.001). When the apple bar was positioned on the left, it was selected 13.3% of the time (8/60), and when it was positioned in the middle, it was selected 36.3% of the time (22/60). There was no gender effect (χ2(2) = 0.713, p = 0.70). The apple bar with lowest calorie content was selected almost three times more often when it was placed in the middle than when it was placed on the left. Changing the physical placement of the snack improved snack choices. Rearranging snacks on shelves and checkout counters in grocery stores or vending machines in schools might be an easy, inexpensive and effective intervention measure to improve consumers’ snack choices.  相似文献   

19.
The aims of this study were to assess bioactive properties (ACE inhibition and antioxidant capacity) from wheat gluten hydrolysate peptides fractionated by pH (4.0, 6.0 and 9.0), to determine peptide action mechanism, and to relate it to the secondary structure and functional groups of peptides. Gluten hydrolysate extracts (GHE) were enriched in peptides with medium hydrophobicity and molecular weight (≈ 60% MH and 5.5 kDa, respectively). Gluten peptides inhibited ACE I by uncompetitive mechanism and a direct relationship between α-helix structure and IC50% value was obtained (r = 0.9127). TEAC and cooper chelating activity from GHE 6.5 were the highest and directly correlated with MH peptides. GHE 9.0 had high carotene bleaching inhibition (47.5 ± 0.3%) and reducing power activity (163.1 ± 2.9 mg S2O32  equivalent g 1 protein), which were directly related to disulfide bonds content of peptides (r = 0.9982 and 0.9216, respectively). pH was a good alternative to select bioactive peptides from wheat gluten hydrolysate.  相似文献   

20.
The potential of Near-Infrared Transmittance (NIT) Spectroscopy for estimation of fatty acid composition in soybean seed samples was studied. Total 612 whole seed samples with wide range of variability for major fatty acids were used to develop calibration equations by applying SNV de-trend and first derivative mathematical treatment in the range of 850–1048 nm. Useful chemometric models for most important fatty acids present in soybean seed oil were developed using Modified Partial Least Squares (MPLS) regression method. In external validation oleic (r2 = 0.89, SEP = 1.61), linoleic (r2 = 0.86, SEP = 1.50) and palmitic (r2 = 0.89, SEP = 0.17) acids were predicted with good accuracy, while the predictions for linolenic acid (r2 = 0.78, SEP = 0.36) and stearic acid (r2 = 0.63, SEP = 0.11) had relatively poor accuracy. The whole-seed NIT spectroscopy equations for fatty acid estimation would be useful for improving efficiency of breeding programs aimed at altering fatty acid composition in soybean.  相似文献   

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