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1.
α-Amylase, a starch splitting enzyme, was purified to homogeneity from post-harvest Pachyrhizus erosus L. tuber by successive chromatography on DEAE- and CM-cellulose columns. Purification achieved was 110 fold from the crude extract with a yield of 22.8%. SDS-PAGE showed a molecular weight of 40 kDa for the enzyme. The enzyme is of α-type as it lost total activity in the presence of EDTA, a chelating agent. It is a glycoprotein that contains 2.6% sugar as estimated by the phenol-sulfuric acid method. The enzyme displayed optimum activity at pH 7.3 and 37 °C with an apparent Km value of 0.29% for starch as substrate. The enzyme was strongly inhibited by Cu2+, Fe2+ and Zn2+, moderately by Li2+, Hg+ and Cd2+ and slightly by Ag+, Mg2+ and K+. Calcium ion almost doubled the activity whereas Fe3+, Mn2+ and Na+ enhanced it appreciably.  相似文献   

2.
Yam soluble fiber (YSF) extracted from Pachyrhizus erosus was added (1 g per 100 mL) to a stirred yogurt (SYYSF). Its syneresis and microstructure properties were evaluated and compared to those of a stirred yogurt (SYC) without added YSF. The SYC yogurt exhibited a more compact casein micelle aggregates network than that of the SYYSF yogurt which was more open, relaxed and covered with fibrous structures attributed to the YSF components. The rheological analysis showed that the SYYSF yogurt had lower storage modulus (G′) and loss modulus (G″) values in the linear viscoelastic region than the SYC yogurt, but its flow behavior was characterized by a lower flow index (n), higher consistency index (k), and higher yield stress (τ0) than the SYC yogurt. Incorporation of the YSF reduced significantly the syneresis and produced a more acceptable mouthfeel in the SYYSF yogurt in comparison to the SYC yogurt, indicating the viability of the process to obtain a commercial product.  相似文献   

3.
The kernels from Canarium album L. (also called Chinese olive), largely cultivated in the southeast of China, were analyzed for their nutritional composition. The kernels had a high percentage of fats (52.8%) and proteins (29.5%). Soxhlet extracted kernel oil presented acid, iodine and saponification values of 0.56, 84.6 and 192, respectively. Gas chromatography–mass spectroscopy (GC–MS) analysis of kernel oil revealed that oleic acid (30.5%) and linoleic acid (41.8%) were the major unsaturated fatty acids, while palmitic acid (18.0%), stearic acid (7.83%) and arachidic acid (0.39%) were the main saturated ones. Potassium, calcium and magnesium were the predominant mineral elements present in the kernels. Sodium, iron, manganese and zinc were also detected in appreciable amounts. The kernel proteins were rich in arginine, glutamic and aspartic acids (3.19%, 5.02% and 2.47%, respectively) while the limiting amino acids were methionine and lysine.  相似文献   

4.
Yellow mombin (Spondias mombin L.) is a tropical fruit with increasing acceptance in both national and international fruit markets. The aim of this work was to evaluate the centesimal composition, mineral content, total phenolics, antioxidant activity, and characterize the carotenoids of frozen yellow mombin pulp. Results indicated that the yellow mombin pulp contained an important amount of potassium and copper. The antioxidant activity and total phenolic values scored 17.5 mmol TEAC g−1 and 260 mg galic acid/100 g respectively, higher than those reported for other fruits. Five carotenoids were identified, ??-cryptoxanthin, lutein, zeinoxanthin, ?? and ?? carotene, being ??-cryptoxanthin the major one, accounting for the high level of pro-vitamin A activity in the pulp. A 100 g portion of yellow mombin pulp can provide more than 37% of the recommended daily allowance of vitamin A.  相似文献   

5.
An activity-directed fractionation and purification process was used to identify the acetylcholinesterase inhibitory-active components of Rhodiola rosea L. (RR). Dried rhizome of RR was extracted with boiled ethanol. After removal of tannins, the extract was separated into chloroform, ethyl acetate, n-butanol and water fractions. Among these, chloroform and n-butanol fractions showed stronger activity by bioassay for anti-cholinesterase activity than did ethyl acetate and water fractions. The chloroform fraction was then subjected to separation and purification using silica gel column chromatography and Sephadex LH-20 chromatography. One compound, showing strong anti-cholinesterase activity, was identified by spectral methods (NMR, UV and MS) and by comparison with authentic samples. It proved to be hydroquinone.  相似文献   

6.
In this study, chemical composition of the 17 different hazelnut varieties grown in the Black Sea Region of Turkey was investigated. The main fatty acids in hazelnut varieties were oleic (79.4%), linoleic (13.0%) and palmitic acid (5.4%). The ratios of polyunsaturated/saturated and unsaturated/saturated fatty acids of hazelnuts varieties were found to be between 1.23 and 2.87, and 11.1 and 16.4, respectively. The average niacin, vitamin B1, vitamin B2, vitamin B6, ascorbic acid, folic acid, retinol and total tocopherol contents of hazelnut kernels were 1.45 mg/100 g, 0.28 mg/100 g, 0.05 mg/100 g, 0.5 mg/100 g, 2.45 mg/100 g, 0.043 mg/100 g, 3.25 mg/100 g and 26.9 mg/100 g, respectively. The amount of the essential amino acids, mostly as arginine (2003 mg/100 g) and leucine (1150 mg/100 g), and the non-essential amino acids, mostly as glutamic acid (2714 mg/100 g) and aspartic acid (1493 mg/100 g) were also determined in the hazelnut varieties. Mineral compositions of the hazelnut varieties, e.g., K, Mn, Mg, Ca, Fe, Zn, Na and Cu were (averagely) measured as 863 mg/100 g, 186 mg/100 g, 173 mg/100 g, 5.6 mg/100 g, 4.2 mg/100 g, 2.9 mg/100 g, 2.6 mg/100 g and 2.3 mg/100 g, respectively.  相似文献   

7.
The kernels of Canarium pimela L., obtained from Guangdong Province, PR China, were analysed for their proximate composition, fatty acid composition, amino acid profile and mineral contents. The kernels were abundant in fats (59.7%) and proteins (23.9%). The acid, iodine, and saponification values of the kernel oil were 0.33, 92.4 and 191, respectively. Oleic acid (43.0%) and linoleic acid (26.5%) constituted the main unsaturated fatty acids of the kernel oil, while palmitic acid (24.8%) was the major saturated fatty acid. The kernel proteins were rich in glutamic acid, arginine and aspartic acid (21.0%, 12.5%, and 6.80%, respectively), but not the limiting amino acid lysine (2.37%). The mineral elements were also involved in this study. The results indicated that C. pimela L. kernels may be a potential source of oil or protein for the human diet.  相似文献   

8.
It was found that ducks fed with Potamogeton crispus L. could lay natural red-yolk eggs with good quality in vast lake areas. P. crispus L. was found to be a new resource of carotenoids based on this fact. Carotenoids from P. crispus L. were extracted using petroleum ether-acetone and saponified using 40% methanolic potassium hydroxide. Four major yellow carotenoid pigments were obtained by a MgO column and thin-layer chromatography. These carotenoids were identified as neoxanthin, violaxanthin, lutein and β-carotene based on visible spectra in different solvents compared with values reported in the literature, functional group tests and mass spectrum by LC-MS. The content of total carotenoids from P. crispus L. was measured to be 231 μg/g (dry weight) by visible absorption spectroscopy.  相似文献   

9.
The seasonal variation of the essential oil composition, the antioxidant activity (DPPH, FRAP assays) and the total phenolic content (Folin-Ciocalteu assay) of two aromatic wild plants, Pistacia lentiscus L. (Anacardiaceae) and Myrtus communis L. (Myrtaceae), grown in Zakynthos, a Greek island, was investigated. The essential oil was obtained by hydrodistillation and subsequently analysed by GC–MS.  相似文献   

10.
11.
Glucosinolates in different ecotypes of Brassica rapa L. subsp. sylvestris L. Janch. var. esculenta Hort. widely distributed in Southern Italy and locally known as “friariello” and “cima di rapa”, were characterized and their glucosinolate composition was compared with that of broccoli (Brassica oleracea L. var. italica).  相似文献   

12.
The identity and quantity of coumarin-like compounds in leaves and anthodia of Matricaria chamomilla L. were studied by LC-DAD and NMR. So far, two monosubstituted coumarins, herniarin and umbelliferone, and two herniarin precursors were identified therein. In this paper, two other coumarin glycosides and one aglycone were confirmed. Skimmin (umbelliferone-7-O-β-d-glucoside), daphnin (daphnetin-7-O-β-d-glucoside) and daphnetin (7,8-dihydroxycoumarin) were found for the first time in diploid and tetraploid leaves and anthodia of M. chamomilla L. Daphnetin is known as a strong sensitizer, so this compound and its glycosidic derivative can contribute to the allergic potential of chamomile. Commercial chamomile preparations were tested for their presence.  相似文献   

13.
The Okinawan folks in Japan use Ficus pumila L. as a beverage or herbal medicine to treat diabetes and high blood pressure. Four flavonoid glycosides were isolated and identified as rutin (1 and 3), apigenin 6-neohesperidose (2), kaempferol 3-robinobioside (4) and kaempferol 3-rutinoside (5). Among these compounds, rutin exhibited the strongest antioxidant activity in DPPH radical scavenging assay and superoxide radical inhibition assay. The preparation of Ooitabi leaves in water provide sufficient amount of flavonoid glycosides to the Okinawan although 50% of aqueous ethanol extracted these flavonoid glycosides more effectively. These results show the potential of Ooitabi leaves as a natural source of antioxidant for health management.  相似文献   

14.
A water-soluble peptide MC2-1-5 from Momordica charantia L. Var. Abbreviata Ser., with hypoglycemic effect, was purified by ultrafiltration, gel filtration chromatography and reverse-phase high performance liquid chromatography (RP-HPLC). The infrared (IR) spectra showed characteristic absorption peaks and the molecular mass of MC2-1-5 was found to be 3405.5174 Da by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS). The sequence of its first 10 N-terminal amino acids was GHPYYSIKKS as determined by a protein sequencer. MC2-1-5 reduced the blood glucose level in alloxan-induced diabetic mice by 61.70% and 69.18% at 2 and 4 h, respectively, after oral administration at a dose of 2 mg/kg. The oral glucose tolerance test (OGTT) showed MC2-1-5 produced a reduction of 25.50%, 39.62% and 41.74% in blood glucose level after 1, 2 and 3 h, respectively, of oral administration compared with a diabetic control.  相似文献   

15.
Table olives' flavour plays an important role in consumer's acceptability and it depends on various factors such as varieties, intrinsic characteristics, ripening of fruit and processing technologies. Flavour biogenesis is also influenced by addition in brine medium of lactic acid bacteria as inoculants, which reduce spoilage risks and improve sensory characteristics. In this work, flavour profiles of uninoculated and inoculated table olives with Lactobacillus plantarum (cv. Moresca and Kalamata) have been analytically characterised and compared. Twenty-one volatile compounds comprise alcohols, aldehydes, ketones, esters as well as acids formed during Greek-style olive fermentation (3 months brining after) have been characterised by gas chromatography and GC/mass spectrometry. Very high contents of ethanol and appreciable amounts of ethyl acetate, isobutanol, 2-butanone, 1-propanol and 1-hexanol were revealed in all samples with a significant increase in inoculated samples with respect to uninoculated ones. Also 1-butanol, 3-pentanol, 3-hydroxy-2-butanone, cis-3-hexen-1-ol and 2-butanol which were present in lower amounts, disclosed a meaningful increase in inoculated samples of both varieties, especially in Moresca inoculated sample. Acetic acid, isopentanol, 2-pentanol, propyl acetate, ethyl propanoate and 4-penten-1-ol showed a significant increase in inoculated Kalamata sample. These results showed that inoculation of brine medium with lactic acid bacteria starters significantly influenced aroma profiles of both varieties, in particular an increase in concentration of various flavour compounds has been revealed in inoculated table olives.  相似文献   

16.
The physicochemical, morphological and crystal structure characterization of the starches separated from rhizomes of Dioscorea opposita Thunb. Dioscorea alata Linn., Dioscorea nipponica Makino, Dioscorea bulbifera Linn. and Dioscorea septemloba Thunb. were studied and compared. Amylose content varied between 13.58% and 20.05%. Water-binding capacity, swelling power, solubility and total starch content of starches differed significantly. Scanning electron micrographs revealed that the surface was smooth or rough, the granules were oval to spherical and the size was obviously different. D. nipponica displayed A-type pattern. D. opposita D. alata, D. septemloba and D. bulbifera starches all exhibited C-type crystal. While the crystallinity degree of the starches separated from the five species were about 33.90%, 37.63%, 43.11%, 32.06% and 53.35%, respectively. The gelatinization transition temperatures (To, Tp and Tc) and enthalpy of gelatinization (ΔHgel) and peak height index (PHI) were determined. D. OT, D. AL and D. BL starches showed the higher enthalpy of gelatinization. Pasting viscosity of D. OT and D. BL starches were much higher than others. The five plants could be separated into two groups: D. OT, D. AL and D. BL; D. ST and D. NM.  相似文献   

17.
The phenolic compounds and organic acids of turnip (Brassica rapa var. rapa L.) edible parts (leaves and stems, flower buds and roots) were determined by HPLC–DAD and HPLC–UV, respectively. The results revealed a profile composed of 14 phenolics (3-p-coumaroylquinic, caffeic, ferulic and sinapic acids, kaempferol 3-O-sophoroside-7-O-glucoside, kaempferol 3-O-sophoroside-7-O-sophoroside, kaempferol 3-O-(feruloyl/caffeoyl)-sophoroside-7-O-glucoside, kaempferol 3,7-O-diglucoside, isorhamnetin 3,7-O-diglucoside, kaempferol 3-O-sophoroside, 1,2-disinapoylgentiobiose, 1,2′-disinapoyl-2-feruloylgentiobiose, kaempferol 3-O-glucoside and isorhamnetin 3-O-glucoside) and six organic acids (aconitic, citric, ketoglutaric, malic, shikimic and fumaric acids). The quantification of the identified compounds showed kaempferol 3-O-sophoroside-7-O-glucoside, kaempferol 3-O-(feruloyl/caffeoyl)-sophoroside-7-O-glucoside, isorhamnetin 3,7-O-diglucoside and isorhamnetin 3-O-glucoside as the main phenolics, and malic acid as the organic acid present in highest amounts. A screening of the antioxidative potential was also performed by means of the DPPH radical scavenging assay. Turnip flower buds exhibited the strongest antioxidant capacity.  相似文献   

18.
The air-dried fruit hull of Phyllanthus emblica L. was extracted with 95% ethanol, and then the extract was partitioned by diethyl ether and ethyl acetate (EA). The EA fraction was then subjected to separation and purification using silica gel and Sephadex LH-20 column chromatography repeatedly to obtain five hydrolysable tannins. They were identified as mucic acid 1,4-lactone 3-o-gallate (C1), isocorilagin (C2), chebulanin (C3), chebulagic acid (C4) and isomallotusinin (C5) using mass spectrometry and nuclear magnetic resonance (NMR) spectrometry. Isomallotusinin and chebulanin were identified from emblica dried fruit hull for the first time, and isomallotusinin was the first time identified from Phyllanthus. Furthermore, the antioxidant abilities of these hydrolysable tannins were investigated using DPPH and ABTS+ radical scavenging systems. All hydrolysable tannins showed strong DPPH and ABTS+ radical scavenging activities. Isomallotusinin and chebulagic acid exhibited the highest antioxidant activity compared to other purified compounds tested.  相似文献   

19.
The aim of this study was to investigate the chemical composition of Origanum vulgare L. essential oil, the inhibitory effect of the oil on the cell viability of Staphylococcus aureus strains isolated from foods, and the influence of sub-inhibitory concentrations of the oil on some physiological attributes of these strains. GC-MS analysis showed that carvacrol (57.71%) was the most prevalent compound in the oil, followed by p-cymene (10.91%), γ-terpinene (7.18%), terpinen-4-ol (6.68%) and thymol (3.83%). The results showed that O. vulgare essential oil at 0.03, 0.6 and 0.12 μL mL−1 inhibited the cell viability of Staph. aureus. At 0.12 μL mL−1 the oil caused cidal effect with decrease ≥3 log cycles of the initial inoculum after 15 min of exposure. Sub-inhibitory concentrations (0.03 and 0.015 μL mL−1) of the oil suppressed some physiological attributes of the Staph. aureus strains such as coagulase, lipase and salt tolerance. The oil interfered on the microbial metabolic activity in a dose-dependent manner. O. vulgare essential oil could be a novel antimicrobial with capability to suppress some physiological characteristics, in addition to inhibit the growth and survival of pathogen bacteria in foods, particularly Staph. aureus.  相似文献   

20.
Lactuca sativa L var. anagustata is widely used as both a delicious vegetable and a traditional medicine in China. Chemical investigation of the methanolic extract of L. sativa L var. anagustata has now led to the isolation of three new sesquiterpenes, together with eight known ones. All the compounds were isolated by chromatography on a silica gel column and preparative thin-layer chromatography (PTLC). Their structures were elucidated by means of spectroscopic methods, including 2D-NMR experiments. Cytotoxicity of the new compounds was assayed against selected cancer cell lines, including the human epithelial carcinoma (HeLa) and human colon carcinoma (HCT-116) cell lines. Radical-scavenging activities of the seven compounds were determined by DPPH radical-scavenging assay.  相似文献   

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