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1.
研究了白刺、沙棘、黑枸杞发酵果酒中黄酮、多酚、多糖、原花青素、花色苷的含量及其对铁离子的还原力和亚油酸脂质过氧化的抑制效果,采用DPPH、ABTS、H2O2/Fe2+/水杨酸、超氧阴离子自由基清除体系考察了3种果酒的抗氧化能力,并对活性成分含量与抗氧化活性进行了相关性分析。结果表明,沙棘酒中多糖含量最高,为0.605 mg/m L,其对·OH的清除率最高,为97.98%;黒枸杞酒中花色苷含量最高,为0.245 mg/m L,其对DPPH·的清除率最好,为97.14%,对铁离子的还原能力最高为11.29 mg/m L;白刺酒对O2-·的清除率最高为90.93%。对活性成分含量与抗氧化活性相关性分析表明,果酒对DPPH·的清除作用与酒中花色苷的含量呈正相关;果酒中多糖含量对·OH的清除呈正相关而对DPPH·的清除呈负相关;果酒中黄酮、多酚和原花青素含量与ABTS·及亚油酸过氧化的抑制呈正相关,与O2-·的清除率呈负相关。  相似文献   

2.
以树莓、石榴复合果汁为原料,采用自然发酵、单一添加嗜热链球菌(Streptococcus thermophilus)、单一添加干酪乳杆菌(Lactobacillus casei)及同时添加嗜热链球菌和干酪乳杆菌发酵四种方式制备酵素,并对其发酵过程中的p H值、总酚、总黄酮及抗氧化能力(·OH、O2-·及DPPH自由基清除率)变化进行研究,以评价不同制备方式对树莓-石榴复合果汁酵素抗氧化活性的影响。结果表明,混菌发酵方式优于单菌发酵和自然发酵方式,能增加树莓-石榴复合果汁酵素中总酚含量、总黄酮含量,并提高其抗氧化能力。混菌发酵72 h时,总酚含量(0.57 mg/m L)、·OH清除率(67%)及O2-·清除率(54%)最高;发酵60 h时,总黄酮含量(0.41 mg/g)及DPPH自由基清除率(94%)最高;p H值变化最小,利于发酵进行。  相似文献   

3.
以女贞子花为原料,研究女贞子花花青素的复合酶协同微波提取工艺及其体外抗氧化活性。结果表明,女贞子花花青素提取最佳工艺条件为纤维素酶和果胶酶按酶活力2︰1复合酶解,复合酶用量为0.95%,酶解温度为49.5℃,微波提取时间35 s,乙醇体积分数为89.5%,此时女贞子花花青素的提取率可达7.315 mg/g。女贞子花花青素具有较强清除DPPH·的能力。随着女贞子花花青素浓度的增加,其清除能力逐渐增强,当花青素浓度大于1.2 mg/m L时,其对DPPH·的清除率大于相同浓度的VC溶液。女贞子花花青素对OH·也有较强清除能力,当女贞子花花青素浓度大于0.9 mg/m L时,其清除OH·的能力总是大于VC,当女贞子花花青素浓度达到2.1 mg/m L,对OH·的最大清除率可达94.3%。因此,女贞子花花青素有较好的体外抗氧化活性。  相似文献   

4.
采用L18(37)正交法优化小球藻C95和小球藻C97的生长培养基,经15 L规模培养并收获小球藻;碱性乙醇法萃取游离脂肪酸,再经脲素包埋提取多不饱和脂肪酸,并用气相色谱检测二十碳五烯酸(eicosapentaenoic acid,EPA)的含量。研究结果表明:小球藻C95最优培养基(微量元素母液0.8 m L/L,维生素母液2.4 mL/L,NaH2PO4·2H2O6.0 g/L,Na2SiO3·9H2O 9.0 g/L,NaNO360.0 g/L,FeC6H5O7·5H2O 3.0 g/L);小球藻C97最优培养基(微量元素母液1.6 m L/L,维生素母液2.4 m L/L,NaH2PO4·2H2O 4.0 g/L,Na2SiO3·9H2O 11.0 g/L,NaNO380.0 g/L,FeC6H5O7·5H2O 3.0 g/L);小球藻C95和小球藻C97对数末期(分别是第4天和第5天)达到的细胞密度分别为9.53×10^7个/mL和8.91×10^7个/mL,EPA含量分别占总脂肪酸的30.2%和29.5%,小球藻C95的EPA含量要高于小球藻C97。  相似文献   

5.
为优化碱性蛋白酶酶解魔芋飞粉蛋白制备抗氧化多肽的条件,采用响应面分析法,以·OH清除率为响应值,研究酶解温度、酶用量、酶解p H值对制备抗氧化肽的影响。此外,还研究了不同分子质量魔芋多肽的抗氧化活性,结果表明:最佳酶解工艺参数:底物质量分数2.25%、温度55℃、酶用量3 228 U/g底物、p H 7.84、水解时间270 min。该条件下抗氧化多肽(18.35 mg/m L)的·OH清除率为73.41%,多肽得率为75.37%。通过Sephadex G-25和Sephadex G-15串联柱分离得到5个多肽组分,其中分子质量为1 500 u和1 000 u的组分抗氧化活性较高,其清除DPPH·的IC50分别为2.82 mg/m L和3.65 mg/m L;清除·OH的IC50分别为9.03mg/m L和14.16 mg/m L;抑制大鼠肝脏自发性脂质过氧化的IC50分别为0.21 mg/m L和0.66 mg/m L;抑制大鼠红细胞H2O2诱导氧化溶血的IC50分别为0.11 mg/m L和0.22 mg/m L。  相似文献   

6.
藤椒油体外抗氧化活性研究   总被引:1,自引:0,他引:1  
以冷榨藤椒油和溶剂萃取的藤椒油为原料,采用体外抗氧化实验研究其抗氧化能力。以BHT和VC为阳性对照,通过测定两种藤椒油还原力、对·OH、DPPH·、O-2·清除率,探讨藤椒油的抗氧化能力。结果表明,冷榨油和溶剂油的还原能力随其质量浓度的增加而增强,对·OH、DPPH·、O-2·清除率随质量浓度的增加而增大;溶剂油对·OH、DPPH·的清除率高于同质量浓度的冷榨油;冷榨油对·OH、DPPH·、O-2·的IC50值分别为4.0675、10.3052和0.5415mg/m L;溶剂油对·OH、DPPH·、O-2·的IC50值分别为1.9606、2.9465和1.6053mg/m L。当溶剂油质量浓度达到9mg/m L时,对·OH清除率达到89.79%,其清除效果高于1mg/m L VC对·OH(清除率71.82%)清除效果;当溶剂油质量浓度达到11mg/m L时,对DPPH·清除率达到86.87%,远高于1mg/m L BHT清除率(44.51%)。  相似文献   

7.
各食用米中活性成分及其抗氧化活性   总被引:2,自引:0,他引:2  
本研究以黑米、白糯米、大米、黄米、糙米、香米、玉米、薏米、西米、高粱米10种常见食用米为研究对象,测定其总黄酮、总酚含量及其体外抗氧化活性。结果显示供试食用米品种间的总酚和总黄酮含量分别在2.61~287.61 mg/g和3.79~175.43 mg/100 g之间,黑米总酚、总黄酮含量最高(分别为287.61±18.38 mg/g和175.43±3.25 mg/100 g),西米的含量均最低(分别为2.61±0.04 mg/g和3.79±0.06 mg/100 g);黑米乙醇提取液的总抗氧化能力(354.18 U/g)和总还原力(吸光度为2.91)最强,大米提取液的总抗氧化能力(4.62 U/g)最弱,而西米的总还原力(5倍稀释时吸光度为0.11)最弱;黑米对DPPH·的清除能力最高(当加入量为2μL时清除率为50%,IC_(50)=2μL),西米的清除能力最弱(当加入体积大于10~5μL时清除率为50%,IC_(50)1×10~5μL);黑米对·OH的清除能力最高(IC_(50)=250倍稀释),西米的最低(IC_(50)=1.71倍稀释);黑米对NO-2的清除能力最高(IC_(50)=500倍稀释),玉米为最低(IC_(50)=2.97倍稀释);西米和糯米对O_2~-·的清除能力最高(IC_(50)10~5倍稀释),玉米最低(IC_(50)=2.467倍稀释)。综合比较发现黑米具有较丰富的生物活性物质,抗氧化活性相对较好,本研究为进一步开发功能性米类产品提供一定的理论基础。  相似文献   

8.
以刺梨果实与冰糖按3种比例(质量比1∶1,2∶1,4∶1)制作酵素,测定酵素及刺梨自然发酵后残余果实中维生素C(VC)、总酚、类黄酮、类胡萝卜素含量及超氧化物歧化酶(SOD)活力,同时采用超氧阴离子自由基(·O~(2-))、羟基自由基(·OH)和1,1-二苯基-2-苦肼基自由基(DPPH·)体系分析体外抗氧化活性,并比较抗氧化物质与抗氧化活性之间的相关性。结果表明,果糖比1∶1制作的刺梨酵素中VC、总酚、SOD酶活性、·OH清除率与·O~(2-)清除率最高,分别达到1 519.31 mg/100mL、60.65 mg/mL、8 571.43 U/mL、78.69%和98.66%,且VC、总酚和SOD酶活性与·OH及·O~(2-)清除率呈显著到极显著正相关;果糖质量比4∶1自然发酵后残余果实中类胡萝卜素、类黄酮、总酚、·OH清除率与DPPH·清除率最高,分别为32.05 mg/100 g、13.55 mg/g、37.58 mg/g、62.42%和95.33%,且类胡萝卜素、类黄酮和总酚均与·OH及DPPH·清除率呈显著到极显著正相关。不论在刺梨酵素中,还是在刺梨自然发酵后的残余果实中,总酚与·OH清除率始终存在极显著的正相关性  相似文献   

9.
以新鲜猪皮为原料,基于凝胶特性以羟脯氨酸含量为指标,对影响胃蛋白酶酶解过程的各个因素进行研究,通过Box-Behnken设计优化酶解工艺;以清除O2-·、·OH、H2O2能力和DNA损伤保护作用为指标研究酶解产物的抗氧化功能。结果表明:最佳酶解条件为加酶量0.25%、料液比1∶2(g/m L)、酶解时间1.65 h、酶解温度41.15℃,在此酶解条件下其产物清除O2-·的IC50值为20.19 mg/m L;清除·OH的IC50值为6.36 mg/m L;清除H2O2的IC50值为0.65 mg/m L;对DNA损伤保护作用的IC50值为1.86 mg/m L。  相似文献   

10.
桑椹酵素是以桑椹汁为原料再加入有益菌发酵而来。本文研究了桑椹酵素在发酵过程中生理活性的变化,采用高效液相色谱法和比色法测定发酵过程中的葡萄糖、果糖、乙醇、有机酸、花青素、原花青素和总酚的含量,并通过羟自由基清除实验和DPPH·清除实验探究发酵过程中桑椹酵素抗氧化活力变化。结果显示:发酵30 d后,体系中葡萄糖和果糖总量下降到66.58 mg/m L,而乙醇、乳酸和醋酸含量明显增加,最后分别为27.19、4.03、4.69 mg/m L;活性成分测定实验结果显示,在发酵30 d后,桑椹酵素中花青素和原花青素含量降低,而总酚含量增加了5.0%,且抗氧化活性也增强;10倍的发酵稀释液对羟自由基清除率和DPPH·自由基清除率最大分别可达48.12%和98.16%。结论表明:桑椹酵素的抗氧化能力在发酵过程得到提升,且其变化与总酚变化存在正相关性。  相似文献   

11.
Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.  相似文献   

12.
An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.  相似文献   

13.
The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.  相似文献   

14.
The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.  相似文献   

15.
16.
A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.  相似文献   

17.
Capillary electrophoresis (CE) and polarized light microscopy (PLM) were utilized in the detection of the adulteration of locust bean gum with guar gum. For CE analyses, standards of locust bean and guar gums were extracted with 30% CH3CN, removing the residual proteins from the gum matrix. A 8.75 mM NaH2PO4-20.6 mM Na2B4O7 buffer, pH 9, was used to separate these proteins and to identify marker proteins that were present in the guar gum. These markers did not co-migrate with components in the extracts of mechanically processed locust bean gum, and are used as indicators of adulteration. Using PLM with toluidine blue and iodine staining techniques, unadulterated locust bean gum samples were distinguished from mixed samples through the differential staining of components in locust bean versus guar and tara gums. These experiments in the use of CE and PLM provide orthogonal and complementary methods for the verification of 'true' positives and the elimination of 'false' positives.  相似文献   

18.
BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H2O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.  相似文献   

19.
An investigation is described in which various polyfunctional compounds were applied to wool in attempts to stabilize the temporary improvements in wrinkle-recovery brought about by ‘annealing’. Several reactive systems involving formaldehyde were found to produce the desired permanently improved wrinkle-recovery.  相似文献   

20.
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