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1.
米胚芽中脂肪酶抑制剂提取工艺及其性质的研究   总被引:2,自引:0,他引:2  
主要研究了脱脂米胚芽中脂肪酶抑制剂的提取工艺及性质。通过正交实验确定了最佳的提取工艺参数:料水比1∶15,提取温度50℃,提取pH7.0,提取时间3h,此工艺能使脱脂米胚芽胰脂肪酶抑制剂的抑酶活性达43.81%未纯化。同时,米胚芽中脂肪酶抑制剂的活性成分分析表明,其主要为蛋白质。  相似文献   

2.
米曲霉固态发酵玉米胚芽粕制备玉米肽的研究   总被引:1,自引:0,他引:1  
经过单因素试验和正交试验,确定了米曲霉发酵玉米胚芽粕生产玉米多肽的最佳发酵条件:玉米胚芽粕含量为40%(60%麸皮),培养基含水量为74%,培养基接种量为7%,培养温度30℃,发酵时间84h。在此条件下玉米肽转化率达到最大为36%。并对制得的玉米肽进行了初步的分离纯化,经截留分子质量104的中空纤维柱超滤,得到分子质量在104以下的超滤液,超滤液经SephadexG-25柱分离和相对分子质量分布的测定,共洗脱出2个峰。经过计算,其各级玉米肽组分相对分子质量分别大约为5128和1626 Da。为了进一步验证这两种组分的纯度,我们在实验中用Tricine-SDS-PAGE电泳进行了验证,并证明确实主要为两种组分,与葡聚糖凝胶柱分离结果相符。  相似文献   

3.
米胚芽中胰脂肪酶抑制剂的抑制机理研究   总被引:4,自引:0,他引:4  
由米胚芽中提取的胰脂肪酶抑制剂主要为蛋白质,研究了不同因素对抑酶活性的影响,并初步探讨了从米胚芽中提取的脂肪酶抑制剂对胰脂肪酶的抑制机理抑制剂不直接与酶分子作用,而是间接改变底物乳化来阻碍底物-酶结合达到抑制作用。通过试验测定了抑制常数Ki=9.8×10-2mg/mL。从Dixon图和Lineweaver-Burk图的特征,表明该抑制剂对胰脂肪酶的抑制呈非竞争性抑制。  相似文献   

4.
米的胚芽占米粒重的2~3%,小麦胚芽占整个麦粒重的2~3.9%。米胚芽中含脂肪约23%、蛋白质21%、维生素含量特别高——占整个米粒维生素总量的66%(每百克米胚芽中含维生素B_1 3.0~8.0mg、维生索B_20.1~0.5mg、维生索B_6 4mg、烟酸35mg、维生素E66~67mg),小麦胚芽的蛋白质含量在40%以上,并且米麦胚芽中还含有钙、磷、钾、铁、镁等人体必须的各种矿物质。胚芽不仅含有极其丰富的蛋白质、脂肪、维生素和矿物质,而且其营养素对人体的效价还非同一般.据研究胚芽维  相似文献   

5.
胚芽是植物种子发芽的基点.米胚芽集中了大米营养成分之精华.大米是由“胚芽”、“米皮”(糠)、“胚乳”(白米)三部分组成.大米的营养成分,诸如蛋白质、脂肪、含水碳素、各种维生素、粗纤维和矿物质等,绝大部分存在于胚芽和糠皮中,胚乳(白米)部分主要是碳水  相似文献   

6.
<正> 米胚芽作为天然保健食品的原料越益受到人们的重视,这是因为其含有丰富的蛋白质(20—25%)和人体必需的脂肪酸——亚油酸,泛酸和烟酸等物质。另外,米胚芽中含有大量维生素 E(200mg/100g 脂肪)。因此,它能改善体质,起到防止衰老等保健作用。  相似文献   

7.
应铁进 《食品科学》1990,(11):53-56
本文总结了作者对米胚芽过氧化值测定的脂肪抽提条件以及不同过氧化值测定方法所作的对比试验。综合试验结果,以无水乙醚为溶剂,用索氏抽提器在60℃、3~4小时的条件下提取米胚芽脂肪.对所得样品不经烘干,直接进行过氧化值测定,可以得到兼顾准确性、精密度与测定工作效率的结果。用D、Pear-son(1976)推荐的Sully法测定过氧化值的精密度(CV=6.62)比相同条件下经典方法的精密度(CV=9.45)略高。回收试验的平均回收率为89.3%,变异系数为5.14。  相似文献   

8.
探讨了2种食品加工中常用的丝状真菌(米根霉和米曲霉)固态发酵小麦麸皮后,其总酚含量的变化,研究了发酵前后小麦麸皮中酚类物质对脂肪酶活性和Hep G2细胞内甘油三酯沉积的抑制作用。结果表明:发酵能显著提高小麦麸皮的总酚以及其抗氧化性(P0.05)。发酵后的小麦麸皮酚类物质抑制胰脂肪酶以及Hep G2细胞内甘油三酯沉积的活性均显著增强(P0.05)。未发酵、米根霉和米曲霉发酵的小麦麸皮乙酸乙酯萃取物抑制胰脂肪酶活性的IC50值分别是1.35、0.78和0.85 mg/m L。在90μg/m L质量浓度条件下,未发酵、米根霉发酵和米曲霉发酵小麦麸皮的乙酸乙酯组分对Hep G2细胞内甘油三酯沉积的抑制率分别为14.4%,26.2%和20.5%。  相似文献   

9.
大米胚芽中脂肪酶抑制剂的研究   总被引:3,自引:0,他引:3  
研究了脱脂米胚芽中具有抑制脂肪酶活性的物质的提取,得到最佳的提取工艺条件为:温度35℃、料水比1:5、pH6.5和提取时间3h,在此条件下米胚芽提取物对脂肪酶活力的抑制率(以下简称抑酶率)为46.7%;最佳的脱脂溶剂为正己烷。通过对米胚芽提取物进行热和蛋白酶处理的结果初步断定,提取物中抑酶活性成分为蛋白质。  相似文献   

10.
黑龙江省绥化市江川机械制造公司与哈尔滨工业大学合作研制成功胚芽精制米机。胚芽米是指稻谷在加工过程中保留其胚芽部分的一种精制米。大米胚芽中含有丰富的蛋白质、脂肪、膳食纤维、磷、钾、镁、钙及多种维生素、谷维素等生物活性物质。胚芽米是近几年我国一些大城市兴起的新型食品。胚芽精制米机采用“一砂一铁”两辊碾米技术 ,生产过程采用微机控制 ,碾出的米洁白均匀 ,破碎率低 ,保留胚芽率达 80 %以上 ,胚芽米比普通精米营养成分可提高 2倍以上。摘自《中国食品报》1 999.1 1 .2 4胚芽精制米机研制成功…  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.
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   

16.
17.
A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.  相似文献   

18.
19.
This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.  相似文献   

20.
<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the  相似文献   

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