超声预处理对米渣酶解制备抗氧化肽的影响

为提高米渣酶解制备抗氧化肽的反应效率,采用超声预处理米渣。以酶解液对1,1-二苯基-2-苦基苯肼(DPPH)自由基的清除率作为评价指标,研究超声功率、超声时间、超声温度对米渣酶解产物抗氧化活性的影响。通过单因素和正交试验,得出超声预处理最佳工艺条件为超声功率150 W,超声时间15 min,超声温度50℃。在最佳条件下,酶解液对DPPH自由基的清除率为75.41%,抗氧化肽的得率为35.55%。与未经超声预处理比较,抗氧化肽得率提高了39.86%,酶解液对DPPH自由基清除率、·OH清除力和还原力吸光度的增长率分别为54.06%,64.87%和82.27%。     

超声辅助酶解茶渣蛋白制备抗氧化活性肽

利用食源蛋白制备具有抗氧化能力的天然活性肽是当前的研究热点。为了优化超声辅助酶解茶渣蛋白制备抗氧化活性肽工艺,本研究以茶渣为原料,以酶解液DPPH清除率为指标,在单因素逐级优化基础上,选定酶解pH值、温度、时间、加酶量进行4因素3水平正交试验设计和分析。结果表明,碱性蛋白酶较好,在p H值为7.5、温度50℃、时间20 min、加酶量为400 U/g、超声功率为105 W的优化条件下酶解,酶解液对DPPH清除率达为85.36%,比对照活性提高了为31.87%。可见,在本试验条件下低功率超声能有效提高碱性蛋白酶酶解茶渣蛋白效率,增加抗氧化活性肽得率,为开辟茶渣高值化利用的新途径提供实验依据。     

牦牛乳酪蛋白酶解产物抗氧化活性研究

为了研究藏区牦牛乳源抗氧化肽活性,对复合蛋白酶优化工艺制取的牦牛乳酪蛋白酶解液进行体内、体外抗氧化试验。以1,1-二苯-2-苦肼基自由基(DPPH·)、超氧阴离子自由基(O₂^-·)、羟自由基(·OH)清除率及还原力为体外评价指标,以小鼠体重、脾脏质量、超氧化物歧化酶(SOD)、丙二醛(MDA)和谷胱甘肽过氧化物酶(GSG-Px)活力为动物试验评价指标。结果表明:当酶解液蛋白浓度在0~50.0 mg/mL时,对DPPH·、O₂^-·、·OH均具有一定的清除能力,在0~30.0 mg/mL时,DPPH·清除率和·OH清除率均随着蛋白浓度的升高而提高,酶解液蛋白浓度为50.0 mg/mL时对DPPH·、O₂^-·和·OH的清除率分别达到66.45%±1.59%、60.40%±1.96%和46.02%±2.26%,另外还原能力也达到了1.775±0.004,具有较强的抗氧化活性,但都始终低于VC。小鼠试验结果表明,小鼠的体重及脾脏指数与对照组相比,中剂量组和高剂量组均有显著增加,其中脾脏指数最高增加了17.01%。与对照组相比,低、中及高剂量组小鼠血清中SOD活力与GSH-Px活力均有提升,MDA含量有一定程度的下降。因此说明牦牛乳酪蛋白酶解产物具有一定的抗氧化活性。     

响应面法优化牡蛎多肽酶解工艺的研究

测定了牡蛎的基本组成和氨基酸分析,采用蛋白酶水解其蛋白制备牡蛎多肽,以水解度和氮素回收率为指标,并以DPPH·清除率为优化指标,确定中性蛋白酶为最佳用酶。研究了温度、pH值、酶解时间、料液比和加酶量对DPPH·清除率的影响。用Design Expert 8.0软件进行响应面最佳条件优化,确定最适酶解条件为50℃,pH值7.0,酶解时间4 h,料液比1∶10,加酶量1 400 U/g,优化后DPPH·清除率达到74.43%,为牡蛎的综合利用提供了一种新方法。     

菌酶联合反应制备兔血抗氧化低聚肽

以兔血为原料,依次采用枯草芽孢杆菌发酵和碱性蛋白酶水解制备兔血抗氧化低聚肽,选取ABTS⁺·清除率和多肽含量作为评价指标,通过响应面试验优化发酵工艺和酶解工艺,确定最优发酵工艺参数和最优酶解工艺参数。结果表明,最优发酵工艺参数为:接菌量5.5 CFU/mL,底物浓度10 g/mL,发酵温度35℃,发酵时间3.5 d,此条件下,兔血低聚肽ABTS⁺·清除率为84.42%,多肽含量为2.84 mg/mL;最优酶解工艺参数为:酶底比200 U/g,酶解时间2.5 h,pH 10.4,酶解温度60℃,此条件下制备得到的兔血低聚肽的ABTS⁺·清除率为87.22%,与单一发酵工艺比较,差异不显著,而多肽含量为3.81 mg/mL,较单一发酵提高了1.34倍。综上,菌酶联合反应制备兔血抗氧化低聚肽法优于传统单一发酵法。     

蚕蛹蛋白抗氧化肽的制备及其纯化

以DPPH自由基清除率为指标,采用正交试验,优化Alcalase酶解蚕蛹蛋白制备抗氧化肽的工艺条件;采用超滤、DEAE-52纤维素柱层析,以及Sephadex G-50柱层析分离纯化蚕蛹蛋白抗氧化肽。试验结果表明,酶解液制备蚕蛹蛋白抗氧化肽的最优工艺条件为:酶解温度30℃,pH值7.5,时间20min,底物质量分数3%,加酶量3.5%。Mr≤5ku时,组分有很强的体外抗氧化活性,从Mr≤5ku组分中获得了5个抗氧化肽组分,它们的体外抗氧化活性大小依次为:组分Ⅱ>组分Ⅲ>组分Ⅰ>组分Ⅴ>组分Ⅳ。     

虾夷扇贝裙边糖胺聚糖的提取及其体外抗氧化活性研究

以虾夷扇贝裙边为原料,采用复合蛋白酶进行酶解,研究糖胺聚糖的最佳提取工艺条件及其体外抗氧化活性。结果表明,酶解虾夷扇贝裙边提取糖胺聚糖的最优工艺条件为提取时间3.0 h,酶添加量0.8%,提取温度50℃,料液比1:2,糖胺聚糖提取率为1.27%。体外抗氧化试验结果表明,提取的虾夷扇贝裙边糖胺聚糖具有较好的抗氧化活性,可清除·OH,O_2~-·,DPPH·,其清除能力与浓度具有显著的量效关系。     

低值水产品蛋白资源酶解产物的抗氧化性分析和评价

为分析评价水产品蛋白酶解产物活性特性及合适水解蛋白酶类的选择。采用不同的商品化蛋白酶和枯草蛋白酶BPN对市场上常见的经济鱼类白鲢和彩云雕蛋白进行酶解,测定各种酶在水解过程中的水解度,并对酶解产物的抗氧化活性进行了比较分析。结果表明：蛋白酶在水解反应的前20 min内水解度迅速增加,20~120 min之间逐渐达到平衡。复合蛋白酶和水解蛋白酶具有较强的水解能力,其中水解蛋白酶对彩云雕2 h的水解产物最高可达15.92%。白鲢鱼枯草蛋白酶水解液的抗氧化活性最好,其DPPH清除能力为87.11%。不同蛋白酶水解不同的水产品蛋白产生的酶解产物活性肽成分具有明显的差异。     

制备乳清抗氧化肽的水解条件优化

采用碱性蛋白酶、中性蛋白酶和胰蛋白酶3种酶对乳清蛋白进行酶水解试验,研究了不同酶解产物、水解时间、水解温度和pH值下的乳清抗氧化肽的水解度和TBARS值,确定了制备乳清抗氧化肽的最佳水解参数。结果表明,乳清蛋白水解物具有抗氧化活性,最佳复配条件是碱性蛋白酶的水解时间5 h,最佳水解温度为65℃,pH值8.5;胰蛋白酶的水解时间1 h,最佳水解温度为45℃,pH值8.0。当水解度达到32.28%时,乳清肽具有较强的抗氧化能力。     

酶解法制备玉米蛋白抗氧化肽的工艺研究

我国为玉米种植大国,玉米年产量达2.5×10~8t。在食品行业中,玉米目前主要用来生产玉米淀粉和玉米油,而副产物玉米蛋白却被丢弃掉,造成蛋白资源的极大浪费。以玉米蛋白粉为原料,首先超声预处理玉米蛋白(超声功率500 W,超声时间10 min),然后以超声预处理过的玉米蛋白为原料,采用酶解法,以水解度及体外抗氧化活性为考查指标,通过单因素试验和正交试验优化酶解法制备玉米蛋白抗氧化肽的工艺参数。最终得到制备玉米蛋白抗氧化肽的最佳工艺参数为超声功率500 W,超声时间10 min,碱性蛋白酶[E]/[S]为10%,胰蛋白酶[E]/[S]为6%,酶解温度60℃,pH值9.0,酶解时间2 h。其中,酶解温度和pH值对玉米蛋白抗氧化肽的ABTS·清除活性影响最大。     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Evolution under domestication involving disturbance of genic balance

Summary An hypothesis is developed that the rapid change from wild plants into domesticated crops principally involves the selection of alleles with non-functional gene products which leads to reduced control of the highly integrated metabolism and morphogenesis previously accumulated by lengthy natural selection. Such disturbance of the genome produces altered physiological and morphological development which, although deleterious in nature, serves mankind better and has been selected.     

Genetic variation for disease and nematode resistances and forage quality in perennial diploid and tetraploid lucerne populations (Medicago sativa L.)

Summary Twenty-five lucerne populations of the Medicago sativa complex, which were either diploid or tetraploid and wild or cultivated, were analysed for their resistance to four different fungal diseases and to stem nematode. Forage quality, including stem digestibility and saponin content, was also tested.Populations varied in susceptibility to the diseases caused by Colletotrichum trifolii, Verticillium albo-atrum, Sclerotinia trifoliorum and Pseudopezizza medicaginis, and to the nematode Ditylenchus dipsaci. Except for Sclerotinia rot, sativa and falcata subspecies differed in susceptibility, but this grouping of populations did not account for the full range of variation among them. However, the resistance to P. medicaginis was much lower in the sativa than in the falcata populations.Populations also varied significantly in stem fiber content and digestibility. Stem digestibility was negatively correlated to forage yield. Wild sativa and falcata populations had lower fiber content and higher digestibility than cultivated sativa populations. The medicagenic acid was the sapogenin responsible for the anti-nutritional effect of the lucerne measured by the yellow mealworm larvae Tenebrio molitor. The medicagenic acid content was lowest for the pure sativa populations, highest for the pure falcata populations, and intermediate for the French sativa varieties that have some traits originating from falcata germplasm. Some populations could be used in breeding programs to improve disease and nematode resistance, and forage quality.     

Review of Effects of Active Components of Gastrodiae Rhizoma on Central Nervous System

In order to explore the pharmacological effects of active components of Gastrodiae Rhizoma on the central nervous system,through consulting related literatures,...     

Effects of Pb on Rhizosphere Soil Enzyme Activity and Chemical Constituents of Achyranthes bidentata Blume

[Objectives]The purpose of this study was to investigate the effects of Pb on rhizosphere soil enzyme activity and chemical constituents of Achyranthes bidentat...     

不同P-Zn配比对小麦幼苗微量元素营养的影响

采用了螯合-缓冲营养液培养方法对小麦进行了苗期培养试验,在3个P水平(0,0.6,3.0 mmol/L)和3个Zn水平(0,3,30 μmol/L)的完全组合下对小麦苗期生长及Zn、Fe、Cu、Mn营养进行了研究,旨在为小麦微肥施用提供理论依据.结果表明,P、Zn的正常供应促进了小麦生长,二者的缺乏与过量均会抑制小麦发育,且这种影响在冠部表现得更为明显.在小麦苗期,Zn与Cu的吸收存在明显的拮抗作用,但供Zn则促进了Zn和Cu的转运,而Mn转运则受到了抑制;过量供Zn时,大量Zn被转运到冠部,同时明显抑制了(Fe+Cu+Mn)的吸收总量;P的供应显著地抑制了Fe的吸收,但P的供应提高了Zn、Cu、Mn的转运率;P、Zn在对Zn与Fe、Cu、Mn间吸收竞争的影响中,Zn本身的影响要比P的影响更为明显,供Zn明显促进了小麦幼苗对Zn的吸收;在小麦幼苗冠部,Zn与Fe的竞争中,供P利于Zn的吸收,缺P则利于Fe的吸收;而Zn与Cu以及Zn与Mn间的竞争中,缺磷时利于Zn的吸收,供磷后则利于Cu和Mn的吸收.总之,小麦幼苗Zn、Fe、Cu、Mn营养中,P、Zn的不同配比会不同程度地改变Zn与Fe、Cu、Mn的协同或拮抗效应.