红三叶叶蛋白浸提和絮凝条件的研究

从牧草中提取叶蛋白是解决我国蛋白质饲料不足的一个有效途径,豆科牧草蛋白质含量高,是生产叶蛋白的优质原料.以红三叶(T.pratense cv.Badong)为原料,采用单因素和正交实验,研究了料液比、浸提时间和浸提温度对叶蛋白浸提效果的影响,并研究了不同加热温度和时间对叶蛋白絮凝率的影响.结果表明:红三叶的LPC最适浸...     

开发叶蛋白生产

制约我国畜牧业发展的一个重要因素是蛋白质饲料的短缺,本文对国外叶蛋白的生产、叶蛋白的营养价值和饲用效果、叶蛋白的生产工艺和我国开发叶蛋白生产前景的介绍与分析表明,开发叶蛋白生产是开辟蛋白质饲料来源的一条重要途径,前景广阔。     

优质蛋白补充饲料─—叶蛋白的提取

叶蛋白又称青草胶，它是从绿色植物中提取出来的一种蛋白质。这种蛋白质来自于植物茎叶，故称叶蛋白。据分析，每公斤叶蛋白干物质含蛋白质450—600克，含胡萝卜素500—1000毫克，还含有丰富的叶黄素，并含有一定量的脂溶性维生素E和维生素K，矿物质含量一般是3—8％。一公斤叶蛋白营养价值相当于数十公斤青草，而且几乎不含粗纤维，是一种优质蛋白质补充饲料。现将叶蛋白提取技术介绍如下：一、叶蛋白生产工艺目前国内外生产叶蛋白的工艺流程是：首蓿鲜叶→碾碎、加压→草（叶）汁→过滤加热→叶蛋白。具体方法是：先把首蓿鲜叶碾碎、加压…     

紫花苜蓿和洋槐叶蛋白提取试验

叶蛋白(LPC)也叫植物浓缩蛋白,蛋白质含量高达32%~60%,各类氨基酸含量和组成优于其他植物蛋白,接近动物蛋白,且富含叶黄素、叶绿素、胡萝卜素、维生素E、维生素B及矿物质等,饲用效果可代替部分鱼粉或大豆粉,以其高营养、高蛋白弥补了非反刍动物蛋白饲料的不足。提取叶蛋白后的副产品———草渣可鲜喂、青贮或干燥后饲喂反刍动物。剩余的残液浓缩后可做饲料,也可作为培养酵母的原料或肥料。我国蛋白质资源不足,利用牧草生产叶蛋白饲料,以其废液生产单细胞蛋白,是草原综合利用和加速草原建设的有效办法。研究通过对紫花苜蓿和洋槐叶蛋白进行…     

饲料桑叶蛋白提取工艺的优化

叶蛋白生产是缓解我国蛋白质饲料资源不足的有效途径。饲料桑蛋白质含量高,单位土地面积生物量大,是生产叶蛋白的优质原料。为了优化饲料桑叶蛋白提取工艺,研究了料液比、浸提液浓度、浸提温度和浸提时间4个因素对饲料桑叶蛋白提取率的影响,并通过正交试验对叶蛋白提取工艺进行了优化。结果表明,饲料桑叶蛋白浸提率在不同处理下存在差异;饲料桑叶蛋白最适浸提条件为:浸提温度为40℃,料液比为1∶16,浸提液浓度为0.5%NaOH,浸提时间为25 min,其最大提取率为2.73 g/100 g。     

叶蛋白饲料生产技术

1 叶蛋白饲料生产技术概况 叶蛋白是直接从植物鲜茎叶中提取的蛋白质制品,农作物鲜叶、树木鲜叶和牧草鲜叶中通常含有2％～6％的叶蛋白。有人测算过,就蛋白质的生产效率而言,苜蓿等每亩鲜草叶蛋白是粮饲作物的10倍,大豆的2～3倍。故发展叶蛋白工业,是缓解蛋白质饲料紧缺的途径之一。     

叶蛋白提取与应用的研究进展

叶蛋白是从绿色植物的茎叶中提取得到的一种功能性蛋白质,其粗蛋白质含量一般可达30%～60%。随着经济与科技的发展,人类营养和动物营养逐渐得到调整完善。叶蛋白作为蛋白质的良好来源,在人类蛋白质营养补充和蛋白源饲料开发中具很大的发展前景。本文根据国内外相关研究资料,概述了叶蛋白的营养价值,对目前叶蛋白常用的提取技术进行了综述和讨论,并展望了叶蛋白的应用前景,以期为未来新型叶蛋白产品开发奠定理论基础。     

叶蛋白的生产与开发新技术

<正> 叶蛋白是从植物叶子中提取出来的蛋白质,它含有丰富的氨基酸和较合理的必需氨基酸配比,可作为家禽的蛋白质饲料或人类膳食蛋白质的补充物。用于生产叶蛋白原料很多。各种豆类、薯类、     

山东省常见藜科植物叶蛋白研究及其营养价值评价

文章首次对山东省常见的10种藜科植物的叶蛋白产量及蛋白质含量进行了测定分析,并对其中提取率大于50%的三种植物的叶蛋白的氨基酸组成和含量进行了测定及营养价值评价,结果表明,藜料植物叶蛋白产量、蛋白质含量及提取率均较高,氨基酸组成齐全,含量丰富、平衡,其中藜和中亚滨藜具有较好的开发前景。由于藜科植物是典型的盐生植物,因此为开发利用山东省黄河三角洲盐渍化荒地及发展海水农业提供了理论依据。     

苜蓿中叶蛋白提取方法的研究

为了有效地从富含蛋白的牧草中提取叶蛋白，对苜蓿采用６种不同的方法进行提取试验，从中选出了最佳提取方法，并对蛋白，纤维，糖浆产品中有关元素，各种氨基酸等进行了详细分析研究，结果表明，蛋白产品中其蛋白质含量在５０％以上，纤维产品中蛋白质含量在２０％以上，值得注意的是蛋白产品中有关元素含量很高，各种氨基酸含量不但高，而且比例协调，因此，从富含蛋白的牧草中提取叶蛋白是解决我国蛋白质营养匮乏的重要途径。     

三叶草叶蛋白提取工艺优化研究

作者选用三叶草为试验材料,通过正交试验L9(3⁴)分别对料水比、加盐比、不同pH和絮凝温度4个因素进行优化。以叶蛋白提取率、蛋白质量分数为指标,以期获得三叶草叶蛋白提取的最佳优化工艺参数。正交试验表明,提取三叶草叶蛋白的最佳提取工艺为A₃B₃C₁D₂,即料水比为1∶3、加盐量为5%、pH为3.0、絮凝温度为70 ℃为最佳的提取工艺组合。本研究初步用正交试验的方法对三叶草叶蛋白的最佳提取工艺进行了优化研究,为三叶草叶蛋白的开发应用提供了理论依据。     

牧草绿肥叶蛋白生产工艺研究

随着畜牧业的迅速发展,牧草、绿肥的深加工显得越来越重要;叶蛋白又称绿色蛋白浓缩物(简称LPC),是以新鲜牧草或其他青绿植物为原料,经压榨后,从其汁液中提取的浓缩粗蛋白质产品。设计主要是利用牧草、绿肥等青料来提取叶蛋白的生产工艺和研究设计生产工艺中的一些辅助设备。该工艺流程及其工序设备相对简单合理,为开发牧草、绿肥饲料资源,发展叶蛋白质饲料的生产提供了技术支持。     

不同处理条件对苜蓿叶蛋白凝聚效果的研究

以现蕾期新鲜苜蓿Medicago sativa为材料,采用温度、pH值单因素处理及温度、加热时间、pH值和NaCl质量分数多因素处理,探讨不同方法对苜蓿叶蛋白凝聚效果的影响。结果表明,在单因素条件下,温度以75℃为宜,pH值4.0对苜蓿叶蛋白产量、叶蛋白纯度和粗蛋白提取率有显著影响。而在多因素条件下,叶蛋白的最适凝聚组合条件为温度85℃,时间2min,pH值4.0,以及NaCl质量分数0.4%。     

洋麻蛋白含量分析及叶蛋白生产利用研究

洋麻Hibiscus cannabinus干物质中粗蛋白含量18%~23%,鲜嫩枝叶味酸甜,家畜适口性好。洋麻嫩枝叶经打浆出汁后加温凝固,负压分离可生产出浓缩叶蛋白(LPC)。压榨后的洋麻残渣干燥后可加工成洋麻纤维素饲料。脱蛋白后的棕色汁液含有较多营养成分,可浓缩或直接加入饲料中。叶蛋白的生产使洋麻的综合开发利用更具经济效益和发展前景。     

Acrosin Activity Regulation by Protein Kinase C and Tyrosine Kinase in Bovine Sperm Acrosome Exocytosis Induced by Lysophosphatidylcholine

Acrosin is an important proteolytic enzyme that is capable of hydrolysing the zona pellucida in bovine oocyte. Lysophosphatydic acid (LPA) derivated from lysophosphatidylcholine (LPC) is known to trigger the acrosome exocytosis. The present study was aimed at examining the acrosin activity variations in LPC‐induced acrosome exocytosis and its regulation by tyrosine kinase, protein kinase C (PKC) and voltage‐dependent calcium channels (VDCC) in spermatozoa previously capacitated with heparin or quercetin. The enzyme activities were spectrophotometrically measured using N‐α‐benzoyl‐DL‐arginine p‐nitroanilide as an acrosin‐specific substrate. The capacitation and acrosomal reaction were evaluated by chlorotetracycline assay, and the viability and acrosome integrity were evaluated by the trypan blue stain/differential interference contrast. It was observed that LPC induced acrosome exocytosis and increased the activity of acrosin in spermatozoa previously capacitated with heparin. In heparin/LPC‐treated samples, it was observed that the inhibition of tyrosine kinase and PKC blocked the acrosome exocytosis and the acrosin activity (p < 0.05). Under these conditions, in heparin‐capacitated spermatozoa, the LPC provokes an acrosin activity increase that is independent of calcium influx through VDCC Type L. In cryopreserved bovine spermatozoa, LPC might require modulation, mainly tyrosine kinase participation with respect to PKC activity to induce acrosome exocytosis and increase acrosin activity.     

白三叶叶蛋白提取及纯化工艺

以白三叶（Trifolium repens）为材料探讨了叶蛋白的提取工艺和纯化方法。对白三叶叶蛋白提取中加热时间、温度、pH值、料液比、酸的种类等单因素以及纯化试剂甲醇、乙醇、丙酮、四氯化碳、水等进行了研究。结果表明,各单因素最佳参数为加热时间9 min,温度90 ℃,pH值 4.0,料液比1∶2,沉淀的酸为硝酸。对加热时间、加热温度、pH值和料液比进行4因素3水平正交试验,发现影响叶蛋白提取因素为pH值>温度>时间>料液比,最佳提取工艺为加热时间9 min,温度80 ℃,pH值4.0,料液比1∶2。对叶蛋白纯化结果表明,纯化剂对叶蛋白纯度的影响依次为甲醇>乙醇>丙酮>四氯化碳>水,但各种纯化剂之间差异不显著（P>0.05）。     

Lysophosphatidylcholine decreases delayed rectifier K+ current in rabbit coronary smooth muscle cells

Lysophosphatidylcholine (LPC), which exists abundantly in lipid fraction of oxidized low density lipoprotein, has been implicated in enhanced agonist-induced contraction and increase of intracellular Ca2+. The effect of LPC on the activity of delayed rectifier K+ current (I(dK)), which is a major determinant of membrane potential and vascular tone under resting condition, was examined in rabbit coronary smooth muscle cells using whole cell patch clamping technique. Application of LPC to the bath solution caused a concentration-dependent inhibition of I(dK), and the concentration to produce half-maximal inhibition was 1.51 microM. This effect of LPC on I(dK) was readily reversed after washout of LPC in the bath. The steady-state voltage dependence of I(dK) was shifted to positive direction by both extra- and intracellular application of LPC. Staurosporine (100 nM) pretreatment significantly suppressed the LPC-induced inhibition of I(dK). These results suggest that LPC inhibits I(dK) in rabbit coronary smooth muscle cells by a pathway that involves protein kinase C, and the LPC-induced inhibition of I(dK) may be, at least in part, responsible for the abnormal vascular reactivity in atherosclerotic coronary artery.     

Colonic lymphocyte and plasma cell populations in dogs with lymphocytic-plasmacytic colitis

OBJECTIVES: To quantitate immunoglobulin-containing cells (IgA, IgG, and IgM) and CD3+ T cells in colonic biopsy specimens obtained from dogs with lymphocytic-plasmacytic colitis (LPC), and to compare lymphocyte and plasma cell populations in dogs with LPC with those in healthy dogs. ANIMALS: 10 healthy dogs and 11 dogs with LPC. PROCEDURE: Colonic mucosal specimens obtained from healthy dogs and dogs with LPC were stained specifically for IgA-, IgG-, and IgM-containing cells and CD3+ T cells by use of immunoperoxidase techniques. Morphometric analyses were done to quantitate lymphocytes and plasma cells in standardized areas of colonic mucosa. Data analyses allowed determination of mean cell numbers in each dog group, and comparison of mean numbers of lymphocytes and plasma cells between dog groups. RESULTS: CD3+ T cells predominated in healthy dogs, whereas CD3+ T cells and IgA-containing cells were most numerous in dogs with LPC. In both dog groups, the IgG- and IgM-containing cells were considerably less numerous than the other 2 cell types. Comparison of cell populations between dog groups indicated that IgA- and IgG-containing cells and CD3+ T cells were significantly more numerous in the colonic mucosa of dogs with LPC. CONCLUSIONS: Dogs with LPC have significantly increased numbers of IgA- and IgG-containing cells and CD3+ T cells. These lymphocyte and plasma cell distributions indicate similarities to and differences from such distributions in human beings with inflammatory bowel disease. Results provide a basis for future correlation between histologic stage of disease activity and immunologic findings in dogs with LPC.     

柠条叶蛋白的提取及残渣生产发酵饲料的研究

柠条枝叶中富含蛋白质和木质纤维素,为了提高柠条的利用率,采用碱法提取柠条叶蛋白,对柠条叶蛋白浓缩物的营养价值及提取蛋白后产生的残渣生产发酵饲料进行了研究。结果表明:柠条叶蛋白浓缩物(简称LPC)得率达15.4%,LPC蛋白含量达31.5%,含有多种氨基酸(色氨酸未进行测定),其中蛋氨酸和胱氨酸为限制性氨基酸,化学评分达58.6%,高于小麦(40%)和玉米(43%);另外,提取柠条叶蛋白后产生的残渣可直接用于生产发酵饲料,最佳工艺条件为接种量5%,料水比1:1.5,发酵温度30℃,发酵时间5 d,得到的发酵饲料没有发生霉变,呈亮黄色,质地良好,具有酸香味,pH值4.06,按V-Score评分体系对其评分,达到70.65%,是一种良好的动物饲料。     

Low-phytic acid corn improves nutrient utilization for growing pigs.

Thirty-five crossbred barrows averaging 14.5 kg initial BW were used in a 5-wk experiment to compare the P availability and nutritional value of a low-phytate hybrid corn (LPC, 0.26% total P, 0.08% phytic acid P) homozygous for the lpa 1-1 allele with a nearly isogenic normal hybrid corn (NC, 0.25% total P, 0.20% phytic acid P). The pigs were fed individually twice daily in metabolism pens. Three semipurified diets were created in which corn was the only source of phytate. Diet 1 contained 72% NC, 0.15% estimated available P (aP) and 0.55% Ca. Diet 2 contained 72% LPC, 0.24% aP, and 0.55% Ca. The only differences between Diets 1 and 2 were the source of corn and the levels of aP. No inorganic P (iP) was added to these diets in order to measure the animal response to the different levels of aP in the corn hybrids. Diet 3 was NC Diet 1 supplemented with iP to equal the level of aP in LPC Diet 2. Diets 4 and 5 were practical corn-soybean meal diets formulated with each corn to meet all minimum nutrient requirements and contained 0.30% aP and 0.65% Ca. For the semipurified diets, pigs fed LPC Diet 2 had higher (P < 0.01) growth performance, bone breaking strength, P absorption and retention, Ca absorption and retention, and N retention than pigs fed NC Diet 1. However, when the NC diet was supplemented with iP to equal the aP in the LPC diet, most criteria were similar (P > or = 0.2), indicating an equal nutritional value for both corn hybrids after adjusting for phytate level. The only treatment difference, other than P excretion, between the practical corn diets supplemented with soybean meal was a higher (P < 0.05) bone breaking strength for pigs fed LPC Diet 5 compared with NC Diet 4. The use of LPC in pig diets reduced P excretion in swine waste by 50 and 18.4% in the semipurified and practical diets, respectively, compared with NC. Using our in vitro procedure designed to simulate the digestive system of the pig, the availability of P for pigs was estimated at 56% for LPC and 11% for NC.