醇法提取大豆浓缩蛋白的工艺优化

用含水乙醇浸提法制备大豆浓缩蛋白,研究制备工艺中的固液比、乙醇浓度、浸提时间和浸提温度对蛋白质含量的影响。根据正交试验,得出最适浸提条件:固液比1:7,乙醇浓度70%,浸提时间为80 min,浸提温度为55℃,在此条件下制得蛋白质含量为73.14%的大豆浓缩蛋白。此方法制备的大豆浓缩蛋白蛋白质含量较高,将为后续实验提供优质原料。     

超声辅助双水相体系提取牛大力总黄酮的研究

利用超声耦合乙醇-硫酸铵双水相萃取技术提取牛大力总黄酮。通过单因素实验和正交实验对影响牛大力总黄酮提取的料液比、硫酸铵浓度、乙醇浓度和超声时间等因素进行探讨,以建立牛大力总黄酮的提取工艺。结果显示：影响牛大力总黄酮提取因素的主次顺序为料液比＞乙醇浓度＞硫酸铵浓度＞超声时间;最优提取条件为乙醇浓度80%、料液比1∶40(m∶V)、超声时间50 min、硫酸铵浓度为0.3 g/mL,在此条件下,牛大力总黄酮得率为5.82 mg/g。     

响应面法优化金柑多糖碱提取工艺的研究

为研究碱溶液提取金柑多糖的最佳工艺,考察液料比、提取时间、提取温度、Na OH浓度和提取次数等5个因素对金柑多糖得率的影响。在单因素研究的基础上,采用五元二次旋转正交设计对其工艺进行优化,利用SAS 9.2响应面分析程序得到回归方程。结果表明:回归方程达到显著水平,多糖的最佳碱提取工艺条件为:液料比(V/W)41∶1,提取时间3.5 h,提取温度89℃,Na OH浓度0.05 mol/L,提取次数3次。在此条件下,多糖得率为(8.56±0.23)%,与理论预测值基本一致,相比传统热水浸提法,多糖得率提高3.73倍。     

超声辅助低共熔溶剂制备咖啡果皮可溶性膳食纤维

为进一步探索制备咖啡果皮中可溶性膳食纤维的绿色新方法。本研究建立了一种省时、高效、环保的超声辅助低共熔溶剂（UAE-DESs）制备咖啡果皮可溶性膳食纤维（SDF）的方法,并通过单因素试验和响应面试验优化了其工艺参数。采用加热法制备了8种氯化胆碱基的DESs作为提取溶剂,并与传统水提法作对比。结果表明：氯化胆碱与尿素摩尔比为1∶2的DES体系制备的咖啡果皮SDF得率最高,为10.10%±0.11%,显著高于传统水提法（6.50%±0.22%）。通过单因素实验,探讨了DES组成（摩尔比、含水量、液固比）和超声波处理（超声功率、超声时间）对咖啡果皮SDF得率的影响。在此基础上,采用响应面法（RSM）结合Box-Behnken设计（BBD）对SDF得率进行优化,考察DES含水量、液固比、超声功率和超声时间对SDF得率的影响。根据RSM的优化结果,确定最佳制备条件为：DES含水量为39.91%,液固比为32.37 mL/g,超声功率为305.20 W,超声时间为33.80 min,在此条件下,咖啡果皮SDF得率最大,为10.74%±0.14%,与其预测值10.80%接近。因此,DES作为一种高效...     

绿茶总黄酮提取方法及对羟自由基清除效果比较研究

通过对传统醇提法、超声波法、微波法、微波-超声协同法4种提取方法的比较,研究绿茶总黄酮的最佳提取方法。结果表明:微波提取法的最佳工艺条件为乙醇浓度70%,液固比45∶1,微波时间40s;微波-超声协同提取法最佳工艺为乙醇浓度70%,液固比45∶1,超声时间30min。4种提取方法以微波-超声协同提取法总黄酮得率最高,并比较4种提取方法获得的绿茶总黄酮提取物对羟自由基(·OH)的清除效果,超声提取法清除·OH效果最佳。     

超声波法与传统醇提法提取茶叶总黄酮的比较研究

采用正交试验设计,对超声波法提取茶叶中总黄酮的工艺条件进行了优化,并与传统醇提法进行比较。结果表明:超声波提取法可以明显提高茶叶总黄酮得率,乙醇浓度和提取次数对超声波提取影响达到极显著水平(P<0.01),液固比的影响达到显著水平(0.01相似文献   

碱提酸沉法制取花生分离蛋白工艺研究

试验采用碱提酸沉法从花生饼粕中提取花生分离蛋白,通过单因素试验和正交试验优化了提取工艺,确定最佳提取花生分离蛋白工艺条件:浸提温度60℃,料液比1∶9,pH值9.0,浸提时间90min,酸沉pH值4.5。在此条件下蛋白质提取率可达42.5%,获得产品蛋白质含量为95.65%。     

超声波法提取普洱茶多糖的研究

为了进一步提高普洱茶中茶多糖的提取得率,试验以水为溶剂,采用超声波法从普洱茶中提取茶多糖。考察了超声温度、超声时间、固液比、提取次数对多糖得率的影响,并以正交试验设计优化工艺条件。结果表明,超声波法提取普洱茶多糖的最佳条件为提取温度70℃,超声波处理时间20min,固液比1：20,提取次数3次。     

超声波辅助提取石崖茶总黄酮工艺优化

应用正交试验方法对石崖茶总黄酮提取工艺进行优化。结果表明:各因素对总黄酮提取量影响大小依次为:料液比超声温度超声时间乙醇浓度。超声波辅助石崖茶总黄酮提取工艺最佳条件为料液比1∶40(g/m L)、乙醇浓度70%、超声时间30 min、超声温度55℃,此条件下总黄酮提取率为30.3%。采用该工艺测定广西昭平、桂平和金秀三个产地的石崖茶总黄酮含量,结果昭平石崖茶总黄酮含量最高,为30.4%。     

响应面法优化超声波辅助提取桑叶多酚工艺

以‘粤椹大10’品种的桑叶粉为原料,选择乙醇浓度、料液质量浓度、超声时间、超声功率、超声次数等5个因素做单因素实验,在这个基础上采用Box-Behnken中心组合试验设计法进行3因素3水平的实验,得到桑叶多酚提取的最佳工艺参数。最终得出的最佳提取工艺条件为:提取次数1次、超声功率400 W、乙醇浓度70%(V/V)、料液质量浓度0.030 g/m L、超声时间60 min,在此条件下桑叶多酚含量为8.33 mg/g。此结果的模型适合桑叶多酚超声波提取,可用于实际生产。     

Evaluation of the protein quality of rice supplemented with bean or crayfish in rats

Weanling male rats (45–60 g) were used to compare the supplemental effects to rice protein of bean or crayfish protein. Rats were fed various combinations of rice plus bean (B) or crayfish (C) to provide 1.6 g N/100 g of the daily diet for 28-day growth studies and a 7-day N balance period. Five different diets were fed. Six rats were assigned to each diet on the basis of body weight. Combinations of R:B of 80:20 and of R:C of 80:20 produced food intake, weight gain, PER, N intake, digested and retained N; and liver weight values that were comparable. However, increasing C to 30% of the dietary protein led to reduced value for food intake, weight gain, PER, N intake, digested and retained N, BV, NPU, and liver weight when compared with values obtained when B was increased to 30% (P<0.05). The results appear to indicate that, above a certain level of supplementation, brown bean protein is superior to crayfish as a supplement to rice protein.     

Protein efficiency ratios and net protein ratios of selected protein foods

As a part of a cooperative study initiated to assess bothin vitro andin vivo protein quality methods, the protein efficiency ratio (PER) and net protein ratios (NPR) of 15 different protein sources were determined. Male weanling Sprague-Dawley rats were fed a 10% protein diet. Fourteen-day NPR and relative NPR (RNPR) values and 14- and 28-day PER and relative PER (RPER) values were calculated for each protein source. When protein quality values were expressed relative to ANRC casein, the 14- and 28-day PER data ranked the protein sources essentially in the same order. RPER values of nonfat dried skim milk (unheated) and tuna were more than 100% that of casein; nonfat dried skim milk (heated), chickpeas, and breakfast sausage were between 50 and 70% of that of casein; and pinto beans and rice-wheat gluten cereal did not support substantial growth of the rat. The NPR method did not always rank the protein sources in the same order as the PER method. For the poor quality proteins, RNPR values were much higher than the RPER values; however, the RNPR and RPER values agreed closely for high quality protein sources.A preliminary report of this work was given at the Annual Meeting of the Federation of American Societies for Experimental Biology, Washington, D.C., March 29–April 2, 1987. Fed. Proc. 1987; 46: 889.     

Changes in the nutritive value of soy protein concentrate during autoclaving

Soy protein concentrate (Promosoy R Plus) was mixed with water to form a thick paste and autoclaved at 121°C for 10 min, 30 min, 2 h, or 4 h. Unautoclaved SPC served as a control. Nitrogen solubility measurements and SDS-PAGE analysis indicated that autoclaving resulted in the formation of soy protein aggregates, with a MW of 1 million daltons, held together by non-covalent and disulfide bonds. The 10 min, 30 min, 2 h, and 4 h SPC samples contained 6, 20, 27 and 39% less cysteine, respectively, than the SPC control. No significant differences were found in the PERs, 2.6-2-7, of a casein control, unautoclaved SPC control and 10 min and 30 min autoclaved samples. PERs of the 2 h and 4 h autoclaved samples, 2.0 and 1.9 respectively, were significantly lower than the other four diets. No significant differences were found in the apparent digestibility of the 10 min, 30 min, and 2 h autoclaved samples; the 4 h autoclaved sample however was significantly less digestible. Decreased PERs of autoclaved SPC samples were likely due to (1) crysteine destruction, (2) decreased protein digestibility, and (3) decreased food intake.     

The composition and nutritive value of protein concentrates from potato haulms

Summary Protein concentrates were prepared from potato haulms by standard, methods. There were distinct differences between potato varieties in chemical composition and nutritive value of their concentrates. The amino acid composition of proteins was similar and deficiency of sulphur amino acids was observed. The biological value of proteins of the best preparations was nearly as good as that of soya bean meal protein but their digestibility was lower.

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Zusammenfassung Aus Kartoffelkraut von 8 Kartoffelsorten wurden Eiweisskonzentrate hergestellt. Eine Parzelle der Sorte Uran wurde mit Stickstoff gedüngt (180 kg N/ha). Frisch geschnittenes Kartoffelkraut wurde gemahlen, der Saft ausgepresst, daraufhin das Safteiweiss thermisch koaguliert und nach Filtration getrocknet. Die H?lfte des feuchten Eiweisskoagulats der Sorte Merkury wurde vor dem Trocknen mit Wasser gespült, dat mit HCl auf pH 4,0 anges?uert wurde. Bei Anwendung dieser Methode konnte bis zu 155 kg Eiweiss pro Hektar erzielt werden. Die Konzentrate enthielten ungef?hr 45% Eiweiss, 12 % Fett und 18 % Asche in der Trockenmasse (Tabelle 1). Der Karotingehalt schwankte zwischen 85 mg und 335 mg und der des Solanins zwischen Spuren und 1015 mg pro Kilogramm des Konzentrates. Die Zusammensetzung der Aminos?uren aller Eiweisskonzentrate war ?hnlich (Tabelle 2). Sie enthielten verh?ltnism?ssig viel Lysin, aber wenig Schwefelaminos?uren. Dennoch enthielten sie mehr Methionin als das Sojabohnenprotein, das als Standard benutzt wurde. Es wurden deutliche Unterschiede im N?hrwert der mit Hilfe der Bilanzmethode von Thomas-Mitchell an Ratten bestimmten Proteine festgestellt (Tabelle 3). Der biologische Eiweisswert betrug 39 bis 62 und war für die besten Konzentrate fast so hoch wie für das Sojaprotein, die Verdaulichkeit war jedoch geringer. Wahrscheinlich war dies auf den hohen Aschegehalt in den Konzentraten zurückzuführen. Die Stickstoffdüngung hatte eine Steigerung der vom Hektar erzielten Eiweissmenge zur Folge. Sie hatte keinen Einfluss auf die Zusammensetzung des Eiweisses, aber erh?hte seine Verdaulichkeit. Dies konnte das Resultat eines h?heren Gehaltes an leicht l?slichen, Protein nicht enthaltenden Substanzen im Konzentrat der gedüngten Pflanzen sein. Das Spülen mit Wasser erh?hte den Gehalt aller Aminos?uren im Konzentrat und den biologischen Wert des Eiweisses, vielleicht als Folge des Auswaschens von Stickstoff aus dem Konzentrat, der nicht an Eiweiss gebunden war. Die erzielten Ergebnisse zeigen, da? das Kartoffelkraut einen guten Rohstoff für die Produktion von Eiweisskonzentraten bilden kann. Diese Konzentrate enthalten eine zufriedenstellende Menge an Eiweiss, Karotin und einzelnen Aminos?uren mit Ausnahme der Schwefelaminos?uren. Der biologische Wert des Eiweisses der besten Konzentrate ist nur et was schlechter als der des Sojabohnenproteins.

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Résumé On a réussi à produire des concentrés protéiques à partir du feuillage de 8 variétés, une partie de la culture d’Uran ayant re?u une fumure azotée (180kg N/ha). Les fanes fra?chement récoltées ont été broyées et pressées. Les protéines contenues dans le jus ont été coagulées par la chaleur et séchées après filtration. La moitié du coagulum protéique humide de la variété Merkury a été rincé avec une eau acidifiée par HCl (pH 4,0) avant séchage. Grace à cette méthode 155 kg de protéines ont été obtenus par hectare. Par rapport à la matière sèche, les concentrés contenaient environ 45% de protéines, 12% de lipides extractibles par l’éther et 18% de cendres. La teneur en carotène variait de 85 à 335 mg/kg et celle de la solanine de quelques traces à 1015 mg/kg de concentré (tableau 1). Les protéines avaient une composition en amino acides semblable (tableau 2). Elles étaient relativement riches en lysine mais pauvre en amino acides soufrés. Cependant elles contenaient plus de méthionine que la protéine du soja utilisée comme témoin. La valeur nutritive des protéines a été déterminée sur des rats par la méthode de bilan de Thomas-Mitchell. Des différences ont été constatées (tableau 3). La valeur biologique variait de 39 à 62 et pour les meilleurs concentrés était presque aussi haute que pour la protéine du soja (VB=66). La digestibilité des protéines de concentrés était relativement basse. Cela était probablement d? à leur teneur élevé en cendres. La fumure azotée a augmenté la quantité de protéines produites à l’ha. Elle n’a pas eu d’effet sur la composition en acides aminés mais a augmenté la digestibilité des protéines. Le lavage augmenterla teneur en amino acides et la valeur biologique de la protéine, peut être parce que le rin?age élimine du coagulum l’azote non protéique. Les résultats obtenus indiquent que les fanes de pommes de terre peuvent être une bonne matière première pour la production de concentrés protéiques. Ces concentrés contiennent des quantités satisfaisantes de protéines, carotène et acides a minés à l’exception des acides aminés soufrés. La valeur biologique de la protéine des meilleurs concentrés est seulement légèrement inférieure à celle de la protéine soja.

     

荔枝种子可溶性贮藏蛋白质的特点

采用蛋白质组织化学染色、SDS-PAGE、双向电泳、蛋白质免疫印迹和间接免疫荧光定位等细胞学和生物化学的技术,分离鉴定荔枝种子中可溶性贮藏蛋白质。荔枝种子富含贮藏蛋白质,积累在子叶和胚乳薄壁细胞的蛋白体里。22ku蛋白质是种子的一种可溶性贮藏蛋白质,为幼苗生长所需氮素的重要来源。该蛋白质与22ku营养贮藏蛋白质有免疫相关性,而且,两者的双向电泳图谱非常相似,表明它们具有较高同源性。由于荔枝22ku营养贮藏蛋白质具有胰蛋白酶抑制剂活性,所以,其同源物积累在种子中可能有抗虫作用。     

大豆保鲜贮藏可行性研究

对大豆特别是鲜食大豆在国内外市场上的经济地位调查考证，发现其开发利用生产潜力巨大，市场前景看好，大豆保鲜是朝阳产业，对当前大豆生产、加工方面存在的主要问题，保鲜贮藏的市场前景、经济效益，对路畅销品种，土地、光能资源的节约利用，减少环境污染，节约能源等方面的可行性进行论述。     

Effect of extent and rate of wilting on nitrogen components of grass silage

Wilting grass prior to ensiling generally increases the dry matter (DM) intake but the effect of wilting on animal performance is still poorly understood. There is a need to improve understanding of the effects of wilting on the nutritional components and chemical composition of grass silage. This study focused on the effects of the extent and rate of wilting on N components of grass silage. Meadow grass was wilted to four DM contents (200, 350, 500, 650 g kg^?1) at two different rates (fast, slow), creating a total of eight silages. Crude protein (CP) fractions were measured using the Cornell Net Carbohydrate and Protein System. Utilizable CP at the duodenum (uCP), a measure of feed protein value, was estimated using the modified Hohenheim gas test. Ruminally insoluble, undegraded feed CP (RUP) was measured using an in situ technique. Amino acid (AA) composition prior to and after rumen incubation was also investigated. Utilizable CP at the duodenum, RUP and true protein fractions B2 and B3 were increased by rapid wilting and high DM content (DM > 500 g kg^?1), although the increase with DM was only mild for uCP, probably due to lower ME content in the DM‐650 silages. Non‐protein‐N decreased with increasing DM and rapid wilting. The higher RUP content from both DM‐650 silages leads to a higher total AA content after rumen incubation. Treatment also influenced the AA composition of the ensiled material, but the AA composition after rumen incubation was similar across treatments. Rapid and extensive wilting (DM > 500 g kg^?1) improved protein value and reduced CP degradability. Increased uCP may result in higher milk protein yield, while reduced degradability may reduce N lost from urinary excretion. The primary effect of wilting on post‐ruminal AA supply from RUP appeared to be quantitative, rather than qualitative.     

水稻种子蛋白质的组成和积累形态对稻米品质的影响

设置水培试验对‘16-17’（谷蛋白前体聚合物明显,含量高）和‘16-20’（谷蛋白前体聚合物不明显,含量低）分别进行CK（氮2800 μmol/L,硫80 μmol/L）、N（氮3640 μmol/L,硫80 μmol/L）、S（氮2800 μmol/L,硫260 μmol/L）、N+S（氮3640 μmol/L,硫260 μmol/L）处理,以此改变稻米品质和稻米贮藏蛋白质的组成与含量,从而对稻米蛋白质各组分及相关品质性状进行分析。结果表明：（1）在N、S和N+S的不同处理下均增加了粗蛋白的含量,使‘16-20’的稻米粗蛋白百分含量分别增加2.35%、2.67%和2.73%;（2）在2个品种的各组分蛋白含量变化中,‘16-17’的醇溶蛋白和谷蛋白的百分含量在N、S和N+S下较对照分别增加了9.75%、4.21%和4.67%,3.92%、7.38%和12.92%。‘16-20’的谷蛋白百分含量在S和N+S处理下增加了17.72%和29.38%,醇溶蛋白百分含量在N+S下增加了3.73%,而球蛋白百分含量在N、S和N+S三个处理下降低了2.86%、3.78%和3.69%,清蛋白在N、S处理下显著降低;（3）谷蛋白的2个亚基的相对含量和57 kDa谷蛋白前体及57 kDa以上谷蛋白聚合体的积累在‘16-20’品种中明显增加。（4）稻米品质中,N、S配施对2个参试品种的碾磨品质性状的影响不明显,但有利于2个品种稻米外观品质和食味品质的改善,并使‘16-20’的营养品质显著增加,另外,‘16-20’的千粒重在S和N+S处理下显著增加。故不同N、S配施处理下,不同品种水稻贮藏蛋白质的组成和积累形态差异很大,并改变了含巯基蛋白质组分的积累量和积累形态。尤其是在富S条件下,蛋白质积累过程中形成较多的巯基及二硫键,并通过二硫键来改变含巯基的蛋白质亚基之间的聚合程度,形成不同分子量的谷蛋白聚合体,使蛋白质的积累形态发生明显改变,进而使稻米相关品质性状发生改变。     

Preparation of sunflower isolates at a pilot-plant scale

At a pilot-plant scale, various patented processes for preparation of sunflower isolates were examined. The objectives of these processes are to improve the quality of the isolates (particularly their protein content), to reduce their content of glucidic substances (which obstruct spinning) and to improve their color. A correlation exists between these parameters and isolate yields. Our results, obtained with industrial meals, should be largely improved with respect to yield and color with meals obtained from dehulled kernels which have not been subjected to as much heat-treatment as the industrial meals.     

Interrelationships of Protein Composition, Protein Level, Baking Process and the Characteristics of Hearth Bread and Pan Bread

Baking performance of hearth bread and pan bread were investigated using 10 wheat varieties with variable protein quality. For most varieties, samples were selected at two protein levels, approximately 11 and 13% (d.m.). The effects of flour quality on loaf characteristics were different for hearth bread compared to pan bread, where both protein quality and protein content affect loaf volume positively in an optimised baking test. Hearth bread is more complex as both the form ratio and loaf volume are critical external characteristics. When using fixed proving time, the form ratio was positively affected by dough resistance and mixing peak time at high speed mixing, and negatively affected by dough extensibility. Dough resistance and mixing peak time correlated strongly to the HMW glutenin composition, whereas dough extensibility was related to protein content. In contrast to the form ratio, loaf volume was positively affected by dough extensibility, whereas protein quality had no significant effect. This was seen both for doughs produced at optimal mixing time at high speed mixing (126 rev/min) and for doughs produced at fixed mixing times at low speed mixing (63 rev/min). When proving time was optimised to achieve a defined form ratio, flours of strong protein quality should be proved longer than flours of week protein quality, resulting in higher loaf volume for flours of the strongest protein quality. With respect to protein content, the positive effect of protein content on loaf volume was counteracted due to reduced proving time when aiming for a defined form ratio.