草鱼多肽功能性质及营养价值

研究草鱼多肽的溶解性、起泡性、乳化性、吸湿保湿性和稳定性等功能性质,以及草鱼多肽的氨基酸组成,并评价其营养价值。结果表明草鱼多肽具有良好的功能特性。草鱼多肽粉18种氨基酸总质量分数为90.94%,必需氨基酸占总氨基酸质量分数的41.33%;草鱼多肽的生物价、必需氨基酸指数、营养指数和氨基酸比值系数分别为71.51,76.34,74.81和77.19。草鱼多肽的氨基酸组成平衡、合理,是一种优质的蛋白质资源。     

磨球超微粉碎改性蚕蛹蛋白的工艺优化及功能特性

经磨球超微粉碎处理后的蚕蛹蛋白,其功能特性和结构会发生的一系列变化,在完成料液比、处理时间、p H对蚕蛹蛋白溶解度影响的单因素试验基础上,以蛋白质溶解度为评价指标,通过响应面分析法对磨球超微粉碎改性蚕蛹蛋白的工艺条件进行了优化,得到的最优工艺条件为料液比8.3 g·L-1、p H8.1、处理时间61 s.在此条件下,经处理后蚕蛹蛋白的溶解性、乳化性、乳化稳定性、起泡性和起泡稳定性分别提高了259.6%,50.0%,141.7%,61.0%和33.8%,而其持水性和吸油性却分别降低了25.3%和27.2%.     

中性蛋白酶对咸鸭蛋蛋清脱盐前后品质的影响

研究鲜鸭蛋蛋清、咸鸭蛋蛋清、脱盐咸鸭蛋蛋清,以及加中性蛋白酶的咸鸭蛋蛋清和加中性蛋白酶的脱盐咸鸭蛋蛋清的黏度、乳化性、乳化稳定性、起泡性及泡沫稳定性。试验结果表明:加酶的脱盐咸鸭蛋蛋清黏度高达58.2Pa·s,得到了极大的提升;加酶的咸鸭蛋蛋清乳化性及乳化稳定性最优,分别为1.108和1 582.86min;未加酶的脱盐咸鸭蛋蛋清起泡性最佳,为587%,加酶的脱盐咸鸭蛋蛋清泡沫稳定性最佳。     

米糠蛋白的脉冲超声辅助提取技术

用脉冲超声辅助提取技术提取脱脂米糠中的蛋白质，考察主要提取因素对米糠蛋白提取率的影响．在液料温度26℃、脉冲超声频率0．25Hz、脉冲超声间隔2s及pH4．5时进行米糠蛋白酸沉的状态下，分别设定不同的提取时间、超声功率、液料比、pH，进行单因素和正交试验，优化得到的工艺条件为：提取时间80min，超声功率600W，液料比9：1，pH9，在此条件下，米糠蛋白提取率为48．3％，纯度为75．9％．脉冲超声辅助法的工艺条件优于碱法和酶法；米糠蛋白提取率高于碱法，稍低于酶法；米糠蛋白纯度与碱法差别不大，稍低于酶法．这表明脉冲超声辅助法能应用于米糠蛋白的提取．     

不同热处理脱脂乳粉对褐色乳酸菌饮料稳定性的影响

比较了不同热处理脱脂乳粉的理化性质,并将其应用于褐色乳酸菌饮料生产,以鲜制脱脂乳为对照,探讨了不同脱脂乳原料以及褐色乳酸菌饮料生产工艺对饮料稳定性的影响。结果表明:不同热处理脱脂乳粉的蛋白质、脂肪、水分含量以及乳酸度均无显著差异(P>0.05)；但其乳化性、起泡性及乳清蛋白氮指数存在显著差异(P<0.05),随着乳粉受热程度增加,其乳化性、起泡性及稳定性下降。在饮料生产过程中,使用中温脱脂乳粉更有利于保持饮料的稳定性,而以高温、低温乳粉以及鲜制脱脂乳为原料的饮料稳定性欠佳；高温褐变使脱脂乳粒径、离心沉淀率增大,zeta电位降低,产品稳定性下降；均质处理及配料定容后稳定性提高。研究旨在为褐色乳酸菌饮料生产中有效地提高产品的稳定性提供技术参考。     

水解度对蚕蛹蛋白酶解物的物化特性和抗氧化能力的影响

对蛋白质进行适度酶解是改善动植物蛋白原料的物化性质和提高其生理活性的常用方法.研究了水解度对蚕蛹蛋白的溶解性、乳化性、起泡性等物化性质的影响,以及水解度对蚕蛹蛋白的还原力,对DPPH自由基、超氧阴离子自由基和羟基自由基的清除能力等抗氧化特性的影响.实验结果表明,蚕蛹蛋白经适度酶解后溶解性得到显著改善,且水解度越大溶解性越好.蚕蛹蛋白经酶解后乳化性与乳化稳定性均降低,但起泡性和起泡稳定性增强,水解度增至5%时,起泡性和起泡稳定性达到最高值,继续增大水解度,反而下降.蚕蛹蛋白经酶解后抗氧化性显著提高,水解度为5%时,还原力和对DPPH自由基和羟基自由基的清除能力最高,水解度为15%时,对超氧阴离子自由基的清除能力最高,继续增加水解度,抗氧化能力反而下降.这说明,对蛋白质原料进行酶解改性时,不能简单的追求高水解度,而应根据产品的要求控制合适的水解度,过度水解是无益的.     

球磨法制备Bi12GeO20/WO3复合材料及可见光催化去除NO性能研究

采用简易球磨法制备了一系列Bi₁₂GeO₂₀/WO₃二元半导体复合材料,并对其物相、光学和电化学性质进行了分析。可见光光催化去除NO试验表明：随着WO₃负载量的逐渐增大,材料去除活性先增大后减小,这主要归结于合适的相组成以及异质结提高了界面载流子的分离效率。另外,WO₃的加入可有效抑制有毒中间产物NO₂的生成,从而促进硝酸根与亚硝酸根的生成。通过活性物种捕捉试验发现,超氧自由基和空穴在光催化反应中均起到了主要作用,羟基自由基起到了辅助作用。能带结构分析表明,复合材料的光催化机制遵从Ⅰ型过程。循环试验证明,材料具有较好的重复利用性和结构稳定性。     

米糠蛋白提取工艺优化研究

采用超声辅助酶法提取米糠蛋白,并对蛋白质的氨基酸组成进行了初步的分析。结果表明,以纤维素酶提取米糠蛋白效果较好,其最佳工艺条件为提取温度60℃、提取时间5h、料液质量体积比1∶9、pH值5.0、纤维素酶添加量0.5%,在此条件下米糠蛋白提取率达到63.11%。超声波辅助纤维素酶法提取的米糠蛋白含有17种氨基酸,其中8种为人体必需氨基酸;最高的3种为谷氨酸、赖氨酸和亮氨酸,含量最少的为脯氨酸、蛋氨酸和酪氨酸。研究结果可作为米糠蛋白提取的参考。     

应用超高压技术改善降脂乳化肠的滴水损失

研究超高压处理(超高压作用压力和超高压作用时间)对降脂乳化肠滴水损失的改善作用。对不同脂肪质量分数、不同超高压作用压力及不同超高压作用时间的乳化肠进行单因素实验,利用滴水损失的测定方法来评定样品发生的品质变化。再采用响应面分析法优化乳化肠脂肪质量分数(15%,20%,25%)、超高压作用压力(150,200,250MPa)和超高压作用时间(5,6,7min)的工艺参数,建立工艺参数与滴水损失的二元回归方程。以超高压作用压力、超高压作用时间和脂肪质量分数为自变量,分别以滴水损失为响应得到的二元回归模型拟合度高,脂肪质量分数、超高压作用压力和超高压作用时间的交互作用对乳化肠的滴水损失影响显著(p<0.05)。新型超高压降脂乳化肠的最佳工艺条件为超高压作用压力198.47MPa,超高压处理时间5.92min,脂肪质量分数20.51%。与未经超高压处理的脂肪质量分数较高的对照组相比,经超高压处理的降脂乳化肠的滴水损失降低了9.71%。研究结果可为低脂肉制品的开发提供参考。     

黑龙江春小麦麸皮抗冻蛋白的制备及性质研究

以小麦麸皮为原料,采用磷酸盐缓冲溶液提取硫酸铵沉淀制备抗冻蛋白,同时对所得抗冻蛋白的特性进行了测定.研究结果表明,从小麦麸皮中提取抗冻蛋白的最优条件为,小麦麸皮与磷酸盐缓冲溶液的固液比1∶9,提取时间2 h,提取温度30℃,固液分离的离心转速3 400 r/min,离心时间20min.在此条件下,小麦麸皮抗冻蛋白粗品的提取率为16.59%;提取得到的抗冻蛋白乳化性为79.87%,乳化稳定性为61.83%,吸油能力为自身质量的1.575倍,持水能力为自身质量的2.5倍左右,起泡性为55.77%,起泡稳定性为10.58%.     

The characteristics of CO2 assimilation of photosynthesis and chlorophyll fluorescence in transgenic PEPC rice

With PEPC, PPDK, NADP-ME and PEPC+ PPDK transgenic and untransformed rice (Orysa sativa L.), the activities of related C₄ photosynthesis enzymes, the chlorophyll fluorescence parameters, CO₂ exchange and other physiological indexes were compared, in which the physiological characteristics of PEPC transgenic rice were mainly studied. The results were as follows: (ⅰ) The activities of PEPC in PEPC transgenic rice were 20-fold higher than those in untransformed rice; the light-saturation photosynthetic rates and the carboxylation efficiency of PEPC transgenic rice were increased by 55% and 50% more than those of untransformed rice, respectively, while the CO₂ compensation point decreased by 27%. (ⅱ) The PSⅡ photochemical efficiency (F_v/F_m) and photochemical quenching (q_P) of transgenic PEPC rice decreased less in comparison with those of untransformed rice after the treatment with high light intensity (3 h) or methyl viologen (MV), a photooxidative reagent, which demonstrated that the tolerance of PEPC transgenic rice to photoinhibition and photooxidation was enhanced. (ⅲ) Under the condition of high light intensity, the activity of RuBPCase in PEPC transgenic rice did not obviously vary while the activity induced of carbonic anhydrase (CA) in PEPC transgenic rice increased by 1.8 fold. These results would provide some beneficial enlightment for revealing the mechanism of high photosynthetic efficiency and breeding with high photosynthetic efficiency in rice.     

单一饲料及其搭配养殖中华真地鳖效果研究

采用单一饲料的玉米、麦麸、米糠以及由它们配制成的粗蛋白质含量分别为13.5%、15.1%和16.5%的3种配合饲料共6种饲料搭配投喂模式,研究其对养殖中华真地鳖效果的影响。结果表明,中华真地鳖分别摄食3种配合饲料后的生长速度均比3种单一饲料的要快,其中以投喂粗蛋白质含量为15.1%组的生长速度最快;分别投喂3种单一饲料的中华真地鳖,除玉米组外的其余2个组的饲料成本均明显低于3种配合饲料各组,并且以投喂麦麸组所取得的经济效益最显著。     

Analysis of Male Sterility-Related Proteins of Young Panicle in Rice （Oryza sativa L. ） by Two-Dimensional Electrophoresis

For searching out male sterility-related proteins (polypeptides) in rice (Oryza sativa L.), we examined the difference of panicle protein (polypeptides) between hybrid rice (Wujin2A/R168, Wujin5A/R988) and their parents (male-sterile line Wujin2A, Wujin5A, and restorer line R168, R988) at the formation stage of pollen mother cell by two-dimensional electrophoresis (2-DE). The results revealed that the 2-DE polypeptide maps were similar among these experimental materials. A small group of polypeptides were disappeared in 2-DE polypeptide maps of male-sterile line (Wujin2A, Wujin5A) by comparing to restorer line (R168, R988) and the first filial (F₁) generation (Wujin2A/R168, Wujin5A/R988). The isoelectric points of these polypeptides were pI 5.8–6.5 molecular, weight 42.7×10³−66.2×10³. Foundation item: Supported by the National Natural Science Foundation of China (30340079) and the Science and Technology Key Research Foundation of the Education Ministry of China (03109) Biography: HU Yao-jun (1960-), male Ph. D candidate, research direction: molecular cytogenetics.     

Production of ultra-transparent glass-ceramics via controlled crystallization of nanocrystals in the glassy matrix of LAST

Microstructural variation in glass-ceramics encompasses the range from nanocrystalline transparent materials to microcrystalline tough materials. In this investigation, the crystallization process was controlled for the development of ultra transparent Li₂O-Al₂O₃-SiO₂ glass-ceramics containing TiO₂ as a nucleating agent (LAST). Results of UV-Vis absorption spectra were compared with the expected theoretical values calculated by the Rayleigh scattering method for the determination of ultra transparency. Results of the investigation illustrate that the control of crystallization increases the range of ultra transparency by the reduction of crystal size and their uniformity in the glassy matrix. Last but not the least, the optimized samples are ultra transparent approximately in the whole light wavelengths.     

生物滞留系统去除氮的影响因素研究

传统雨水生物滞留系统对氮的去除很不稳定,为了提高硝氮和总氮的去除效果,尝试在生物滞留系统底部增加内部淹没区,提供所需的缺氧环境并延长系统内雨水的停留时间,改善系统的除氮能力。对有淹没区运行条件下进水有机物浓度和滞留时间除氮的影响进行了试验。结果表明系统在有淹没区和无淹没区运行条件下,对NH₄₊-N的平均去除率均在90%以上。无淹没区时系统对NO_3--N的去除率为21%。有淹没区时(滞留时间2 h)系统对NO_3--N和TN的去除作用显著提高到74%和78%。淹没运行时进水中COD浓度可以显著影响NO_3--N的去除效果,当COD浓度为0-100 mg/L,NO_3--N(7-9 mg/L)去除率随COD浓度的增加而显著升高。滞留时间对NO_3--N去除效果的影响较为明显,滞留时间从1 h增加到8 h,系统的NO_3--N平均去除率从21%增加到93%。     

Trichloroacetate affects the EPR Signal IIslow and Signal I in the thylakoid ofChlamydomonas reinhardtii

One electron paramagnetic resonance (EPR) signal, named Signal II_slow, originates from the oxidized Tyrosine 160 (Y_D) of D2 polypeptide of photosystem II reaction center. After adding high concentration trichloroacetate (TCA) to theChlamydomonas reinhardtii thylakoid suspension, this signal was abolished in a minute. Treatment of TCA also removes a few of polypeptides, including three extrinsic polypeptides of oxygen-evolving complex, from the thylakoid membrane. Based upon the analysis of the microenvironment around Y_D with a three-dimensional model, it is indicated that relatively high hydrophobicity of this microenvironment may be the essential prerequisite for TCA to affect Y_D. It has been observed that TCA treatment also retards the decay of the Signal 1, produced by the oxidized reaction center chlorophyll dimer (P700⁺) of photosystem I.     

米糠中植酸的提取

采用从天然植物(水稻米糠饼粕)中提取植酸盐的方法,并对其工艺条件进行了探讨。试验表明,以本文采用的方法,从米糠中提取的植酸产率高,且由于原料丰富、市场广阔、工艺条件简单,因而,有利于米糠的进一步开发和利用。     

Hydrogen storage performance of LaNi3.95Al0.75Co0.3 alloy with different preparation methods

Rare-earth AB₅-type La–Ni–Al hydrogen storage alloys are widely studied due to their extensive application potentials in hydrogen isotope storage, hydrogen isotope isolation and hydrogen compressors, etc. Good hydriding/dehydriding kinetics, easily activation, high reversibility are important factors for their practical application. However, their overall hydrogen storage performance, especially plateau pressure and hydrogen absorption/desorption durability need to be further optimized. In this study, the microstructures and the hydrogen storage properties of as-cast, annealed, and melt-spun LaNi_3.95Al_0.75Co_0.3 alloys were investigated. The experimental results of XRD and SEM showed that all alloys contained a pure CaCu₅ type hexagonal structure LaNi₄Al phase. The cell volume increased in an order of annealed ?> ?melt-spun ?> ?as-cast, resulting in a lower hydrogen absorption/desorption plateau pressure and a more stable hydride phase. The hydrogen storage capacity of three alloys was almost the same. The slope factor of the annealed and melt-spun alloys is smaller than the as-cast alloy, indicating that heat-treatment process can make the alloys more uniform. For the cycle stability of the alloys, the hydrogen absorption rate of the annealed alloy and melt-spun alloy was much faster than that of the as-cast alloy after 500 cycles. The melt-spun alloy showed high pulverization resistance during hydrogen absorption/desorption, and exhibited an excellent cycling retention of 99% after 500 cycles, suggesting that melt-spinning process can enhance the cycle stability and improve the cycle life of the alloy.     

污水停留时间对多级人工湿地塘组合系统除氮的影响

通过多级人工湿地-塘组合系统在不同的污水停留时间下处理污染水体,对各项出水污染物进行测试对比。结果表明:在初春低温条件下,COD、TN和NH_4~+-N的去除率随着污水停留时间的增加显著提高,其中COD在污水停留时间达到5 d之后去除率开始趋于平缓,TN和NH_4~+-N的去除率在污水停留时间达到5 d之后出现下降。表明在保证处理效果的前提下,污水停留时间选在4~5 d之间较为合理。这为实际处理污染水体提供了一定的参考。