超高效液相色谱-串联质谱法快速测定保健食品中大豆异黄酮含量

建立保健食品中6种大豆异黄酮的超高效液相色谱串联质谱(UPLC-MS/MS)同时检测方法。样品中大豆异黄酮采用80%甲醇超声提取、Florisil固相萃取柱净化,C₁₈色谱柱分离,以0.1%甲酸水溶液和乙腈为流动相,流速0.3 mL/min,柱温30 ℃,质谱正离子多反应监测(MRM)模式进行检测。结果表明,大豆苷、大豆黄苷、染料木苷、大豆素、大豆黄素以及染料木素在各自浓度范围内线性关系良好;大豆黄苷、大豆黄素检出限均为10 μg/kg;大豆苷、染料木苷检出限均为20 μg/kg;大豆素、染料木素检出限均为30 μg/kg,加标回收率为81.8%~98.4%,相对标准偏差为1.8%~6.7%。所建立的超高效液相色谱串联质谱是一种高灵敏度、高准确度的测定方法,对保健食品中大豆异黄酮的质量控制提供了参考依据,具有一定的理论意义和应用价值。     

Fe~(3+)配位对水溶性大豆多糖性质的影响

以柠檬酸三钠-三氯化铁法合成水溶性大豆多糖-铁(Ⅲ)配合物,采用邻菲罗啉分光光度法测得其含铁量为18.1%,表明Fe3+与水溶性大豆多糖基本形成了稳定的配合物,在pH值1～14内不沉淀。对其抗氧化活性的研究表明,水溶性大豆多糖与铁配合后,对羟基自由基、亚硝酸盐的清除活性及对脂质抗氧化的活性均比水溶性大豆多糖好。在浓度为10 mg/mL时,水溶性大豆多糖对羟基自由基的清除率为16.0%,对亚硝酸盐的清除率为53.9%,对脂质体氧化的抑制率为34.9%,而相同条件下水溶性大豆多糖-铁(Ⅲ)配合物对羟基自由基的清除率为29.6%,对亚硝酸盐的清除率为67.5%,对脂质体氧化的抑制率为77.9%。     

磷脂酶A_2用于大豆油脱胶研究

利用磷脂酶A2对大豆油进行脱胶试验,且通过正交试验得出磷脂酶A2用于大豆油脱胶最佳工艺参数:酶用量35μl/kg(油)、pH值6.0、反应温度40℃、反应时间3h,在此条件下脱胶后,油中磷含量降至10ppm以下,达到理想脱胶效果,可完全满足后续物理精炼要求。     

发酵牛肉香肠中菌相变化和理化特性的研究

采用植物乳杆菌和啤酒酵母菌按一定比例混合的组合发酵剂生产牛肉发酵香肠,并对其菌相及其理化性质进行研究,得出微生物的变化规律和理化变化规律。结果表明：实验组的肠杆菌数量明显低于对照组,游离氨基酸的含量比对照组有所增加,亚硝酸盐的含量明显下降。     

Influence of inclusion shapes on the effective linear elastic properties of hardened cement pastes

In most micromechanical models applied to cement pastes, particulate phases are modeled as spheres. However, experimental observations clearly show that certain of them are far from being spherical. The present work focuses on the effects of particle phase shapes on the effective isotropic linear elastic moduli of hardened cement pastes (HCP). An attempt to develop a more realistic micromechanical model is proposed by using spheroidal inclusions and including a novel morphological parameter. The latter is identified on the basis of experimental result issue for example from microtomographic images of Portland cement grains. With the help of the proposed model, the validity range of spherical particulate approximations is examined for both sound and leached pastes.     

基于粒度仪的双枪喷涂雾化场的粒度的研究

目的 在保证喷涂雾化表征均匀性的前提下实现宽幅覆膜,提高覆膜的效率,以期得到均匀一致的大豆蛋白覆膜。方法 利用粒度仪测量不同干涉程度下的大豆蛋白液双枪喷涂雾化场的索特平均直径（Sauter Mean Diameter,SMD）,利用Spraylink软件处理粒度数据,得到粒度数据并对比。结果 双枪喷涂喷雾场的SMD随着液压的增大先增大后趋于平稳,随着气压的增大先减小后趋于平稳。当液压分别为0.08 MPa和0.16 MPa时,SMD基本不随偏转程度的变化而变化;当液压为0.24 MPa时,SMD随着偏转程度的增大而增大。双枪喷涂喷雾场的径向SMD从中心到边缘缓慢减小,在干涉区域内的轴向2点粒径基本相等。结论 当液压为0.08 MPa、气压为0.24 MPa、偏转角为0°时,SMD相对较小。文中的研究为实现宽幅覆膜奠定了理论基础。     

粉煤灰对水泥浆体早期水化和孔结构的影响

通过硬化水泥浆体力学性能、交流阻抗和孔结构等性能的测试,以及扫描电镜分析,研究了不同掺量的粉煤灰对硬化水泥浆体早期水化和孔结构的影响。结果表明：随着粉煤灰掺量的增加,水泥的凝结时间增加,抗压强度降低,熟料矿物的水化速率提高,但水泥-粉煤灰体系的水化速率降低,水泥浆体中孔溶液电阻和阻抗相应降低,硬化水泥浆体中大孔数量减少,微孔数量增加。     

Effect of processing on sphingolipid content in soybean products

Soybeans are believed to be a rich source of sphingolipids, a class of polar lipids that has received attention for their possible cancer-inhibiting activities. The effect of processing on the sphingolipid content of various soybean products has not been determined. Glucosylceramide (GlcCer), the major sphingolipid type in soybeans, was measured in several processed soybean products to illustrate which product(s) GlcCer is partitioned into during processing and where it is lost. Whole soybeans were processed into full-fat flakes, from which crude oil was extracted. Crude oil was refined by conventional methods, and defatted soy flakes were further processed into alcohol-washed and acid-washed soy protein concentrates (SPC) and soy protein isolates (SPI) by laboratory-scale methods that simulated industrial practices. GlcCer was isolated from the samples by solvent extraction, solvent partition, and TLC and was quantified by HPLC. GlcCer remained mostly within the defatted soy flakes (91%) rather than in the oil (9%) after oil extraction. Only 52, 42, and 26% of GlcCer from defatted soy flakes was recovered in the acid-washed SPC, alcohol-washed SPC, and SPI products, respectively. All protein products had a similar GlcCer concentration of about 281 nmol/g (dry wt basis). The minor quantity of GlcCer in the crude oil was almost completely removed by water degumming.     

钨基催化剂体系下甲醇开环环氧大豆油制备多元醇

以环氧大豆油和甲醇为原料,通过开环加成制备植物油基多元醇。在自制的二氯二氧化钨(WO2Cl2)作催化剂、三氟甲磺酸银(Ag OTf)作助催化剂的条件下,考察了催化剂用量、助催化剂用量、反应时间、温度和醇油物质的量比等对环氧大豆油开环转化率的影响,并对产物的环氧值进行了测试。结果表明,当催化剂用量为3%(以甲醇和环氧大豆油总质量为基准,下同),三氟甲磺酸银用量为4%,反应温度为70℃,反应时间为8 h,醇油物质的量比为28∶1时,环氧大豆油的开环转化率较高,为89.13%。对开环产物进行了FTIR、1HNMR、TG以及流变性分析。通过热重分析得出,多元醇的分解温度(334℃)比环氧大豆油的分解温度(305℃)高。流变性分析得出,随着温度的升高,环氧大豆油和多元醇的黏度逐渐下降。在温度较低时,大豆油多元醇的黏度明显低于环氧大豆油的黏度。     

生产周围糊与炭块频繁更换筛网的工艺技术探讨

对在生产铝用阴极炭块和糊料的破碎筛分生产工序产生的频繁更换筛网而影响企业产能发挥的问题进行了工艺技术探讨及解决.生产实践证明,通过调整周围糊工艺配方的粒度级别与阴极炭块的粒度级别相一致,重新选择生产周围糊的最佳工艺技术配方的措施的实施,效果优良切实可行.