多酶复合水解微波加热制备小分子大豆肽

以水解度和AN为指标,确定了微波加热条件下,三种单酶(碱性蛋白酶、中性蛋白酶、酸性蛋白酶)水解大豆蛋白的最佳工艺条件及三种酶复合水解的加酶顺序,将大豆蛋白最大限度的分解为小分子大豆多肽和氨基酸。毛细管电泳实验表明:多酶复合水解优于单酶。     

皂化P204微乳体系萃取大豆蛋白的研究

研究了NaOH皂化P204/正辛烷微乳体系萃取大豆蛋白的机理和工艺,考察了大豆加入量、P204的浓度、NaOH的浓度、萃取时间、水相pH值及离子强度等对大豆蛋白萃取率的影响。实验结果表明,该微乳体系萃取大豆蛋白的优化工艺条件为:大豆粉与微乳液的质量体积比1∶10,P204在油相中浓度0.8 mol/L,NaOH的浓度1.25 mol/L,萃取时间15 min,外水相pH值5,萃取率可达88.48%。通过调节水相pH和离子强度可实现大豆蛋白的萃取和反萃取。     

微酸性条件下环己基过氧化氢分解制备环己酮工艺研究

针对传统碱性分解的不足,以有机铬酸酯为催化剂,对环己烷氧化液中的环己基过氧化氢分解制备环己酮工艺进行了探索,考察了在催化剂铬离子浓度150 ppm时,分解温度及时间对环己烷氧化液分解产物的影响,得出最佳的微酸性分解工艺条件。并在连续分解实验装置对前面得到的微酸性分解工艺条件进行验证。     

功能性大分子的相互作用及其应用研究

以葡甘聚糖、κ-卡拉胶、黄原胶、大豆分离蛋白为主要原料,研究了三种多糖之间以及多糖与蛋白质之间的相互作用.结果表明,多种多糖及多糖与蛋白质共混后在分子间力的作用下,呈现出良好的增效性,其综合性能(如凝胶强度、弹性、透明度等)得到了提高.利用这一性质,开发出了一种兼有膳食纤维和蛋白质的新型功能性基料.同时探讨了温度、时间、浓度、电解质各因素对多糖之间及多糖与蛋白质之间相互作用的影响,得出工艺配方,制成了多糖复合保健食品和仿生海洋产品.     

大豆分离蛋白结构与性能

大豆分离蛋白是大豆的重要组成部分,含有大量活性基团,具有可再生、可生物降解性等优点,可以成为制备环境友好材料的主要原料。由于大豆分离蛋白的组成和构象会对其功能特性产生明显的影响,因此对其结构和性能之间的关系进行系统的研究无疑会对材料学家在今后开发出新型的具有优异性能的大豆蛋白材料具有相当的帮助。本文首先介绍了大豆分离蛋白的组成、亚基的结构以及对其两种主要成分——β-大豆伴球蛋白（7S球蛋白）和大豆球蛋白（11S球蛋白）的分离方法;然后对大豆分离蛋白在不同条件下的构象研究和其主要物理化学性质,如溶解性和凝胶性的研究进展作了介绍;最后对大豆分离蛋白在薄膜、纤维和塑料等材料领域的应用进行了简要的综述。     

大豆蛋白接枝苯乙烯的合成及膜性能

大豆蛋白膜是无污染的包装涂布材料.但目前大豆蛋白膜尚不能取代合成高分子薄膜。其原因是亲水性使得它对水蒸气的阻隔有限,且它的力学性能无法达到要求。将苯乙烯接枝到大豆蛋白上,将有望提高大豆蛋白膜的力学性能。本文采用大豆分离蛋白和苯乙烯合成了接枝共聚物（SPI-g-PSt）。用流涎法分别制成SPI膜和SPI-g-PSt膜,并研究了它们的力学性能。     

生物法与化学法制备硫酸软骨素

硫酸软骨素（ChS）是一种天然的酸性黏多糖,生物活性多样,在医学、生物、制药、食品、化妆品和材料等领域均有广泛应用,特别是在治愈骨关节病上具有颇为理想的效果。本文系统地总结了有关硫酸软骨素及其类似物的生物与化学制备方法的研究进展,如高产微生物菌株筛选与改良,培养条件优化与调控,汇聚式合成策略构建,经济易得的起始物原料等,并指出制备硫酸软骨素中存在的问题以及发展方向。     

以“豆腐的制作”畅谈胶体知识与水凝胶的前沿应用

通过深入挖掘“豆腐的制作”工艺中渗透的科学知识,介绍了如何充分提取大豆蛋白质、如何将生豆浆转变为豆腐等内容,主要呈现了豆腐制作过程中体现的蛋白质性质、胶体的稳定性及凝固剂促使大豆蛋白聚沉原理等知识,并对豆腐产品的结构特点进行适当延伸,进而介绍水凝胶的发展与前沿应用。加深学生对所学知识的理解,拓展视野,培养学生热爱生活的态度及科研乐趣。     

大豆多糖固定化脲酶

本文以大豆多糖为载体，分别用吸附法与戊二醛交联法固定化脲酶，测得了吸附法的最佳反应温度为６５～７５℃，ｐＨ为６．０～７．０。并对大豆多糖固定化脲酶柱式反应器的动态活性作了初步的测试。     

百合皂甙多糖的连续提取工艺研究

皂甙和多糖是药用百合的两个主要有效成份。文章用正交实验法对百合皂甙多糖的提取工艺进行了研究。优选出简便可靠且适合工业化生产的连续提取百合皂甙多糖的工艺。百合皂甙的最佳提取工艺条件是:温度为70℃,乙醇浓度为80%,固液比例为1:6,提取时间3h,提取次数3次。多糖的最佳提取工艺条件是:温度为95℃,固液比例为1:10,提取时间3h,提取次数2次。用AB-8大孔吸附树脂分离、乙醚-丙酮分步沉淀得到纯百合皂甙。     

Quality of Soybean Products in Terms of Essential Amino Acids Composition

The content of protein, moisture content and essential amino acids in conventional and genetically modified soybean grain and selected soybean products (soybean pâté, soybean drink, soybean dessert, tofu) was analyzed in this paper. The following comparative analysis of these products has not yet been carried out. No differences were observed in the amino acid profiles of soybeans and soybean products. The presence of essential amino acids was confirmed except for tryptophan. Its absence, however, may be due not to its absence in the raw material, but to its decomposition as a result of the acid hydrolysis of the sample occurring during its preparation for amino acid determination. Regardless of the type of soybean grain, the content of protein, moisture content and essential amino acids was similar (statistically insignificant difference). Thus, the type of raw material did not determine these parameters. There was a significant imbalance in the quantitative composition of essential amino acids in individual soybean products. Only statistically significant variation was found in genetically modified and conventional soybean pâté. Moreover, in each soy product their amount was lower irrespective of the raw material from which they were manufactured. Therefore, the authors indicate the necessity of enriching soybean products with complete protein to increase their nutritional value.     

Predigestion of soybean proteins with immobilized trypsin for infant formula

Soybean protein isolates of low soybean trypsin inhibitor (STI) residue were prepared by acidic precipitation of soybean flour water extracts (0.8–1.2%) at pH 5.0, followed by acidic washing at this pH and affinity adsorption of residual STI with immobilized trypsin on polystyrene anion-exchange resin GM 201. After heat treatment, soybean protein isolates were subjected to controlled hydrolysis with the immobilized trypsin. Then, the predigested soybean protein was prepared. The predigested soybean protein was free of STI activity, and its solubility at acidic pH range was greatly increased. Sedimentation test showed that it formed a much finer clot at pH 4.5 than that of untreated soybean protein. The pepsin digestibility index at pH 4.0 and chymotrypsin digestibility index at pH 8.0 were obviously improved. These results suggested that the predigested soybean protein prepared by this method may be used in infant formulas.     

H2SO4-SiO2固体酸的结构及酸性研究

以溶胶-凝胶法制备了H2SO4-SiO2固体酸催化剂，并对其结构和酸性进行了系统表征．FT—IR和^29Si—NMR结果表明H2SO4和SiO2间存在相互作用，因此硫酸与硅胶形成稳定的固体、XRD、SEM和TEM结果表明，H2SO4-SiO2固体酸是一多孔无定型材料；BET法测定的H2SO4-SiO2固体酸的比表面积和孔体积结果表明，随着H2SO4与SiO2质量比增加，其比表面减少，孔体积增大；H2SO4-SiO2固体酸的酸强度和液体浓硫酸相当，酸强度与干燥温度和H2SO4加入量有关，固体酸的这一性质以^1H—MAS NMR进行了系统的表征．     

Designing Functional Fruit-Based Recovery Drinks in Powder Form That Contain Electrolytes,Peptides, Carbohydrates and Prebiotic Fiber Taking into Account Each Component’s Osmolality

High levels of osmolalities have been found in manufactured carbohydrate-based functional drinks that occasionally include added protein; however, fruit components rich in bioactive ingredients have been absent. It has proved difficult to obtain recovery drinks based on natural fruit components that deliver calories and nutrients to the body whilst simultaneously ensuring that the body is adequately hydrated after physical exertion; the problem being that it is difficult to ensure the drinks’ stability at low pH levels and maintain an appropriate sensory quality. This study aims to develop drinks based on natural fruit components that contain added electrolytes, carbohydrates, prebiotic fiber and protein; an improved water and electrolyte balance; the calories needed after intense physical exertion; a high content of nutrients; and a favorable sensory quality. Furthermore, the relationships between regressive osmolalities of beverage components are herein investigated. The study materials were raspberry powders (prepared via fluidized-bed jet milling, drying, freeze-drying and spray-drying) as well as citrated sodium, potassium, magnesium salts, isomaltulose, hydrolyzed collagen, whey protein isolate and prebiotic fiber. The drinks’ polyphenols and antioxidant properties were measured spectrophotometrically, whilst vitamin C content was determined using high-pressure liquid chromatography. The sensory qualities of each drink were assessed according to a scaling method. Six test versions of recovery drinks were prepared in which osmolalities ranged from 388 to 607 mOsm/kg water, total polyphenol content was 27–49 mg GAE/100 mL and vitamin C level was 8.1–20.6 mg/100 mL, following compositions defined by the study results. It is thus possible to obtain fruit-based recovery drinks of the recommended osmolality that contain added protein, prebiotics and fiber, as well as defined amounts of electrolytes and carbohydrates. All drinks were found to have a satisfactorily sensory quality. The design of appropriate recovery drink compositions was also greatly helped by investigating the relationships among the regressive osmolalities of beverage components (i.e., electrolytes, carbohydrates, fruit powders and protein).     

Preparation of rapid (chain-stopped) alkyds by incorporation of gum rosin and investigation of coating properties

In this study, the synthesis, characterization, and properties of a short oil length chain–stopped(rapid) alkyd resin is investigated. Gum rosin modified alkyd resin (RA-GR) was prepared using soybean oil, phthalic anhydride, glycerin and gum rosin acid. An alkyd modified with benzoic acid (RA-BA) was also prepared for comparison. FTIR analyses and GPC measurements of the alkyds were used for characterization. Other properties such as the viscosity, acid value, and solid content of the final resins were determined. Separately, the synthesized resins were used in paint formulations without any changes in other parameters such as filler, airdrying agents, solvents, etc. Paints were applied to metal and glass surfaces and the effect of gum rosin was investigated by looking at touch and hard drying times, adhesion to metals and gloss changes. Compared to the benzoic acid modified resin (RA-BA), gum rosin modified resin (RA-GR) exhibited remarkable positive effects on the paint with a better adhesion to the metals, and short drying times without any loses in the glosses.     

Antioxidant capacity and sensory quality of soy-based powder drink mix enriched with functional hydrolysates of swiftlet (Aerodramus fuciphagus)

The enrichment with low amount of bioactive protein of spray-dried edible bird’s nest hydrolysates (EBNH) (3.0 %) in view of its cost and high solubility provided significant value added to the overall in vitro antioxidant capacity of soy-based powder drink mix (PDM). Its beverage (12.5 % concentration, consistency index 0.39 Pa.sⁿ) antioxidant capacity as measured by ABTS and FRAP was comparable (p > 0.05) but significantly higher than antioxidant assays of FCR and DPPH. The respective antioxidant capacity of the PDM beverage in terms of trolox equivalent (TE) and gallic acid equivalent (GAE) were 21.95 TE mg/g, 20.75 TE mg/g, 2.93 TE mg/g and 14.72 GAE mg/g for FRAP, ABTS, DPPH and FCR. Depending on antioxidant assay, EBNH in beverage of PDM contributed an increase in the range of 3.7–9.3 % (which was significant (p < 0.05) according to ABTS and FCR assays) or about 6.0 % to its overall antioxidant capacity. The interaction among the antioxidant activity of all the food product’s ingredients is antagonistic since the difference between the expected and observed total antioxidant potential is significantly higher (p < 0.05) for all antioxidants assays, except FCR. The beverage of PDM has excellent sensory quality. It is sugar free and high protein PDM that has excellent cocoa flavour and possesses sufficient sweetness with acceptable beany aroma and taste when served as hot beverage.     

Synthesis of novel acidic ionic liquid immobilized on silica

A novel acidic ionic liquid immobilized on silica has been synthesized by hydrolyzing tetraethyl orthosilicate (TEOS) and the acidic ionic liquid derived from (3-aminopropyl) trimethoxysilane. The catalytic activities were evaluated in the acetalization and biodiesel synthesis. The results showed that the solid acid was a very efficient catalyst for the traditional acid-catalyzed reactions with the yield over 99.0%. A novel solid acid combined both the high activities inherent to the acidic ionic liquid and the feasibility of separation of the solid catalysts. High acidity, enhanced catalytic activities and improved stability were the key properties of the novel solid acid.     

Enhanced analysis of triterpenes, flavonoids and phenolic compounds in Prunella vulgaris L. by capillary zone electrophoresis with the addition of running buffer modifiers

A cyclodextrin-modified capillary zone electrophoresis method was developed for the separation and determination of three isomeric compounds (ursolic acid, oleanolic acid and betulinic acid), caffeic acid, p-coumaric acid, rosmarinic acid, rutin and quercetin. Without the addition of beta-cyclodextrin (beta-CD) and methanol, the separation of these analytes was poorly resolved. These eight compounds, however, were well separated from each other within 20 min with a borax running buffer (40 mM of borax, pH 9.4) containing 2mM beta-CD and 4% (v/v) methanol at the voltage of 25 kV, temperature of 25 degrees C and detection wavelength of 210 nm. The relative standard deviations (RSDs) of migration time ranged from 0.16 to 0.74% while those of the peak area ratios ranged from 2.17 to 4.61% for six determinations of the analytes at concentration of 10 and 25 microg mL(-1). The correlation coefficients of the calibration curves of the analytes were all >0.998, and the recoveries were from 96.8 to 103.6%. The method was successfully applied to determine these bioactive components in the samples of Prunella vulgaris L. and its beverage drink products. Our results reveal that only the isomeric compounds and rosmarinic acid could be detected in the spikes of P. vulgaris L.; other components were either too low to be detected or not present while only rosmarinic acid was detected in the beverage products.     

离子色谱法同时分析董酒中的有机酸与无机阴离子

研究了用离子色谱法同时分析董酒中可离解性有机酸和无机阴离子。首次采用邻苯二甲酸氢钾和邻苯二甲酸的混合水溶液作淋洗剂,改善了分离效果,提高了检测灵敏度。所建立的方法无需进行样品前处理,无干扰,有一定的实用价值。     

Rapid Nanomolar Detection of Guaiacol from its Precursors Using a Core-shell Reversed-phase Column Coupled with a Boron-doped Diamond Electrode

The electrooxidation mechanisms of guaiacol (2-methoxyphenol), a food and beverage spoilage metabolite, and its precursors; vanillic acid (VA), vanillin, and ferulic acid (FA) were investigated by cyclic voltammetry (CV) with a boron-doped diamond (BDD) electrode. Reversed-phase liquid chromatography (RPLC) together with a BDD electrode poised at +1.6 V vs. Pd/H₂, was optimized for their sensitive detection. The separation was achieved in 60 s with a core-shell column (HALO C₁₈). The detection limits of these analytes ranged from 10–30 nM. The method was applicable for the analysis of guaiacol and its precursors from a popular commercial drink.