提取条件对粗提取阿拉伯木聚糖中蛋白质残余量影响规律研究

阿拉伯木聚糖粗提物均会残余一定量的蛋白质,这些交联或游离的蛋白质会影响阿拉伯木聚糖的乳化性、溶解性、凝胶特性、成膜性等诸多特性。文章以粗提取阿拉伯木聚糖的蛋白质含量为考察指标,研究了温度、时间、NaOH浓度和pH值对碱提麦麸阿拉伯木聚糖中蛋白含量的影响,并采用正交试验方法对碱提工艺条件进行优化。结果表明,在反应时间120 min、反应温度90℃、NaOH浓度0.25 mol/L、pH值3.8条件下,阿拉伯木聚糖具有最小的蛋白含量(6.339±0.31)%。     

碱提条件对麸皮阿拉伯木聚糖组成、理化性质、流变学特性的影响

以碱提取法制备小麦麸皮阿拉伯木聚糖,采用高效液相色谱法、高效凝胶过滤色谱法和流变分析方法考察不同NaOH浓度、提取温度和提取时间对阿拉伯木聚糖的单糖组成、分子质量分布和黏度的影响。结果表明,随NaOH浓度的增加,阿拉伯木聚糖的纯度呈现先下降后上升的趋势,而得率则先上升后下降;随提取温度和时间的增加,阿拉伯木聚糖的纯度和得率均先增加后趋于平衡。在NaOH浓度、提取温度和提取时间分别为0.5 mol/L、85℃和120 min条件下所得阿拉伯木聚糖的纯度和提取得率分别为88.72%和32.8%。阿拉伯木聚糖的分子质量随提取温度的升高而明显减小;溶液的黏度随NaOH浓度的增加明显增大,随提取温度和时间的增加而显著减小。结果表明,不同碱提取条件所得阿拉伯木聚糖的性质差异较大,本实验可为麦麸阿拉伯木聚糖的碱提取和应用研究提供一定理论支持。     

麦麸阿拉伯木聚糖的羧甲基化改性及理化性质表征

为探究麦麸阿拉伯木聚糖的羧甲基化改性对其理化性质的影响,以碱提取法从麦麸中分离阿拉伯木聚糖,通过单因素试验探究NaOH质量浓度、物质的量比、反应温度和反应时间对羧甲基化阿拉伯木聚糖取代度的影响,并考察不同取代度羧甲基化阿拉伯木聚糖的结构、单糖组成、分子质量、黏度和热稳定性的性质差异。结果表明,当NaOH质量浓度、物质的量比、反应温度和反应时间分别为100 mg/mL、阿拉伯木聚糖-氯乙酸钠-NaOH=1∶2∶2、65 ℃和4 h时,所得羧甲基化阿拉伯木聚糖的取代度最高为0.66,红外光谱分析证明了羧甲基化反应的成功。相比于未改性的阿拉伯木聚糖,取代度为0.66的羧甲基化阿拉伯木聚糖中木糖和阿拉伯糖的含量之和由88.72%减少至14.72%,分子质量也由改性前的6.07×105 Da减小至4.18×105 Da。此外,随羧甲基化阿拉伯木聚糖取代度的增加,剪切黏度呈现出明显的降低,而其热稳定性有所提高,改性样品的最大热分解速率所对应的温度由285 ℃升高至306 ℃。本研究结果表明,麦麸阿拉伯木聚糖经羧甲基化改性后的理化性质具有显著的变化,本实验可为麦麸阿拉伯木聚糖的羧甲基化改性及其应用提供理论依据。     

麦麸阿拉伯木聚糖-牛血清蛋白质酶促共聚物制备及表征

研究麦麸阿拉伯木聚糖与牛血清白蛋白在漆酶的催化下形成酶促共聚物。通过用紫外分光光度法(UVvis)、十二烷基硫酸钠聚丙烯胺凝胶电泳法(SDS-PAGE)及红外光谱法(FT-IR)对酶促共聚物进行定性表征,并测定酶促共聚物与麦麸阿拉伯木聚糖及牛血清白蛋白乳化特性。结果表明,麦麸阿拉伯木聚糖在漆酶的作用下与牛血清白蛋白发生接枝反应,制得的麦麸阿拉伯木聚糖-牛血清白蛋白酶促共聚物(155.8 m~2/g, 23.7 min)运用在乳状液体系中时,乳化活性及乳化稳定性优于麦麸阿拉伯木聚糖/牛血清白蛋白混合物(144.8 m~2/g, 18.5 min)及麦麸阿拉伯木聚糖(75.3 m~2/g, 17.5 min)及牛血清白蛋白单体(128.0 m~2/g, 15.7 min)。     

玉米芯中阿拉伯木聚糖碱提取工艺优化研究

为了提高阿拉伯木聚糖的得率,主要通过液料比值、NaOH溶液浓度、时间和温度四个单因素来研究玉米芯中AX得率影响,并在此基础上采用正交试验对阿拉伯木聚糖的碱提工艺进行优化。试验结果表明:在液料比值20 mL/g,NaOH溶液的浓度为0.20 mol/L,时间为120 min,温度为90℃的条件下,阿拉伯木聚糖的得率最大,值为32.5%。     

超微粉碎预处理对碱提和水提麦麸多糖理化特性的影响

为了高值化利用麦麸副产物,对麦麸原料进行超微粉碎预处理（0、10、20、30 min）后分别以水提法和碱提法获得麦麸多糖,以得率、化学成分（阿拉伯木聚糖、总糖、蛋白质和阿魏酸）、红外光谱、单糖组成、电位、粒径、溶解度和微观结构分析超微粉碎预处理对麦麸多糖理化特性的影响。结果表明：超微粉碎预处理使得碱提与水提麦麸多糖的得率分别由6.6%和1.34%增加至15.03%和6.28%。碱提与水提阿拉伯木聚糖（Arabinoxylan,AX）含量从53.13%和33.32%分别增加至73.35%和37.52%。碱提与水提麦麸多糖的粒径从308.47和919.23 nm分别降低至203.8和168.03 nm。红外光谱和单糖组成结果显示,超微粉碎预处理对碱提和水提麦麸多糖官能团结构影响较小,但会破坏麦麸多糖的有序结构。麦麸多糖的主要成分阿拉伯糖和木糖的总含量及所占比重随着超微粉碎处理时间而显著提高（P<0.05）。扫描电镜显示,多糖的颗粒形状从大颗粒转为小颗粒且多糖之间表现出较高的黏附性。综上所述,超微粉碎预处理可以提高麦麸多糖的得率及阿拉伯木聚糖的含量,降低麦麸多糖的粒径。     

响应面法优化稻壳中木聚糖的提取工艺

为提高稻壳中木聚糖的提取率,稻壳经3％的硫酸预处理后再用碱法进行木聚糖的提取,采用响应面法优化工艺条件,先对提取温度、NaOH浓度、固液比、提取时间4个因素进行单因素试验.根据单因素试验结果设计中心组合试验,以木聚糖提取率为考察指标,采用响应面分析法确定最优工艺参数.结果表明:提取温度69.8℃、NaOH浓度10.7％、固液比1∶13(m∶V)、提取时间5.1h.该条件下,木聚糖提取率可达76.57％.     

提取条件对小麦麸皮阿拉伯木聚糖相对分子质量分布的影响

以小麦麸皮为原料,通过化学分析法和高效凝胶渗透色谱法,探讨提取时间、pH值和温度对阿拉伯木聚糖提取得率及其产品相对分子质量分布的影响。结果表明,随着提取时间的延长、pH值和温度的升高,阿拉伯木聚糖的得率显著提高。延长提取时间（5 h）,可以提高产品中低相对分子质量阿拉伯木聚糖的含量;提高反应的pH值（13.0）和温度（90 ℃）则可以获得富含多种高相对分子质量阿拉伯木聚糖的产品。     

麦麸阿拉伯木聚糖-牛血清白蛋白酶促共聚物制备及其乳化性能研究

研究麦麸阿拉伯木聚糖与牛血清白蛋白在过氧化物酶的催化下形成多糖-蛋白质共聚物。通过紫外可见光分光光度计测定不同过氧化物酶添加量、不同H_2O_2浓度、不同麦麸阿拉伯木聚糖与牛血清白蛋白质量比3个因素下,麦麸阿拉伯木聚糖与牛血清白蛋白酶促共聚物紫外吸收光度值变化,并利用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate-polyacrylamide gel electrophoresis,SDS-PAGE)及高效尺寸排阻色谱(high performance size exclusion chromatography,HPSEC)技术对酶促共聚物进行定性表征,研究在3个因素下,麦麸阿拉伯木聚糖与牛血清白蛋白酶促共聚物乳化活性及乳化稳定性变化规律。结果表明麦麸阿拉伯木聚糖可以通过过氧化物酶与牛血清白蛋白发生接枝反应,且酶添加量为0.2 U/g,H_2O_2浓度为0.5 mol/L,麦麸阿拉伯木聚糖与牛血清白蛋白质量比为10∶1时,紫外吸收光度值变化最明显,且酶促共聚物具有较好的乳化活性及乳化稳定性,分别为212.426 m~2/g及32.419 min。     

青稞麸皮阿拉伯木聚糖的提取工艺优化及结构分析

以青稞麸皮为原料,利用响应面法优化NaOH溶液提取阿拉伯木聚糖的最佳工艺条件。在单因素试验的基础上,以料液比、提取温度、提取时间、NaOH质量浓度为自变量,以青稞麸皮阿拉伯木聚糖得率为响应值,作四因素三水平的响应面回归分析。得到最佳提取工艺为料液比1∶25（g/mL）、提取温度55?℃、提取时间3?h、NaOH质量浓度15?g/L,在此条件下阿拉伯木聚糖得率为14.31%,与理论值14.27%无显著差异。因此利用响应面优化得到的青稞麸皮阿拉伯木聚糖提取工艺稳定可行。采用高效凝胶渗透色谱、紫外吸收光谱、红外吸收光谱、高效离子交换色谱对提取的多糖进行纯度鉴定及初步结构分析,结果表明青稞麸皮阿拉伯木聚糖均一性较好;多糖中含有微量蛋白质,不含核酸,并且含有α、β-糖苷键结构;其主要单糖组成为阿拉伯糖、半乳糖、葡萄糖和木糖,各单糖对应物质的量比为11.61∶1∶3.62∶18,阿拉伯糖与木糖物质的量比值为0.645。     

纳米SiO2改性4 种大分子材料的乳液制备及性质

为提高乳液稳定性,采用纳米SiO2改性明胶（gelatin,GE）、大豆分离蛋白、壳聚糖和阿拉伯胶（gum arabic,GA）制备茶油乳液。以乳化活性、乳化稳定性、离心稳定性、平均粒径、流变特性为考察指标,探究质量分数3.000%的纳米SiO2对4 种大分子材料复合乳液性质的影响,并对乳液的微观结构及油滴分布进行观察。结果表明,纳米SiO2能增强乳液稳定性,其中GE-纳米SiO2复合乳液综合性质最佳。添加纳米SiO2后乳化活性和乳化稳定性显著增加（P＜0.05）,离心稳定性降低68.444%。平均粒径为8.472 μm,乳液粒径最小且分布均匀,表面光滑呈球状。流变表现为典型的弱凝胶特性,稳定性良好。研究结果可为天然高分子和纳米SiO2乳液的制备和应用提供实践基础。     

Emulsifying activity and emulsion stability of corn gluten meal

Corn gluten meal with good emulsifying activity and emulsion stability may have potential in food uses. Commercial corn gluten meal from various producers had a pH around 4 and showed no emulsifying activity. Reducing the particle size to below 15 µm or increasing the pH to 6.6 (with particle size above 53 µm) did not improve the emulsifying activity. When the particle size was reduced to below 44 µm and the pH was adjusted to 6.6 or above, good emulsifying activity and good emulsion stability could be obtained. The emulsifying activities of corn gluten meals (<44 µm) from four different producers at around pH 8 ranged from 49.3 to 51.5 and the corresponding emulsion stabilities ranged from 39.7 to 49.5. There was no significant variation in emulsifying activity between pH 6.9 and 7.8 when NaOH, LiOH and KOH were used to adjust the pH, but LiOH‐ and KOH‐adjusted meal at around pH 7.8 showed better emulsion stability than NaOH‐adjusted meal. Good emulsifying activity of corn gluten meal could be obtained in NaCl solutions at sufficiently high pH. Published in 2001 for SCI by John Wiley & Sons, Ltd.     

面筋蛋白粒子-黄原胶Pickering乳液的制备及其表征

制备黄原胶与面筋蛋白纳米粒协同稳的Pickering乳液,表征Pickering乳液的物理化学性能和微观结构。结果显示：通过黄原胶与面筋蛋白纳米粒协同作用,可制备出稳定性较好的Pickering乳液。低质量分数的黄原胶（0.2%）会促进乳析;当黄原胶质量分数不小于0.3%时,乳液于4 ℃贮存30 d仍无乳析现象;当黄原胶质量分数为1%时,贮存30 d乳液出现析油的现象。不同乳化顺序得到乳液的稳定性不同。乳液M-WG-XG（面筋蛋白纳米粒与玉米油乳化得粗乳液,然后加入黄原胶二次分散）的稳定性最好,同时乳液的平均粒径最小（21.4±0.314）μm。黄原胶的加入增大了乳液的净电荷,乳液的稳定性提高。共聚焦显微镜结果表明,乳液M-WG-XG液滴分布均匀,界面层呈现出多层结构。相比于其他方式制备的乳液,乳液M-WG-XG有更好的黏弹性和离子稳定性。     

基于复凝聚法的纳米TiO2微胶囊制备

本文以纳米二氧化钛(TiO2)为芯材,明胶和阿拉伯胶为壁材,研究复凝聚法制备TiO2微胶囊的工艺。以微胶囊的平均粒径、包埋率和粒径分布方差作为评价工艺优劣的指标,利用正交试验法研究反应溶液pH值、反应温度、搅拌速率和壁材质量分数对微胶囊成囊效果的影响。通过优化工艺,获得最佳的工艺参数：溶液pH值为4.2、壁材质量分数为2%、反应温度50℃、搅拌转速为750r?min-1,在上述条件下,所得微胶囊平均粒径为90.1μm,包埋率超过86.2%,粒径分布方差12.1。     

Rheological behavior and stability of d-limonene emulsions made by a novel hydrocolloid (Angum gum) compared with Arabic gum

Our goal was to evaluate emulsion stability, droplet size analysis and rheological behavior of the emulsions prepared by a native biopolymer namely Angum gum (An) compared with Arabic gum (Ar) stabilized emulsions. After gum extraction, gum dispersions with maltodextrin were prepared in water (in 1-5% concentrations) and emulsified with 5% and 10% d-limonene using high pressure homogenization. Statistical analysis revealed a significant influence of gum type and gum concentration on emulsion stability at α = 0.05. Flavor level was not important statistically in emulsion stability but it was the only factor with a significant influence (P < 0.05) on surface tension of the emulsions. The results showed that Angum gum was superior to Arabic gum in stabilizing emulsions during storage. Also, rheological data revealed that Angum gum-emulsions’ behavior was following the Herschel-Bulkley model with higher viscosities compared to Arabic gum emulsions, which could be the main reason of higher emulsion stabilities with this novel hydrocolloid.     

Response surface methodology and multivariate analysis of equilibrium headspace concentration of orange beverage emulsion as function of emulsion composition and structure

The influence of emulsion composition (i.e. Arabic gum, xanthan gum and, orange oil) and structural emulsion properties (i.e. average droplet size and apparent viscosity) on equilibrium headspace concentration of beverage emulsions was investigated. Increase in average droplet size led to increase the equilibrium headspace concentration of more hydrophilic volatile compounds (i.e. lower log P) such as ethyl acetate and octanal, but decrease in more hydrophobic volatile compounds such as 3-carene, myrcene and limonene. In most cases, apparent viscosity had significant positive effect on equilibrium headspace concentration. Principle component analysis (PCA) score discriminated the beverage emulsions containing the same orange oil content but different contents of emulsifiers in different classes, thus indicating the significant (p < 0.05) effect of emulsifier fraction on equilibrium headspace concentration. Beverage emulsion containing 22.2% (w/w) Arabic gum, 0.52% (w/w) xanthan gum and 14.21% (w/w) orange oil was estimated to provide the highest equilibrium headspace concentration.     

Mannans as stabilizers of oil-in-water beverage emulsions

The stabilizing effect of spruce galactoglucomannan (GGM) on a model beverage emulsion system was studied and compared to that of guar gum and locust bean gum galactomannans, konjac glucomannan, and corn arabinoxylan. In addition, guar gum was enzymatically modified in order to examine the effect of the degree of polymerization and the degree of substitution of galactomannans on emulsion stability. Use of GGM increased the turbidity of emulsions both immediately after preparation and after storage of up to 14 days at room temperature. GGM emulsions had higher turbidity than the emulsions containing other mannans. The initial turbidity increased with increasing GGM content, but after 14 days storage at room temperature, the turbidity was the highest for GGM/oil ratio of 0.10:1 when ethanol-precipitated GGM was used. Increasing the storage temperature to +45 °C led to rapid emulsion breakdown, but a decrease in storage temperature increased emulsion stability after 14 days. Confocal microscopy showed that the average particle size in the bottom part of GGM emulsions stored for 14 days was smaller than 1 μm. A low degree of polymerization and a high degree of substitution of the modified galactomannans were associated with a decrease in emulsion turbidity.     

COLOR DEGRADATION AND COALESCENCE KINETICS OF AZTEC MARIGOLD OLEORESIN-IN-WATER EMULSIONS STABILIZED BY MESQUITE OR ARABIC GUMS AND THEIR BLENDS

Aztec marigold oleoresin-in-water (O/W) emulsions were formulated with mesquite gum or gum arabic and their blends as emulsifying and protective agents, at pH values of 3, 5 and 7. Changes in the emulsions average particle size were determined by laser ray diffraction, in tinctorial power by visible spectrophotometry and in color by reflectance measurements. Both gums and their blends form highly stable O/W emulsions against drop coalescence and color loss. The emulsifying agent composition and pH have an important role in determining the degree of effectiveness of the emulsions against color loss and drop coalescence kinetics. Mesquite gum provided a better stability against drop coalescence than gum arabic, and furthermore their blends had a synergistic effect providing a higher stability     

不同NaCl浓度条件下亚麻籽胶对肌原纤维蛋白凝胶作用力及乳化特性的影响

为改善低盐肉制品凝胶乳化品质的降低,明确亚麻籽胶（flaxseed gum,FG）添加对肉制品品质的影响,以肌原纤维蛋白（myofibrillar protein,MP）为研究对象,通过测定乳析指数、电位值、粒径、显微观察研究不同NaCl浓度条件下FG对MP乳液乳化稳定性的影响,而化学键的测定显示FG对MP凝胶化学作用力的影响。结果表明,形成MP凝胶及FG-MP凝胶体系的关键是二硫键和非二硫共价键的贡献;不同NaCl浓度对FG-MP乳液的乳析指数、ζ-电位、粒径的影响均不显著（P＞0.05）,而MP乳液随着NaCl浓度的提高,乳化稳定性、ζ-电位、粒径均显著变化（P＜0.05）。特别是在低浓度NaCl条件下,FG的加入可以显著提高MP乳液的稳定性（P＜0.05）。显微观察发现加入FG可以改善MP乳液液滴聚集的现象。因此,说明在低浓度NaCl条件下加入FG可以显著提高肌原纤维蛋白乳液的乳化稳定性,提高其抗盐能力,促进亚麻籽在肉制品中的应用。     

The emulsifying properties of Persian gum (Amygdalus scoparia Spach) as compared with gum Arabic

The current study compares the emulsifying properties of Persian gum (PG) and gum Arabic (GA) in emulsions. The effects of concentration (0.5–3% w/v PG, 2.5–15% w/v PG), pH (2–7), ionic strength [NaCl, CaCl₂ (0–300 mM)], and temperature (40–90°C) were investigated. The surface–volume mean diameter (D₃₂) of the emulsions showed that the minimum values were 9.89 ± 0.68 and 4.52 ± 0.03 µm for emulsions containing 1.5% w/v PG and 15% w/v GA, respectively. In addition, the zeta potential of PG and GA emulsion changed from ?23.5 to ?39.5 and ?30.5 to ?46.0 mV, respectively. The interfacial tensions of PG and GA emulsions were varied in the ranges of 34.0–15.0 and 29.0–9.0 mN/m, respectively. Changes in the D₃₂ value of GA emulsions showed were not significantly different (p > 0.05) with respect to the effects of pH, NaCl, CaCl_2, and temperature. The NaCl concentration had no significant effect on D₃₂; but its value decreased from 13.11 to 5.70 µm as the CaCl₂ concentration increased. The interfacial tension of PG significantly increased with decreasing pH 7–2 and increasing 0–300 mM salts. After heating (25–90°C), the D₃₂ values of PG and GA emulsions changed to 11.04–14.54 and 4.21–4.21 μm, respectively. The results of this study can be useful for the application of PG as an emulsifier in beverage emulsions.