湿法糖基化改性玉米醇溶蛋白的物化特性以及在胶囊壳中的应用

利用麦芽糖浆对玉米醇溶蛋白进行湿法糖基化改性,以抗张强度为指标,考察改性后蛋白膜的机械性能,通过SDS-PAGE、DSC、傅里叶红外和扫描电子显微镜等手段考察蛋白改性前后的物化性质。结果表明：改性后蛋白膜较传统的明胶膜和纯玉米醇溶蛋白膜机械性能有较大提高。对SDS-PAGE电泳谱图分析可知玉米醇溶蛋白与麦芽糖浆进行了有效的糖基化接合。经傅里叶红外光谱扫描,可知改性后的玉米醇溶蛋白的化学结构发生了变化。差示量热扫描仪分析表明湿法改性的产物zein-MS膜热变性温度从由为改性前的188.47℃提高到了206.87℃,增加了膜的稳定性。扫描电子显微镜发现改性后膜的表面较改性前更加平整,孔洞基本消失。将玉米醇溶蛋白改性产物制成胶囊壳,以常规明胶胶囊壳作对照,参考《中华药典》（2015版）的相关检测指标进行检测,各项指标均合格。     

葡萄糖糖基化改性玉米醇溶蛋白膜的物化性质 及在胶囊壳中的应用

以葡萄糖为原料对玉米醇溶蛋白进行糖基化改性,以抗拉强度为指标,考察最佳改性成膜工艺,并通过差示扫描量热法(DSC)、傅里叶变换红外光谱(FT-IR)、扫描电子显微镜(SEM)对改性蛋白膜的物化性质进行研究。结果表明:在葡萄糖与玉米醇溶蛋白质量比1∶10、超声功率450 W、反应时间30 min的条件下,制得玉米醇溶蛋白-葡萄糖膜的抗拉强度达到34.06 MPa,接枝度为63.05%。玉米醇溶蛋白以共价键的方式与葡萄糖结合,使糖基化改性产物结构更加稳定。改性蛋白膜的表面较改性前更加平整,凹陷凸起基本消失。玉米醇溶蛋白-葡萄糖膜热变性温度从改性前的157.95℃升高到164.26℃,膜的热稳定性提高。经葡萄糖糖基化改性后的玉米醇溶蛋白胶囊壳指标符合《中华人民共和国药典》(2015版)要求。     

玉米抗性淀粉形成过程的研究

研究了水解-压热法制备玉米抗性淀粉的形成过程,通过扫描电子显微镜、X射线衍射及差示扫描量热法对玉米抗性淀粉形成过程中颗粒结构、结晶结构和热特性的变化进行了分析。实验分别从不同角度揭示了水解和压热处理对淀粉结构的破坏方式和程度,得出玉米抗性淀粉在形成过程中失去了原淀粉的结晶结构,形成了新的结晶结构。     

干法糖基化改性玉米醇溶蛋白产物的物化特性及在胶囊壳中的应用

利用菊粉对玉米醇溶蛋白进行干法糖基化改性,通过SDS-PAGE凝胶电泳、热分析(DSC)、傅里叶红外和扫描电子显微镜等手段考察改性前后蛋白的变化。结果表明:SDSPAGE电泳谱图可确认玉米醇溶蛋白与菊粉进行了有效的接合;傅里叶红外分析也确认糖基化改性后,玉米醇溶蛋白以共价键的形式接入了菊粉糖分子;DSC分析所得玉米醇溶蛋白膜及其改性产物膜的变性温度分别为188.47,194.02℃;扫描电子显微镜发现改性后膜的表面更加平整,无孔洞。参照《中华人民共和国药典(2015版)》中关于明胶胶囊壳的相关检测指标,对菊粉改性的玉米醇溶蛋白产物制成胶囊壳进行测定,该产品各项指标均达到要求。     

PPC对挤压成型Zein-PPC复合薄膜性质的影响

以玉米醇溶蛋白(zein)和聚丙撑碳酸酯(PPC)为主原料,以甘油为可塑剂,利用挤压法制备Zein-PPC复合薄膜,并对复合薄膜的机械性能、形态学和结构进行研究。结果表明:PPC的引入提高了复合薄膜的拉伸强度,当PPC含量为30%时,其拉伸强度最大,为30.11MPa;应用Halsey方程,建立了拉伸强度与相对湿度关系模型;差示扫描量热仪(DSC)分析表明复合薄膜具有稳定的热特性;傅里叶变换红外光谱(FT-IR)和X射线衍射实验发现,复合薄膜中玉米醇溶蛋白的羧基与PPC中的羟基发生反应生成了酯键,保证了复合膜的稳定性。     

亚麻籽胶对玉米淀粉糊化特性的影响

采用差示扫描量热仪(DSC)、傅里叶变换红外光谱分析(FT-IR)、X射线衍射分析(XRD)和扫描电子显微镜(SEM)研究添加亚麻籽胶对玉米淀粉糊化的影响。DSC结果表明,添加亚麻籽胶显著地提高了玉米淀粉的糊化起始温度和熔晶热焓值;FT-IR结果表明,添加或未添加亚麻籽胶玉米淀粉结构没有发生变化,在65℃时,亚麻籽胶和玉米淀粉之间没有发生明显的相互作用,在75℃时添加亚麻籽胶促进了淀粉分子结合水的能力增强;X射线衍射分析显示,糊化前添加亚麻籽胶玉米淀粉相对结晶度没有太明显变化,糊化能显著降低玉米淀粉的结晶度,同时也表明添加亚麻籽胶对玉米淀粉糊化有一定延迟作用;SEM也直观地证明了亚麻籽胶延缓了玉米淀粉的糊化。     

超临界CO2反溶剂法制备大豆异黄酮-玉米醇溶蛋白复合纳米颗粒

通过超临界CO₂反溶剂法制备大豆异黄酮-玉米醇溶蛋白复合颗粒。采用原子力显微镜观察发现,荷载大豆异黄酮的玉米醇溶蛋白分子可以形成球形颗粒。以玉米醇溶蛋白的自组装特性为基础,改变玉米醇溶蛋白与大豆异黄酮的比例,能使两者形成的复合颗粒的数量平均粒径不超过200nm,其表面负电荷分布在-22.7^-34.8mV之间。通过差示扫描量热法、傅里叶变换红外光谱分析表明,氢键、疏水相互作用是玉米醇溶蛋白与大豆异黄酮形成复合颗粒的主要作用力。     

单月桂酸甘油酯添加量对大豆分离蛋白复合膜成膜特性的影响

研究了单月桂酸甘油酯(glycerol monolaurate,GML)添加量对大豆分离蛋白(soy protein isolate,SPI)复合膜成膜特性的影响,并运用傅里叶变换红外光谱、X射线衍射、差示扫描量热和扫描电子显微镜技术初步探讨了两者的成膜机制。结果表明:随着GML添加量的增加,GML-SPI复合膜的抗拉强度和断裂延伸率呈先上升后下降趋势,该复合膜的水蒸气透过率、透光率、水溶性逐渐下降,而亮度和白度有所增加。傅里叶变换红外光谱证实,复合膜中GML和SPI两种组分主要通过氢键、疏水作用力等次级键相互结合;X射线衍射和差示扫描量热结果显示,与空白对照组相比,GML-SPI复合膜的结晶度和熔融温度均有所提高;扫描电子显微镜结果表明,添加GML有利于减少复合膜内部空隙,但GML添加量超过0.8%时,复合膜中GML和SPI两类组分会出现两相分离现象。本研究成果可为以SPI复合膜为代表的新型可食性包装材料的研发与应用提供理论依据。     

挤压剪切活化对添加耐高温α-淀粉酶脱胚玉米淀粉结构和理化特性的影响

本研究通过偏光显微镜、扫描电子显微镜、热台显微镜、X射线衍射、差示扫描量热分析、傅里叶变换红 外光谱分析等手段,研究原脱胚玉米、挤压脱胚玉米和添加耐高温α-淀粉酶挤压脱胚玉米的淀粉结构及性质变化, 并探究其相互关系,揭示挤压剪切活化对脱胚玉米的淀粉颗粒机械力化学效应。研究表明：与原脱胚玉米和挤压脱 胚玉米相比较,挤压处理对添加耐高温α-淀粉酶脱胚玉米的淀粉结构及性质产生显著影响,酶解力和糊化度增大,碘 蓝值、直链淀粉含量减小。添加耐高温α-淀粉酶挤压脱胚玉米淀粉颗粒形貌破坏,偏光十字破坏,结晶度变小;升温糊 化过程中,焓变降低;挤压使淀粉颗粒的结晶结构破坏,淀粉颗粒发生聚集,破损淀粉颗粒易糊化和裂解。     

湿法糖基化改性玉米醇溶蛋白的物化特性及其在胶囊壳中的应用

利用麦芽糖浆对玉米醇溶蛋白进行湿法糖基化改性,以抗张强度为指标,考察改性后蛋白膜的机械性能,通过SDS-PAGE、DSC、傅里叶红外和扫描电子显微镜等手段考察蛋白改性前后的物化性质。结果表明:改性后蛋白膜较传统的明胶膜和纯玉米醇溶蛋白膜机械性能有较大提高。对SDS-PAGE电泳谱图分析可知玉米醇溶蛋白与麦芽糖浆进行了有效的糖基化接合。经傅里叶红外光谱扫描,可知改性后的玉米醇溶蛋白的化学结构发生了变化。差示量热扫描仪分析表明湿法改性的产物zein-MS膜热变性温度从由为改性前的188. 47℃提高到了206. 87℃,增加了膜的稳定性。扫描电子显微镜发现改性后膜的表面较改性前更加平整,孔洞基本消失。将玉米醇溶蛋白改性产物制成胶囊壳,以常规明胶胶囊壳作对照,参考《中华药典》(2015版)的相关检测指标进行检测,各项指标均合格。     

Preparation and Physical Properties of Zein-Coated High-Amylose Corn Starch Film

The objective of this study was to prepare the edible composite films using high-amylose corn starch (HACS) and corn zein and to determine their physical properties. HACS was gelatinized using the specially designed high-pressure container. HACS film containing 20 g sorbitol/100 g as a plasticizer had suitable physical properties. The HACS film coated with corn zein containing 20 g oleic acid/100 g had moderate physical properties and barrier properties.     

冻藏处理对糯玉米淀粉微观结构和理化特性的影响

将新鲜糯玉米进行不同冻藏时间(0、10、20、30 d)的处理,通过傅里叶红外光谱仪、便携式拉曼光谱仪、X射线衍射仪、扫描电镜、差示扫描量热仪、快速黏度分析仪等研究冻藏处理对其内部淀粉微观结构和理化性能的影响规律,以期为延缓其品质劣变提供基础数据。结果表明：冻藏处理导致糯玉米淀粉的R_{1 045/1 022}减小,半峰宽增大,相对结晶度降低,淀粉颗粒表面出现凹陷和破碎,粒径变小,且随着冻藏时间的延长,冻藏对玉米淀粉微观结构的破坏更加明显;糯玉米经冻藏处理后,其淀粉的糊化温度、糊化焓值、峰值黏度、崩解值下降,最终黏度和回生值升高,表明冻藏淀粉更容易发生糊化,且糊化黏度降低,但淀粉热糊的稳定性有所提高,更容易发生老化。此外,冻藏处理还可导致玉米淀粉内的抗性淀粉和慢消化淀粉转变为快消化淀粉,表明冻藏具有提高鲜食玉米的消化速率和程度的潜力。     

Effect of γ-irradiation on some physicochemical and thermal properties of cowpea (Vigna unguiculata L. Walp) starch

Previously, we reported that starch-related functional properties of cowpea flours and pastes were modified by 2, 10 and 50 kGy γ-irradiation doses. To elucidate some of the effects of γ-irradiation specifically on cowpea starch as well as the actual contribution of starch to the observed functional modifications at the flour and paste level, starch was isolated from irradiated cowpea flours and pastes and studied using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Fourier Transform Infra-Red (FTIR) spectroscopy, Rapid Visco-Analyser (RVA) pasting properties, and some functional properties. Pasting (peak, trough, breakdown, final, and setback viscosities) and swelling properties were significantly decreased in a dose-dependent manner. DSC of cowpea starch showed increases in peak gelatinisation temperature with increasing irradiation dose. SEM (2500×) microphotographs showed that up to 50 kGy irradiation did not present any visible physical effect on the cowpea starch granule. FTIR indicated that starch granule surface order (crystallinity) was not affected by the irradiation doses employed.     

添加丁香精油对玉米醇溶蛋白膜性能及结构的影响

以玉米醇溶蛋白为原料制备可食性膜,将丁香精油添加到玉米醇溶蛋白膜中,研究其对玉米醇溶蛋白膜物理性能及微观结构的影响。结果表明,丁香精油体积分数在0.5%～2.0%范围内时,随着体积分数的增加,玉米醇溶蛋白膜的厚度、断裂伸长率和水蒸气透过系数逐渐增加。丁香精油体积分数为0.5%～1.0%时,玉米醇溶蛋白膜的拉伸强度显著增加（P＜0.05）。添加丁香精油改善了膜的机械性能,增加了阻光性和透湿性。通过红外光谱和扫描电镜分析表明,添加丁香精油并未显著改变玉米醇溶蛋白的结构,且添加丁香精油的成膜液在干燥过程中会产生微孔,使得玉米醇溶蛋白膜的表面粗糙不均匀。     

高压均质对玉米淀粉机械力化学效应研究

以玉米淀粉为原料,通过扫描电镜(scanning electron microscope,SEM)、X-射线衍射(X-ray diffraction,XRD)、激光共聚焦显微镜(confocal laser scanning microscopy,CLSM)、快速黏度分析仪(rapid visco analyser,RVA)、差示扫描量热仪(differential scanning calorimetry,DSC)、偏光显微镜(polarizing microscope,PLM)等手段研究高压均质处理对玉米淀粉微观结构及理化性质的影响,揭示高压均质对玉米淀粉机械力化学效应。结果表明,高压均质对淀粉颗粒的无定形区、结晶区产生很强的机械力化学作用,推断淀粉颗粒内部依次发生了聚集和团聚效应。     

Effects of Extrusion Temperature and Plasticizers on the Physical and Functional Properties of Starch Films

Cornstarch, at 20% moisture content (dry basis, d.b.), was mixed with glycerol at 3:1 ratio to form the base material for extruded starch films. Stearic acid, sucrose and urea, at varying concentrations, were tested as secondary plasticizers for the starch‐glycerol mixture. The ingredients were extruded at 110 and 120°C barrel temperatures to determine the effects of extrusion temperature, plasticizer type and their concentrations on the film‐forming characteristics of starch, as well as their effects on selected physical and functional properties of the films. The physical and mechanical properties of the films were studied by scanning electron microscopy (SEM) and tensile testing, while the glass transition and gelatinization properties were analyzed using differential scanning calorimetry (DSC). The interactions between the functional groups of starch and plasticizers were investigated using Fourier‐transform infrared (FTIR) spectroscopy. The water vapor permeability (WVP) properties of starch films were determined using ASTM standard E96‐95. Scanning electron micrographs exhibited the presence of native and partially melted starch granules in the extruded films. The tensile stress, strain at break and Young's modulus of starch films ranged from 0.9 to 3.2 MPa, 26.9 to 56.2% and 4.5 to 67.7 MPa, respectively. DSC scans displayed two glass transitions in the temperature ranges of 0.1 to 1°C and 9.6 to 12°C. Multiple melting endotherms, including that of amylose‐lipid complexes, were observed in the thermoplastic extrudates. The gelatinization enthalpies of the starch in the extruded films varied from 0 to 1.7 J/g, and were dependent largely on the extrusion temperature and plasticizer content. The shift in the FTIR spectral bands, as well as the appearance of double‐peaks, suggested strong hydrogen bonding interactions between the starch and plasticizers. The WVP of starch films ranged from 10.9 to 15.7 g mm h^‐1 m^‐2 kPa^‐1, depending on the extrusion temperature and the type of plasticizer used.     

Effects of protein interactions on properties and microstructure of zein–gliadin composite films

Zein and gliadin are both readily dissolved in aqueous ethanol and have good film-forming property. This article describes an attempt to improve the flexibility of zein films by the addition of gliadin to the zein film-forming solution. The properties of zein–gliadin composite films, i.e., color, transparency, moisture content, water solubility, water vapor permeability, dynamic contact angle which in turn affected the mechanical property, water resistance and glass transition temperature of films were investigated. The contents of second structure were characterized via Fourier transform infrared spectroscopy (FTIR), whereas morphology of films was examined by scanning electron microscopy (SEM). It was observed that the addition of gliadin enhanced the strain at break of zein–gliadin composite films as a result of the increase in the content of α-helix, β-turn structures and decrease in the level of β-sheet structure. The water resistance of films decreased with the content of gliadin increasing. Morphology of composite films showed that gliadin and zein organized a homogeneous material. This work opens a new perspective for zein in flexible food package.     

Barrier properties of corn zein nanocomposite coated polypropylene films for food packaging applications

The feasibility of corn zein nanocomposite (CZNC) coatings as an alternative to synthetic polymer barrier layer on polypropylene (PP) films was examined. The effect of layered silicate content in the CZNC layers on the barrier and surface hydrophobicity of the CZNC-PP films were investigated. Incorporation of organomodified montmorillonite (OMMT) by solution intercalation into zein matrix significantly improved oxygen and water vapor barrier of coated PP films. The barrier properties were also investigated theoretically by using various phenomenological permeability models. Tortuous permeation path formed by the fine delamination of nanoclays was found to be responsible for the barrier improvements in zein layers. In conclusion, durable CZNC-PP laminates were developed. CZNC coating of PP films has reduced the oxygen permeability nearly four times, while water vapor permeability reduced by 30% with 5 wt.% OMMT content in 5.9 μm corn zein coating.     

超声处理对马铃薯淀粉结构特性及理化性质的影响

为了研究超声对马铃薯淀粉微观结构及理化性质的影响,以马铃薯淀粉为原料,通过扫描电子显微镜、激 光共聚焦显微镜、X射线衍射、傅里叶变换红外光谱、差示扫描量热法、快速黏度分析、偏光显微镜观察等方法, 研究了超声对马铃薯淀粉微观结构及理化性质的影响,揭示超声对马铃薯淀粉的机械力化学效应。结果表明：由于 马铃薯淀粉颗粒内部“狭长的脐点区”结构比较疏松,超声处理对马铃薯淀粉可产生显著机械力化学效应;随着超 声时间延长,马铃薯淀粉颗粒内部依次经过受力阶段、聚集阶段、团聚阶段;同时由于超声处理引起了马铃薯淀粉 颗粒结构变化,故导致了马铃薯淀粉理化性质显著变化。     

碾轧对马铃薯淀粉的机械力化学效应

以马铃薯淀粉为原料,研究碾轧处理对淀粉结构和性质的影响。通过扫描电子显微镜、X射线衍射、差示扫描量热仪、傅里叶变换红外光谱仪、快速黏度分析仪、偏光显微镜等手段揭示碾轧对马铃薯淀粉的机械力化学效应。结果表明,碾轧处理对淀粉颗粒的无定形区、结晶区产生不同程度的机械力化学作用,导致马铃薯淀粉性质发生显著变化。由此推断淀粉颗粒内部依次发生了受力、聚集和团聚效应。