木塑复合材料加工工艺与设备的研究

介绍了木塑复合材料的发展趋势和成型方法，并针对木塑复合材料成型中的关键问题，详述了木塑复合材料挤出成型过程中原料及助剂选择和工艺参数的设定，以及其特殊的成型设备。     

挤出温度和螺杆转速对木塑制品外观性能的影响

介绍了木塑复合材料的主要生产工艺.实验采用两步法挤出成型工艺制作HDPE基木塑复合材料,研究挤出温度和螺杆转速对木塑复合材料外观性能的影响.结果表明:当木塑复合材料使用HDPE和杨木粉作为主要原料,木塑比为6∶4时,与之相适应的工艺条件为:挤出成型温度为130℃,150℃,155℃,155℃,135℃;螺杆转速为7.5r/min.     

浅谈木塑复合材料及其生产工艺

针对木塑复合材料生产中存在的问题,提供了改善植物纤维与高分子材料相容性的3种有效途径,并通过介绍该复合材料基材和成型设备等选择,简述其生产工艺流程,最后论述了木塑复合材料应用前景。     

填料和润滑剂对木塑复合材料力学性能的影响

研究填料和润滑剂对挤出成型工艺制作木粉/高密度聚乙烯(HDPE)木塑复合材料力学性能的影响。研究结果表明,当木塑质量比为6:4,选择碳酸钙为填料,硬脂酸为内润滑剂,PE蜡为外润滑剂时,木塑复合材料可以获得较好的力学性能。     

木塑复合材料老化性能表征概述

木塑复合材料是以木本等可再生资源为主要原材料,并同一定比例的热塑性聚合物混合加工成型而得的绿色环保复合材料。文章介绍了木塑复合材料老化作用的因素,并对其老化性能的表征方法进行概述。     

基于ANSYS的木塑挤出3D成型研究

针对目前3D成型技术原材料单一以及木塑挤出成型的局限性,提出了一种木塑挤出3D成型方法。建立了三维成型平台与挤出部分的匹配关系;探究了在成型层厚度为0.5 mm,挤出速度匹配范围在12.74~63.69 mm/s的条件下,动模板移动速度范围为20~100 mm/s。通过分析聚丙烯基木塑复合材料成型温度场和应力场模拟得出:随着动模板移动速度提高,应力波动减小,成型过程中的最大应力值和最大变形量增大。研究表明,动模板移动速度是木塑挤出3D成型的一个重要因素。在实际生产中,为保证成型效率和质量,可以适当提高动模板移动速度,同时也要按照匹配关系提高挤出速度。     

木塑复合材料的应用与发展

通过对国内外木塑复合材料应用状况的调查,分析了推广应用木塑复合材料的重要性,介绍了木塑复合材料的主要应用领域以及在国内外的发展现状,阐述了木塑复合材料产业的发展方向,肯定了发展木塑复合材料的必要性和可行性.     

木塑复合材料表面胶接特性研究进展

简要介绍了木塑复合材料目前常采用的连接方式及胶黏剂,并从木塑复合材料的表面处理方法和胶接机理这两方面对木塑复合材料表面胶接特性的研究进展进行了综述,展望了今后木塑复合材料表面胶接特性的重点和发展方向。     

热处理对WPC尺寸稳定性的影响

木塑复合材料目前已被广泛应用于户外用材如健康步道中,为了了解其在使用过程中尺寸变化与温度的关系,本文以PVC木塑复合材料、PP木塑复合材料以及PE木塑复合材料为试验对象,通过恒温干燥箱模拟自然使用温度,测试了在50℃、60℃、70℃、80℃、90℃的温度条件下各种木塑复合材料的长、宽、厚的尺寸,并归纳分析了温度对PVC木塑复合材料长度方向上的尺寸变化影响;同一温度处理条件下PVC木塑复合材料在不同方向上尺寸变化影响以及同一温度处理条件下对三种木塑复合材料尺寸稳定性的影响。结果表明:对于同种木塑复合材料,温度越高,尺寸变化越明显;长度方向较宽度方向和厚度方向尺寸变化率低,相比PP基、PE基和PVC基三种木塑复合材料,PVC木塑复合材料的尺寸变化率最高,PE木塑复合材料其次,PP木塑复合材料变化率最小。     

木塑复合材料应用与研究进展

介绍了国内外有关木塑复合材料的应用与研究现状,阐述了木塑复合材料研究开发的题,论述了木塑复合材料改善复合界面相容性的方法,分析了木塑复合材料的加工工艺与配方设计.     

乳清浓缩蛋白可食用包装膜的研制

以乳清浓缩蛋白为基质,通过加入成膜剂、增塑剂制得可食用包装膜。研究了不同成膜剂添加量、不同增塑剂添加量、不同转谷氨酰胺酶添加量对成膜的影响。通过响应面分析表明,制备乳清浓缩蛋白可食用膜的最佳条件是：乳清浓缩蛋白浓度10%、添加山梨醇5%、无水氯化钙1.2166%、转谷氨酰胺酶0.018%,在60~65℃的温度范围成膜。     

乳清浓缩蛋白与卵清蛋白复合膜的制备及其性能

本文以乳清蛋白（Whey protein concentrate,WPC）和卵清蛋白（Egg white protein,EWP）为成膜基质,添加5 U/g_蛋白转谷氨酰胺酶（Transglutaminase,TG）制备WPC/EWP复合膜,分别研究WPC和EWP质量比、膜液pH、甘油添加量对WPC/EWP复合膜结构及性能的影响。结果表明,当WPC/EWP质量比为1:3,成膜液pH为8,甘油添加量为35%时,电镜结果表明形成的复合膜结构致密无孔隙,红外结果显示WPC和EWP有较好的相容性。WPC/EWP复合膜的水蒸气透过率为2.08×10?10 g·s?1m?1Pa?1,透光率为73.90%,抗拉强度为1.60 MPa,断裂伸长率为151.96%。WPC、EWP和甘油在膜液pH为8时具有良好的融合性,能显著（P<0.05）提高WPC/EWP复合膜的机械性能。     

我国木塑产品标准现状及其存在问题

介绍了我国木塑产品相关标准现状和存在的一些问题,并对今后木塑产品标准体系的发展方向提出了建议。     

Comparison of functional properties of 34% and 80% whey protein and milk serum protein concentrates

This study compared the functional properties of serum protein concentrate (SPC) with whey protein concentrate (WPC) made from the same milk and with commercial WPC. The experimental SPC and WPC were produced at 34% or 80% protein from the same lot of milk. Protein contents of WPC and SPC were comparable; however, fat content was much lower in SPC compared with WPC and commercial WPC. The effect of drying methods (freeze vs. spray drying) was studied for 34% WPC and SPC. Few differences due to drying method were found in turbidity and gelation; however, drying method made a large difference in foam formation for WPC but not SPC. Between pH 3 and 7, SPC was found to have lower turbidity than WPC; however, protein solubility was similar between SPC and WPC. Foaming and gelation properties of SPC were better than those of WPC. Differences in functional properties may be explained by differences in composition and extent of denaturation or aggregation.     

Short communication: Low-fat ice cream flavor not modified by high hydrostatic pressure treatment of whey protein concentrate

The purpose of this study was to examine flavor binding of high hydrostatic pressure (HHP)-treated whey protein concentrate (WPC) in a real food system. Fresh Washington State University (WSU, Pullman) WPC, produced by ultrafiltration of separated Cheddar cheese whey, was treated at 300 MPa for 15 min. Commercial WPC 35 powder was reconstituted to equivalent total solids as WSU WPC (8.23%). Six batches of low-fat ice cream were produced: A) HHP-treated WSU WPC without diacetyl; B) and E) WSU WPC with 2 mg/L of diacetyl added before HHP; C) WSU WPC with 2 mg/L of diacetyl added after HHP; D) untreated WSU WPC with 2 mg/L of diacetyl; and F) untreated commercial WPC 35 with 2 mg/L of diacetyl. The solution of WSU WPC or commercial WPC 35 contributed 10% to the mix formulation. Ice creams were produced by using standard ice cream ingredients and processes. Low-fat ice creams containing HHP-treated WSU WPC and untreated WSU WPC were analyzed using headspace-solid phase microextraction-gas chromatography. Sensory evaluation by balanced reference duo-trio test was carried out using 50 untrained panelists in 2 sessions on 2 different days. The headspace-solid phase microextraction-gas chromatography analysis revealed that ice cream containing HHP-treated WSU WPC had almost 3 times the concentration of diacetyl compared with ice cream containing untreated WSU WPC at d 1 of storage. However, diacetyl was not detected in ice creams after 14 d of storage. Eighty percent of panelists were able to distinguish between low-fat ice creams containing untreated WSU WPC with and without diacetyl, confirming panelists’ ability to detect diacetyl. However, panelists were not able to distinguish between low-fat ice creams containing untreated and HHP-treated WSU WPC with diacetyl. These results show that WPC diacetyl-binding properties were not enhanced by 300-MPa HHP treatment for 15 min, indicating that HHP may not be suitable for such applications.     

SMALL AMPLITUDE OSCILLATORY TESTING (SAOT). INSTRUMENTATION DEVELOPMENT AND APPLICATION TO COAGULATION OF EGG ALBUMEN,WHEY PROTEIN CONCENTRATE AND BEEF WIENER EMULSION3

An instrument to measure the development of protein gels during thermal coagulation was developed. Very small oscillatory movements, sufficiently small to avoid damaging forming structures, were imposed on the sample trapped within a specially constructed cell, and the torques transferred through the sample sensed with strain gauges. Temperatures were controlled with one heating and one refrigerated (20°C) bath and the sample properties determined through both heating and cooling cycles. Egg white (EW) whey protein concentrate (WPC) and beef wiener emulsion (BWE) were tested. EW and WPC were characterized by delayed onset of gelation followed by high temperature thickening. Cooling further stiffened the gel in both cases. B WE was characterized by an initial decrease in transmitted torque as fat melting was detected. This was followed by a rapid rise in transmitted torque as the protein coagulated, followed by a further increase or stiffening on cooling. Detailed parameters describing the thermal gelation of the three materials are given.     

Comparison of composition and sensory properties of 80% whey protein and milk serum protein concentrates

Milk serum protein concentrates (SPC) are proteins found in cheese whey that are removed directly from milk. Because SPC are not exposed to the cheese-making process, enzymatic or chemical reactions that can lead to off-flavors are reduced. The objectives of this study were to identify and compare the composition, flavor, and volatile components of 80% protein SPC and whey protein concentrates (WPC). Each pair of 80% SPC and WPC was manufactured from the same lot of milk and this was replicated 3 times. At each replication, spray-dried product from each protein source was collected. Commercial 80% WPC were also collected from several manufacturers for sensory and volatile analyses. A trained sensory panel documented the sensory profiles of the rehydrated powders. Volatile components were extracted by solid-phase microextraction and solvent extraction followed by solvent-assisted flavor evaporation with gas chromatography-mass spectrometry and gas chromatography-olfactometry. Consumer acceptance testing of acidified 6% protein beverages made with 80% SPC and WPC produced in the pilot plant and with WPC from commercial sources was conducted. The SPC was lower in fat and had a higher pH than the WPC produced in the pilot plant or commercial WPC. Few sensory differences were found between the rehydrated SPC and WPC manufactured in this study, but their flavor profiles were distinct from the flavor of rehydrated commercial WPC. The pilot-plant WPC had higher concentrations of lipid oxidation products compared with SPC, which may be related to the higher fat content of WPC. There was a large difference in appearance between 80% SPC and WPC: solutions of SPC were clear and those of WPC were opaque. Concentrations of lipid oxidation products in commercial WPC were generally higher than those in pilot-plant SPC or WPC. Sensory profiles of the peach-flavored protein beverage included cereal, free fatty acid, and soapy flavors and bitter taste in beverages made from pilot-plant products, whereas cardboard flavors were detected in those made with commercial WPC. Consumer liking scores for the beverages made with SPC were ranked highest or equally high with beverages made with WPC for aroma, appearance, and mouthfeel, but the beverages made with SPC had lower flavor and overall liking scores compared with beverages made with 3 of the 4 WPC.     

High Hydrostatic Pressure Affects Flavor-binding Properties of Whey Protein Concentrate

ABSTRACT: The effects of high hydrostatic pressure (HHP) on flavor-binding properties of whey protein concentrate (WPC) were determined with benzaldehyde, heptanone, octanone, and nonanone. After HHP treatment (600 MPa, 50 °C, for 0-, 10-, or 30-min holding time), flavor-binding properties of WPC were studied by intrinsic fluorescence titration and static headspace analysis. The HHP treatments increased the number of binding sites and the apparent dissociation constants of WPC for benzaldehyde. HHP treatment of WPC for 0 min increased the number of binding sites of WPC for heptanone and octanone. As observed by headspace analysis, HHP treatments did not result in significant changes in the flavor retention for benzaldehyde in WPC solutions. Flavor retention of 100 ppm and 200 ppm heptanone and octanone in HHP-treated (10 min) WPC was significantly lower than for untreated WPC and HHP-treated WPC for 0 min or 30 min. For flavor retention of nonanone, significant decreases were only observed at 100 ppm when WPC solutions were HHP-treated for 10 min. While use of HHP treatment of WPC has potential in real food systems, these findings demonstrate the importance of careful selection of HHP treatment times and flavor concentrations for desired outcomes in food applications.     

Foaming and Emulsifying Properties of Whey Protein Concentrates As Affected by Lipid Composition

Freeze-dried WPC, containing 35 and 75% protein were manufactured by pretreating whey with calcium chloride and heat. These and commercial WPC were subjected to proximate analysis and lipid classes, phospholipid classes, free fatty acids (FFA), and monoacylglycerols (MAG) composition were determined. Solubility, thermal, foaming, and emulsifying properties of the WPC were studied. Pretreatment increased calcium and phosphorus contents and decreased the contents of all other minerals. The pretreatment had no effect on solubility, denaturation enthalpy, and onset temperature of denaturation of WPC. These values were comparable to those of commercial WPC. Foaming capacity and emulsion stability were unaffected, but foam stability increased and emulsifying capacity decreased due to pretreatment. Overall, total lipids and lipid class contents of experimental WPC were too low to affect surface properties of WPC.