挤压膨化过程中物料的变化

挤压膨化因生产周期短 ,成本低 ,产品多样 ,有利于保存等特点而广泛用于即食谷物早餐食品、小吃食品等的生产中 ,挤压膨化技术具有广阔的应用前景。挤压法利用温度和压力两个因素 ,使得物料膨化。通常 ,含有一定水分的物料在挤压机套筒内受到螺杆推动作用和卸料模具或套筒内节流装置的反向阻滞作用 ,另外还受到了来自于外部的加热或物料与螺杆和套筒的内部摩擦热的加热作用。这种综合作用的结果使物料处于高达 3～ 8ＭＰａ的高压和2 0 0℃左右的高温状态之下 ,一旦物料由模具口挤压 ,压力骤然下降为常压 ,水分便急骤蒸发 ,产生了类似于“爆…     

Changes in Starch and Protein on Extrusion of Corn Starch and Sunflower Protein Blends

We investigated the use of electron spin resonance spectroscopy (ESR) and the spin labelled fatty acid, 16 doxylstearic acid (16-DSA) in the study of starch and protein modification during extrusion processing of corn starch (CS), corn meal (CM), and their blends with sunflower protein isolate (SPI). Spectra due to binding of the spin probe to starch and protein were identified. Changes in spectra after extrusion of all materials indicated that: (1) ~90% of the starch was modified (gelatinized); (2) The globular protein structure was disrupted. These changes demonstrate that spin probes and ESR spectroscopy may be used to study starch and protein modification during extrusion and other food processes.     

淀粉反应挤出改性及挤出过程中淀粉颗粒变化

原淀粉经各种改性后性质发生变化,使其应用范围更加广阔。淀粉改性方法有化学法、物理法和生物法,其中化学法改性工艺比较成熟,但改性过程需使用大量化学试剂,应用受到限制,而物理法改性不存在这个问题。反应挤出法是物理改性一种,作为一种新技术,在淀粉改性中有很多优点。该文主要介绍反应挤出政性原理、特点、应用现状、影响因素及挤出过程中淀粉颗粒变化。     

植物蛋白原料体系影响挤压组织化研究进展

蛋白原料是挤压生产组织化产品的基础,只有适宜的蛋白原料配以合适的挤压操作工艺,才能生产出满足要求的组织化蛋白产品。通过归纳国内外相关文献资料,从蛋白原料种类、蛋白质含量、蛋白质变性程度、蛋白质组分和结构以及蛋白原料中其他共存成分5大方面,系统分析影响植物蛋白挤压过程和产品特性的因素;指出不同类别蛋白原料的复配挤压以及原料制备工艺,蛋白质组成、蛋白质改性和添加剂等对挤压产品特性的影响,可能是植物蛋白挤压组织化领域将来的研究热点和方向。     

蒸煮挤压过程中淀粉的变化

研究了挤压过程中，挤压温度、螺杆转速、进料速度、原料水分含量对淀粉的糊化、降解及对挤出物的溶解指数和膨化度的影响。     

Single-Screw Extrusion of Defatted Soy Flour, Corn Starch and Raw Beef Blends

Effects of feed moisture, fat and corn starch levels and process temperature on physical properties of extrudates of defatted soy flour-amylose corn starch-raw beef blends were investigated using response surface methodology. Contour plots showed a convex curve of expansion ratio (ER) with moisture, concave curves of bulk density (BD) and shear-force (SF) with moisture, and concave cmves of SF with each of the four extrusion variables. Fat decreased ER and increased BD, whereas corn starch increased ER. Products with high ER and low BD and SF tended to have prominent air cells, continuous protein matrices, and smooth cell wall surfaces in scanning electron micrographs. The optimum extrusion conditions for minimal SF values, with 20% non-dehydrated beef muscle and varied amounts of defatted soy flour, were: 29.1% feed moisture; 2.96% feed fat; 22% feed corn starch; and 162°C process temperature.     

Extrusion of Rice,Bean and Corn Starches: Extrudate Structure and Molecular Changes in Amylose and Amylopectin

The objective of this study was to evaluate the effects of starch source and amylose content on the expansion ratio, density, and texture of expanded extrudates, as well as to investigate the structural and molecular changes that occur in starch granules as a function of extrusion. The starches employed were rice starches (8%, 20%, and 32% amylose), carioca bean starch (35% amylose), and Hylon V^® corn starch (55% amylose). The extrudates from rice starches containing 20% and 32% amylose exhibited the highest expansion ratio, while, extrudates from Hylon V^® corn starch containing 55% amylose exhibited the lowest expansion ratio. The hardness values of the extrudates with 55% amylose were twice those of the extrudates with 20%, 32%, and 35% amylose. An additional finding was that although the amylopectin promoted the expansion of the gelatinized starch matrix, it failed to strengthen and sustain the walls of the extrudate bubbles during expansion.     

挤压处理下组织化核桃蛋白品质变化

作为核桃制油副产物的核桃蛋白是一种优质植物蛋白,核桃蛋白高值化利用,对核桃产业可持续发展具有重要意义。该研究采用挤压法对核桃蛋白进行组织化,考察挤压工艺参数对组织化核桃蛋白色泽、质构特性和组织化度的影响。通过采用单因素法,研究了挤压温度、水分含量、螺杆转速、喂料速度和冷却温度5个挤压工艺参数对组织化核桃蛋白的影响。根据单因素试验结果,选择挤压温度、水分含量和喂料速度三个参数为响应面实验的试验因素,以组织化度为响应值,应用响应面分析法对挤压工艺参数进行优化,得到了最优挤压工艺参数为挤压温度141 ℃,水分含量52.7%,螺杆转速160 r/min,喂料速度26 g/min,冷却温度65 ℃,此时组织化度为1.209。该研究为核桃蛋白基素肉开发奠定了基础。     

Shear Induced Starch Conversion During Extrusion

Using a capillary rheometer and a singlerscrew extruder, waxy corn starch was extruded at a relatively low temperature range. Notable conversions induced by shear energy were obtained in very short residence times (from several sec to 1 min). Conversions up to > 70% were also achieved. Kinetic studies showed that conversion caused by shear energy was more efficient than that by thermal energy. The shear rate constant, k, was an exponential function of shear stress and a linear function of shear rate. The minimum shear stress required to cause starch conversion was from 10⁴ to 10⁶ N/m² for 100°C to 21°C. In such “shear” experiments, the maximum temperature rise due to viscous thermal dissipation, measured experimentally and calculated theoretically, was too low to cause any significant thermal cooking of starch. The shear converted starch extrudates were unpuffed and had shapes of traditional pasta.     

挤压法制备的硬脂酸玉米淀粉酯的性质研究

以玉米淀粉为原料,硬脂酸为酯化剂,用双螺杆挤压机作反应器制备了硬脂酸玉米淀粉酯.对硬脂酸玉米淀粉酯的黏度、稳定性、溶解度、糊化度、乳化特性和消化性等性质进行了测定和分析.     

挤压对豌豆淀粉的消化及理化特性评价

本文旨在探究单螺杆挤压对豌豆淀粉消化特性的作用机理,阐述物料水分、螺杆转速和挤出温度影响规律,并通过扫描电子显微镜,X-衍射,快速黏度仪从分子晶型、结构、黏度性质等角度,揭示豌豆抗性淀粉的理化性质.结果表明,豌豆淀粉经挤压处理,快消化淀粉含量显著降低,抗性淀粉和慢消化淀粉含量也发生不同程度影响,其中在水分含量26％,螺...