同向旋转双螺杆挤压机产品和膨化效果的实验研究

采用向应面法研究同向旋转双螺杆挤压机操作变量对产量的影响，实验研究表明料速度和螺杆转速对常量有著影响，并在获得最大产量和良好膨胀化效果状态下对喂料速度和螺杆转速进行了优化，拟合的二阶统计模型适用于生产和挤压控制设计。     

膨化亚麻籽模头压力的变化规律研究

采用SLG67-18.5双螺杆挤压机优化亚麻籽挤压膨化工艺.通过二次正交旋转组合设计试验,研究了温度、含水率、螺杆转速、喂料速度对模头压力的影响.研究结果表明,影响性能指标模头压力的因素主次关系为含水率、喂料速度、螺杆转速、温度,其中温度影响不显著.在实际生产中,需要着重考虑含水率和喂料速度、温度和含水率、温度和螺杆转速、温度和喂料速度的交互作用对模头压力的交互作用.     

淡水鱼糜挤压膨化技术研究

本实验研究了不同加工温度、物料含水量、螺杆转速、喂料速度对挤压膨化产品系统参数扭矩、4区压力、5区压力、两区压力差的影响。研究表明:加工温度、物料含水量、螺杆转速、喂料速度对挤压膨化产品系统参数的影响,只有螺杆转速对两区压力差不显著,其余都达到极显著水平;随着加工温度、物料含水量、螺杆转速升高,扭矩、4区压力、5区压力、两区压力差呈大致降低趋势;随着喂料速度升高,扭矩、4区压力、5区压力、两区压力差呈现大致升高的趋势。     

挤压空心面的工艺参数优化研究

参照国际标准分析方法,对挤压空心面的烹煮特性和质构特性进行分析,使用正交试验优化了挤压工艺条件,通过感官评定实验验证了优化工艺条件。结果表明,挤压时的螺杆转速对空心面烹煮时间、烹煮吸水率、烹煮损失率、硬度以及剪切力均有显著影响,而喂料水分含量与喂料速度的影响不显著,因素影响主次顺序为螺杆转速〉喂料速度〉水分含量。当喂料水分含量为28%、喂料速度为20 r/min、螺杆转速为30 Hz时,制成的空心面具有良好的强度和韧性、琥珀色的外观以及优良的烹煮特性和品质特性。     

挤压蒸煮对豆粕体外消化率的影响

以脱脂豆粕为原料,采用双螺杆挤压技术,研究了喂料速度、物料含水量、螺杆转速、挤压温度对蛋白质消化率的影响,在单因素试验的基础上,通过正交试验确定出了豆粕最佳的挤压工艺条件。结果表明:影响消化率的主要因素是挤压温度和物料含水量,而喂料速度与螺杆转速影响较小。豆粕挤压蒸煮的最佳工艺条件是:喂料速度0.35 kg/min、物料含水量33%、螺杆转速130 r/min、挤压温度150℃,在该工艺条件下,消化率达到95.7%,比原始豆粕消化率提高12.1%。     

螺杆挤压加工对干香菇可溶氮及氨基氮影响的研究

为提高香菇可溶性含氮化合物的溶出,采用螺杆挤压处理,研究了筒体温度、螺杆转速、喂料速度、物料含水量以及蛋白酶解的影响。实验结果,以NSI、氨基态氮为主要指标辅以其他物理特性参数,确定螺杆挤压最佳工艺参数为：螺杆转速25r／min,物料含水量10％,简体温度160℃,喂料速度9r／min,此时NSI可达73．93％。各因素对NSI影响次序为：螺杆转速〉物料含水量〉筒体温度〉喂料速度。进一步采用胰蛋白酶酶解可使NSI及氨基态氮含量分别提高94．94％、82．94％。     

双螺杆挤压对大豆蛋白体外消化率的影响

采用双螺杆挤压技术,研究了挤压工艺参数对大豆蛋白体外消化率的影响,并采用二次通用旋转组合设计,建立了大豆蛋白体外消化率与物料含水量、挤压温度、喂料速度、螺杆转速的二次回归方程,并利用该方程探讨了各因子对消化率的影响.结果表明,各因子对大豆蛋白体外消化率的影响顺序为:挤压温度>物料含水量>螺杆转速>喂料速度,物料含水量与挤压温度交互作用显著.利用统计优选法寻优,确定了大豆蛋白消化率的最佳挤压工艺条件:物料含水量35%,挤压温度155℃,喂料速度0.4 kg·min-1,螺杆转速150r·min-1,大豆蛋白体外消化率最高值为95.83%.     

高温脱脂花生粕双螺杆挤压组织化的工艺研究

利用响应面分析法,采用双螺杆挤压膨化机,以高温脱脂花生粕为原料,研究了双螺杆挤压组织化加工中操作参数对感官评定的影响,并通过优化与试验验证得到最佳工艺条件。结果表明:机筒温度、物料含水率、喂料速度、螺杆转速对产品的感官质量具有显著影响,感官评定随着机筒温度、物料含水率和喂料速度的升高均表现出先升后降的趋势,随着螺杆转速的升高则表现出降低的趋势。在机筒温度(第4区)147℃,物料含水率30%,喂料速度560 kg/h,螺杆转速340 r/min的条件下挤出物具有良好的组织化感官质量。     

二次通用旋转组合设计优化亚麻籽挤压膨化工艺的研究

采用SLG67-18.5双螺杆挤压机进行亚麻籽挤压膨化加工,以提高亚麻籽食用品质.研究了模孔直径、粉碎粒度、膨化温度、螺杆转速、喂料转速、含水率6个工艺参数对挤压膨化亚麻籽中HCN(氰化氢)去除率和膨化度的影响规律.通过二次通用旋转组合设计法,得到温度、含水率、螺杆转速、喂料速度对亚麻籽中HCN去除率、体外消化率、模头压力的数学模型,并进行优化,优化结果表明,温度156℃,含水率16.6%,螺杆转速219 r/min,喂料速度76.1 kg/h,亚麻籽挤压膨化效果最好.研究结果为亚麻籽的开发利用及现有挤压膨化机的操作和调整提供了理论依据.     

双螺杆挤压鸡肉混合物工艺参数的优化

以大豆、大米、鸡肉、全脂乳粉为原料,按一定比例混合,采用Box-Behnken中心组合试验研究双螺杆挤压工艺参数。综合考察物料含水率、喂料速度、螺杆转速、温度对糊化度的影响,在此基础上对变量进行响应面分析,得出最佳挤压参数是:物料含水率23.32%,五区温度105℃,螺杆转速160r/min,喂料速度30r/min。     

螺杆转速和原料含水率对糯米单螺杆挤出过程的影响

本文利用组合实验研究了糯米单螺杆挤出过程中操作参数(螺杆转速、原料含水率]对挤出设备和产品性能(生产率、功耗、度电产量、膨化指数、吸水指数、水溶性指数)的影响,建立了相互影响关系的回归方程,得出随螺杆转速的增加,生产率、功耗、水溶性指数增大,而度电产量、膨化指数、吸水指数开始上升,然后下降,存在极大值,综合各指标,该设备的最佳螺杆转速在240—260rpm;随原料含水率的增加,生产率、度电产量、吸水指数增加,而功耗、膨化指数、水溶指数减小,该设备挤出膨化糯米时的最佳原料含水率在18％～21％范围内。     

Effects of extrusion conditions on secondary extrusion variables and physical properties of fish, rice-based snacks

A formulation containing rice flour, fish powder, menhaden oil and vitamin E was extruded at a feed rate of 10 kg/h using a co-rotating twin-screw extruder. Primary extrusion (independent) variables were temperature (125-145 °C), screw speed (150-300 rpm) and feed moisture (19-23 g/100 g db). Response surface methodology (RSM) was used to study the effects of extrusion conditions on secondary extrusion variables (product temperature, pressure at the die, motor torque, specific mechanical energy input and mean residence time) and physical properties of the extrudates. Second-order polynomial models were computed and used to generate contour plots. Increasing feed moisture and screw speed decreased pressure at the die. Increased screw speed increased product temperature at the die but increased feed moisture lowered it. Increased barrel temperature, feed moisture and screw speed decreased motor torque. Increased screw speed increased specific mechanical energy, while increased feed moisture reduced it. Longer mean residence times were observed at lower screw speeds. Product density increased as feed moisture increased, but decreased with screw speed. Increased feed moisture decreased radial expansion.     

EXTRUSION COOKING OF BLENDS OF SOY FLOUR AND SWEET POTATO FLOUR ON SPECIFIC MECHANICAL ENERGY (SME), EXTRUDATE TEMPERATURE AND TORQUE

Defatted soy flour and sweet potato flour containing 18% moisture were mixed in a pilot mixer, and extruded in an Almex-Bettenfeld single-screw extruder operated at varying rotational speed and die diameter. A central composite, rotatable nearly orthogonal design, which required 23 experiments for three factors (feed composition (fc), screw speed (ss) and die diameter (dd)) was developed and used for the generation of response surfaces. Effects of the extrusion variables on specific mechanical energy (SME), extrudate temperature (ET), and torque (T) were evaluated using response surface analysis. Results showed that product temperature increased with increases in die diameter, screw speed and feed composition. However, the effect of die diameter was greater than those of screw speed and feed composition. Decrease in die diameter with increase in sweet potato content increased torque. Screw speed exhibited a linear effect on torque.     

Reduction of Cyanogenic Compounds in Flaxseed (Linum usitatissimum L.) Meal Using Thermal Treatment

Flaxseed (Linum usitatissimum L.) provides multiple nutritional benefits, including high quality protein, dietary fiber, and is the most abundant source of α-linolenic acid (C_18:3). However, the presence of anti-nutritional factors, such as cyanogenic compounds, restricts flaxseed's consumption as a food or feed. This study investigated the reduction of cyanogenic compounds, measured as hydrocyanic acid (HCN), in full-fat flaxseed using extrusion processing without a die by following the response surface methodology. The ranges of processing variables selected were: barrel exit temperature of 76.3–143.6°C; screw speed of 59.6–160.5 rpm; and feed rate of 26.4–93.6 kg/h. The experimental values of HCN reduction obtained were from 60.8 to 86.6%. Optimum extrusion conditions of barrel exit temperature, screw speed, and feed rate were found to be 143.6°C, 133.5 rpm, and 57.8 kg/h for maximum (89.1%) reduction of HCN. This effect was mainly dependent on barrel exit temperature, whereas screw speed and feed rate had no or minimal effect. The mutual interaction effect of barrel exit temperature and screw speed was found to be significant (p ≤ 0.01). The degree of correlation (R²) for HCN reduction was 97.2%, which showed the validity of applied second-order response model. The results of this study demonstrated that significant reduction of HCN in flaxseed can be achieved commercially using an extruder without a die.     

Effect of extrusion process on the antioxidant activity and total phenolics in a nutritious snack food

The effect of screw speed (220–340 rpm), moisture content of the feed (11.0–15.0%, wet base) and feed rate (22.0–26.0 kg h^?1, wet base) on the total antioxidant capacity (TAA) and concentration of total phenolics (TP) in a nutritionally balanced extruded snack were investigated. Regression equations describing the effect of each variable on the responses were obtained. Results indicated that screw speed, moisture content of the feed and feed rate had an effect on the TAA values of the samples at 95% confidence interval (CI). The interaction between the three factors was also found to be significant at 95% CI for TAA values. Extrusion conditions applied in this study did not change the TP values in the samples. The TAA value of samples decreased with an increase in screw speed and decrease in moisture content.     

Texture and Microstructure of Cassava (Manihot esculenta Crantz) Flour Extrudate

Cassava flour (Manihot esculenta Crantz) was texturized by single-screw extrusion processing. Relationships between texture and micro-structure as a function of extrusion variables were examined. The effect of feed moisture or screw speed was significant (P < 0.01) on all textural parameters except springiness and energy first bite. Hardness, gumminess (P < 0.05) fracturability and cohesiveness (P < 0.01) decreased with increasing temperature. Hardness, fracturability and firmness were lowest at screw speed 520 rpm with feed rate 300g/min, 120–125°C and 11% feed moisture. Scanning electron micrographs showed structural change from a coarse cell mass at high feed moisture to a porous, thin-walled structure with decreased feed moisture.     

Effect of Extrusion Variables on Cassava Extrudates

Cassava flour was extruded by varying parameters of feed moisture; temperature; screw speed and feed rate. We investigated significance of each variable and interactions between variables on each extrudate characteristic. Optimum expansion (2.82) was at 11% feed moisture 120–125 °C; screw speed, 520rpm; feed rate, 250g/min. Effect of feed moisture was most significant on expansion, bulk density and extrudate moisture. Increasing temperature, increased expansion and water solubility, but decreased bulk density, extrudate moisture and water absorption. Screw speed most influenced water absorption and solubility. Extrudate moisture correlated negatively (P<0.01) with extrudate expansion. Water solubility index of extrudate negatively correlated (P<0.05) with extrudate moisture and water absorption index but correlated positively (p<0.05) with expansion.     

Expansion characteristics of a nutritious extruded snack food using response surface methodology

Response surface methodology was used to analyze the effect of screw speed (220–340 rpm), feed moisture (11.0–15.0%, wet basis) and feed rate (22.0–26.0 kg/h, wet basis) on the physical properties (i.e., bulk density, expansion, porosity) of a nutritionally balanced extruded snack food. Regression equations describing the effect of each variable on the responses were obtained. Responses were most affected by changes in screw speed followed by feed moisture and feed rate (P<0.05). Expansion and porosity increased with screw speed and feed moisture whereas the opposite was observed for bulk density. Radial expansion was found to be a better index to measure the extent of expansion than the axial and overall expansions, indicated by a higher correlation coefficient.     

棉籽饼粕双螺杆挤压脱毒中的参数研究

考察了棉籽饼粕双螺杆挤压脱毒中不同加工参数对脱毒效果的影响。结果表明：增大螺杆转速、减低喂料速度，脱毒效果变好。但考虑到产量要求，喂料速度不宜过低，故实际中应做到均衡。含水率的影响较为复杂，因原料、操作条件不同而异，一定范围内含水率提高可配以较高螺杆转速、温度及较小口模直径，不同捏合盘长度和位置其效果也不一样，因而一定操作条件下各加工参数间应适宜匹配。此外，实验结果还表明棉籽饼粕双螺杆挤压脱毒是成功的，效果显著。