挤压膨化对绿茶茶渣中没食子酸影响实验研究

利用DS30-III型双螺杆挤压膨化机对绿茶茶渣进行挤压膨化加工,在单因素试验的基础上,选取了物料含水量、喂料速度、螺杆转速、套筒温度为影响因子,以绿茶茶渣中没食子酸为响应面值,应用响应面设计方法建立数学模型,进行响应面分析。结论表明,获得高没食子酸含量的最佳工艺参数为:物料含水量70%,喂料速度58 r/min,螺杆转速60 r/min,套筒温度60℃。挤压膨化参数对没食子酸含量影响的大小依次为:物料含水量螺杆转速套筒温度喂料速度。经过最佳挤压膨化参数处理的绿茶茶渣中没食子酸含量为3.57 mg/g,与原料相比,没食子酸含量增加2.69 mg/g。     

双螺杆挤压对膨化小米糊化特性的影响研究

以优质小米为原料,采用双螺杆挤压膨化技术,对小米挤压糊化特性进行了研究.结果表明:影响双螺杆挤压膨化小米糊化度的主要因素是膨化温度,其次是螺杆转速和物料含水量,物料粒度影响较小.最佳工艺条件是物料粒度60目、物料含水量16%、膨化温度160℃、螺杆转速425 r/min,糊化度为93.4%.     

挤压膨化对酶解高温豆粕肽得率的影响研究

以大豆片为原料,利用双螺杆挤压膨化机进行实验研究,大豆片经挤压膨化、脱脂、高温脱溶得高温豆粕,研究不同物料含水量、套筒温度、模孔孔径和螺杆转速对酶解高温豆粕肽得率的影响。通过单因素和正交实验,确定最佳的挤压膨化参数为:物料含水量20%,套筒温度60℃,螺杆转速100r/min,模孔孔径15mm,肽得率36.88%。挤压膨化技术可以有效提高豆粕利用率,为今后工业化生产提供理论依据。     

挤压膨化对玉米豆粕混合物糊化度及脲酶活性的影响

以玉米豆粕为原料,研究了不同挤压膨化条件对挤出物的糊化度及脲酶活性的影响。通过单因素结果得知:随着出口段温度、物料含水量、螺杆转速、喂料速度的增加,挤出物的糊化度均呈现先增大后减小的趋势;随着物料配比(豆粕∶玉米)的增大,挤出物的糊化度逐渐减小。通过脲酶活性正交试验结果得知,4个因素对脲酶活性的影响顺序为出口段温度螺杆转速喂料速度物料含水量。     

玉米产品挤压膨化特性的影响因素

以优质的玉米为原料,采用挤压膨化技术,研制出玉米膨化产品。通过正交试验确定了挤压温度、物料水分含量、螺杆转速对产品膨化物糊化度的影响,并找出了最佳工艺参数值:挤压温度160℃,物料水分含量20%,螺杆转速300r/min。     

挤压膨化条件对青稞产品膨化度的影响

将挤压膨化过程中主要影响产品膨化度的因素条件进行了研究,结果表明：物料水分含量为20％、螺杆转速为280r/min、膨化温度为200℃和喂料速率1．8kg/min时产品膨化度最佳。     

双螺杆挤压膨化大豆模头压力对粕残油率的影响

以单因素试验为基础,采用响应曲面设计的试验方法研究了挤压膨化工艺参数(物料含水率、套筒温度、轴头间隙、螺杆转速)对挤压机模头压力和粕残油率的影响规律。用SAS 9.1软件对试验数据进行处理并建立数学模型,并运用SPSS 17.0分析软件对所得数据进行分析,获得模头压力与粕残油率之间的相关性。结果表明:挤压膨化工艺参数对模头压力的影响程度依次为:轴头间隙、螺杆转速、物料含水率、套筒温度。对粕残油率的影响程度依次为:轴头间隙、物料含水率、套筒温度、螺杆转速。模头压力越高物料被挤出的油脂量就越多,膨化物含油率也就越低,致使浸出粕的残油率越低。     

苦荞麦粉的挤压膨化特性研究

本文研究了苦荞麦粉在QPS65X2型双螺杆挤压膨化机膨化时,螺杆转速,含水量,进料量对膨化度的影响,结果表明化度随含水量增加而下降,随杆转速,进料量的增加而上升,研究了苦荞麦粉与其它辅料（大豆,芝麻,南瓜粉）的配比,螺杆转速,进料量,含水量协同挤压膨化,结果表明：苦荞麦心粉与皮粉的比例为70：30,螺杆转速为350r/min,进料量为450g/min,水分含量为15％时膨化效果最好;苦荞麦粉与大豆的比例为95：5,螺杆转速为350r/min,进料量为350g/min,水分含量为10％时膨化效果最好;苦荞麦粉与芝麻的比例为98：2,螺杆转速为350r/min,进料量为450g/min,水分含量为15％时膨化效果最好;苦荞麦粉与南瓜的比例为95：5,螺杆转速为350r/min,进料量为550g/min,水分含量为10％时膨化效果最好。     

挤压膨化系统参数对玉米胚芽膨化物容重的影响

通过四因素五水平二次正交旋转组合试验设计,探讨用于浸油的玉米胚挤压膨化预处理过程中的套筒温度、模孔孔径、物料含水率、螺杆转速等挤压系统参数对膨化物容重的影响规律.得到最佳挤压工艺参数:模孔直径Φ=6 mm,物料出口温度T=105 ℃,喂入物料水分含量W=7.5%,螺杆转速N=200 r/min,在此条件下得出膨化物容重的最优值为620.42 kg/m3.     

高蛋白营养膨化粉的工艺研究

以豆粕为主要原料,与玉米、绿豆混合,利用小型单螺杆挤压膨化机进行膨化实验,研究了不同物料水分含量、模头温度、螺杆转速对产品膨化效果的影响,并对挤压膨化过程中产品的水溶性和吸水性的变化进行了研究分析。确定最佳的挤压膨化工艺参数为:模头温度140℃,水分含量为19%,螺杆转速为180r/min,经过挤压膨化后,原料的水溶性和吸水性增大。     

冲泡条件对日照绿茶茶多酚得率的影响

为探究不同冲泡条件对绿茶茶多酚得率的影响,该文选取山东省日照市产地绿茶,首先对冲泡温度、冲泡时间和料液比进行单因素试验,分别得到各因素的最佳条件,然后采用正交试验设计,探究3个因素对日照绿茶茶多酚得率的影响.结果显示,当温度在60℃～80℃时,茶多酚得率随着冲泡温度的升高而提高,当温度在90℃～100℃时,茶多酚得率随...     

微波杀青工艺对秋季绿茶的保绿降苦作用

目的：探究微波杀青工艺对秋季绿茶的保绿降苦作用;方法：以茶树品种碧香早秋季一芽二叶茶鲜叶为原料,在传统绿茶杀青、揉捻、干燥加工工艺的基础上,将微波杀青工艺替代传统滚筒杀青工艺,按不同微波强度、微波时间设置了14组微波杀青处理,从感官品质、滋味品质、干茶与汤色色泽三个方面探究微波杀青工艺对秋季绿茶的保绿降苦作用;结果：与传统滚筒杀青工艺相比,采用微波强度500w、杀青时间为3min的微波杀青工艺,所制绿茶色绿味醇且综合感官品质最佳,其水浸出物、茶多酚、氨基酸、咖啡碱、总儿茶素、简单儿茶素的含量显著升高（P<0.05）,苦味评价指标酚/氨比、酯型儿茶素含量与总儿茶素含量的比值则显著降低（P<0.05）,且干茶与茶汤色泽在绿、明度上均有不同程度的改善;结论：利用微波杀青工艺加工秋季绿茶具有较好的保绿降苦效果,可应用于提高秋季绿茶品质的生产实践。     

Effects of Extrusion Process Variables on Quality Properties of Wheat-Ginseng Extrudates

The present study investigated the effects of extrusion process variables (feed moisture, screw speed, and barrel temperature) on the physical [expansion ratio, water absorption index (WAI), and water solubility index (WSI)], pasting, and thermal properties of wheat-ginseng extrudates (WGE). A wheat flour-ginseng powder (GP) blend (10% GP, w/w) was extruded in a twin-screw extruder (L/D ratio of 25:1) with full factorial combinations of feed moisture (25, 30, and 35%), screw speed (200 and 300 rpm), and zone 5 barrel temperature (110, 120, 130, and 140°C). The expansion ratios of WGE were significantly increased with decreasing feed moisture, decreasing screw speed, and increasing barrel temperature. Increasing feed moisture significantly increased WAI values of WGE and significantly decreased WSI values of WGE. However, an increase in either screw speed or barrel temperature caused a significant decrease in WAI values of WGE and a significant increase in WSI values of WGE. Rapid visco analyzer peak viscosity values of WGE were significantly affected by changes in extrusion process variables studied, indicating that the degree of starch degradation and/or gelatinization in WGE is a very important factor associated with their peak viscosity. WAI values of WGE were positively correlated (r = 0.88, p ≤ 0.001) with peak viscosity values of WGE samples, whereas WSI values of WGE samples were negatively correlated (r = 0.82, p ≤ 0.001). Increasing feed moisture resulted in an increase in values of transition peak temperature (T_p) of WGE, whereas increasing screw speed and barrel temperature each led to a decrease in T_p values of WGE, determined by differential scanning calorimetry.     

夏秋灵芝菌茶的制备及内含物质分析研究

目的 探究灵芝菌(Ganodermalucidum)对夏秋茶品质的影响,提高夏秋茶资源利用率。方法 以夏秋茶为原料,经加工成黑毛茶后,灵芝菌作为发酵剂进行发酵制备灵芝菌茶,测定发酵前后茶中18种游离氨基酸含量、茶多酚、pH、感官评分、色差L*及滋味(酸、甜、苦、鲜、涩度)等品质指标,运用Plackett-Burman实验对夏秋茶品质指标参数进行优化,建立综合评价指标的回归模型。结果 黑毛茶经灵芝菌发酵处理后,游离氨基酸总含量增加了8.70 mg/g,茶多酚质量分数减少了0.9%,甜度由11.12增加到14.36,苦涩度由4.98减少到2.53;构建数学模型Y(综合评分)=93.00-0.23A-0.84B+0.21C+0.01AB+2.100AC+1.50BC-3.40A²-3.20B²-2.60C² (A、B、C分别表示茶多酚含量、感官评分、氨基酸含量),模型决定系数R²=0.9812,调整决定系数R_adj²=0.9570。结论 灵芝菌发酵夏秋黑毛茶在一...     

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。     

Influence of process and product variables on extrusion energy and pressure requirements

Energy and pressure requirements for processing foods as affected by product moisture content and extruder barrel temperature and screw speed were studied using corn gluten meal (CGM) processed in a C.W. Brabender laboratory single-screw cooker-extruder. The extruder screw was 1·9 cm in diameter, had a 3:1 compression ratio and a 20:1 barrel length-to-diameter ratio. The die-end nozzle was 3 mm in diameter. Moisture contents were 14, 20 and 26% (dry basis), extruder barrel temperatures were 120, 145 and 170°C and the extruder screw speeds were 100, 150 and 200 rpm. Regression analysis showed that moisture content contributed most to the variation in energy requirements (32·4%), followed by temperature (12·4%). Effect of screw speed was found to be insignificant. Increasing moisture content and barrel temperature caused specific energy to decrease. Pressure was found to be significantly affected and decreased with increases in all three variables.     

Effects of potassium and magnesium nutrition on the quality components of different types of tea

In field experiments, the effects of potassium and magnesium nutrition on the quality components of different types of tea, including black tea, oolong tea and green tea, were studied. The results show that K and Mg fertilizer application increased the contents of free amino acids and caffeine of the various tea types with the maximum increase found in the treatment including both nutrients. The content of polyphenols in tea leaves was also increased by K application. The effect of Mg on polyphenol content was inconsistent. In general, Mg apparently decreased the content of polyphenols and only in case the soils were depleted of plant available K and Mg, a slight increase could be observed. The contents of theaflavins and thearubigins, important quality components of brewed black tea, were also increased by K application. Flavour compounds in brewed oolong tea were considerably improved by K and Mg application. © 1999 Society of Chemical Industry     

灰树花固体发酵茶青的研究

以茶青为发酵培养基质,对灰树花固体发酵过程中的各种内含物含量的变化及其品质进行了研究。结果表明,灰树花的最佳发酵培养基成分及培养条件:中叶茶,2%大豆粉,接种量1%,培养温度25℃,培养时间9d。发酵后其菌质的有效成分为:茶多酚1.78%,游离氨基酸0.77%,酚氨比2.3,多糖4.69%。与发酵前比较其多糖含量增加了31.7%,茶多酚降解了77.8%,游离氨基酸降低了26.7%,酚氨比降低了69.9%,茶叶品质得到很大改善。     

夏季绿茶发酵产品研制及其品质评价

夏季绿茶滋味苦涩,品质远不及春茶,为提高夏季绿茶滋味品质、拓宽资源利用,文章以夏季绿茶为原料,筛选最佳发酵菌种,研制夏季绿茶发酵产品.通过单因素与响应面优化试验,探究夏季绿茶发酵产品最佳工艺参数,并检测分析夏季绿茶发酵产品的主要生化成分及抗氧化能力.结果 表明,乳酸菌对夏季绿茶浸提液发酵作用效果较佳,优于双歧杆菌和酵母...     

基于单宁酶处理原料制备的高茶黄素速溶红茶品质分析

目的 研究基于单宁酶发酵加工的红茶原料,制备高茶黄素含量的速溶红茶。方法 以速溶红茶中的茶黄素含量为主要评价指标,对红茶原料进行两种提取溶剂处理和不同茶叶状态,即茶叶和茶叶磨碎样处理,同时分析其感官品质及其它化学成分含量。结果 本研究发现用60%乙醇提取工艺制备的速溶红茶中,茶黄素含量显著高于水提取工艺,茶叶状态则是茶粉原料浸提效果显著高于茶叶原料浸提效果,且速溶红茶中茶黄素含量达到2.3%,是传统红茶原料中茶黄素的3倍,速溶红茶得率达到了38%。结论 以高茶黄素茶叶为原料,并将其磨成粉,用60%乙醇提取作为提取剂制备速溶红茶,其制备的速溶红茶富含茶黄素,为速溶茶的生产加工提供了一定的理论依据,也可以为夏秋茶资源的开发利用提供新方法。