以挤压膨化脱胚玉米作啤酒辅料的试验研究

通过实验室试验 ,研究了作啤酒辅料的脱胚玉米挤压膨化系统诸参数 (模孔孔径、套筒温度、物料含水率、螺杆转速 ) ,对各考察指标 (麦汁醪液的总还原糖、α 氨基氮、过滤速度 )的影响规律 ,指出挤压膨化脱胚玉米作啤酒辅料的可行性。     

挤压膨化技术在玉米胚浸出提油中的应用研究

探讨了玉米胚经挤压膨化后对浸出提油的影响,通过响应面分析方法对玉米胚挤压膨化的参数(喂料含水率、模孔直径、套筒温度、螺杆转速)进行优化,建立回归模型,优化得到最佳工艺条件为:喂料含水率11.27%、模孔直径6 mm,套筒温度102.6℃、螺杆转速170 r/min,此条件下残油率最小为0.342%。     

加酸挤压膨化玉米粉工艺条件及对其品质影响研究

以玉米为原料,酸为处理试剂,采用挤压膨化的方法,研究了酸剂、物料含水量、酸液浓度、膨化温度、螺杆转速对挤压膨化玉米粉还原糖含量的影响。确定了加酸挤压膨化玉米粉的工艺参数为:HCl为处理试剂、物料含水量27%、酸液浓度0.027mol/L、膨化温度145℃、螺杆转速250r?min。在该工艺条件下膨化与未加酸相比,还原糖、水溶性成分含量分别提高51.4%、23.5%,α-化度提高14.8%,粗纤维下降88.12%。     

脱胚玉米糁在啤酒生产中的应用研究

用玉米替代大米作啤酒的辅料，关键要解决脂肪含量和粒度分级问题，玉米经脱皮脱胚后，在保证脂肪含量不超过1%的前提下，完全可以应用于啤酒酿造，脱胚玉米糁的粒度应控制在350～1500μm之间，作为辅料使用时用量可达到30%，挤压膨化处理玉米糁可缩短糊化时间，酿制的啤酒也能达到国家标准规定的质量要求。     

脱胚玉米与加酶和不加酶挤压脱胚玉米淀粉颗粒结构和热特性研究

为研究不加酶和加酶挤压对脱胚玉米颗粒结构和热性能影响,采用扫描电镜的方法观察玉米淀粉颗粒形态,采用X-射线测定脱胚玉米淀粉颗粒晶体类型,运用差示扫描量热法分析玉米淀粉的热特性,并测定其糊化度。通过扫描电镜观察未经过挤压的脱胚玉米颗粒表面光滑完整,未加酶挤压和加酶挤压的脱胚玉米颗粒形态遭到破坏,整体结构不完整,表面出现孔洞;X-射线实验测得未挤压脱胚玉米结晶度为15.84,未加酶挤压脱胚玉米结晶度为5.63,加酶挤压脱胚玉米结晶度为7.94;DSC测试结果为未挤压脱胚玉米、未加酶挤压脱胚玉米和加酶挤压脱胚玉米的起始温度分别为46.97、43.11、48.18℃,峰值温度分别为98.63、93.61、98.25℃,结束温度分别为196.79、185.20、188.54℃,焓变分别为325.40、271.30、284.80 J/g;测得糊化度值分别为0.16、0.87、0.61。表明挤压能够破坏脱胚玉米淀粉颗粒完整度,部分微晶结构遭到破坏,结晶度降低,焓变值降低,糊化度增加;加酶挤压脱胚玉米焓变值高于未加酶挤压脱胚玉米,糊化度低于未加酶挤压脱胚玉米。      

脱胚玉米在加酶挤压过程中化学成分的变化

为了研究添加酶制剂的脱胚玉米在挤压机内部化学性质的变化情况,将正常工作的挤压机急停,迅速左右分开套筒,沿螺杆分段采集样品,分析挤压物的化学组成及降解特性。脱胚玉米在螺纹推送下由松散状态逐渐被压实,在螺杆前端发生塑性形变进而熔融。挤压脱胚玉米和挤压添加酶制剂脱胚玉米中的淀粉、直链淀粉和脂肪含量沿物料输送方向降低,而糊化度、还原糖和抗性淀粉含量逐渐增加。添加酶制剂的挤压脱胚玉米与挤压脱胚玉米相比较,在相同取料部位,淀粉、直链淀粉、抗性淀粉含量和糊化度降低,而还原糖含量增加。挤压改变了脱胚玉米成分的含量以及淀粉糊化和水解特性,酶制剂在挤压过程提升了淀粉的水解特性,但缺降低了糊化度。然而由于挤压剪切的破坏,酶活性沿物料输送方向降低。通过对脱胚玉米挤压机理的研究,可以更好地为脱胚玉米挤压蒸煮系统的设计和参数选择提供科学依据和理论基础。     

玉米胚挤压膨化预处理浸油微观机理研究

应用植物显微技术,通过石蜡切片观察,对用于浸油的玉米胚挤压膨化预处理工艺的微观机理进行了探讨,结果表明,挤压膨化物比轧坯和预轧样浸提时间缩短、残油率低,主要是因为挤压膨化后油料细胞壁破坏较彻底,油脂有明显的聚集现象,以及水分瞬间汽化后形成大量的毛细孔道所造成的。      

挤压膨化技术在乙醇生产中的应用

采用挤压膨化技术代替传统乙醇发酵生产中的蒸煮液化阶段,对挤压膨化工艺参数进行了系统探讨。通过L16(44)正交实验确定了其适宜工艺参数:挤压机模孔直径11 mm,挤出物料温度170℃,物料含水量24%,挤压机螺杆转速200 r/min。在该工艺条件下,其乙醇体积分数提高了0.32%,原料出酒率比传统乙醇发酵生产工艺提高了1.06%,发酵时间缩短8 h。     

挤压膨化系统参数对脱胚玉米蛋白质含量影响规律的研究

探讨以蛋白质含量为评价指标,以挤压机模孔孔径、挤压机套筒加热温度、挤压机螺杆转速和喂入挤压机原料含水量为考察因素,用脱胚玉米为原料生产淀粉糖浆、作辅料生产啤酒以提高糖化液的过滤速度。选定四因素五水平进行二次正交旋转组合试验设计,利用Reda软件建立回归方程及进行单因素图形分析,结果得出各影响因素对试验指标的影响规律,并考察了各试验因素对指标因子贡献率的大小。结论:在实际生产中,如果通过蛋白质含量的变化来反映与调节糖化醪及糖化液的过滤速度,则玉米粉含水量和挤压机螺杆转速应作为首要调节因素。     

玉米挤压膨化机理的研究

本文以经过挤压膨化后的玉米为研究对象,在膨化倍数、碘蓝值、α-化度、还原能力等指标上进行对照试验,得出结论：玉米经过挤压膨化后,淀粉粒解体,糊精和还原糖增加,蛋白质变性,氨基酸和缩氨酸含量增加,脂肪减少,水溶性成分增加,从而为挤压膨化技术在玉米深加工领域中的应用提供了理论依据。     

麦胚芽挤压膨化加工特性及其理化性质研究

研究了挤压加工过程中物料配比、物料水分含量及加工温度等主要参数对麦胚芽膨化效果的影响及其理化性质的变化。结果表明：麦胚芽挤压膨化后,粗纤维含量明显下降,其食用口感得到了明显改善。随加工温度的上升,膨化物中粗纤维含量极显著地下降（p〈0．01）,而色差值则显著增A（p〈0．05）。随着螺杆转速的增大,膨化产物的色差值呈下降趋势。     

超声波辅助萃取玉米胚芽油的研究

利用超声波辅助有机溶剂提取玉米胚芽油。选取正己烷为最佳浸提溶剂,研究了超声波辅助提取的液料比、时间、温度、以及超声波频率对玉米胚芽油得率的影响。结果表明,超声波辅助提取的最佳条件为:液料比为10∶1(mL/g),提取时间为50 min,提取温度为50℃,超声波频率28 kHz,在此条件下油脂得率79.19%。     

玉米油脱臭馏出物酶法甲酯化的研究

以固定化脂肪酶Novozym 435为催化剂,以叔丁醇为反应体系的溶剂,催化玉米油脱臭馏出物中的脂肪酸进行甲酯化反应,确定最佳反应条件。结果表明,脂肪酶添加量为80 mg/g,反应温度55℃,反应时间为20 h,醇料比为1.5∶1,叔丁醇添加量为6%,此时酯化率可达到96.84%。每次反应后的脂肪酶用丙酮处理,可循环使用7次,活性无明显降低。     

挤压处理对麸皮、胚芽及全麦粉品质的影响研究

研究了全麦粉稳定化加工过程中挤压热处理对麸皮与胚芽的脂肪酸值、烷基间苯二酚、B族维生素、植酸、总酚、总抗氧化值等品质指标的影响。结果表明,挤压处理能有效地降低麸皮和胚芽的脂肪酸值,提高其抗氧化活性;有利于提高全麦粉的储藏稳定性;同时有利于保留麸皮与胚芽中的生理活性组分,很好的保持全麦粉的营养价值。因此,挤压加工是一种有效的全麦粉稳定化处理工艺。      

Effect of extrusion on nutritional quality of maize and Lima bean flour blends

Maize flour (Zea mays) (M), Lima bean flour (Phaseolus lunatus) (B) and blends of these in proportions of 75M/25B, 50M/50B and 25M/75B (w/w) were extruded and their nutritional quality evaluated. Extrusion was done with a single screw extruder at 160 °C, 100 rpm and 15.5% moisture. In vitro protein digestibility (87%) was higher in the extruded products. Available lysine and resistant starch were highest in 50M/50B raw flour (59.5 g kg⁻¹ protein, 67.9 g kg⁻¹, respectively) but decreased after extrusion (45.5 g kg⁻¹ protein, 16.6 g kg⁻¹, respectively). The same treatment had the lowest available starch (561.6 g kg⁻¹ flour, 507.9 g kg⁻¹ extrudate). Total dietary fiber in the 50M/50B raw flour blend was 144 g kg⁻¹ versus 176 g kg⁻¹ in its extrudate. This was most noticeable for soluble dietary fiber, which increased from 10.6 g kg⁻¹ to 79.4 g kg⁻¹ after processing. Extrusion of blends is feasible up to a 50% bean inclusion level, which improves the nutritional value of the expanded product.Copyright © 2006 Society of Chemical Industry     

Maximizing alcohol yields from wheat and maize and their co‐products for distilling or bioethanol production

The key to optimizing alcohol production from cereals is a full understanding of the physiology and processing characteristics of different cereals. This study examined the maximum alcohol yields that can be obtained from wheat and maize using different processing technologies. Lower processing temperatures (85°C) resulted in high alcohol yields from wheat (a temperate crop), whereas higher processing temperatures (142°C) gave maximum alcohol yields from maize (a tropical crop). Similar trends were also observed when the spent grains from these cereals were processed using commercial enzymes. Mill settings were additional factors in influencing alcohol production. Wheat has the potential to produce higher alcohol yields when compared with maize, when residual biomass (i.e. spent grains) saccharification using selected commercial enzymes is taken into account. While this approach is not applicable for the Scotch whisky industry owing to strict legislation forbidding the use of exogenous enzymes, this is pertinent for bioethanol production to increase the alcohol yield obtained from both starch and lignocellulosic components of whole cereal grains. Wheat and maize processing temperatures and the use of processing aids are of potential economic benefit to bioethanol producers and to beverage alcohol producers seeking to understand the factors influencing the processing properties of different cereals. Copyright © 2015 The Institute of Brewing & Distilling     

麸胚挤压稳定化处理对面团特性的影响

为提高麸胚在面制品中的加工适宜性,本文对麸胚粉进行挤压稳定化处理。以未处理麸胚粉为对照,探究挤压处理对麸胚粉晶体构型的影响及不同添加量的挤压麸胚粉对面团热机械学特性、动态流变学特性、微观结构和傅里叶红外谱图的影响。结果表明,经挤压处理,麸胚粉的淀粉结晶度降低。在同一添加量时,挤压麸胚面团较未处理麸胚面团的吸水率增加,蛋白质弱化度、稳定时间、黏度峰值和回生值降低,有助于延缓面团的老化;当全麦粉添加量大于25%时,挤压麸胚面团的弹性模量（G''）和黏性模量（G″）均提高。此外,麸胚粉的加入使面团新增C≡C特征峰;挤压麸胚面团在1650 cm-1处的吸收峰强度较未处理麸胚面团减弱,而在3400 cm-1处吸收峰较强。扫描电镜图显示,挤压麸胚面团形成的网络结构交联程度增强。     

小麦胚微波稳定化工艺参数初探

研究了微波功率、处理时间、小麦胚原料水分对小麦胚的脂肪酶活力及其储藏稳定性的影响。结果表明,微波处理可钝化小麦胚的脂肪酶,有利于小麦胚的储存;水分在微波稳定小麦胚过程中起着重要的作用,适当提高水分有助于小麦胚吸收微波能量,加快酶失活速率,提高小麦胚储藏稳定性。     

Effect of defatted maize germ flour addition on the physical and sensory quality of wheat bread

Maize (Zea mays L.) processing produces large quantities of defatted maize germ (DMG) that is being used mainly for animal feed. The objective of this study was to exploit use of this nutrient-rich by-product in bread by replacing wheat flour at 5-20 g/100 g levels. Breads prepared with wheat-DMG flour blends were analyzed for loaf volume, density, instrumental dough hardness and bread firmness, Hunter color (“L”, “a”, “b”, chroma, and hue angle), and selected sensory attributes. Loaf volumes decreased significantly, from 318.8 ml to 216.3 ml, as the DMG flour supplementation was increased from 0 to 20 g/100 g; a similar effect was observed for bread specific volume. Increase in dough hardness (7.56-71.32 N) was directly related to increase in DMG flour levels. Instrumental firmness values were significantly higher for breads containing DMG flours, 61.58 N in 20 g/100 g DMG bread versus 32.84 N for the control bread, made with wheat flour only. The control bread was lighter in color, as shown by higher “L” values, than those having DMG flour, with chroma and hue angle values significantly higher in treatment breads. In general, no differences were observed for the sensory attributes of crumb color, cells uniformity, aroma, firmness, mouthfeel, and off-flavor in breads with up to 15 g/100 g DMG flour, while the overall acceptability scores showed a mixed pattern. The results of this study demonstrated that acceptable quality bread could be made with DMG flour addition at ≤15 g/100 g.