【作者】 马成业；

【导师】 申德超；

【作者基本信息】 东北农业大学 ， 农业机械化工程， 2010， 博士

【摘要】 目前国内外传统的双酶法制取淀粉糖浆的工艺为:玉米→浸泡→分离胚芽→分离蛋白质→淀粉洗涤→淀粉浆调制→喷射液化→糖化→灭酶→过滤→脱色→离子交换→糖浆。此工艺中使用的淀粉是采用湿法生产的。湿法生产淀粉有其优点:全部工序是物理加工过程,能获得纯度较高的淀粉。但湿法加工淀粉的缺点是:(1)流程长、投入大;(2)用水多,废水处理负荷大;(3)喷射液化工序耗能高。针对以上情况,Linko等提出了高温挤压淀粉制取糖浆的研究,但是糖化时间长,糖化液过滤速度非常慢。本文进行了低温挤压添加淀粉酶脱胚玉米制取葡萄糖浆的试验研究,以干法生产的脱胚玉米为原料,并省去传统双酶法淀粉糖浆工艺中的喷射液化工序,提高糖化液过滤速度,缩短糖化时间,提高糖浆收率,并能大幅度降低生产投资、减少环境污染、节约能耗。在发明专利《挤压蒸煮淀粉糖浆原料的加工方法、加工装置和糖化方法,专利号:ZL200510045327.1》和《挤压加酶淀粉糖浆原料的加工方法、装置和糖化方法,申请号:200710015601.X》及其科研成果的基础上,开展了本文研究添加酶制剂脱胚玉米挤出物的液化、糖化方法,以获得脱胚玉米制取葡萄糖浆的新工艺,为葡萄糖浆及其深加工制品生产提供综合经济效益较好的技术支持。(1)探讨了挤压-糖化系统参数(挤压时耐高温α-淀粉酶添加酶量、挤压机螺杆转速、液化时耐高温α-淀粉酶添加酶量、液化时间和糖化时葡萄糖淀粉酶添加量)对添加耐高温α-淀粉酶脱胚玉米挤出物制取葡萄糖浆各项考察指标的影响。对各考察指标的分析与优化处理,得到较优挤压-糖化系统参数组合,经过验证试验表明,挤压添加耐高温α-淀粉酶脱胚玉米制取葡糖糖浆在技术上是可行的,而且各项指标均优于对照试验。通过正交试验和验证实验结果,得到了较优挤压-糖化系统参数:挤压时耐高温α-淀粉酶添加酶量为0.80L/t、挤压机螺杆转速140r/min、液化时高温α-淀粉酶添加酶量0.60L/t、液化时间20.0min、糖化时葡萄糖淀粉酶添加量1.50L/t。(2)探讨了挤压-糖化系统参数对添加中温α-淀粉酶脱胚玉米挤出物制取葡萄糖浆各项考察指标的影响。对各考察指标的分析与优化处理,得到较优挤压-糖化系统参数组合,经过验证试验表明,挤压添加中温α-淀粉酶脱胚玉米制取葡糖糖浆在技术上是可行的,而且各项指标均优于对照试验。通过正交试验和验证实验结果,得到了较优挤压-糖化系统参数:套筒温度75℃、挤压时中温α-淀粉酶添加酶量为10.0L/t、液化时中温α-淀粉酶添加酶量4.6L/t、液化时间28.0min、糖化时葡萄糖淀粉酶添加量0.9L/t。采用上述较优参数,得到糖浆的考察指标与挤压添加耐高温α-淀粉酶对比,可以看出,糖化液过滤速度、糖浆DE值、比重、出品率、淀粉转化率等指标相当。(3)传统双酶法制取葡萄糖浆生产工艺中,淀粉原料经过调浆后经过糊化、喷射液化、糖化、精制等工序,得到葡萄糖浆。采用挤压加酶脱胚玉米制取糖浆时,省去了喷射液化,而且糖化时间有传统的36~40h缩短至12h。同时使用的原料为脱胚玉米,不是商品淀粉,省去了淀粉湿法生产工艺,节约用水,而且环保。(4)脱胚玉米主要的化学成分为淀粉、脂类、蛋白质等。在挤压过程中这些物质发生了复杂物理、化学变化。采用“急停法”—将挤压机在正常工作条件下即刻停止螺杆的转动,迅速打开套筒,在5min内将挤压机沿螺杆中轴线左右打开,沿螺杆分段采集样品。测试每段物料的相应指标,结果表明,随着取料部位向挤压模孔方向推进,淀粉含量降低,淀粉的糊化度和降解程度增大,尤其在添加酶制剂后降解程度更大,还原糖含量增加,添加的酶制剂活性降低,直链淀粉含量和脂类含量降低,抗性淀粉含量增加。(5)研究挤压过程中淀粉-脂类、淀粉-蛋白质复合物产生规律。通过CI、DSC、红外光谱和X-射线分析淀粉与脂类和蛋白质发生复合的情况。CI分析结果表明,淀粉/胚芽混合挤出物、淀粉/蛋白粉混合挤出物的CI表明,淀粉与脂类、蛋白均发生复合反应,产生新的物质,使直链淀粉结合碘的能力降低。随着胚芽或蛋白粉添加比例的增加,CI增大。添加中温α-淀粉酶和高温α-淀粉酶脱胚玉米挤出物CI值较高,均大于55。但是淀粉-脂类复合物结够不稳定,可以分离。DSC分析结果表明,淀粉与十六酸混合挤出物的熔融焓变也随着十六酸添加比例的增加而升高。表明在挤压过程中淀粉与十六酸发生复合,产生复合物的数量多,在升温过程中就需要吸收更多的热量,因而导致吸热峰焓变升高。而且复合物的熔融吸热峰尖峰温度均>100℃。FT-IR分析结果表明,淀粉-脂类复合物的红外图谱表明没有新官能团特征吸收峰出现,说明挤压淀粉/胚芽没有基团产生。原淀粉与挤压淀粉的红外谱图可以看出没有官能团特征吸收峰出现和消失,说明挤压淀粉没有新物质生成,仅可能发生晶型的改变,而非化学结构改变。原淀粉与蛋白粉挤出物红外图谱可以表明挤压纯蛋白可能发生降解,进而催生较多酯基。X-射线分析结果表明,原淀粉经过挤压处理以后,大部分的微晶消失,只有少量的微晶存在,亚微晶数量增多,同时相对应的衍射峰强度降低,并产生了一个具有高强度的特征衍射峰,这表明在挤压过程中产生了具有较强衍射特征峰的新物质。在挤压过程中,添加中温酶的脱胚玉米结晶结构破坏程度比添加高温酶的脱胚玉米的稍大。添加酶制剂脱胚玉米挤出物的X-射线图谱与原脱胚玉米的X-射线图片相比较,可以看出,挤出物的衍生峰强度低,在挤压过程中淀粉的结晶结构破坏,有淀粉-脂复合物的衍射峰出现。更多还原

【Abstract】 The technical flow of double enzyme method for starch sugar at home and abroad was: starch→steeping→germ separation→protein separation→starch washing→pulp-mixing→jet liquefaction→saccharifaction→enzyme deactivation→filtration→decoloration→ion exchange→syrup. The flow was wet method, which was a physical technics, and the starch was purer. But the method had disadvantage: (1) long process and high cost; (2) used large water and huge waste water;(3) the energy expending of the jet liquefaction was large. Aim at above disadvantage, Linko introduced high temperature extruded starch to produce syrup. But filtration speed of the saccharified liquid was slow and the saccharifaction time was long. Thus the paper studied the saccharification experiment used extruded degermed corn added amylase at low temperature. The corn was made by dry method and was degermed. The jet liquefaction was omitted. Thus it can reduce the investment, reducing environment pollution and save the energy cost, In order to get a new process to produce glucose syrup, it was studied the liquefaction, saccharifaction and refining of extruded degermed corn added enzyme. Thus it provided a new technical method to producing glucose syrup and corn deep processing.The paper studied the method of liquefaction and saccharifacton used extruded degermed corn added enzyme at the base of patents of <Processing method, equipment and saccharifaction method of extruded cooking starchy material (Patent No.200510045327.1)> and <Processing method, equipment and saccharifaction method of extruded cooking starchy material added enzyme于(Application No.200710015601.X) > combined the achievement in order to obtain the technics of producing glucose syrup used degermed and providing technology support.(1)It was studied the influence of extrusion-saccharifaction system pararmeters(the content ofα-amylase during extrusion, screw rotate speed, the content ofα-amylase during liquefaction, liquefaction time, the content of glucoamylase added in saccharifaction) on the index of glucose syrup made from extruded degermed corn added thermostableα-amylases.The optimized pararmeters of extrusion-saccharifaction system were got through analysising and optimizing the index. The validated results showed that the process of producing glucose syrup used extruded degermed corn added thermostableα-amylases was feasible, and the index of validated results were advantage than those of contrast experiment.The optimized pararmeters of extrusion-saccharifaction system by orthogonal tests and validated experiments were below: the content of thermostableα-amylase during extrusion was 0.80L/t, screw rotate speed 140r/min, the content of thermostableα-amylase during liquefaction 0.60L/t, liquefaction time 20.0min, the content of glucoamylase added in saccharifaction 1.50L/t.(2)It was studied the influence of extrusion-saccharifaction system pararmeters on the index of glucose syrup made from extruded degermed corn added mesophilicα-amylase.The optimized pararmeters of extrusion-saccharifaction system were got through analysising and optimizing the index. The validated results showed that the process of producing glucose syrup used extruded degermed corn added mesophilicα-amylases was feasible, and the index of validated results were advantage than those of contrast experiment.The optimized pararmeters of extrusion-saccharifaction system by orthogonal tests and validated experiments were below: the temperature of barrel was 75℃, the content of mesophilicα-amylase during extrusion 10.0L/t, the content of mesophilicα-amylase during liquefaction 4.6L/t, liquefaction time 28.0min, the content of glucoamylase added in saccharifaction 0.9L/t.(3)Glucose syrup was made from starch through mixing, gelatinization, jet liquefaction, saccharifaction, refining. The process used extruded degermed corn added enzyme without jet liquefaction and the saccharifaction time was shorten from 36~40h to 12h. At the same time the material was degermend corn made by dry method, not the market starch. The wet method was deleted and saving water and protecting environment.(4)The main chemical component of degermed was starch, fat and protein happened complicated physical and chemical reaction.The extruder was sudden stop, opened the barrel immediately in 5 minutes and took the sample at the specified points. The index measured shown that starch was gelatinized and degraded, especially the extrudate of degermed corn added enmzye, reducing sugar was produced, the enzyme activity was lower, the content of fat and amylose was decrease. Starch-lipid complex was yield thus it decrease the utilization ration of starch to produce glucose.(5)Studied starch-lipid complex, starch-protein complex during extrusion by complex index, DSC, FTIR and X-ray.The results of CI extrudate of starh/germ mixture and starch/gluten meal mixture showed that the starch was complexed with lipid and gluten meal and produce new matter. The iodine affinity of amylose was decreased.There was not new groups of the diagram of native and extruded starch, it was shown that there was not a new material appeared, it could the crystalline forms was changed not chemical structure change. CI was increased with the added content of germ or gluten meal increased. The CI of extruded degermed added amylase was more than 55. But the complex was not steady and could separate.The results of DSC showed that the melt peak temperature was more than 100℃, the FTIR diagram of starch-lipid complex showed there was not new functional groups. The melt enthalpy increased with the content of palmitic acid.The results of FT-IR showed that there was not new characteristic peaks of group appeared in extruded starch/germ mixture. The FT-IR diagram of native and extruded starch there was not new group appeared of extruded starch compared to native starch.The results of X-ray showd that lots of microcrystalline disappered, submicrocrystallinity increased and the intensity of diffraction peak was decreased, and a new high intensity diffraction peak appeared. The crystallinity destroy of extruded degermed corn added mesophilicα-amylase was higher than that of extruded degermed corn added thermostableα-amylase. The diffraction intensity of extruded degermed corn added amylase was lower than that of native degermed cornnd and a new high intensity diffraction peak appeared.更多还原