双酶法制备小麦微孔淀粉的动力学

食品科学 ›› 2012, Vol. 33 ›› Issue (23): 184-188.

双酶法制备小麦微孔淀粉的动力学

张国权，张艳，张洁，梅仕峰，罗勤贵

西北农林科技大学食品科学与工程学院

收稿日期:2011-08-01 修回日期:2012-11-22 出版日期:2012-12-15 发布日期:2012-12-12
通讯作者: 张国权 E-mail:zhanggq98@126.com
基金资助:
现代小麦产业技术体系建设专项

Kinetics of Enzymatic Hydrolysis of Wheat Starch by α-Amylase and Glucoamylase for Preparation of Microporous Starch

Received:2011-08-01 Revised:2012-11-22 Online:2012-12-15 Published:2012-12-12

摘要/Abstract

摘要： 为明确α-淀粉酶和糖化酶协同水解小麦淀粉制备微孔淀粉的动力学特征，以小麦A淀粉为材料，系统地分析pH值、反应温度、α-淀粉酶及糖化酶用量对水解速率的影响，并确定α-淀粉酶、糖化酶单一酶的米氏常数以及双酶协同效应。结果表明：在单一水解体系中，α-淀粉酶和糖化酶对小麦A淀粉的降解均遵循Michaelis-Menten方程，α-淀粉酶的米氏常数Km为9.548mg/mL，最大反应初速率(Vmax)为0.659mg/(mL·min)，糖化酶以淀粉为底物的米氏常数(Km)为12.676mg/mL，最大反应初速率(Vmax)为0.555mg/(mL·min)。水解产物葡萄糖对反应体系具有竞争性抑制剂的作用，其抑制常数(Ki)为4.288mg/mL。在小麦A淀粉质量浓度为5mg/mL、α-淀粉酶10U/mL、糖化酶20U/mL、反应温度55℃、pH4.5、水解时间为25min的条件下，可达到淀粉的水解极限即还原糖生成质量浓度为2.54mg/mL。α-淀粉酶和糖化酶可协同水解小麦A淀粉制备微孔淀粉，双酶协同作用的水解效率明显高于单酶的水解效率。

关键词: 小麦Ａ淀粉, 微孔淀粉, α-淀粉酶, 糖化酶, 动力学

Abstract: In order to understand the kinetic characteristics of the synergistic hydrolysis of wheat starch by α-amylase and glucoamylase for preparing microporous starch, the effects of pH, reaction temperature and enzyme dosage on hydrolysis rate during the hydrolysis of wheat type A granular starch by both enzymes were investigated and the Michaelis constants (Km) for the individual and combined enzymatic hydrolysis of wheat starch were determined. Both individual enzymatic hydrolysis processes obeyed the Michaelis-Menten equation, and the Km and Vmax (maximum reaction velocity) were 9.548 mg/mL and 0.659 mg/(mL•min) for and α-amylase, and 12.676 mg/mL and 0.555 mg/ (mL•min) for glucoamylase, respectively. The hydrolysis product glucose was a competitive inhibitor against the enzymes with an inhibitory constant (Ki) of 4.288 mg/mL. Maximum hydrolysis was reached when 5 mg/mL of wheat type A granular starch was hydrolyzed with 10 U/mL of α-amylase and 20 U/mL of glucoamylase under the conditions of 55 ℃ and pH 4.5 for 25 min. As a result, 2.54 mg/mL of reducing sugar was produced. In conclusion, α-amylase and glucoamylase can be used together to hydrolyze wheat starch for the preparation of microporous starch and their combination shows significantly higher hydrolysis efficiency than individual use.

Key words: wheat type A granular starch, microporous starch, α-amylase, glucoamylase, kinetics

中图分类号:

TS231

张国权，张?艳，张?洁，梅仕峰，罗勤贵. 双酶法制备小麦微孔淀粉的动力学[J]. 食品科学, 2012, 33(23): 184-188.

参考文献

[1]Stoddard F L. Genetics of starch granule size distribution in tetrap loid and hexap loid wheats[J]. Australian Journal of Agricultural Research, 2004. 54 (7): 637~648.
[2] Stoddard F L. Survey of starch particle-size distribution in wheat and related species[J]. Cereal Chemistry, 1999, 76(1): 145~149.
[3] Kim H S, Huber K C. Channels within soft wheat starch A- and B-type granules[J]. Journal of Cereal Science, 2007, 9: 2~14.
[4]Peng M, Gao M, Abdel-Aal E S M, Hucl P, Chibbar R N. Separation and characterization of A- and B-type starch granules in wheat endosperm[J]. Cereal Chemistry, 1999, 76: 375~379.
[5]顾正彪,王良东.小麦淀粉颗粒大小和糊化特性的相关性研究[J].中国粮油学报, 2006, 21(4): 32~34.
[6]刘雄,阚建全,陈宗道,等. 酸法制备微孔淀粉的技术研究[ J ].食品科学, 2003, 24 (10):81~83.
[7]张燕萍. 变性淀粉制造与应用[M].化学工业出版社,2007.155~174.
[8]吴非,李永平,印方平. 玉米微孔淀粉酸法制备及其特性研究[J].中国粮油学报,2008,23(6):89~92.
[9]徐忠,刘明丽. 玉米交联微孔淀粉制备工艺的研究[J].食品科学,2007,28(2):94~98.
[10]周琼,张涛,刘雄. 木薯微孔淀粉制备技术的研究[J].食品工业科技,2005,26(10):127~129.
[11]刘文宏,袁怀波,王宇. 木薯微孔淀粉的制备及性质研究[J].食品科学,2006,27(10):265~268.
[12]杜敏华,刘福林. 大米微孔淀粉的酶法制备工艺优化研究[J].粮油加工,2007,5:104~106.
[13]王华,韩金玉,钟穗生,常贺英. 双酶一步法水解马铃薯淀粉的动力学研究[J].高校化学工程学报,2001, 5(15): 446~451.
[14]周申,李万平. 不同小麦谷朊粉加工工艺对小麦粉质量的要求[J].粮油加工,2008,(8)41~42.
[15]颜思旭,蔡红玉. 酶催化动力学原理与方法[M].厦门:厦门大学出版社,1987.
[16]Vanee Komolprasert.Starch hydrolysis kinetics of bacillus licheniformis[J].Chem Tech Biotechnol.1991,51:
209~223.
[17]孙伟伟,曹维强,王静. DSN法测玉米秸杆中总糖[J].食品研究与开发,2006,27(6):120~122
[18]Dixon M. The determination of enzyme inhibitor constants[J]. Biochemistry Journal, 1953,55:107~171.
[19]郭桥. α-淀粉酶和糖化酶的共固定化研究[J].生物化学杂志,1994,3(10):259~262.
[20]Michihiro Fujii, Taira Homma. Synergism of a-amylase and glucoamylase on hydrolysis of native starch granules[J].Biotechnology and Bioengineering ,1988,32: 910~915.
[21]Koichro kusunoki, Koeikawakami. A kinetic expression for hydrolysis of soluble starch by glucoamylase[J], Biotechnology and Bioengineering,1982,24:347~354.
[22]Whistler. Microporous granular starch matrix compositions[P]. 1991,U S Patent 4985082.