| The process research on high concentrations of corn starch enzymatic to preparecorn starch sugar is part of the the Key Projects in the National Science&TechnologyPillar Program during the Twelfth Five-Year Plan Period (2012BAD34B00). Theresearch is also a part of the Science Technology Achievements TransformationProgram of Jilin Province Science and Technology Department—Key technologies ofhigh-quality corn starch sugar production (20130305026NY). The research wassummarized as following:(1) Corn starch powder, as raw material, was treated bypulsed electric field,extrusion processing and irradiation.One-factor-at-a-time experiment and BBDexperiments were used to optimize the corn viscosity. The final mathematical modelcould be expressed by the following second-order polynomial equation:Y=1038.4188+13.163875X1+17.358375X2+262.022X3-2.8475X1X2+6.32725X1X3+18.61625X2X3+20.7081X12+77.3006X22+189.58085X32. Where, X1is the field strength(kv/cm); X2is the frequency (Hz); X3is the feeding concentration (%).The optimum parameters of corn starch treated by pulsed electric field were:field strength19.8kv/cm, the frequency1485Hz, feeding concentration31.55%;verified experiment was carried out with the condition of electric field strength of20kv/cm, the frequency of1500Hz, feeding concentration31.55%, viscosity of cornstarch slurry was943.709±1.013cP. The optimal irradiation dose (3.24kGy) wasselected by one-factor-at-a-time experiment.(2) Thecorn starch trested by ctron beam irradiation was studied bygranules rolescanning electron microscope, fourier transform infrared spectroscopy and X-raydiffraction to analyzed the effect of ctron beam irradiation on corn starch. Scanning electron microscopy analysis showed that there were many penetrating holes onirradiation-starch granule surface, and holes appeared more intensive. It is suggestedthat electron irradiation could significantly change the shape and surface structure ofstarch granules. Fourier transform infrared spectroscopy showed that corn starchtreaedby the electron beam irradiation increased certain chemical bond, which maylead to corn starch viscosity for the decrease. X-ray diffraction experiment resultsshow that the electron beam irradiation did not change the crystal structure of cornstarch, but the radiation processing corn starch showed a trend of lower crystallizationdegree, reduce corn starch crystallization degree increase corn starch amorphous areacan effectively improve the chemical and physical properties of corn starch is thisradiation processing corn starch can reduce corn starch emulsion viscosity is one ofthe reasons for improving the efficiency of liquefied.(3) The corn starch treated by electron beam irradiation wasliquefied by α-amylase. OFAT and response surface metrology BBD experiment were used tooptimize the dosage of enzyme, liquefaction time, liquefaction temperature,irradiation dose, DE value were used as indexs. The final mathematical model couldbe expressed by the following second-order polynomial equation:Y=17.662+0.605X1+0.2375X2+0.0125X3+0.0675X1X2-0.0525X1X3-0.0625X2X3-0.464756X12-1.07975X22-1.93975X32. Where, X1is the dosage of enzyme (u/g); X2is the liquefaction time (min); X3is the liquefaction temperature (℃).The results ofliquidation process were: dosage of enzyme96.555u/g,liquefaction time11.95min and liquefaction temperature90.2℃, under thiscondition DE value of liquefied liquid was17.8217. Verified experiment was carriedout with the condition of dosage of enzyme96.55u/g, liquefaction time12min andliquefaction temperature90℃, under this condition DE value of liquefied liquid was17.133±0.508, liquefied DE value of0kGy corn starch was22.044±1.165.(4) The corn starch treated by irradiation was saccharified by amyloglucosidase,OFAT and response surface metrology BBD experiment were used to optimize thedosage of enzyme, saccharification time, saccharification temperature, DE value asthe index, through the single factor experiment and BBD experiment design. The final mathematical model could be expressed by the following second-order polynomialequation:Y=89.19-1.00X1+0.47X2+1.34X3+1.19X1X2-0.67X1X3+1.50X2X3-2.16X12-4.64X22-1.93X32. Where, X1is the enzyme amount (u/g); X2is the saccharification time (h); X3is the saccharification temperature (℃).The best technological parameters for electron beam irradiation corn starchsaccharification had optimized, saccharification with enzyme amount336.5u/g,saccharification time32.46h and saccharification temperature50.0℃, under thetechnological conditions saccharification DE value prediction was89.6384. Verifiedexperiment was carried out with the condition of enzyme amount336..5u/g,saccharification time32.5h and saccharification temperature50.0℃, under thiscondition saccharification DE value prediction was88.920±0.734, saccharificationDE value of0kGy corn starch was74.331±0.359. |
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