【作者】 何瑰；

【导师】 程备久； 朱苏文；

【作者基本信息】 安徽农业大学 ， 生物物理学， 2006， 硕士

【摘要】 本研究以玉米样品为材料,利用FOSS公司的Infratec1241型近红外谷物分析仪,对样品进行光谱扫描,并测定直链淀粉含量的参比数据,借助于WinISI软件,采用多种数学处理方法和不同的回归统计方法进行定标曲线的开发,优化得到了玉米籽粒直链淀粉含量测定的近红外定标方程。同时以60Co为辐射源,研究了辐射剂量在0～1000 kGy间,玉米淀粉物理和化学性质的变化以及辐射剂量与寡糖生成间的关系。获得如下结果:1.用于定标和模型分析的样品分布范围较广,代表性较好,油分、蛋白质和淀粉含量范围分别为:3.3～8.7%、8.1～17.1%和64.6～73.2%,基本包括了常见玉米类型。2.定标参比化学方法的实验误差:玉米直链淀粉占总淀粉含量%(SAC)和直链淀粉占样品干重%(GAC)分别为1.4387和1.0314。收集的214份定标样品的化学测定结果为:SAC 9.05～66.98%,GAC 6.35～46.22%,代表性较好,变异程度较大。3.讨论了建立直链淀粉含量的最佳数学处理方式和定标方法并对一些样品进行预测分析。建立的SAC和GAC定标方程的交叉验证相关系数为0.8672和0.8575,交叉验证误差为2.5896和1.1747。利用选择的最优方程,对独立的验证样品集进行预测结果为:SAC和GAC预测误差(SEP)分别为3.368和2.133,散点图比较集中,具有较好的相关系数。对其它的230份常规自交系、杂交种和高直链淀粉自交系进行预测分析表明,该模型可以较好的区分出高直链样品与普通玉米样品。光谱特征可以反映样品的遗传背景,亲代光谱对子代光谱有较好的覆盖性。建立的玉米直链淀粉含量测定模型对于常规玉米品种及高直链淀粉玉米品种(SAC<66%的籽粒样品)的预测效果较理想。但对于糯玉米品种预测效果不理想,这些品种在育种的早期阶段可以通过碘染色方法或直接从外观上(籽粒切面光亮)加以区别,不需要精确测定,所以并不会影响模型的适用性。4.辐射对淀粉的降解作用明显,辐射剂量与降解程度呈正相关性。辐射后淀粉的聚合度下降。酸度、溶解度随辐射剂量的增加而上升,透明度的变化较复杂,总体呈增加趋势。5.在0～1000 kGy间,随辐射程度的加大,淀粉中总糖的含量下降,还原糖含量上升,可超滤部分增多。在1000kGy时,可溶性还原糖含量达到最大值,达到43.89%。而分子量大于3000Da和1000～3000Da(DP:6~18)间的可溶性低聚糖含量达到最高,分别为33.57%和7.23%。700 kGy时分子量小于1000Da低聚糖含量最高为3.64%。更多还原

【Abstract】 Using some inbred and hybrid kernel samples of maize as materials, a study was conducted to investigate the method of measuring amylose content by near-infrared transmittance spectroscopy (NITS). The samples were scanned by FOSS Infratec1241 Analyzer. With the powerful WinISI calibration maker software, several mathematics treatments to the sample spectra and several different regression methods were adopted to optimize a good calibration equation for determination of amylose content in maize. And we discussed the effect of gamma-ray irradiation on common maize starch. The samples were treated with 0～1000 kGyγ-radiation. We studied the physicochemical changes of maize starch and the relationship between irradiation dose and oligosaccharides production. The results are as follows:1. The samples using to set calibration and analyze corn quality distributed well and have good representation. The range of oil, protein and starch content is 3.3～8.7%,8.1～17.1% and 64.6～73.2%.2. The experiment error of chemical method are 1.4387(Starch amylose content, SAC) and 1.0314(Grain amylose content, GAC). The range of chemistry results are 9.05~66.98%(SAC) and 6.35~46.22%(GAC).3. We discussed the math treatment and regression method to set up amylose calibrations of maize. The results showed that using SNV&detrending, PLS regression method and second derivative is the best equation to SAC. SNV&Detrending, MPLS regression method and firsh derivative is the best equation to GAC. We choosed the best equations to predict amylase content about other samples. The standard error of calibration(SEC), regression squared(RSQ), standard error of cross-validation(SECV) and standard error of prediction (SEP) of calibration selected about the SAC and GAC were 2.3201 and 1.2064、0.8860 and 0.8856、2.5896 and 1.3769、3.368 and 2.133, respectively. The method of NITS had high accuracy in predicted tests of cross validation and independent validation. Using the calibration mode to predict the other 230 samples it showed good application value. It can tell difference between high-amylose maize and common maize. The character of spectrum can reflect samples` genetic background. The spectrum of parents samples can cover well with filial generations’. The calibration mode have good efficiency to predict common maize and high-amylose maize. But it is not so exact to predict waxy corn. We can use other method to tell the waxy maize from other kinds. So it could be used for early generation selection in maize breeding program and quick testing for maize quality.4. After being irradiated by 60Co-γwe found that the DP of starch amylose and amylopectin is changed. The effect of irradiation is significant to the properties of starch. Acidity and solubility rose when the irradiation dose increased, but the changes are not significant below 300 kGy. Paste clarity showed complex changes.5. The sugar content decreased significantly when the irradiation dose increased above 100 kGy. The production of ultrafiltration increased when the irradiation dose increased. The content of soluble saccharides and soluble oligosaccharides which the molecular weight above 3000 Da and between 1000 and 3000 Da got the max in 1000kGy irradiation dose. But the oligosaccharides which molecular weight below 1000 Da got max in 700 kGy. The aim oligosaccharides(DP:6~18) is nearly eight percent in 1000 kGy.更多还原