Zhang Genyi, Ao Zihua, Hamaker Bruce R
School of Food Science and Technology, Jiangnan University, Wuxi 214122, Jiangsu Province, People's Republic of China.
J Agric Food Chem. 2008 Jun 25;56(12):4686-94. doi: 10.1021/jf072822m. Epub 2008 May 31.
The relationship between the slow digestion property of cooked maize starch and its molecular fine structure was investigated. Results of the in vitro Englyst assay showed a range of rapidly digestible starch (RDS) (70.1-98.9%), slowly digestible starch (SDS) (0.2-20.3%), and resistant starch (RS) (0.0-13.7%) among the tested maize mutant flour samples. Further analysis showed that amylose content was significantly correlated ( R = 0.763, P < 0.001) with RS amount but not with that of SDS, indicating that amylopectin is the starch molecule associated with SDS. Total starch debranching analysis revealed a parabolic relationship between SDS content and the weight ratio of amylopectin short chains (DP < 13, named SF) to long chains (DP >/= 13, named LF), which means amylopectin with a higher amount of either short chains or long chains can produce relatively high amounts of SDS. Furthermore, debranching analysis of the SDS materials from samples with the highest and lowest weight ratios of SF/LF (both had a high amount SDS) showed significantly different profiles, indicating there is not a uniform molecular structure for SDS. Thus, genetic mutants of maize samples have a good potential to provide raw starch materials of high nutritional quality. An additional finding showed that a simple and comparably high-throughput technique of Rapid Visco-Analyzer (RVA) can be used to screen genetic mutants on the basis of their RVA profiles.
研究了熟玉米淀粉的缓慢消化特性与其分子精细结构之间的关系。体外Englyst分析结果显示，在所测试的玉米突变体面粉样品中，快速消化淀粉（RDS）含量范围为70.1 - 98.9%，缓慢消化淀粉（SDS）含量范围为0.2 - 20.3%，抗性淀粉（RS）含量范围为0.0 - 13.7%。进一步分析表明，直链淀粉含量与RS含量显著相关（R = 0.763，P < 0.001），但与SDS含量无关，这表明支链淀粉是与SDS相关的淀粉分子。总淀粉脱支分析揭示了SDS含量与支链淀粉短链（DP < 13，称为SF）与长链（DP >= 13，称为LF）的重量比之间呈抛物线关系，这意味着短链或长链含量较高的支链淀粉可产生相对较高含量的SDS。此外，对SF/LF重量比最高和最低的样品（两者SDS含量都很高）中的SDS材料进行脱支分析，结果显示出显著不同的图谱，表明SDS不存在统一的分子结构。因此，玉米样品的基因突变体具有提供高营养品质生淀粉原料的良好潜力。另一个发现表明，一种简单且相对高通量的快速粘度分析仪（RVA）技术可用于根据其RVA图谱筛选基因突变体。
