郭运玲　孔华　左娇　贾瑞宗　黄启星　郭静远　周霞　郭安平

摘 要 直链淀粉和支链淀粉含量及其比例是木薯淀粉品质的重要指标。采用双波长法对30个木薯株系的直、支链淀粉的含量进行了测定，根据碘分别与直链和支链淀粉反应生成复合物的吸收光谱，我们最后确定了直链淀粉的和支链淀粉的参比波长和测定波长分别是609和469.5 nm、542和721 nm。根据回归方程得到了30个木薯株系的直链淀粉和支链淀粉的含量。本实验中用于测定木薯的直链淀粉浓度在0～26 μg/mL，支链淀粉浓度在0～100 μg/mL范围内符合比耳定律。结果表明： SC8不同株系的直链淀粉含量变化范围：14.879%～21.905%，支链淀粉含量变化范围：47.864%～56.955%；SC6不同株系的直链淀粉含量变化范围：15.494%～24.726%，支链淀粉含量变化范围44.292%～57.465%。该方法准确性高、重复性好、效率高，工作量小，适于批量木薯样品分析。

关键词 木薯；双波长法；直链淀粉；支链淀粉；

中图分类号 TS235.2 文献标识码 A

Abstract The content and proportion of amylose and amylopectin are important indices of cassava. A dual-wavelength method was applied to the determination of amylose and amylopectin in 30 cassava varieties. According to the absorption spectra of the two complexes， the determination of wavelength and reference wavelength of amylose， 609 nm and 469.5 nm， and the determination of wavelength and reference wavelength of amylopectin， 542 nm and 721 nm， were selected as the measuring wavelength. The content of amylose and amylopectin were figured out from the two regressive equations. Beer′s law was obeyed in 0-26 μg/mL for amylose and 0-100 μg/mL for amylopectin. The results showed that the amylose content of SC8 different strains was 14.879% to 21.905%， the amylopectin content was 47.864% to 59.955%； The amylose content of SC6 different strains was 15.494% to 24.726%， and the amylopectin content was 44.292% to 57.465%. The method had a good repetition and could be applied for analyzing plentiful samples of cassava due to its accuracy and rapidness.

Key words Cassava；Dual-Wavelength method；Amylose；Amylopectin

doi 10.3969/j.issn.1000-2561.2016.06.027

木薯（Manihot esculenta Crantz）属于大戟科块根作物，是热带、亚热带地区重要传统的经济作物和粮食作物，木薯是主要以地下块根形式储存合成的淀粉，木薯适应范围非常广，具有抗逆、耐贫瘠，以及生物量很高和淀粉含量高等多种特点。木薯淀粉在淀粉食品、工业原料等领域有十分广泛的用途，在中国木薯作为新兴的能源作物受到重视，木薯生产和加工产业有很大的发展前景[1]。木薯淀粉的主要成份是直链淀粉和支链淀粉，直链淀粉和支链淀粉的组成比例直接影响着淀粉的化学特性以及加工用途[2]。测定淀粉含量及淀粉中直链淀粉、支链淀粉组成比例的方法有很多，如碘亲和力测定法、排阻色谱分析法、旋光法、国标法、双波长法和多波长法、比色法、近红外法、差示扫描量热法等。……