籼型稻米糊化温度和直链淀粉含量一体化的半粒测定法研究

DETERMINATION OF GELATINIZATION TEMPERATURE AND AMYLOSE CONTENT BY THE METHOD OF USING SAME HALF GRAIN OF INDICA RICE

首次提出稻米碱消值 -糊化温度和直链淀粉含量一体化的半粒测定法 ,即采用同一半粒稻米在测定了碱消值 -糊化温度后 ,继续测定其直链淀粉含量 .取远胚端半粒籼稻米在质量分数为0 .5 %NaOH溶液中保持在 30℃的恒温箱中 2 3h ,按农业部部标准米质测定方法 (NY147- 88)中碱消值的判断依据与方法 ,可以较准确地测定其碱消值 -糊化温度 ,测定结果与农业部部标准方法的结果一致 ;将测定了碱消值 -糊化温度后的半粒稻米及其消解液在沸水浴中继续分散 ,用乙酸调节pH值后 ,按碘蓝比色法可以进一步测定其直链淀粉含量 ,其结果与国家标准稻米直链淀粉含量的测定方法 (GB/T15 6 83- 1995 )的结果差异不显著 .发芽的结果表明 ,近胚端半粒稻米的发芽率在 90 %以上 .取半粒稻米一体化测定其碱消值 -糊化温度和直链淀粉含量 ,留半粒稻米繁种 ,既可以提高材料的利用率 ,减少分析误差 。

Determination method of gelatinization temperature and amylose content using same half grain of indica rice was proposed. The same half rice grain was used to determine alkali spreading value-gelatinization temperature, and then continue to determine its amylose content. Distal half rice grain from embryo was weighed accurately, and immersed in 4mL 0.5%NaOH and incubated at 30℃ for 23h, its alkali spreading value-gelatinization temperature can be determined accurately according to scoring standards of alkali spreading value specified in Ministry of Agriculture Rice Quality Determination Method. The alkali spreading values-gelatinization temperature determined by this method are same as those determined by Ministry of Agriculture Rice Quality Determination Method. Following the determination of alkali spreading value-gelatinization temperature, the same half rice grain and its spreading liquid continue to be dispersed in boiling water bath for 20 min, its pH is adjusted with acetic acid, its amylose content is further determined with iodine-blue colorimetry. The amylose contents determined by this method are not significantly different from those determined by State rice grain AC standard determination method(GB/T15683-1995). The germination rates of proximal half rice grains from embryos were over 90%. The method that the same distal half rice grain from embryo is used to determine alkali spreading value-gelatinization temperature and amylose content, while proximal half rice grain from embryo is kept for breeding, can not only improve utilization rate of experimental material, reduce analysis variances, but also improve efficiency of rice quality improvement.