青稞籽粒主要组分对其淀粉膨胀势的影响

Effect of main grain components on the starch swelling power of Tibetan hull-less barley(Hordeum vulgare var.nudum)

青稞是我国藏区的主要粮食作物,其淀粉膨胀势是淀粉特性的重要指标.为明确青稞籽粒组分对青稞膨胀势的影响以及淀粉膨胀势与全麦粉膨胀势之间的关系,研究了25份青稞材料籽粒主要成分的含量差异、淀粉与全麦粉的膨胀势差异以及籽粒组分与膨胀势的关系.结果显示,青稞的蛋白质含量、β-葡聚糖含量和直链淀粉含量的平均值分别为13.83%、5.74%和27.44%,材料间差异很大,变幅分别为11.70%-16.40%、4.07%-9.70%和0.23%-37.81%.用以预测α-淀粉酶活性的降落值变异也很大,变幅为76-515 s,平均值为365.12 s.不同青稞材料的淀粉和全麦粉的膨胀势都有明显差异,淀粉膨胀势为10.45-21.03,而全麦粉为2.91-16.03.青稞籽粒不同组分对淀粉或全麦粉膨胀势的影响不同,直链淀粉抑制淀粉膨胀,β-葡聚糖含量与青稞全麦粉的膨胀势成正相关,而高α-淀粉酶活性会降低青稞粉的膨胀势.青稞全麦粉膨胀势与淀粉膨胀势呈显著正相关.本研究表明不同青稞材料的膨胀势差异较大,不同籽粒组分对膨胀势的影响不同,不同青稞全麦粉膨胀势变化趋势与其淀粉膨胀势的变化一致,因此可使用全麦粉膨胀势替代淀粉膨胀势进行青稞材料的筛选,具有方便、省时、快捷的优势.

Hull-less barley （Hordeum vulgare var. nudum） is the major food crop in the Tibetan region of China as well as a healthy global food source. Starch is one of the most important components in hull-less barley grain, and starch swelling power is one of the most important indicators of starch properties. The aims of this study were to clarify the effect of the main grain components of hull-less barley on the starch swelling power, and determine the relationship of swelling power between the starch and wholegrain flour. In particular, the differences among the major components of hull-less barley grain, swelling power of wholegrain flour, and starch were determined in a total of 25 hull-less barley accessions. The results were as follows. The average （range） contents of protein, β-glucan, and amylose were 13.83% （11.70%–16.40%）, 5.74% （4.07%–9.70%）, and 27.44% （0.23%–37.81%）, respectively. Wide variation in falling number, which could predict α-amylase activity, was found among the 25 hull-less barley accessions, with values ranging from 76 s to 515 s and an average of 365.12 s. There were obvious differences in the swelling power of either the wholegrain flour or starch among these accessions. The swelling power value of hull-less barley starch ranged from 10.45 to 21.03, whereas that of the wholegrain flour ranged from 2.91 to 21.03. In addition, the contents of the grain composition in hull-less barley had different effects on the swelling power of starch or wholegrain flour. For example, amylose suppressed starch granule expansion; the β-glucan content was positively correlated to the swelling power of wholegrain flour, whereas high α-amylase activity could reduce the swelling power of hull-less barley flour. The swelling power of starch was significantly and positively correlated with that of wholegrain flour. These results are applicable and time-saving while screening for breeding lines with wholegrain flour swelling power.