Analysis of Resistant Starch Content and Accumulation Characteristics in the Glutinous Barley Grains with Different Genotypes

In order to explore the effects of amylose, amylopectin and β-glucan on the synthesis of resistant starch, 30 glutinous barley with different genotypes were used as the experimental materials to determine the starch components, β-glucan content and resistant starch content at 7, 14, and 21 days after flowering (early grain-filling stage), and the maturation period. The results showed that there were significant differences among the starch components, β-glucan content and resistant starch content in the mature grains of 30 barley materials with different genotypes. The content of resistant starch ranged from 0.28% to 1.22%, with an average value of 0.56%. The content of resistant starch in the strain Xi C1 was the highest (1.22%), followed by Gankennuo No.3 (0.91%). The two strains with the lowest content of resistant starch were 2014(7)-5-1-2 (0.28%) and 2014(1)-1-2-1 (0.29%). With the advance of grain filling process, the content of resistant starch in Gankennuo No.3 showed an increasing trend, and reached the maximum at the maturation period. The strain 2014(1)-1-2-1 showed a trend of first increasing and then decreasing, while the variation trends for the strain Xi C1 and strain 2014(7)-5-1-2 were exactly opposite to that of the strain 2014(1)-1-2-1. Among the 30 barley materials, the contents of β-glucan in 13 materials were higher than 6%, indicating that they were typical high β-glucan materials. The content of β-glucan in Zhongnuo No.8 was as high as 8.59%. The amylose content ranged from 1.81% to 18.54%, and the amylopectin content ranged from 81.46% to 98.19%. Among the 30 barley materials, the contents of amylopectin in 22 materials were more than 90%, indicating that they were high-amylopectin starch materials. The contents of resistant starch in 30 barley grains with different genotypes were different, and the accumulation characteristics of resistant starch were also different. Therefore, the correlation analysis showed that the content of resistant starch was significantly positively correlated with the content of amylose, but was significantly negatively correlated with the content of β-glucan.