Ultrastructure Observation Of Starch Granules And Evaluation Of Pasta Products In A New Wheat Cultiar 'Xinhuamai 818'

Starch is the main storage material of wheat kernels and presents in the form of starch granules.Starch quality is the determinate factor affecting the food quality of wheat flour,and wheat starch quality is mainly affected by its morphology,structure and volume.Xinhuamai 818,released in 2018(No.20180022),is a new wheat variety cultivated by our research group.It is characterized with good fruiting,strong stalks and many ears,large size of grains,long grain filling,high grain weight,good-shape of grain,half-horny grain,stable yield,multi-resistance and eurytopicity.This experiment explored the dynamic changes of starch granules in Xinhuamai 818 grain and the evaluation of pasta products,providing a theoretical basis for its promotion and utilization and variety improvement.The results are as follows:(1)Wheat starch grains are composed of two types,A(>9.8 ?m in diameter)and B(<9.8 ?m in diameter)elliptical granules.Our observation showed that A-type starch granules appeared in Xinhuamai 818 endosperm at 5 d after anthesis and their arrangement were loose at this time,then they were slowly anthesized,and at 20 d after anthesis they quickly accumulated and their volumes were enlarged,and persisted until maturation.At 10 d after anthesis,B-type starch granules were formed and attached on A-type granules,and proteins appeared among the large sizes of B-type granules and the volume was significant.At 15 d after flowering,B-type starch granules formed and arranged closely,and then continued accumulation.A large amount of accumulation began 25 d after flowering,and the volume and surface area increased significantly,and then continued until the grain matured.the A and B-type starch granules were closely arranged in the endosperm cells to fill the endosperm cells.The granule-type protein appeared in the large starch granules in the endosperm cells 10 d after flowering,and then accumulated rapidly.The granule protein increased significantly after 20 d of flowering,and the matrix protein wrapped the starch granules,which continued until the grain matured to fill the endosperm cells.In the particle size distribution of Xinhuamai 818 grain starch granules,the number distribution characteristics showed a single-peak curve,and the volume and surface area distribution showed a double-peak curve.(2)The results of starch quality and food quality of Xinhuamai 818 showed that the total starch content,linear and amylopectin content of Xinhuamai 818 were significantly higher than that of the control variety Zhoumai 18.Among the starch gelatinization characteristics,the peak viscosity,valley viscosity and lean value of Xinhuamai 818 were significantly lower than Zhoumai 18,while the rebound and expansion potential of Xinhuamai 818 were significantly higher than Zhoumai 18;The height-diameter ratio,hardness and chewiness of Xinhuamai 818 steamed bread were significantly higher than that of the control Zhoumai 18,while the adhesion,cohesiveness and recovery were lower than that of Zhoumai 18,and the hardness and adhesion of noodles made by Xinhuamai 818 The sex was higher than that of Zhoumai 18,and the elasticity,adhesiveness,cohesiveness,recovery and chewiness were lower than those of Zhoumai 18.The sensory evaluation scores of steamed bread and noodle made by Xinhuamai 818 were significantly lower than Zhoumai 18.The results of edible quality research showed that the appearance and color of steamed bread and noodles made by Xinhuamai 818 were better than Zhoumai 18,but the taste was worse than Zhoumai 18.(3)The starch quality of Xinhuamai 818 is closely related to its products.The starch quality was significantly correlated with the texture characteristics and sensory evaluation of steamed bread and noodles.Among those,the amylose content has a significant or highly significant(p?0.05 or 0.01)negative correlation with the ensory evaluation of steamed bread and noodles,while the peak viscosity,valley viscosity and the dilute value has a significant or highly significant positive correlation.Which indicates that reducing the amylose content,increasing the peak viscosity,valley viscosity,and the dilute value play an important role in improving the quality of steamed bread and noodles in Xinhuamai 818 cultivar.