| Naked Barley contains more protein,dietary fiber,vitamins and unsaturated fatty acids than ordinary grains,has good health effects,especially the content of β-glucan is the first in naked barley,which has physiological functions such as clearing stomach,lowering cholesterol and regulating blood sugar,so naked barely has high development value in food and non-food industry.Starch is one of the main storage substances in naked barley,amyloplast is the organelle storing starch.The development and physicochemical properties of starch granule are directly related to the processing quality of naked barley.However,there are few reports on the development of starch granule,the degradation of starch granule in the process of seed germination and the differences of physicochemical properties from different kinds of naked barley.TM6,SLM2,QYM and HYM were used as materials.The differences in the development and germination of endosperm starch bodies of four kinds of naked barley were studied by resin semi thin section,histochemical staining and microscope observation.The morphological structure and physical and chemical properties of starch grains of four kinds of naked barley were studied by scanning electron microscopy,X-ray diffraction,Fourier transform far infrared spectroscopy and 13C solid nuclear magnetic resonance spectroscopy Comparative research.The main results are as follows:(1)The changes in size,shape and surface color of four kinds of naked barely were similar,and the skin color of HYM changed greatly and gradually turned yellow and black.The trend of fresh and dry weight of Caryopsis of the four kinds of naked barley was basically the same,and they all grow in "s" shape.The content of water and soluble sugar decreased and the content of total starch increased.In the early stage of development,the soluble sugar content of SLM2 was significantly higher than that of the other three types.During the whole development period,the total starch content of QYM was obviously higher than other naked barleys.(2)The endosperm amyloplast all appeared at 5 DAF,and the proteins appeared at about 9 DAF.Endosperm amyloplast extended and multiplied at 13-27 DAF.The volume and quantity of starch granule and protein body increase gradually and the endosperm cells were highly enriched at 27 DAF.The endosperm amyloplast of HYM and SLM2 appeared earlier,the proportion of small amyloid and starch enrichment degree were higher.(3)I2-KI staining showed that the endosperm stained by I2-KI were different among the four kinds of naked barley.The endosperm of HYM was dyed red brown,the other three kinds of endosperm showed blue black,and with the increase of development time,the accumulation of starch,the degree of coloring deepened,and the area of coloring area increased.(4)The rate of extinction of the endosperm of the four species was significantly different during germination,the speed of SLM2 was the fastest and QYM was the slowest.Compared with the four varieties,TM6 endosperm starch consumption rate was faster than the other three varieties.(5)There are two kinds of starch grains in the four kinds of naked barley starch grains:big and small.The shape of large amyloplast was mostly spherical,the small amyloplast was mostly ellipsoidal,irregular or polyhedral.The grain size distribution of starch grains of four kinds of naked barley were bimodal,the average grain size of QYM was the largest,and that of HYM was the smallest.The surface of starch granules of four kinds of naked barley were round,and there were more small starch granules and less large starch granules in HYM and SLM2.TM6 and QYM had more big starch grains and less small starch grains.(6)XRD patterns showed four kinds of naked barley were typical A-type crystal,but had different crystallinity,and the relative crystallinity of HYM was the highest.The ratio of 1045/1022 cm-1 was the highest in QYM,and the order degree of starch surface was the highest.The ratio of TM6 was the lowest,and the order degree of starch surface was the lowest.(7)HYM had higher solubility and QYM had higher expansion potential.The degree of hydrolysis of QYM and TM6 starch under the three hydrolysis of α-amylase,glucamylase and hydrochloric acid were all significantly higher than other varieties.The above results not only systematically studied the development,extinction and differences of physical and chemical properties of four kinds of naked barley starch,but also provided theoretical reference for the development and utilization of naked barley starch in the field of food and industry. |
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