| Adlay（Coix lachryma-jobi L.）,a once-a-year or repeating every year grass group,adlay seed is its ripe seeds and has high healthy food-based value and effectiveness of health care.Adlay seed is one of production and application value of cereals.China is a major country in the cultivation and consumption of adlay seeds,and Guizhou is the largest province in terms of planting area,with an average yield of about 300 kg per mu.However,the processing of adlay seeds in China is still at the primary stage,and most of the enterprises related to adlay seeds are limited to the sale of adlay seeds and the production of baked nutritional powder,and the deep processing and application of adlay seeds are still lacking.Starch is one of the main storage substances of adlay seeds,accounting for about 60%of its content,and its physicochemical properties are the main determinant of whether adlay seeds have acceptable food and steaming qualities.Few studies have been conducted on the differences in the physicochemical properties of starch grains during seed development and seed germination of adlay.In this study,the small white shell of Xing ren,Guizhou was used as the material to determine the related growth indexes,grain morphology and chemical composition during the seed development and seed germination of adlay,and the morphological changes of starch granules were observed by optical microscope and scanning electron microscope.The physicochemical properties of starch were compared by x-ray diffraction,fourier change infrared spectroscopy and differential scanning calorimetry.The main research results are as follows:1、There are some differences in the morphology and epidermal color of the seeds of adlay at different times of development,and the surface color of the seeds gradually changes from light green to yellow-brown as the development time increases,and the mature seeds become completely gray-white.At 7 d of development,the seeds were smaller in size,mainly longitudinally,and at 14 d of development,the seeds were significantly larger in size,almost unchanged longitudinally,mainly thickened laterally,and at 21-35 d of development,the seeds were basically formed and no longer changed in form and size.During the development process,the dry and fresh weight of seeds increased first and then decreased,and decreased quickly in the later stage.With the extension of development time,the water content and able to be dissolved in something sugar content kept decreasing,and the total starch content showed an overall increasing popular thing,which increased quickly from 7 to 14 d of development and began to level off after 28 d of development.2、The shape of starch granules did not differ much in each developmental period,and generally appeared to be ellipsoidal and polygonal;with the extension of developmental time,the small starch granules gradually decreased and the medium-sized granules gradually increased until the late developmental period,when a small number of large starch granules appeared.The volumetric mean particle size,area mean particle size and peak particle size of starch grains all showed an increasing trend with the extension of development time.The quantitative mean particle size reached its maximum value at 14 d of development,and decreased continuously with the extension of development time.The amylose content increased significantly with the development time,and the iodine blue value showed a continuous decreasing trend.The transparency and swelling potential decreased significantly and the solubility increased significantly.The starch grains all had a typical A-type crystal structure,and the relative crystallinity increased with the development time,with a significant increase in the 1045/1022 cm-1ratio.The pasting temperature and pasting enthalpy of starch grains were significantly lower,fast digesting starch（RDS）and slow digesting starch（SDS）were significantly lower,and resistant starch（RS）was significantly higher.3、Seeds of adlay began to grow shoots at 2 d of germination and increased rapidly with the increase of germination time.Germinated seeds began to root 3d after germination and increased with germination rate.The seeds germinated almost completely in the 6 d,reaching 98.6%.Compared with the ungerminated seeds,the total starch content of adlay decreased gradually from 59.2 mg/g to 22.3 mg/g,the soluble sugar content increased from 1.01%to 4.9%,the crude protein content increased from 2.21%to 3.01%,the crude fat content decreased from 1.01%to 0.66%,and the coixin content increased from 17.7μg/g to 385.6μg/g after germination.4、As the germination time increased,the starch grains showed some holes and cracks,and became deeper and larger as the germination proceeded.Small granular starch gradually increased,medium granular starch gradually decreased,and no large granular starch was present in the later stages of germination.Amylose content increased first and then decreased,iodine blue value showed a continuous upward trend.The water absorption,oil absorption,transparency and solubility increased significantly,while the swelling potential first increased and then decreased.The starch grains all had a typical A-type crystal structure,and the relative crystallinity decreased with increasing germination time,with a significant change in the1045/1022 cm-1ratio.The hardness,resilience,cohesiveness and gumminess properties of the starch gel were significantly reduced and the adhesiveness was significantly increased.The proportion of short-branched A-chains decreased and the proportion of long-branched B-chains increased in the starch grains.The pasting temperature of starch increased significantly,and the pasting enthalpy showed a trend of increasing and then decreasing.The rapidly digesting starch（RDS）increased significantly,and the slowly digesting starch（SDS）and resistant starch（RS）decreased significantly.The above results not only systematically investigated the differences of starch physical and chemical properties of adlay seeds during development and germination,but also provided theoretical references for the development and utilization of adlay seeds starch in food and industrial fields. |
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