Accumulation Characteristics And Physicochemical Properties Of The A And B-granule Wheat Starches On Different Combination Of Nitrogen And Sulfur

In order to test the effects of nitrogen and sulfur fertilizer on wheat starch granule sizedistribution and physical and chemical properties, Wheat cultivars Xinong9718andShaannong138were grown at different combination of nitrogen and sulfur fertilizerreference to the part of “3414” pilot program. Effect of development process of A、B-granulewheat starch on different nitrogen-sulfur treatments during grain filling stage were analyzed.And the effects of nitrogen-sulfur on wheat starch granule size distribution, composition,swelling power and pasting properties were studied. The main conclusions are as follows:（1） The Wheat A-granule starch formed in a single amyloplast in the wheat grain fillingand have a rapid increase in the milk stage. A-granule starch possessed the typical elliptical ordisc-like shape, while B-granule exhibited spherical morphology which formed in the milkstage and have a rapid increase in the dough stage. Some of B-granule starch formed of thedivision of the A-granule, the other formed of the detachment form amyloplast membrance.Shaannong138and Xinong9718have a similar development process of starch contentduring grain filling stage. From the wheat grain filling to the dough stage, the content of totalstarch, amylose and amylopectin have a faster accumulation. Until the full ripe stage, thecontent get to the maximum accumulation. The rate of the Amylopectin accumulation in theearly grain filling stage was significantly higher than that of amylose.（2） Shaannong138and Xinong9718have a similar impact on the Starch granuledistribution at different fertility treatments in the grain filling stage. Nitrogen and sulfurfertilization promote the synthesis of A and B-granule starch, making the distribution ofstarch more compact. Fertilization has strong impact on the content of the total starch andamylose in the early and mid of the grain filling stage, while the amylopectin in the late of thegrain filling stage. This study has shown that combined application of nitrogen and sulfurfertilizer is more conducive to wheat starch accumulation. In a certain percentage of nitrogenand sulfur fertilizer conditions, fertility can be improved to the accumulation of the starch content and to change the proportion of the starch components.When nitrogen fertilizer was230kg·hm^-2and sulfur fertilizer46kg·hm^-2～56kg·hm^-2, the cumulative amount of wheatstarch and ratio of amylopectin and amylose is the maximum.（3） The results indicated that wheat starch granule size distribution of Xinong9718andShaannong138were consistent, but the physicochemical properties of A、B-granule starchhave a significantly different. The grain size distribution of A-granule starch is almost threetimes the B starch, but much less than the number of B-granule. The crystal structure of A、B-granule starch are typical A-type crystalline, but the crystallinity of A-granule wassignificantly larger than the B starch.The amylose content, starch-iodine-blue, peak viscosity,trough viscosity, breakdown, final viscosity and setback of A-type granule were higher thanB-type granule, and B had a higher starch amylopectin content, swelling power and pastingtemperature. In the first1.5h stages of digestion, the B-granule starch was digested to agreater extent than A-granule, but after2.5h of digestion A-granule was digested moreextensively than B-granule. To reveal whether the granule size of the starch or the chemicalstructures of the starch was more important in determining the Starch components and thepasting properties, we compared the reconstituted wheat starch that consisted of differentproportions of A and B-granule. The results showed that increasing the A-granule contentfrom0%to40%significantly increased the content of the amylose and increasing（4） Different fertility treatments changed with different size distribution of wheat starch,thereby affecting the composition and pasting properties of starch. When nitrogen fertilizerwas230kg·hm^-2, A-type granule and B-type granule starch of Xinong9718and Shaannong138had lower amylose content, higher swelling power and better pasting propertiesrespectively at sulfur fertilizer46kg·hm^-2and56kg·hm^-2than other nitrogen-sulfurtreatments. Starch granule size distribution, composition and pasting properties of Shaannong138were sensitive to fertilization. Appropriate nitrogen and sulfur fertilization will help toimprove the quality of wheat starch.