Study On The Physicochemical Properties Of Wheat Cultivars With Good Quality Processing For Both Bread And Noodle

In this study,the wheat germplasm resources worldwidely were collected and 12 representative cultivars possessing similar protein characteristics were screened according to their protein properties,starch physicochemical properties,bread and noodle making quality.These 12 cultivars can be divided into six types based on their bread and noodle quality: good bread quality wheat cultivar(GBQW),bad bread quality wheat cultivar(BBQW),good noodle quality wheat cultivar(GNQW),bad noodle quality wheat cultivar(BNQW),good both bread and noodle quality wheat cultivar(GBNQW),and bad both bread and noodle quality wheat cultvar(BBNQW).In order to deduce the key indicators to screen wheat cultivars with good bread and noodle quality beneficial for breeding program,the starch physiochemical properties including amylose content,amylopectin content and its chain length and distribution,starch particle size,content,distribution,starch gelatinization characteristics,swelling properties,DSC thermos-physical properties were investigated,as well as the expression of some key genes encoding starch biosynthetic enzymes during grain filling.The results showed that there was no significant difference in total starch content among 6 types of wheat cultivars.However,amylose content of GBQW,GNQW,and GBNQW is significantly less than that of BBQW,BNQW and BBNQW.The Amylopectin content,the ratio of amylopectin content to amylose content(AP/AM)of GBQW,GNQW,and GBNQW are significantly higher than those of BBQW,BNQW and BBNQW.The amylose content,amylopectin content and branched chain ratio in wheat starch were closely related to the quality of bread and noodle.Among them,much more amylopectin,less amylose,higher AP/AM is conducive to improve bread and noodle processing quality.AP/AM was considered as the most important influencing factor and probably can be used as the indicator(2.1-2.6)for bread and noodle quality improvement.Through scanning electron microscopy(SEM),we can see that the C-type starch granule number of GBQW,GNQW,and GBNQW is higher than that of BBQW,BNQW and BBNQW.While the large starch granules(type A starch granules)can not be found significant difference among types.In further investigation,the number of C-type starch granules is found higher in GBQW,GNQW,and GBNQW(37.3%,42.6%,42.2% respectively)than that in BBQW,BNQW and BBNQW(31%,32.2%,31.2% respectively).The number of B-type starch granules of GBQW,GNQW,and GBNQW(58.6%,54.2%,55.3% respectively)is less than the number of starch grains of BBQW,BNQW and BBNQW(65%,64.8%,64.6% respectively).There was no significant difference in the number distribution of type A starch granules among different type cultivars.The results of SEW are consistent with the results of wheat starch granule distribution.Therefore,the proportion of wheat starch granules could be used as a breeding index for bread and noodle quality.The higher proportion of wheat type C starch granules is beneficial to improve bread and noodles making quality.The wheat cultivars with proportion of C-type starch granules between 36.2% and 46.7%,and B-type starch granules between 51% and 59.5% were more suitable for processing bread and noodle.The proportion of short chain amylopectin(2?DP?10)was between 47.84% and 51.00%,and the proportion of longchain amylopectin(28?DP?89)was between 13.44% and 14.37% among 12 differrnt type cultivars.The proportion of short-chain amylopectin of GBQW,GNQW,and GBNQW(48.2%,46.33%,50.14%,respectively),is higher than that of BBQW,BNQW and BBNQW(45.34%,43.18%,46.1%,respectively).While the proportion of long chain amylopectin in GBQW,GNQW,and GBNQW(14.01%,15.7%,13.59%,respectively)is less than that in BBQW,BNQW and BBNQW(15.06%,19.14%,15.9%,respectively).It may be deduced that wheat short-chain amylopectin can improve bread and noodle processing quality from the above results.The peak viscosity,breakdown,swelling power and DSC termination temperature of GBQW,GNQW,and GBNQW were higher than those of BBQW,BNQW and BBNQW.The peak viscosity of starch between 2890-3450 cP is suitable for both bread and noodle making,as well as the breakdown between 916-1446 cP and the swelling power between 7.53-9.04,and the termination temperature between 68.5-69.6?,respectively.There were significant differences in the expression levels of 11 kinds of starch synthatic genes among 12 cultivars,but there was no significant difference between high and low quality wheat.There is no obvious correlation between the gene expression of thse key starch biothetic enzymes and bread and noodle end use from the result.Therefore,AP/AM of GBNQW is between 2.1 and 2.6,together with the proportion of type C starch granules between 36.2% and 46.7%,type B between 51% and 59.5%,short-chain amylopectin between 47.84% and 51.00%,the peak viscosity between 2890-3450 cP,breakdown between 916-1446,the DSC termination temperature between 68.5-69.6?,and the swelling power between 7.53-9.04,which are conducive to improving the bread and noodle quality.Among them,the content of short-chain amylopectin,the number of B-type and C-type starch granules and the termination temperature of starch could be used as key index es for the selection of wheat cultivars with high bread and noodle quality.