Analysis Of Taste Quality And Digestion Characteristics Of Southern Soft Rice Japonica Rice Based On Starch

In this study,semi-waxy japonica rice(Nanjing 9108,Suxiangjing 3,Xudao 9)widely cultivated in Jiangsu province was used as experimental material,and waxy japonica rice(Huainuo 12,Zhennuo 19,Yangjingnuo 2),non-waxy japonica rice(Huidao 5,Sujing 815,Yangyujing 2)as control.The cooking quality,eating quality,digestion quality and their relationships with starch structure were studied.The main findings are as follows:1.During cooking,water migration in cooked semi-waxy japonica rice increased with the increasing cooking time.After cooking for 5 minutes,the water migration rate reached its peak value.Ten minutes later,the water migration were stable,and the content of semi-bound water and bound water basically didn't change.After cooking,the bound water content of semi-waxy japonica rice was similar to that of non-waxy japonica rice,and was significantly higher than that of waxy japonica rice,while the semi-bound water content of semi-waxy japonica rice was lower than that of waxy japonica rice.The RVA characteristic values of semi-waxy japonica rice were between waxy and non-waxy japonica rice.Similar to non-waxy japonica rice,semi-waxy japonica rice needed a higher gelatinization temperature to gelatinize starch.The texture of semi-waxy japonica rice was soft and elastic,and showed an excellent ability to resist retrogradation.The setback value of semi-waxy japonica rice flour was significantly lower than that of non-waxy japonica rice flour,indicating that compared with non-waxy japonica rice,semi-waxy japonica rice was not easy to retrograde and was able to maintain a better taste.2.The taste values of semi-waxy japonica rice were between that of waxy japonica rice and non-waxy japonica rice.Compared to waxy and non-waxy japonica rice,the texture of semi-waxy japonica rice was soft,elastic and non-sticky,and showed better palatability.The balance values of semi-waxy japonica rice was close to those of waxy japonica rice,but it was less sticky than waxy japonica rice.During retrogradation,the bound water content of semi-waxy japonica rice slowly increased.After 120 min,the bound water content of semi-waxy japonica rice increased by only 2.25%.At the same time,the internal structure of semi-waxy japonica rice was very important for bound water.The water mobility of semi-waxy japonica rice was significantly weaker than that of waxy japonica rice,but stronger than that of non-waxy japonica rice.3.During oral processing,the work done during the first chewing of the semi-waxy japonica rice was significantly less than that of the non-waxy japonica rice,but more than that of the waxy japonica rice.It shows that the hardness of semi-waxy japonica rice is lower than that of non-waxy japonica rice,but higher than that of waxy japonica rice.In addition,compared with non-waxy japonica rice,the chewing process of semi-waxy japonica rice requires less total work for the breakable structure and less breakable structure.Semi-waxy japonica rice produced low glucose content in the mouth,which was not significantly different from non-waxy japonica rice and was significantly lower than waxy japonica rice.The Englyst method was further used to determine the digestibility of semi-waxy japonica rice starch.It was found that the starch digestibility of semi-waxy japonica rice was between waxy and non-waxy japonica rice,and the content of fast digestible starch(RDS)was higher than that of non-waxy japonica rice.It is 5.41%lower than waxy japonica rice;the content of slow digestion starch(SDS)is close to that of non-waxy japonica rice,and is significantly higher than that of waxy japonica rice;resistant starch(RS)was higher than waxy japonica rice and significantly lower than non-waxy japonica rice4.Through studying the fine structure of japonica rice starch,it was found that the amylose content in semi-waxy japonica rice starch was between waxy japonica rice starch and non-waxy japonica rice starch,and the short chain content in the amylopectin structure was the least.Amylose content has a significant negative correlation with tasting characteristics,and a significant positive correlation with digestion characteristics.The hardness and elasticity of japonica rice increased with the increase of amylose content,and the balance value decreased with the increase of amylose content.During the rejuvenation process,the water movement capacity of the rice decreases with the increase of the amylose content,and the water binding capacity of the gel structure increases with the increase of the amylose content.With the increase of amylose content,the harder the rice texture,the lower the viscosity,and the greater the chewing work.Amylose content has a very significant negative correlation with RDS content,and a significant or very significant positive correlation with SDS content and RS content.5.The starch accumulation in the grains of the semi-waxy japonica rice Nanjing 9108 showed an "S" shape change with the growth process.The average accumulation rate showed an upward trend from 0 to 30 days after anthesis,and the maximum appeared at about 30 days.The main reason why the accumulation of amylose of Nanjing 9108 was less than that of Huaidao 5 was that the maximum accumulation rate appeared later,and the main reason that it was more than Zhennuo 19 was that the maximum accumulation rate was large and the active accumulation days were long.The content of amylose in Nanjing 9108 grain starch has rapidly accumulated 4.56%within 10 d,and gradually increased to 9.10%within 10-40 d with the progress of filling.The higher the content of amylose,the more rapid the accumulation of amylose in the early stage of filling.The peak time of the average accumulation rate of Nanjing 9108 total starch was more consistent with the peak time of AGPase activity at about 30 d,and the peaks of SSS and SBE activity also appeared at about 30 dIn summary,amylose is the most important factor affecting the cooking and eating quality and digestion characteristics of rice.The amylose content in semi-waxy japonica rice starch is less than 10%,and the short chain content in the amylopectin structure is less.The cooking quality of semi-waxy japonica rice is similar to that of non-waxy japonica rice.The gelatinization temperature is high,the disintegration value is large,it is not easy to gelatinize,and the recovery value is small.After cooking,the bound water content is high,the semi-bound water content is low,and the rice has a strong water holding capacity.It has strong resistance to retrogradation,and the rice is cold but not hard,which helps the rice maintain a better taste.Compared with the other two kinds of japonica rice,the semi-waxy japonica rice has a moderate texture,is soft,elastic and does not stick to the teeth,has a better mouthfeel,and has a good palatability.Semi-waxy japonica rice is less digestible than waxy,and produces lower glucose content in the mouth.During the grain filling process,the accumulation rate of amylose content in semi-waxy japonica rice is higher than that of waxy japonica rice and lower than that of non-waxy japonica rice.GBSS directly affects the accumulation of amylose.SBE and DBE affect the synthesis of amylopectin to a certain extent.