| At present,people believe that diabetes,hyperglycemia,hypertension and other related diseases are related to the blood sugar level in the body,and starch crops are the main source of blood sugar.Studying the digestive characteristics of starch and understanding its digestive patterns is of great significance for guiding healthy eating.Rice is an important source of energy for humans,divided into glutinous rice and sticky rice.Glutinous rice has amylopectin content of over 95 %,and its rice has a soft and glutinous taste,which is highly favored by some people.Of course,there are also a considerable number of people who do not accept glutinous rice because it has a strong sense of fullness after consumption.Glutinous rice has a slow digestion and strong satiety response in consumption,while in digestion experiments,it is the result of fast digestion and fast sugar increase,which are two extreme reactions of a food.There are few reports on this issue.Although there are currently many reports on the fine structure characteristics and digestive characteristics of starch based foods.However,there is still limited research on the impact of starch component differences among different genotypes on digestion.Especially,there are fewer reports on the differences in starch composition and structural characteristics of different glutinous rice genotypes,as well as their impact on digestion processes.In this study,the differences in starch content in endosperm of 65 glutinous rice varieties(lines)were analyzed,and the digestion rate of these varieties was measured using in vitro enzyme digestion method,and the glycemic index was predicted.Four glutinous rice varieties with different digestive characteristics were selected to determine the structural characteristics of starch granules by scanning electron microscope,Fourier transform infrared spectroscopy,gel permeation chromatography and high-performance anion exchange chromatography.The research results obtained are as follows:(1)The starch content of 65 glutinous rice varieties varies greatly,with amylose starch content ranging from 0.72 %~1.79 %,total starch content ranging from70.63 %~76.72 %,resistant Starch content ranging from 0.17 %~3.79 %,rapidly digestible starch content ranging from 40.51 %~52.37 %,and slowly digestible starch content ranging from 19.92 %~32.47 %.The average glycemic index value is 72.9,among which the glycemic index values for Bannanuo 18,Dianxiannuo 18,Diangu 2047,and Jingming77 are 68.76,71.39,73.26,and 75.67,respectively.There is a correlation between starch components and the amount of glucose produced during digestion,as well as the glycemic index value.Glutinous rice can quickly release a large amount of glucose within 30 minutes after a meal,with a high sugar release rate and high sugar content,resulting in a fast blood sugar response.The sugar release lasts for a long time and has a sense of hunger tolerance and satiety.Glutinous rice is basically a high glycemic index food with fast digestion speed,and people who control blood sugar levels should be cautious when consuming it.(2)The morphology and size of natural starch particles in four types of glutinous rice are similar.As digestion progresses,the surface of particles undergoes varying degrees of damage,with the ratio,short branch chain ratio,and polydispersity index gradually increasing at 1047 cm-1/1022 cm-1,while the medium long chain ratio,average degree of polymerization,relative molecular mass,and radius of gyration gradually decreasing.The short chain ratio of Bannanuo 18 and Dianxiannuo 18 is small and the long chain ratio is high,while Diangu 2047 and Jingming 77 are opposite.The relative molecular mass of Banna Nuo 18 and Dianxian Nuo 18 is smaller than the other two varieties.The particle surface order of Dianxian Nuo 18 is the smallest,while Diangu 2047 is the largest.(3)There is a significant correlation between starch components and starch structure.The higher the rapidly digestible starch content,the higher the proportion of A chain and A+B1 chain,while the B1 chain,B3 chain,and average degree of polymerization decrease.There is a significant negative correlation between resistant Starch and the ratio and radius of gyration at 1047 cm-1/1022 cm-1.Starch with strong blood sugar raising ability has a large proportion of A chain and A+B1 chain,while the proportion of B1 chain,B2 chain,B3 chain,and average degree of polymerization is small.(4)The short range order,chain length distribution,and relative molecular mass characteristics of glutinous rice starch structure are highly correlated.A higher proportion of short chains and relative molecular mass both contribute to an increase in short-range ordering.There is a highly significant negative correlation between A chain and B chain,and a significant positive correlation with relative molecular mass.Short chains are the foundation for forming long chains,which contribute to the increase of average degree of polymerization.The larger the average degree of polymerization,the smaller the relative molecular mass.There is a proportional relationship between relative molecular mass,radius of gyration,and polydispersity index.In summary,Bannanuo 18 and Dianxiannuo 18 belong to glutinous rice varieties with weaker digestion ability,while Diangu 2047 and Jingming 77 belong to glutinous rice varieties with relatively stronger digestion ability.The research results can provide technical reference for cultivating glutinous rice genotypes with different digestion reactions,as well as data support for the consumption of glutinous rice genotypes with different digestion reactions and understanding the relationship between digestion and structure. |
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