Safety Evaluation And Digestibility Of Hydroxypropyl-phosphated Modified Glutinous Rice Starches

Glutinous rice is rich in amylopectin,it is not easily digested by human,thus,and seriously effects on the glutinous rice planting and processing for economic benefits.In this paper,in order to expand the application way of glutinous rice starch,homemade glutinous rice starch was prepared through processing,and then it was double modified by hydroxypropyl-phosphated.The Kunming mice were selected for acute toxicity test,sub-acute toxicity test,evaluation of hydroxypropyl-phosphated double modified glutinous rice starch and the in vitro digestion characteristics were analyzed.The main conclusions are as follows:1.The extracted glutinous rice starch was determined,it contains 9.97% moisture,0.09% fat,0.47% protein and 0.09% ash.The amylose content in the total starches was 8.58%.After the double modification,the degree of hydroxypropyl substitution of starch is 0.179,the degree of substitution of phosphate is 0.018,which is according to the degree of substitution of single modified starch,and also meets the requirement of the degree of substitution of double modified starch.2.All the mice in the acute toxicity test were survived.The clinical observation was normal,no adverse reaction occurred,the weight of the mice increased steadily,the appearance of the main organs were healthy,no hyperplasia,edema,atrophy occurred.The hematological results showed that a high dose of double modified starch did not significantly effect on liver and kidney.The LD50 of double modified starch was more than 10000 mg / kg body weight,belongs to the actual non-toxic.3.All the mice in the sub-acute toxicity experiment were also survived.The clinical observation was normal,no adverse reaction appeared.The weight of the mice increased steadily,the appearance of the main organs was healthy,no hyperplasia,edema,atrophy occurred.The hematology results showed that the morphology and quantity of red blood cells in the experimental group were normal,the immune function was normal.The results of the biochemical indexes and the biopsy showed that the double modified starch was not small at the dose of 5000 mg / kg body weight for 28 days.The mice had no significant effect on liver and kidney,and the daily allowable intake of the double modified starch was 2723 g(70 kg adult).4.The in vitro digestion experiment showed that the digestibility of modified glutinous rice starch was lower than that of the original starch.The contents of slow digestion starch and resistant starch in the original starch were 23.6% and 14.7% respectively.The contents of slow digestion starch and resistant starch after modified reached 30.2% and 39.4%,respectively and content increased significantly.The hydrolysis index and glycemic index of the glutinous rice starch was 76.14% and 81.51%,which belonged to high GI foods.After the double modification,the hydrolysis index and glycemic index of glutinous rice starch was 52.54% and 68.55% respectively,it belongs to medium GI foods.