Study On The Optimization And Properties Of Preparation Of Tartary Buckwheat Nano-starch By Enzymatic Hydrolysis

Tartary buckwheat is a food crop with the same medicine and food of Polygonaceae buckwheat genus(Fagopyrum),which has health functions such as lowering blood sugar and lowering blood lipids.Compared with other starches such as corn starch and potato starch,tartary buckwheat starch has uniform particle size distribution and moderate particle size.Nano starch has attracted more and more attention in recent years because of its surface rich in hydroxyl groups and small particles.Compared with the traditional method for preparing nano starch,the enzymatic retrogradation method has the advantages of simple operation,environmental friendliness,and higher yield.However,there are few studies on this method at present,and there is no report on the preparation of nano-tartary buckwheat starch by enzymatic hydrolysis.This article uses tartary buckwheat starch as the experimental material and the particle size of tartary buckwheat nano-starch as an indicator to explore the optimal conditions for preparing tartary buckwheat nano-starch by enzymatic retrogradation.Scanning electron microscope(SEM),X-ray diffraction analysis(XRD),The inner leaf infrared spectroscopy(FTIR),differential scanning calorimetry(DSC)and other techniques analyze the structural characteristics of the tartary buckwheat nano-starch prepared by the enzymatic retrogradation method,and study the aging,processing and digestion characteristics of the tartary buckwheat nano-starch,in order to further improve the grain The green preparation method of nano-starch provides a basis for the in-depth development,processing and application of tartary buckwheat starch resources.This paper obtains the following research results:(1)The best process for preparing tartary buckwheat nano-starch by enzymolysis retrogradation method is as follows: starch solution concentration is 16%,enzyme addition amount is 5.2 PUN/g,enzymolysis time is 7 h,and regeneration time is 25 h.Tartary buckwheat nano-starch prepared under these conditions The average particle size of starch is231.36 nm,and the yield is 34.7%.(2)Compared with the original starch,the particle size of the tartary buckwheat nanostarch prepared by the enzymatic retrogradation method was significantly reduced to231.36 nm;the crystal form changed from A to B+V,and the relative crystallinity increased from 26.78% to 40.94 %;The number of methylene groups and hydroxyl groups increases,and the intermolecular hydrogen bonding force increases;?H value increased from 6.57 J/g of native starch to 17.56 J/g,the crystal distribution is wider,the crystallization is more perfect,and the thermodynamic stability is enhanced.(3)Compared with the original tartary buckwheat starch,the tartary buckwheat nano-starch prepared by the enzymatic retrogradation method has better anti-aging properties.The transparency of tartary buckwheat nanostarch is significantly improved,from 51.7% of the original starch to 84.7%;the water separation rate is significantly reduced,from 60.6%of the original starch to 35.7%,which has better freeze-thaw stability;the solubility is increased from 11.9% to 44.8%,the swelling degree was reduced from 13.8% to 8.9%;the retrograde volume was smaller,from 19.5 m L of the original starch to 1.1 m L;the digestibility was higher,from 85.9% to 93.6%.