| Oat has the effect of reducing blood sugar and blood lipid,and its main functional components are as?-glucan,However,oat rice is easy to aging,which reduces its nutritional value.Ultra high pressure(UHP)technology is a non thermal processing technology which can better retain the nutrition of food and prolong the storage period of food.Therefore,in this paper,we used ultra-high pressure treatment of oat,through different treatments,to further screen out the experimental conditions based on the changes of oat grain microstructure and main components.The effects of ultra-high pressure on?-glucan content and structure on the rehydration rate,texture,thermal properties and crystallinity of oat rice during aging were studied.The main results are as follows:1.Scanning electron microscope(SEM)was used to observe the cross-section of oat grains after different ultra-high pressure treatments.It was found that the aleurone layer and endosperm cells in the grains were separated after ultra-high pressure treatment.The cells in the aleurone layer were obviously ruptured,a large number of substances in the cells flowed out,and the pericarp became thinner,showing a lamellar structure.2.When the ratio of material to water reaches 1:2.5 under ultra-high pressure,?-The highest content of dextran was 5.78%,and the lowest content of starch was 60.11%;15 min,The highest content of?-glucan was 5.89%,and the lowest content of fat was6.87%;When the pressure reaches 500 MPa,The highest content of?-glucan was4.49%.3.The optimal extraction process conditions for?-glucan obtained by orthogonal method are:temperature 65?,time 3.2 h,material-to-water ratio 1:23,extraction 2times;the purity of the material purified by the optimal optimization process is above96%,The weight average molecular weight of M_Wwas 1.948×10~6.The polydispersity coefficient M_W/Mn is 1.505;HPLC and infrared spectroscopy analysis further proved that the purified product was?-glucan.4.Different pressure and different treatment time can effectively improve the efficiency?-glucan.The highest content of?-glucan was 5.89%when the pressure was500 MPa or the treatment time was 10 min;different treatment times and different pressure treatments do not change the structure of functional groups between?-glucans.5.After UHP treatment,the water activity of oatmeal rice during storage does not change significantly;the rehydration rate is the highest on the 5th day of storage under the treatment of 10 min/500 MPa;the dissolution of amylose decreased with the increase of pressure;the gelatinization curve and data of oats showed that the retrogradation value(SB)of the ultra-high pressure treatment group decreased compared with the blank control group(CK);the texture properties of oatmeal rice are better than CK;comparing the enthalpy(?H)and the degree of retrogradation of rice during storage,the ultra-high pressure treatment group was significantly lower and lower than CK,and tended to be flat at 500 MPa or 10 min;the aging kinetic model shows that the aging rate constant K of CK is 1.5 times that of 600 MPa;the X-ray diffraction pattern of oat rice during the storage period(14 d)showed that the starch crystal form changed from A to B+V,and the crystallization peak was the lowest at 500 MPa.6.The time of UHP treatment was negatively correlated with hardness,cohesiveness,chewiness,?H,retrogradation,maximum temperature(T_P),final temperature(T_C),FV,SB and amylose content;pressure was negatively correlated with hardness,cohesiveness,retrogradation,to,T_P,T_Cand FV;?-glucan content was negatively correlated with hardness,chewiness,T_C,FV,SB and amylose content. |
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