| Quinoa is called “pseudo grain” not only because of its dicotyledon similarity with grain in terms of plant composition and functional characteristics,but also because of its relatively balanced nutrition,so it is also known as “the mother of food” and “the king of vegetarian diet”.Sprouted quinoa is richer in nutrients,especially the content of bioactive substances such as polyphenols,flavonoids,?-aminobutyric acid(GABA)will increase,germination not only improvs the nutritional value of quinoa,but also reduces the content of anti-nutritional factors(phytate,saponin,etc.)to a certain extent,and improved the bioavailability of quinoa.The application of quinoa in food is mainly in pasta,cakes,beverages,etc.,and sprouted quinoa products are still a vacancy,so the study of sprouted quinoa will have great practical significance.In this study,Gansu Tianzhu quinoa was used as the raw material,and quinoa was germinated at 20? to study the germination ability and the changes of various nutrients during the germination of quinoa.Study on the structure and physicochemical properties of quinoa starch in different germination stages.On this basis,the optimal process conditions for spray drying sprouted quinoa flour were explored,and the effects of different heat treatments on sprouted quinoa flour were studied through flushing and blending characteristics,in vitro digestion characteristics,and sensory evaluation.In order to prepare a sprouted quinoa powder with rich nutritional value and good taste.The main results are as follows:1.By analyzing the germination ability of quinoa and the change law of nutrients during germination,the germination rate of quinoa can reach 97%,the elongation of radicle at the end of germination was 40?50 mm,and the volume of quinoa particles gradually decreased;The activities of total amylase and ?-amylase increased;the contents of total starch,soluble dietary fiber and saponins decreased;the contents of total sugar,reducing sugar,total dietary fiber,insoluble fiber,total phenols and flavonoids increased gradually;the content of amylose it showed a trend of first increase and then decrease;the changes of soluble protein and crude fat content showed a trend of first decrease and then increase.Comprehensive consideration,48 h of germination of quinoa was relatively high in nutrient content,rich in nutritional value,and relatively low in saponin content.Finally,48 h of germination was selected as the best time for subsequent germination of quinoa powder.2.Effects of germination treatments on quinoa starch.Germination treatment significantly reduced the particle size and crystallinity of starch granules,the order of starch granule structure was disrupted;while solubility,attenuation value,gelatinization temperature,and gel strength all increased with the increase of germination time(P<0.05),swelling force,viscosity value,the gelatinization enthalpy gradually decreased(P<0.05),and the retrogradation value increased first and then decreased;germination enhanced the pseudoplastic fluid properties of starch,and with the extension of germination time and shear rate increased,the starch paste appeared shear-thinning.3.Taking the flour yield and moisture content as the investigation indexes,the response surface optimization test design was carried out on the four factors of inlet air temperature,outlet air temperature,material concentration and feed quantity,and combined with the feasibility of the method and the convenience of practical operation.The conditions were set as inlet air temperature of 172?,outlet air temperature of 70?,material concentration of 16% and feed volume of 15 m L/min.Under these conditions,the powder yield was 47.28% and water content was 3.89%.4.Using the germinated quinoa flour obtained by spray drying,frying,extrusion puffing,and hot air drying as raw materials,the differences in reconstitution,in vitro digestion characteristics,and sensory evaluation were compared and analyzed.The results show that,compared with the raw powder,the heat-treated brewed powder has a more significant change in color,the brightness value is decreased,the red/green and yellow/blue values are increased,and the WSI,stability coefficient,gelatinization viscosity and retrogradation value are all significant.Increase(P < 0.05),WAI,dispersion time,attenuation value were significantly decreased(P < 0.05),in terms of agglomeration rate,the agglomeration rate of sprouted quinoa powder after spray drying was the smallest;The gelatinization temperature of germinated quinoa flour increased after heat treatment;dynamic rheological properties showed that the G? of all samples was greater than the G?,and the samples exhibited weak gel properties;the results of in vitro starch digestion showed that all samples exhibited hypoglycemia The index food was generated,in which the starch digestibility of spray-dried decreased by 9.1%,and the e GI was the lowest of49.31;the sensory evaluation results showed that compared with the other three heat treatment methods,the spray-dried sprouted quinoa powder had the highest comprehensive score(8.5),and it was easier to let consumers accept it. |
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