| With the promotion of the potato staple food strategy in 2015,the development of potato products has attracted the attention of many researchers and is gradually realizing the transformation of potato consumption from non-staple food to staple food.Bread,as a staple food favored by consumers,has a high glycemic index(GI),which is not suitable for patients with chronic diabetes.In this paper,on the basis of guaranteeing the quality of potato bread,more attention is paid to the embodiment of functionality,aiming at developing low-GI potato bread for diabetic population and obese population.The main research contents of this paper include the following three aspects:1.In order to study the effects of different drying methods and different orders of potato on the characteristics of full roux and the quality of potato bread,after fresh potato slices were processed,potato powder was prepared by blanching,steaming and vacuum freeze-drying respectively.The gelatinization characteristics,flavor,flour characteristics and texture and sensory characteristics of potato flour bread were measured.The results showed that the evaporation powder had the lowest regression and disintegration values.The electronic nose can well distinguish the smell of potato powder prepared by three different drying methods,among which the electronic nose of steamed powder has the highest detection response value and the strongest flavor.The addition of steam powder has the least damage to the dough and the least weakening degree.Bread with steam powder has the lowest hardness and the greatest elasticity.The specific volume and sensory scores were the highest.Therefore,the best comprehensive quality of potato bread is made by steam powder.The electronic nose was used to detect potato steam powder with different mesh Numbers and the response values were different,from high to low,60 mesh >,100 mesh ?80 mesh ?120 mesh > 140 mesh.The number of potato flour has a certain influence on the silty properties of the mixed flour,among which the dough with 140 potato flour has the longest stability and better toughness.Potato flour of 80 purposes had obvious odor characteristics,the highest sensory score(80.33 points),larger specific volume(3.69 points)and higher elasticity.Therefore,the 80 purpose steamed and dried potato flour has higher comprehensive quality and is more suitable for the preparation of potato bread products.2.The effects of five fermentation methods on the GI value and bread quality of bread were compared.Potato whole powder replaced high gluten powder with 20%.The effects of fermentation methods on the quality of potato bread were determined by its texture,specific volume and sensory characteristics.Results: direct fermentation method and overnight seed dough method had no significant difference in hardness,adhesion,elasticity and chewing degree(P>0.05),which was better than rapid fermentation method and overnight low-temperature fermentation method.Medium fermentation method had the best specific volume(4.43)and sensory score(89.33).The fermentation method can affect the GI value of bread.The GI value of bread prepared by rapid fermentation is the lowest(87.11),while the GI value of bread prepared by medium fermentation is the highest(112.18).Finally,direct fermentation method was adopted as the follow-up experiment,and the bread produced by direct fermentation method had relatively good quality and relatively low GI value.3.The effects of potato flour replacement ratio,erythritol replacement ratio and inulin,grape seed extract and sugarcane extract on the properties of powder,quality of potato bread and GI value of mixed powder were studied respectively.The orthogonal experiment was carried out to optimize the formula,and the results showed that the optimal formula for low-GI potato bread was as follows: 80 mesh potato steam dry powder replaced high-gluten flour with 20%,inulin 9%,erythritol 4% and sugarcane extract 2%.At this time,the external GI of potato bread was 31.08 and sensory score was 74.33. |
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