| This experiment uses sweet buckwheat as raw material and adopts the method of alkali to acid sinking preparation to prepare buckwheat protein isolated.On this basis,the experiment tries to study the distribution of buckwheat protein isolated and several important features,including solubility,emulsification,foaming,oil absorption,water absorption to provide guidance and data for the development and utilization of sweet buckwheat resources.1.On the basis of single factor,process parameters are optimized by orthogonal experiment.The optimal conditions can be listed as follows: temperature 25℃,solid-liquid ratio 1:12g/ml,pH value 10,and extraction time 30min.Under the optimized conditions,the extraction yield of buckwheat protein isolate can reach 53.8%.2.The solubility of buckwheat protein isolate rise slowly as the increase of temperature reaching the highest at 40℃,and dropping the lowest at 80℃.Compared with the neutral and alkaline conditions,buckwheat protein isolate is more soluble on the slightly acidic conditions.The change of sucrose concentration shows little effect on the solubility of buckwheat protein isolate.Buckwheat protein isolate is the most soluble when sodium chloride concentration is 0%.3.With the continuous improvement of protein concentration,the emulsifying property of buckwheat protein isolate is gradually improved.When the protein concentration reaches 1%,the emulsifying property is the strongest.The emulsifying property is affected by p H value obviously.The emulsifying ability of buckwheat protein isolate is weak when it is weakly acidic,and strong when the solution is alkaline.With the increase of temperature,the emulsifying ability will be enhanced.The emulsifying ability reached the highest value when the temperature is 20℃.The change of sucrose concentration has little influence on the emulsification of protein.When the concentration of sodium chloride reaches 0.4%,the emulsifying ability becomes strongest.4.With the increasing of protein concentration,the foaming ability of buckwheat protein isolate decreases and the foam stability increases.The foaming ability is nearly not affected by p H,and the foaming ability is stronger than that of alkaline under slightly acidic conditions.But the foam stability is better under slightly alkaline conditions.The increase of sucrose solution has a negative effect on the foaming ability of buckwheat protein isolate,but it shows a positive effect on the foam stability.With the increase of temperature,its foaming ability and foam temperature property gradually increases,reaching the maximum value at 60℃,then foaming ability shows the maximum value at 80℃.With the increase of the concentration of sodium chloride solution,the foaming ability of the protein increases gradually,and reaches the highest value at 0.8%,on this condition,the foaming ability was the strongest.However,for the foam stability of buckwheat protein isolate,the optimal foam stability is at the concentration of 0.4% sodium chloride,and then the foam stability begin to decrease.5.With the increase of temperature,the water absorption of buckwheat protein isolate is enhanced.When the temperature reaches 35℃,the water absorption reaches the highest,then the water absorption decreases when the temperature becomes higher. |
