Study On Preparation Of Rubber Seed Protein And Its Application Properties

Rubber seed protein content as high as 35.87%, it can be used as a new resources of high quality plant protein. In order to deepen utilization of rubber seed resource comprehensively and prepare rubber seed protein isolate, extraction process and functional properties of rubber seed protein isolate were researched in this study.The optimal extracting conditions of protein in rubber seed meal was studied by acid alkali mention. Plackett Burman design was applied to study the factors of extraction and it was found that pH, temperature and solid-liquid ratio were the key factors to the extraction. On the basis of single-factor experiments, the extraction conditions were optimized by response surface method. The results show that the optimal extraction conditions of rubber seed protein were as follows:pH 9.8, extraction temperature 65℃ and solid-liquid ratio 1:43.5, acid precipitation pH 4.4. Under the optimal conditions the extraction ratio of protein was 70.64% and the purity of the finished product was 83.56%.The composition and content of the amino acid were analyzed. The SAS-PAGE electrophoresis indicated the rubber seed protein isolate are mainly distributed in the molecular weight of 50 to 60 kDa.The changeable law of rubber seed protein isolate functional properties under different conditions was investigated comprehensively in this study.NSI of rubber seed protein isolate was affected by the pH value, it decreasd before pi and increased after pI. When the temperature rises and the NaCl concentration tends to higher, NSI of rubber seed protein isolate decreases at first while rises later.When the ionic strength increases, the water absorption of rubber seed proteins will decrease at first, while will increase later. Along with the rise of temperature, the water absorption first increases then decreases. Along with the rise of pH, the water absorption tends to fall after rising.The foaming ability and foaming stability of rubber seed protein rising along with the increase of protein concentration. Along with the increase of ionic strength, the foaming ability increased, and the foam stability decreased, when NaCl concentration was less than 0.2 mol/L. Along with the increase of ionic strength, it showed weak foamability, and strong foam stability, when NaCl concentration was more than 0.2 mol/L. Rubber seed protein foaming ability will fall after rising along with the rise of pH. When the temperature falls below 60℃, the foaming ability of rubber seed protein will increase with the rising of temperature. When the temperature is higher than 60℃, foaming ability will decrease with the rising of temperature, Rubber seed protein foaming stability will weaken along with the rise of pH.Emulsification and emulsion stability of rubber seed protein isolate will increase along with the increasing of protein concentration. Less than 0.2 mol/L NaCl concentration, Emulsification and emulsion stability increase with the increase of ionic strength. More than 0.2 mol/L NaCl concentration, emulsification and emulsion stability decrease with the increase of ionic strength. Emulsification and emulsion stability of rubber seed protein isolate will fall after rising along with the rise of pH. When the temperature falls below 60℃, emulsification and emulsion stability of rubber seed protein isolate will increase with the rise of temperature, and when the temperature falls below 60℃, rubber seed protein emulsification and emulsion stability will decrease with the rise of temperature.Temperature of rubber seed protein has a great influence on oil absorption,30-50℃, rubber seed protein, low oil absorption, when the temperature is above 50℃, oil-absorbing rubber seed protein will increase with the rise of temperature.The Least Gelation Concentration Endpoint of Rubber seed protein isolate is 10%, and the gel strength increase with elevated protein concentration, after the first increased with the increase of NaCl concentration, gel strength biggest in 0.3 mol/L. When it’s heated to 85℃, 60 min gel strength larger rubber seed protein gel can be obtained.