Extraction, Functional Properties And Application Of Chinese Chestnut Protein

The extraction technology of chestnut protein was optimized, and the composition of crude chestnut protein was analyzed in the present study. Subsequently, the functional properties of chestnut protein in several kinds of system conditions were analyzed, and the application of crude chestnut protein in particular food system was explored. The main results are as follows:(1) Through single factor experiment and response surface methodology, the extraction parameters of chestnut protein were optimized:the ratio of material to liquid was 1:15, the extraction temperature was 40℃, the extraction time was 83 min. the extraction of pH was 10, and the ultrasonic time was 14 min. Under above conditions, the extraction rate reached 65.38%.(2) The primary nutrients of crude chestnut protein were analyzed to be 75.7% of protein,9.02% of total sugar,6.43% of water and 4.8% of ash.(3) The solubility of chestnut protein showed a V-shaped curve within the pH range of 2-12. The solubility of protein was the lowest at pH 4, and became soluble at high pH. Protein solubility reached the highest value at 60 ℃. At the same ionic strength, NaCl was more effective than CaCl2 in increasing protein solubility.(4) At the pI value (pH 4.1), the protein showed the lowest foam capacity and highest foam stability. The addition of CaZ+ could greatly improve the foam capacity and stability of chestnut protein. The effect of Na+ on foam capacity and stability was not significant. Sugar showed an inhibitory effect on foam capacity but a significant effect on promoting foam stability.(5) A consistent relationship between pH-protein solubility and pH-emulsion activity was observed. The effect of ionic strength was not significant on protein emulsifying properties. At low ionic strength, the emulsion stability was better than high ionic strength. At the sucrose concentration of higher than 1%, the increasing of sugar concentration inhibited the emulsion activity. The emulsion stability increased with the increasing of sugar concentration.(6) Near the isoelectric point, chestnut protein showed the lowest viscosity. The viscosity increased with the increasing of protein concentration. At the ionic strength of 1.0mol/L, the chestnut protein showed the highest viscosity (1.21mPa·S).(7) The chestnut protein was turned out to have good emulsion properties, so salad sauce system was chosen for the application of chestnut protein. Sodium caseinate and yolk powder in salad sauce was partially replaced by chestnut protein, and then the properties of salad sauce were analysed. The results showed that the optimal alternative amount for chestnut protein was 50%.