Study Of High Value Use Of The Peanut Protein Meal By Low-temperature Pressing

Peanut is very used widely in China, as one of the major oil crops, the quantity of peanut meal from oil manufacture is very large. Except a very small amount of it is used as protein additive, the most principal use of peanut meal is animal feeds, which wastes lots of protein and dietary fiber resources in it. The low-temperature peanut protein meal produced by the low-temperature oil extraction technology, with high nutritional and functional value, makes the further utilization of it possible.In this thesis, the technology of peanut protein concentrate and peanut isolate were systematic studied and optimized, the functional properties of peanut protein concentrate produced were evaluated, then further discussed modified methods of the gelation of peanut protein concentrate and its application. At last, the way of making use of the residue after extraction of proteins wre studied. The main results are as follows:1. Used alkaline extract and acid coagulation way to extract peanut protein concentrate. By single factor experiments and RSM evaluation of the alkali extract and acid coagulate extraction method, the protein extraction process parameter were optimized, the optimal protein extraction process parameter were:extract temperature at 50.49℃, pH8.57, solid to liquid ratio 0.11, the proposed protein yield was 46.57%; after comprehensive comparison of the homemade peanut protein concentrate with the peanut protein concentrate, soybean protein concentrate commercially available, the physical and chemical properties of the homemade peanut protein concentrate Can meet the requirements of the market condition;2. Use three common methods of physical protein modification:heat treatment, ultrasonic treatment and microwave treatment to treat peanut protein concentrate. By measuring the free sulfhydryl content (-SH), disulfide (-SS-) content and surface hydrophobicity index (So), analyze its variation to response the gelation property. In the three kinds of treatments, ultrasonic treatment is more effective than heat treatment, while microwave affects little. When the ultrasonic processing power is 1000W, processing time at 8min, the sequel is the best, with free sulfhydryl content hoist to 11.20μmol/g, disulfide bond reduced to 22.18μmol/g, and the surface hydrophobicity index(So) is 10.09;3. Under different ionic strength, pH conditions, peanut protein concentrate/ modified peanut protein's LEG(The least Gelation Concentration Endpoint concentrate) is different. The LEG were evaluated under various conditions, the lowest peanut protein concentrate's LEG was 16%, ultrasound treatment modified peanut protein concentrate's LEG was 14%-16%; different pH and ion type conditions were compared, it was found that under the condition of pH7.0, the existence of ion is unfavourable for the protein to form strong gel, the gel hardness was significantly higher at pH3.0 rather than 7.0, ultrasonic modified protein behaved the largest influence; the addition of ions had no significant effects on the flexibility and adhesion propertys of protein, but the existence of ions is opportune for the protein to form better gel;4. The total dietary fiber and protein contents in the treated peanut residue are 64.21% and 23.14%. Take Single factor and orthogonal experiments to form the optimal dietary fiber biscuit recipe:peanut residue of grinding degree is 180 mesh, the amount of peanut residue added is 5% of the flour's addition, sugar addition is 110g, oil dose is 140g.