Study On The Modification Of Peanut Protein And Its Application In Food

Peanut oil by direct cold pressing could produce defatted or semi-defatted peanut protein flour, which could provide abundant nutrients, low fat. Peanut protein flour is beneficial to human’s health and is a high quality edible protein, however, protein content was relatively low, functional properties like emulsibility and gelation was not very well. Its application in the food industry was limited. In this present paper, taken defatted peanut flour as a raw material, prepared the peanut protein concentrate (PPC) by alcohol extraction, and then digested by bromelain. The digested hydrolysate was added it to noodle and meat minced production, and preliminary discussed the application of it on the pasta product and meat product processing, which were for the purpose of laying a foundation for further enhancing the application of peanut protein and its production on food industry.This exeriment adopt ethyl alcohol extraction for twice method to prepare peanut protein concentrate. The optimum processing condition of peanut protein concentrate was determined by orthogonal test. The results showed that a solid-to-liquid ratio of 1:12(m/v), an ethanol concentration of 75%, at 50℃, 1h, for the primary extraction and a corresponding list of variables of 1:8(m/v), 90%,30℃and 30min, for the secondary extraction were found to be optimal for the protein extraction from the defatted peanut protein flour. In this way, the protein content of the PPC achieved 73.2%, and the extraction rate was 81%.Peanut protein concentrate was subjected to digested by bromelain. The optimum processing condition of peanut protein concentrate was determined by orthogonal experiment. The results showed that added ratio of bromelain was 6%, substrate was 5%, reaction temperature was 55℃, for 1.5h, 4000rpmin centrifuged 20min. Macromolecular proteins and peptides of PPC were mainly hydrolyzed into micromolecule peptide and subunit under 23kD. In this way, the emulsibility of peanut protein concentrate hydrolysate(PPCH) increased to 72.6%, emulsifying stability had been increased to 97.2%, its water binding capability and fat binding capacity of PPCH is also more significant improvement, respectively, to 177.8% and 275.2%.Peanut protein and its products was mixed with wheat flour, adding certain amount of glutamine transaminase(TGase) for noodles processing. The optimum condition of processed noodles was determined by orthogonal test and sensory evaluation. The results showed that the noodles had best characteristics when added ratio of PPCH was 8%, the percentage of TGase was 0.5%. The noodles’quality and nutritional value were effectively improved after adding PPCH.Peanut protein and its products was mixed with chicken and beef minced for meat minced processing. The optimum condition of processed noodles was determined by steaming yield, sensory evaluation and texture properties. The results showed that when added ratio of PPCH was 10%, the chicken minced had best characteristics, diminished offensive smell,good color and luster,and much better hardness and gelation; for beef minced, which had best characteristics when the added ratio of PPCH was 12%, the quality and nutritional value were effectively improved.