The Studies On Preparation And Application Of Peanut Protein Concentrate

Peanut is a kind of oil crop which contains high fat and high protein. Cold-pressedpeanut cake from low temperature pressing has low degeneration degree. Those cold pressingcakes have high residual oil rate (about8%) while their protein content is relatively low(about50%-55%), which limits their applications in food processing industry. In view ofthose problems, this paper used the cold-pressed peanut cakes as raw materials and preparedpeanut protein concentrate (PPC) by ethanol washing, then the emulsion was modified andwe got the better functional modified peanut protein concentrate (MPPC). Moreover, theirapplication in emulsified meat products is discussed. From those studies, this article aims toprovide more comprehensive theoretical basis in the productions of peanut proteinconcentrates.This subjects aims at producing peanut protein concentrate by ethanol elution methodfrom cold-pressed peanut cake. The effects of ethanol concentration, extraction temperature,extraction times and the ratio of solid to liquid on the protein content were investigated. Theparameters of extraction process were optimized through response surface test. The bestextraction condition is ethanol concentration of the first-time elution72.63%, temperature60℃, time75min, the ratio of liquid to solid ratio7:1, reduction ratio70, ethanol concentrationof the second time elution90%, with other conditions remaining constant. Under this bestoptimized conditions, the peanut protein concentrate product has a protein content of66.24%(N×6.25, dry base) and a protein yield of93.32%.Alcohol leached peanut protein concentrate was modified by water-bath heating underthe alkaline condition. The influences of pH, the temperature, the time, the ratio of liquid tosolid on emulsifying ability and emulsion stability were investigated. The parameters ofmodification process were optimized through response surface test. The best modificationcondition is pH9.5, heating temperature82.6℃，heating time20.4min, the ratio of liquid tosolid (v/w)7.7. Under this best optimized condition, emulsifying ability is increased47.1%,emulsion stability increased is75.8%. Functionalities of alcohol leached peanut proteinconcentrate which was modified by water-bath heating were improved under the alkalinecondition, except slightly low gelatin hardness. This indicates the feasibility to increase theemulsifying ability and emulsion stability of peanut protein concentrates by hot alkalimodified. Hot alkali modified alcohol leached peanut protein concentrate, compared withfunctional soybean protein concentrates (FSPC), shows better functional properties in otheraspects, except weaker water-holding capacity and slightly low gelatin hardness. At theaddition rates of MPPC in3%to4%, the emulsified comminuled meat products achieve thebest evaluating results in yielding rates and texture profile property, with a stuffing effectapproaching or exceeding that of the FSPC that is broadly applied in meat products. Thisindicates the feasibility to use MPPC to partly supplicate FSPC in emulsified comminuledmeal products. The relativity analysis indicates that between the protein adding rates and theemulcified comminuled meat products’ texture profile properties there are relativities; thereare also certain extents of relativity between every index of gel texture profile properties.