Influence Of High Pressure Microfluidization On The Functional Properties Of Arachin And Its Mechanism Study

Arachin, a salt soluble protein, is one of peanut storage protein components. It accounts for 73% in total peanut protein and its sedimentation coefficient is 14S. In this paper, arachin extracted from peanut seeds using saturated ammonium sulfate precipitation was modified by high pressure microfluidization. The effect of high pressure microfluidization on functional properties and its mechanism of arachin were studied. The results were as follows:(1) Effect of high pressure microfluidization on the functional properties of arachin: solubility, foaming capability and emulsifying property of 2%, 4% and 6% arachin treated by high pressure microfluidization were improved to a certain extent, increased with the elevation of treatment pressure, whereas started to decrease when they reached a maximum value at a certain pressure. Meanwhile, the rheological models of 2%,4% and 6% arachin treated by high pressure microfluidization were transformed into approximate Newton fluid from pseudoplastic fluid.(2) Effect of high pressure microfluidization on the microstructure of arachin: high pressure microfluidization treatment was capable of leading the arachin particles to pieces. As a result, the average particle size became smaller and the particle size distribution became narrower. This phenomenon was remarkable when treatment pressure is lower than 80MPa, however, when the pressure is greater than 80MPa, particle size began to recover slowly and the particles size distribution became wide. At the same time, the microcrystal structure was damaged slightly, the thermal stability decreased and the energy for denaturation reduced.(3) Effect of high pressure microfluidization on molecular structure of arachin: Nearly no changes occurred in subunits and molecular weigh of arachin while its secondary structure and conformation were modified significantly; Surface hydrophobicity was enhanced as treatment pressure increasing; free sulphydryl content decreased as treatment pressure increasing and and the minimum of free sulphydryl content appeared after treatment at 120MPa;α-helix andβ-turn content decreased significantly, wheasβ- sheet and random coil content increased.(4) The mechanism analysis of high pressure microfluidization on the effect of functional properties of arachin: high pressure microfluidization was capable of partially change microstructure and molecular structure of arachin. After high pressure microfluidization treatment, its particle size decreased; crystal structure was destroyed; thermal stability reduced; surface hydrophobicity increased; free sulphydryl content decreased; secondary structure and senior structure were changed. It was possible that these modifications caused the change of functional properties of arachin.