Studies On Mass Transfer Mechanism In Reverse Micelle Systems Extraction Of Peanut Protein

Peanuts are one of the world’s most widely used oil crops, which contain40%-50%oiland25%-29%protein, with high nutritional value. In this paper，a new type extractiontechnology of reverse micelle was used for the extraction of peanut protein. The basicproperties of sodium bis (2-ethylhexyl) sulfosuccinate (AOT), sodium dodecyl sulfate (SDS)and AOT/SDS reverse micelle system were researched. The forward and backward extractionprocess, the mass transfer kinetic of backward extraction, and the functional properties andmicroscopic structures of peanut protein prepared by reverse micelle extraction andcommercial alkali soluble acid sinking method were also researched.The basic properties of AOT/SDS composite reverse micelle were researched andcompared with single reverse micelle AOT and SDS. The results showed that with theincreasing of surfactant concentration, the value of W0became larger, the specific viscositygradually increased, and the conductivity of reverse micelles was essentially no change. TheW0，specific viscosity and conductivity of the three reverse micelle system became larger withthe add water increasing. It turned out that AOT/SDS composite reverse micelle could achievea high W0and the specific viscosity was much higher. The composite reverse micelle can bemore stable.Peanut protein forward and backward extraction procedure by AOT/SDS compositereverse micelle was studied. The optimum forward extraction was achieved by quadraticgeneral rotary unitized design. It turned out that the highest forward extraction efficiency ofpeanut protein was reached at KCl concentration0, temperature35℃, pH8.0, the ratio ofAOT and SDS4︰3, ultrasonic power180W, surfactant concentration0.08g/mL, W015. W0has an extremely significant effect on forward extraction ratio. The optimum backwardextraction was reached at pH7.5, time30min，KCl concentration1.1mol/L, temperature35℃. Among them, the influence of pH and KCl concentration to the backward extractionprocess researched extremely significant level.The backward extraction kinetics of AOT/SDS composite reverse micelle was researched.The study found that the dual-mode theory was suitable for the reverse micelle extractionkinetics research, and total mass transfer coefficient was strongly influenced by pH, KClconcentration and temperature. When the value of pH raised from6to7, the total mass transfer coefficient increased from0.68×10-5m3·s-1to0.84×10-5m3·s-1，and when the pHvalue increased from7to8, the total mass transfer coefficient reduced from0.84×10-5m3·s-1to0.60×10-5m3·s-1. Furthermore, the results can be inferred that the reverse micelle backwardextraction kinetic was mainly effected by interfacial resistance，belong to interface controlreaction type.Peanut protein of three kinds of reverse micelle system extraction and commerciallyavailable peanut protein was researched. Experimental results showed that the peanut proteinextracted from reverse micelle system possessed higher water absorption，foaming capacityand foam stability. Scanning electron microscopy map displayed that the shapes of the peanutprotein extracted from the two kinds of method were different and peanut protein particlesextracting from AOT/SDS composite reverse micelle was smaller.