Size Changes of Reverse Micelles after Extraction of Peanut Protein and Their Forward Extraction Rates

Abstract

Abstract: The aim of this study was to detect the size changes of reverse micelles after extraction of peanut protein and their forward extraction rates. Factors that affect the size of reverse micelles and the extraction of peanut protein were also investigated. The size of reverse micelles and the size changes were measured according to the theory of dynamic light scattering under different conditions such as different sodium bis (2-ethylhexyl) sulfosuccinate (AOT) concentrations, pH values, ion concentrations, and salt species. With the increase of AOT surfactant concentrations in a certain range, the size of empty and full reverse micelles increased and the forward extraction rate decreased. The effect of pH on empty reverse micelles was not significant. However, the effect of pH on the full reverse micelle size and forward extraction rate were significant. Its forward extraction rate increased to the maximum 39.6% at pH 7.5. The increase of the salt concentration of a buffer solution in a certain range decreased the size of empty and full reverse micelles and reduced the forward extraction rate of peanut protein. Ionic species had important effects on reverse micelles and peanut protein extraction. An increase in the amount of buffer solution enlarged the empty reverse micelle size in 0.03%‒0.11% (V/V). However, it did not translate to a larger reverse micelle size. The size of the empty reverse micelles containing K2SO4 reached 24.1 nm with a 0.19% (V/V) buffer solution added. The sizes of the full reverse micelles were larger than those of the empty reverse micelles after forward extraction. However, maximum sizes were achieved with the addition of a 0.03% (V/V) buffer solution. The amount of 0.03% (V/V) buffer solution added was appropriate for extracting peanut protein. Supported by National Natural Science Foundation of China (21176058, 31171790, 21376064, 31201293), and Innovation Scientists and Technicians Troop Construction Projects of Zhengzhou City (ISTTCPZZC).