Abstract:The arachin/conarachin-rich fractions were isolated from the defatted peanut flour by cryoprecipitation, and the physicochemical and functional properties of both fractions were studied. The protein contents of arachin/conarachin fractions prepared by cryoprecipitation were 91.27 and 84.87%, respectively, while the corresponding protein purities were 93.1 and 71.4%, respectively. The study results indicated that the arachin-rich fraction prepared by this method had a lower degree of thermal denaturation and higher thermal stability compared with the conarachin-rich fraction and peanut protein isolate (PPI). Conarachin-rich fraction and PPI had a more loose tertiary conformation and surface hydrophobicity compared to the arachin-rich fraction. The arachin-rich fraction showed the highest solubility in the entire pH range except at pH 6.0; however, the solubility of the conarachin-rich fraction was the most susceptible to change in pH value between 3.0 and 6.0. The arachin-rich fraction showed the highest emulsifying activity and stability, followed by conarachin-rich fraction and PPI. The conarachin-rich fraction exhibited the best heat-induced gelation properties at neutral pH, followed by the arachin-rich fraction and PPI.
