Abstract:

Alkaline extraction and subsequent acid precipitation were employed to produce peanut protein isolate from lowtemperature
peanut meal as a byproduct from the production of cold-pressed peanut oil, and the preparation process was
investigated. The results showed that when the extraction process was carried out at 55 ℃ for 2.5 h at an alkali pH of 9.5
with a solid-to-solvent ratio of 1:11 (g/mL), the maximum extraction yield of 90.25% was obtained. SDS-PAGE analysis
indicated that electrophoretic bands of the peanut protein isolate were consistent with the typical bands of peanut proteins.
Then, some functional properties including nitrogen solubility index (NSI), emulsifying activity and emulsion stability of
this protein isolate were analyzed. Particle size analysis showed that the average particle size D[4,3] was 4.31 μm, and the
slope for dynamic particle change, as checked by a stability analyzer, was 26.66%/h. The beverage prepared from the peanut
protein isolate had a significant stability. This study may provide a new direction for the value-added utilization of peanut
meal protein.

Key words: cold-pressed peanut cake, peanut protein isolate, peanut protein drink, particle size, stability