Effects of Pretreatment on the Yield of Peanut Oil and Protein Extracted
by Aqueous Enzymatic Extraction and the Characteristics of Emulsion
Abstract
Peanut was crushed by dry comminution and wet comminution, and effects
of comminution on peanut particle size and yield of peanut oil and
protein were analyzed. The properties (surface protein concentration,
particle size, and ξ-potential) of emulsion were compared. Moreover,
different demulsification methods were used to investigate the stability
of the emulsion. Results showed that yield of peanut oil and protein
reached highest (87.23% and 82.05%, respectively) at dry comminution
72 s. At wet comminution 120 s, yield of peanut oil and protein was
89.91% and 84.70%, respectively, which were both higher than that of
dry comminution significantly (P < 0.05). The surface protein
concentration and ξ-potential of emulsion made by dry comminution (DCE)
was 7.02 mg/m2 and 12.08 mV, respectively, and that was 10.71 mg/m2 and
15.25 mV of emulsion made by wet comminution (WCE), which were
significantly higher than that of DCE (P < 0.05). The volume
average particle size (D(4,3)) of DCE was 3.41 µm, which was
significantly higher than D(4,3) of WCE (3.18µm, P < 0.05).
Collectively, results of emulsion properties indicated stability of WCE
was higher than DCE. Further, demulsification rate of DCE was
significantly higher than that of WCE treated by freeze-thawing, pH,
Papain, and Phospholipase A2 (P < 0.05). Demulsification
effect of Alcalase 2.4L was best in these five demulsification methods,
and demulsification rate of DCE reached 92.77%, slightly higher than
WCE (92.67%), further illustrated stability of WCE was higher than DCE.