Extraction of protein from high-temperature peanut meal using combination process with steam flash-explosion, alkaline-extraction and acid-precipitation

A combined process with steam flash-explosion, alkaline-extraction and acid-precipitation was used to extract protein from high-temperature peanut meal.Through single factor and orthogonal test, the optimum conditions were figured out.Firstly, the high-temperature peanut meal was soaked in 0.3% sulfuric acid solution at 60℃ for 2h, then drained it and washed with water to remove the acid solution remained in the surface of the meal.The pretreated meal was treated with steam flash-explosion at 1.6MPa for 5min.The protein in the steam flash-exploded meal was extracted by alkaline-extraction and acid-precipitation process.The optimal condition for alkaline-extraction was solid to water ratio:1∶12 (g/mL) , pH9.5, 60℃ and 2h.Under these conditions, the protein extraction rate reached 52.6%, which was 10.8% higher than conventional alkaline extraction and acid-precipitation process.The water holding capacity, emulsifying activity index, foaming capacity and foaming stability of the protein extracted using this combined process were significantly improved, which increased by 67.1%, 141.0%, 131.3% and 107.4% respectively.R esults showed that the combined process with steam flash-explosion, alkaline-extraction and acid-precipitation was appropriate for extracting protein from high temperature peanut meal, which could increase the protein extraction rate and also improve the functional properties.