Differential Centrifugation of Peanut and Soybean Protein Concentrates as Influenced by Preparation Technique and Heat Treatment1

Abstract

Abstract Protein extracts prepared from defatted Florunner peanuts and Cobb soybeans were dried by spray-, freeze- and drum-drying techniques. Differential centrifugation was performed on 1.0% protein dispersions at 2,000 and 40,000 x g for 20 min at 24°C and at 200,000 × g for 1 hr at 15°C Lowest supernatant protein content under all centrifugation conditions studied was observed in drum-dried protein preparations. Increased centrifugal force from 2,000 to 40,000 × g only slightly affected supernatant protein in freeze-dried and spray-dried oilseed preparations and did not affect drum-dried preparations. Heat treatment (70°C for 30 min) of the protein dispersions increased supernatant protein (2,000 and 40,000 × g) for spray-and drum-dried peanut, and for all soy protein preparations. Heat treatment only slightly affected ultracentrifuge supernatant protein. Sepharose 6B gel filtration indicated four major fractions in spray- and freeze-dried peanut preparations and three major fractions in spray- and freeze-dried soy protein preparations.