The effect of dry roasting on proteins of the peanut reserve protein, a-arachin, increased in electrowas investigated by chromatography on DEAEphoretic mobility but maintained its antigenic cellulose, polyacrylamide gel-electrophoresis, imstructure. Both dissociation and association OCniunoelectrophoresis, and ultracentrifugation. Sevcurred, as evidenced by sedimentation analysis. All era1 basic changes apparently resulted from roasting.other proteins show modified physicochemical The solubility of the proteins in phosphate buffer properties, some with changes in primary and/or was reduced t o less than one half. The major secondary structures.he use of oilseed proteins for nutritional purposes has come into prominence because of the needs of T an expanding world population. Modern research in the food industry is elucidating the biochemical changes affecting taste, odor, texture, and nutritive value of these proteins under various processing conditions. Basic research on the peanut proteins has been going on for over a hundred years. The two major globulin fractions, arachin and conarachin, were first isolated by Johns and Jones (1916). Subsequent studies by several investigators (Dechary et d., 1961; Johnson and Naismith, 1953; Johnson and Shooter, 1950; Johnson et al., 1950; Tombs, 1965) further characterized these proteins by precise analytical methods. The findings of Dieckert et a/. (1962) and Daussant et c t / . (1967) suggest that a-arachin (the niajor component of the arachin fraction) is located in the protein bodies and that ai-conarachin (the major component of the conarachin fraction) is dispersed in the cytoplasm.The erect of heat on plant proteins has been studied in relation to taste, odor, and nutritive value. For example, Newel1 et ul. (1967) reported biochemical changes attributing to "typical" and "atypical" roasted peanut flavor. They suggested a possible reaction between sugars and amino acids to produce specific flavor components (pyrazine derivatives). Bensabat et ul. (1958) found that cooking peanuts in 5.6 to 6.0% moisture for one hour at 232-234" F. caused a drop from 3.4 to 2.8 grams of lysine (per 16 grams of nitrogen). Protein deterioration during processing could be measured by following the decrease in free epsilon-amino groups of lysine. Evans and Bandenier (1967) showed that the nutritive value of sunflower seed proteins decreases after heating. Others have shown that certain limiting amino acids in chickpea proteins are further reduced on autoclaving (Gonzalez del Cueto et a/., 1960).Roasting of whole peanuts is a prerequisite in the nianufacture of candies and peanut butter. Normally, one would expect heating to denature irreversibly all of the proteins, especially those having enzymic and/or antigenic properties. The aim of this study was not to elucidate the -___ Southern Regional Research Laboratory, New Orleans. L d . 70119prlxise reactions induced by heating per se, but to investigate the physicochemical changes in proteins with respect to their structure, funct...
