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Abstract. Fourteen antigenic constituents have been detected in A rachis hypogaea seeds. The major proteins of the classic arachin and conarachin fractions have been identified. Arachin contains 4 antigens (the major one called a-arachin) and conarachin contains 2 which have been called a,, and a2-conarachin. Structural differences between a-arachin, a1 and a2-conarachin are indioated by their different antigenic specificities. a-Arachin precipitates as a separate entity at low temperature. The action of trypsin on this protein induces an increase in electrophoretic mobility and prevents precipitation at low temperature. This enzyme has no detectable effect on a., and a,-conarachin.The proteins of the ootyledon and of the entire axis are quite similar in their immunoelectrophoretic patterns. However, quantitative and qualitative differences oocur between the proteins found in the cotyledon and those of the 1-millimeter tip of the axis. In the latter, there is a 4-fold smaller proportion of a-arachin than in the cotyledon. Immunoelectrophoretic analysis of subcellular preparations from cotytedons confirms that a-arachin is an aleurin and that c1-conarachin is a typical cytoplasmic protein. Large and small aleurone grains appear very similar in their qualitative antigenic composition.Proteins extracted from mature seeds of Arachis hypogaea appear heterogeneous by chromatography on DEAE-cellulose, ultracentrifugation and polvacrylamide gel electrophoresis (7, 10). Moreover, 2 of the reserve proteins, a-arachin and a-conarachin, associate or dissociate under different conditions of pH and ionic strength (17,18,19) to make the precise identification of individual components difficult or even uncertain. The fact that these 2 proteins exhibit similar electrophoretic mobilities (16) suggests structural similarities.Because of their high degree of specificity, immunological methods offer another approach for the study of peanut proteins. A general picture of the total proteins was established and the 2 major reserve proteins were characterized after submission to phys-

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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...