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Headspace volatiles from ground roasted Florunner medium peanuts, stored at 65ЊC for 1-68 days, were separated and identified by GC/MS. Selected pyrazines, resulting from Maillard browning and selected aldehydes from autoxidation were evaluated to determine their mechanistic contributions to peanut 'flavor-fade.' The 2,6-dimethylpyrazine, 2-methylpyrazine, 2-ethyl-5-methyl or 6-methylpyrazine, 2,3,5-trimethylpyrazine, and pentanal remained constant during storage (p Ͻ 0.05). Flavor scores for 'roasted peanut' decreased slightly, then leveled off and hexanal, heptanal, octanal and nonanal increased during storage (p Ͻ 0.05). Oxidative 'rancid' flavor scores and thiobarbituric acid values also increased during storage (p Ͻ 0.05). Based on results, the 'flavor-fade' of stored roasted peanuts is due to masking of pyrazines and other 'roasted peanut' flavor compounds by large quantities of low-molecular weight aldehydes from lipid autoxidation, and not due to polymerization and/or degradation of the pyrazines.

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Soybean (Glyciiae omax L.) cotyledon callus grown on radioactive 2,4-dichlorophenoxyacetic acid (2,4-D-l-14C) as an auxin produced 2, 4D metabolites, which qualitatively and quantitatively changed with time. Water soluble fractions from the tissue exhibited a steady increase in radioactivity during the course of 24 days. Following p-glucosidase treatment, at least eight aglycones were obtained from the water soluble fraction of the tissue after 8 days. The metabolite, 4-hydroxy-2, 5-di-chlorophenoxyacetic acid was the most abundant aglycone during the entire 32 day growth period while 4-hydroxy-2,3-dichlorophenoxyacetic acid was detected as a minor metabolite. Radioactivity in the ether soluble acidic fractions reached a maximum of 82 % of the total in the tissue after 2 days. The level then decreased to 44% by the end of 24 days. A total of seven ether soluble components were detected. In addition to 2,4-D glutamic acid, which was detected in high amounts after 24 hours, 2,4-D aspartic acid was found to be the most abundant ether soluble metabolite after longer time periods. Mass spectral data and a fragmentation pattern are presented for 2,4-D aspartic acid. In a previous paper, we described the isolation and identification of several 2, 4-D metabolites after a 48-hr incubation of soybean callus tissue in sterile aqueous 2,4-D-l-14C (4). Two aglycones produced by /-glucosidase treatment of water soluble fractions were identified as 4-OH-2 , 5-D2 and 4-OH-2, 3-D. In addition, an ether soluble metabolite was identified as 2,4-D glutamic acid. In this paper soybean callus tissue was grown on a complete medium using 2,4-D-1-14C as the auxin. Under these more physiological conditions changes in the relative abundance of the various 2, 4-D metabolites in the callus were observed. 'Contribution No. 78 from the Department of Biology, The Pennsylvania State University and Paper No. 4047 from the Pennsylvania Agricultural Experiment Station. 2Abbreviations: 4-OH-2, 5-D: 4-hydroxy-2, 5-dichlorophenoxy-acetic acid; 4-OH-2, 3-D: 4-hydroxy-2, 3-dichlorophenoxyacetic acid; NAA: a-naphthaleneacetic acid; 2,4-D-Cl: 2 .4-dichloro-phenoxyacetyl chloride. MATERIALS AND METHODS Tissue Culture Techniques and Assay. Soybean (Glycine max L. Merrill var. Acme) cotyledon callus stock cultures were grown on an agar solidified medium of Miller (10) with 3% sucrose, NAA (2.0 mg/l) and kinetin (0.5 mg/l). The stock tissues were grown under fluorescent light at 27 C for approximately 4 weeks. For the auxin assay experiments, the metabolites of 2,4-D were incorporated into the basal medium minus NAA prior to autoclaving (15 min, 121 C, 15 psi). Three small pieces of soybean callus (approximately 5 mg) were planted aseptically on the solidified medium (50 ml in 125-ml Erlenmeyer flasks) and cultured under the same conditions as for the stock tissue. After 28 days growth the tissues were removed from the agar and weighed. Growth of Soybean Callus in Medium Containing 2,4-D-1-'4C. Three pieces of callus (approximately 200 mg each) were aseptica...