Clyde T. Young

Comparison of fatty acid content of imported peanuts

Variability in fatty acid compositions of peanuts imported from six different countries into the United States were studied to determine their effect on processing and storage conditions. The oil content ranged from 44.1 to 50.4%. Major fatty acids, palmitic acid (C16:0), oleic acid (C18:l), and linoleic acid (C18:2) ranged from 8.6 to 12.7, 35.9 to 61.1 and 21.7 to 44.2%, respectively. Oleic and lino-leic acids together comprised ca. 78.0–83.0% of the total fatty acids. Highly significant differences (P<.01) in fatty acid compositions were obtained between samples and between locations (countries of origin). Indicators of stability of the peanut samples as measured by the oleic/linoleic acid ratio (O/L) and iodine value (IV) of the extracted peanut oils showed variable but significant differences (P <.05) between locations. Generally, higher O/L ratios corresponding to lower IV indicate better stability and longer shelf-life of the samples.

Factors affecting peanut butter preference

A sensory evaluation test with 320 subjects provided information pertinent to the preference of peanut butters. Results of paired preference test indicated that more than half the subjects (59%) preferred the “old fashioned” sample; flavor (aroma and taste) would have to be the primary reason since particle size was nearly the same in the prepared test samples. Chi-square tests of independence showed that the preference for the “old fashioned” sample was dependent on age (P<.05) and sensory attributes of flavor and textural perception (P<.05). Results of the survey showed that 47% of the total responding subjects listed “crunchy” peanut butter as their favorite type. Selection of one’s favorite brand of commercial peanut butter was found to be based primarily on its particle size.

Peanut Quality: Effects of Cultivar, Growth, Environment, and Storage

The peanut, Arachis hypogaea L., has its origin in the Andes of South America and was part of the native diet in the sixteenth and seventeenth centuries throughout the Caribbean area (Hammons 1982). Its route of introduction to the New World seems to trace through South Africa, Europe, the Middle East, and finally to the North American colonies. Although the peanut is commonly known and used in the diet, the understanding of its reproduction has a long history of confusion in the literature because of the uncommon relationship between aerially borne flowers and subterranean fruits. The relationship between the flower and fruit was not fully clarified until 1950 (Gregory et al. 1973). Gregory et al. (1973) also point out that misinformation may still be found in the literature on this subject as late as 1969.

Ultrastructural Development of Starch Granules in Peanut (Arachis hypogaea L., NC 7) Cotyledonary Cells1

Abstract Peanut cotyledonary cells were observed with transmission and scanning electron microscopy during starch granule formation. Developing starch granules were primarily electron translucent, and both simple and compound granules were observed. Fully developed starch granules were observed during both early and late stages of seed development. Major findings include observation of electron dense materials within the stroma of developing starch granules that may be ultrastructural evidence of the location of enzymes involved in the synthesis of starch.

Histochemical Localization of Amino Acids and Sugars in Peanut Cotyledons for Light Microscopy1

Abstract Light microscopy staining methods for amino acids and sugars were adapted for glutaraldehyde vapor-fixed, freeze dried, plastic embedded tissue of peanut cotyledons (Arachis hypogaea L.). These methods revealed the locale of amino acids and sugars, which are regarded as precursors of roasted peanut flavor compounds. Amino acids were localized in the protein bodies and cytoplasmic network by Coomassie Brilliant Blue G-250, Orange G, and diacetylbenzene. Sugars were localized in the protein bodies and cytoplasmic network by Alcian Blue - PAS procedure and an adaptation of the Okamoto method for sugars. Localization of the amino acids and sugars provide further evidence to the importance of the protein bodies in the cotyledon in the production of roasted peanut flavor.