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

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.