JOURNAL OFFERMENTATION AND BIOENGINEERING Vol. 80, No. 1, 104-106. 1995 Production of the Edible Fungus Huitlacoche (Ustilago zyxwvutsrqponmlkjihgfedcb maydis): Effect of Maize Genotype on Chemical Composition PABLO EMIL10 VANEGAS,’ MARIA ELENA VALVERDE,’ OCTAVIO PAREDES-LOPEZ,‘* AND JERALD K. PATAKY2 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIH Centro de Investigacidn y de Estudios Avanzados-IPN, Depto. de Biotecnologia y Bioquimica, Apdo. Postal 629, 36500 Irapuato, Gto., Mkxico’ and University of Illinois at Urbana-Champaign, Dept. of Plant Pathology, Urbana, IL 61801, USA2 Received 14 November 1994/Accepted 31 March 1995 zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQP Huitlacoche was produced by injection of two compatible isolates of Ustilago maydis into ears of 19 maize hybrids and analyzed for proximate composition and fatty acid content. Protein content ranged from 10.0 to 14.5% (dry basis) and fat content from 2.7 to 6.5%. Samples showed high contents of oleic and linoleic acids. [Key words: cuitlacoche, proximate composition, fatty acids] Nearly 2000 fungal species belonging to Class Basidiomycetes are edible, but only a few are consumed and cultivated on a large scale (l-3). Common smut, caused by Ustiiago maydis (DC) Corda, is a disease of maize causing economically significant yield reduction (4-8). Infection occurs at random. Figure 1 shows U. maydis growing on a maize ear. In Mexico and some other Latin American countries, galls on maize ears, known as huitlacoche or cuitlacoche, are an edible deli- cacy which has been highly prized since Precolombian times (4, 9, 10). Recently, huitlacoche has been consi- dered as an alternative crop due to the increase in popularity of this fungus as food. The popular press in the USA has termed huitlacoche as the “Maize Mushroom”, “Mexican Truffle”, “Maizteca Mushroom” or “Caviar Azteca” (6, 11-14). The determination of composition of huitlacoche is fundamental in the assessment of its nutritional value and acceptance by the consumer. Huitlacoche has a high content of lysine (6.6g/lOOg protein) relative to lysine content in vegetables (13). We have observed a remarka- ble variability in proximate composition, and in contents of amino acids and fatty acids in huitlacoche collected from three different geographical regions of Mexico. Thus, we decided to study changes in proximate composi- tion and in fatty acid content of huitlacoche produced by infection of 19 different maize hybrids with two com- patible strains of U. maydis. Huitlacoche samples Huitlacoche was produced in a field experiment at the University of Illinois at Urbana- Champaign by inoculating maize plants with two isolates of U. maydis that were identified as compatible mating types in previous studies (8). The list of hybrids used in this work is shown in Table 1. The 14 sweet corn hybrids included three different endosperm mutants (sugary 1, su; sugary enhanced, se; and shrunken 2, sh2) which greatly affect kernel carbohydrate composition. Four popcorn and one dent corn hybrid were also eval- uated. Standard production practices were followed, ex- cept that insecticides were not applied. The design was a split-plot of a randomized complete block with three replications. Each main plot consisted of five subplots. Each subplot included 3.2 m rows spaced at 76 cm inter- * Corresponding author. vals with approximately 10 plants per row. Controls were used to compare inoculated and noninoculated plants. Two monosporidial U. maydis lines were used to produce inocula. The isolates were cultured at room tem- perature on potato dextrose agar or in potato dextrose broth (Sigma Chemical Company, St. Louis, MO, USA) for 3 d prior to inoculation. The plants were inoculated on different dates when the silks had emerged 3 to 6 cm. Agar and broth cultures were mixed and diluted to produce a suspension of ap- proximately 5ooO sporidia/ml. Eight ml of the sporidial suspension was injected down the silk channel with a hand-held spray gun (Meterjet, model 23624; Spraying System Co., Wheaton, IL, USA) attached by a hose to a backpack sprayer (Solo, model 425; Grower Equipment Supply, Hainesville, IL, USA) containing the sporidial suspension. All primary ears were harvested and husk leaves re- moved. The huitlacoche was separated from the ears and then lyophilized in a Virtis lyophilizer (Virtis Co., inc., Gardiner, NY, USA). Huitlacoche samples were then passed through a mill (UD Cyclone Sample Mill, UD Corp., Boulder, CO) using an 80 mesh sieve (USA Stan- dard Testing Sieve). Lyophilized samples were stored at FIG. 1. General appearance of huitlacoche covering the maize ear. 104