Time Course Study of Substrate Utilization by Aspergillus flavus in Medium Simulating Corn (Zea mays) Kernels
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- 作者：Jay E. Mellon ; Michael K. Dowd ; and Peter J. Cotty
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2002
- 出版时间：January 30, 2002
- 年：2002
- 卷：50
- 期：3
- 页码：648 - 652
- 全文大小：65K
- 年卷期：v.50,no.3(January 30, 2002)
- ISSN：1520-5118
文摘
Utilization of the three major corn reserve materials, starch, triglycerides (refined corn oil), and zein(storage protein), by Aspergillus flavus was monitored in vitro over a 7-day fermentation. Mediumcomposition in which proportions of reserve materials initially approximated proportions in maturecorn kernels changed little over the first 18 h. Subsequently, hydrolysis of both starch and triglyceridesoccurred simultaneously, with peak concentrations of glucose and free fatty acids on day 2 of thefermentation period. Fatty acid concentrations dropped relatively rapidly after day 2 but increasedagain after day 6. Aflatoxin B1 production increased after 36 h, with a peak at day 4. Aflatoxin B1production paralleled fungal biomass production during the exponential growth phase. A. flavus didnot appear to preferentially utilize any of the released fatty acids. A number of fungus-specificmetabolites were detected, including arabitol, erythritol, mannitol, trehalose, and kojic acid. Mannitolexceeded the other metabolites in concentration, and the timing of mannitol production closelyparalleled that of aflatoxin B1. Kojic acid concentrations peaked at day 6. In contrast to previouslydescribed selective use of simple carbohydrates by A. flavus, less discrimination was displayed whenfaced with utilization of complex substrates such as starch or triglycerides.Keywords: Aflatoxin; Aspergillus flavus; corn lipids; cornstarch; Zea mays; zein