Centro de Pesquisa e Desenvolvimento em Sanidade Animal, Instituto Biológico São Paulo, Brazil.
Centro de Pesquisa e Desenvolvimento de Recursos Genéticos Vegetais, Instituto Agronômico Campinas, Brazil.
Front Microbiol. 2014 Jun 4;5:269. doi: 10.3389/fmicb.2014.00269. eCollection 2014.
Aflatoxin B1 (AFB1) is a highly toxic and carcinogenic metabolite produced by Aspergillus species on food and agricultural commodities. Inhibitory effects of essential oils of Ageratum conyzoides (mentrasto) and Origanum vulgare (oregano) on the mycelial growth and aflatoxin B1 production by Aspergillus flavus have been studied previously in culture medium. The aim of this study was to evaluate aflatoxin B1 production by Aspergillus flavus in real food systems (corn and soybean) treated with Ageratum conyzoides (mentrasto) and Origanum vulgare (oregano) essential oils. Samples with 60 g of the grains were treated with different volumes of essential oils, 200, 100, 50, and 10 μL for oregano and 50, 30, 15, and 10 μL for mentrasto. Fungal growth was evaluated by disk diffusion method. Aflatoxin B1 production was evaluated inoculating suspensions of A. flavus containing 1.3 × 10(5) spores/mL in 60 g of grains (corn and soybeans) after adjusting the water activity at 0.94. Aflatoxin was quantified by photodensitometry. Fungal growth and aflatoxin production were inhibited by essential oils, but the mentrasto oil was more effective in soybeans than that of oregano. On the other hand, in corn samples, the oregano essential oil was more effective than that of mentrasto. Chemical compositions of the essential oils were also investigated. The GC/MS oils analysis showed that the main component of mentrasto essential oil is precocene I and of the main component of oregano essential oil is 4-terpineol. The results indicate that both essential oils can become an alternative for the control of aflatoxins in corn and soybeans.
黄曲霉毒素 B1（AFB1）是一种由曲霉属物种在食品和农产品上产生的高毒性和致癌代谢物。先前已经在培养基中研究了蓝蓟（mentrasto）和牛至（oregano）精油对黄曲霉（Aspergillus flavus）菌丝生长和黄曲霉毒素 B1 产生的抑制作用。本研究的目的是评估用蓝蓟（mentrasto）和牛至（oregano）精油处理的真实食品系统（玉米和大豆）中黄曲霉毒素 B1 的产生。用不同体积的精油（牛至精油 200、100、50 和 10 μL，蓝蓟精油 50、30、15 和 10 μL）处理 60 g 谷物样品。采用圆盘扩散法评估真菌生长。通过调节水活度为 0.94，在 60 g 谷物（玉米和大豆）中接种含有 1.3×10(5)个孢子/mL 的黄曲霉悬浮液，评估黄曲霉毒素 B1 的产生。通过光密度法定量黄曲霉毒素。精油抑制了真菌的生长和黄曲霉毒素的产生，但蓝蓟精油在大豆中的效果优于牛至精油。另一方面，在玉米样品中，牛至精油比蓝蓟精油更有效。还研究了精油的化学成分。GC/MS 油分析表明，蓝蓟精油的主要成分是 Precocene I，牛至精油的主要成分是 4-松油醇。结果表明，这两种精油都可以成为控制玉米和大豆中黄曲霉毒素的替代物。
