Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/2/2001
Publication Date: 6/18/2001
Interpretive Summary: Fumonisins are made by common Fusarium molds. They are found in corn and corn-based foods. The most common fumonisin, fumonisin B1 (FB1), kills animals and causes cancer in rats and mice. There is circumstantial evidence linking high esophageal cancer rates of some human populations, for which corn is a dietary staple, with fumonisin exposure. It is therefore important from a food safety standpoint to develop strategies for controlling fumonisins in foods made from corn. We studied what happens to FB1 during the commercial manufacture of tortilla chips, a popular snack food. Our findings show that a) the amount of FB1 in the fried chips is appreciably less than the amount in the corn from which they were made; b) reduction in FB1 amounts occurs primarily during the first step of the manufacturing process, called nixtamalization (cooking and steeping the corn in lime water); and c) relatively little hydrolyzed FB1, a fumonisin formed during nixtamalization, is found in the finished chips. This information serves as a basis for more extensive studies on the fate of fumonisins during the preparation of corn based foods and, ultimately, for developing strategies for controlling fumonisin levels therein.
Technical Abstract: Fumonisins are mycotoxins produced by Fusarium moniliforme (=F. verticillioides) and related fungi. They are common in corn worldwide and occur in corn-based foods. Fumonisin B1 (FB1), the most common homologue, causes fatal diseases in farm animals and is carcinogenic to laboratory animals. Consumption of home grown corn, contaminated with fumonisin, as a adietary staple has been correlated with high esophageal cancer rates in man. To obtain information on the fate of fumonisins when corn is processed, fried tortilla chips were made from four lots of raw corn under factory production line conditions. The amounts of FB1, its hydrolyzed (HFB1) and partially hydrolyzed (PHFB1) forms, and compounds indicative of fumonisin-sugar adduct formation in the corn, masa, other intermediates and products, and the fried chips were then determined. FB1 concentrations in the chips varied, but were 40-80 percent lower than their respective corn samples. HFB1 and PHFB1 were found at comparatively low (to FB1) levels in cooking/steeping liquid, which is discarded. Relatively high amounts of HFB1 and PHFB1 were also found in the solid waste. No evidence for the formation of significant amounts of fumonisin-sugar compounds was found. Thus, cooking/steeping the corn in alkaline water (nixtamalization) followed by rinsing reduced fumonisin concentrations in the masa and chips. The grinding, sheeting, baking and frying steps of the process had no significant effect on measurable fumonisin concentrations in the fried chips.