6. Conclusions
In general, protein structures are only stable under a limited range of physiological conditions, with their secondary and tertiary structures, and associated functionality, easily disrupted by environmental changes such as shifts in temperature, variation of pH, or physical disruption. The proteins introduced through modern biotechnology into food crops such as corn and soy are similarly susceptible to denaturation when exposed to non-physiological conditions and digestive environments. The majority of processes used for food preparation involve one or more conditions that are disruptive to protein integrity: heating (e.g., baking, frying), pH shifts (e.g., nixtamalization, steeping), and physical disruption (e.g., extrusion, grinding). Consequently, for proteins that can be readily inactivated by food preparation processes, there is likely to be negligible dietary exposure to the functionally active form from consumption of prepared foods derived from corn and soybeans.Potential dietary exposures to functionally active introduced proteins could therefore be orders of magnitude below those administered to rodents in numerous published toxicology studies which produced no treatment-related adverse observations. Characterization of the potential denaturation of introduced proteins during normal food preparation processes should be considered as part of the ‘‘reliable information’’ to assess their safety.