Revising the role of pH and thermal treatments in aflatoxin content reduction during the tortilla and deep frying processes.
Naturally aflatoxin-contaminated corn (Zea mays L.) was made into tortillas, tortilla chips, and corn chips by the traditional and commercial alkaline cooking processes. The traditional nixtamalization (alkaline-cooking) process involved cooking and steeping the corn, whereas the commercial nixtamalization process only steeps the corn in a hot alkaline solution (initially boiling). A pilot plant that includes the cooker, stone grinder, celorio cutter, and oven was used for the experiments. The traditional process eliminated 51.7, 84.5, and 78.8% of the aflatoxins content in tortilla, tortilla chips, and corn chips, respectively. The commercial process was less effective: it removed 29.5, 71.2, and 71.2 of the aflatoxin in the same products. Intermediate and final products did not reach a high enough pH to allow permanent aflatoxin reduction during thermal processing. The cooking or steeping liquor (nejayote) is the only component of the system with a sufficiently high pH (10.2-10.7) to allow modification and detoxification of aflatoxins present in the corn grain. The importance of removal of tip, pericarp, and germ during nixtamalization for aflatoxin reduction in tortilla is evident.
Torres
P
P
Departamento de Investigación y Posgrado en Alimentos, Universidad de Sonora, Apdo. Postal 11-49, Hermosillo, Sonora, México. pitorres@guayacan.uson.mx
Guzmán-Ortiz
M
M
Ramírez-Wong
B
B
D000348:Aflatoxins / Q000032:analysis*; D003296:Cooking; D005506:Food Contamination; D005511:Food Handling / Q000379:methods*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D003313:Zea mays
D000348:Aflatoxins