Effect of traditional nixtamalization process on starch annealing and the relation to pozole quality

Abstract

Several maize landraces were evaluated using microstructural and rheological starch properties and related them to pozole quality. Annealed starch produced during traditional nixtamalization and additional boiling step enhances the viscosity, swelling and starch stability to collapse by forming amylose-lipid complexes. Regarding pozole broth, Cacahuacintle maize (pozole end-use) presented significantly higher (P < 0.05) soluble solids (0.41%) compared with tortilla end-use landraces Pepitilla (0.16%) and Celaya (0.32%). The explanation is that Cacahuacintle pozole matrix did not collapse, but it eroded, forming a sponge structure. Celaya had a compact matrix structure. Pozole yield was significantly higher (P < 0.05) in Cacahuacintle as it was 100% soft endosperm type. X-ray diffraction suggests changes from A-type starch in nixtamal to V-type pattern in pozole, typical of amylose-lipid complexes. Those changes in processing and in quality of the final products are important economic issues that merit further investigations concerning annealing temperatures, steeping and processing times. Practical Applications Pozole is a pre-Columbian exotic soup or stew that once had a ritual significance for the Aztecs of Mexico; it is made with a very special floury type of maize named Cacahuacintle. Despite the economic importance of the Cacahuacintle maize race in Mexico and in Southwest U.S.A., the quality characteristics that the maize kernel should have to give good quality pozole are not well known, which is in part due to the ready availability of poor quality canned products in the market. Combined treatments involving starch annealing during nixtamalization and heat treatment of the wet nixtamal during boiling lead to increase the pozole quality. A practical way to produce thermally resistant starches is through the use of selected maize and heat/moisture treatments. The amylose-lipid complexes formed increase starch gelatinization temperatures and its stability to produce puckered granules at water boiling temperatures, giving the unique sponge structure with soft texture and high swelling properties in the final product. © 2013 Wiley Periodicals, Inc.