Physicochemical and rheological characteristics of commercial nixtamalisedMexican maize flours for tortillas

Three commercial nixtamalised Mexican maize flours (CNMFs) designated HI-A, HI-B and HI-C were evaluated in this work. For each brand, four samples co rresponding to four consecutive months of production were evaluated. Tortil las prepared by the traditional process of nixtamalisation were used as the control. The maize flours and their respective tortillas showed variations between samples in their physical, chemical and rheological parameters. Th e three commercial maize flours incorporated additives and preservatives. T he moisture content, colour, pH, subjective water absorption capacity, wate r solubility index, water absorption index and swelling capacity of flours showed strong differences between the three CNMFs with respect to the chemi cal analysis. Important differences in the protein, calcium and amylose con tents were observed. Tortillas from CNMFs had a blander maize flavour, less desirable texture and staled more rapidly than traditional tortillas. Some modifications are required in the current Official Mexican Quality Standar d, principally in the appropriate selection of additives and levels used in the preparation of CNMFs. (C) 2000 Society of Chemical Industry.