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Little attention has been given to the influence of non-gluten components on the viscoelastic properties of wheat flour dough, bread making process and their products. The aim of this study was to evaluate by creep tests the viscoelastic properties of tablets manufactured from Osborne solubility fractions (globulins, gliadins, glutenins, albumins and residue), pentosans, flour and bread. Hard and soft wheat cultivars were used to prepare the reconstituted tablets. Sintered tablets (except flour and bread) showed similar values to those obtained from the sum of the regression coefficients of the fractions. Gliadins and albumins accounted for about 54% of the total elasticity. Gliadins contributed with almost half of the total viscosity (45.7%), and showed the highest value for the viscosity coefficient of the viscous element. When the effect of dilution was evaluated, the residue showed the highest instantaneous elastic modulus (788.2 MPa). Retardation times of the first element (λ1~ 3.5 s) were about 10 times lower than the second element (λ2~ 39.3 s). The analysis of compliance of data corrected by protein content in flour showed that the residue fraction presented the highest values. An important contribution of non-gluten components (starch, albumins and globulins) on the viscoelastic performance of sintered tablets from Osborne fractions, flour and bread was found.

Summary Corn tortillas are produced using the traditional nixtamalisation process (TP). Nevertheless, one of the greatest problems that the tortilla industry faces is the high level of losses of solids. The aim of this research was to evaluate the nutritional value of a whole-grain tortilla, produced using an ecological process (EP). In the EP corn was cooked at 90 °C with 1.8% (w/w) calcium sulphate. The grains were steeped, washed and grounded to obtain the masa, which was baked to produce tortillas. Also, tortillas were prepared using the TP and following the same steps as those used in the EP, except that 1.0% (w/w) of calcium hydroxide was used. The tortillas from EP retained 14.05, 6.03, and 54.02% more fat, protein and fibre than tortillas produced by the TP. The PER value of rats fed whole-grain tortillas (1.81) was not different from that of rats fed the traditional tortillas (1.85).

Sorghum contaminated with a total concentration of aflatoxin B 1 (AFB 1 ) and aflatoxin B 2 (AFB 2 ) at 140 ± 7.3 ng/g was extrusion-cooked in a single screw extruder. The temperature profile in the barrel sections of the extruder was 80–150–200 °C. The flour moisture content (M.C.) was adjusted at 200, 250 and 300 g/kg by means of aqueous citric acid at concentrations of 0, 0.5, 1, 2, 4 and 8N. The barrel temperature profile, in combination with the M.C. and the citric acid concentration, significantly affected the extent of aflatoxin reduction in the extruded sorghum. The recovered aflatoxin decreased with an increase in M.C. and acid concentration. The maximum percentage of aflatoxins degraded from cooking the milled sorghum ranged from 17 to 92%. Even when using a severe extrusion condition combined with high citric acid concentrations, acceptable product colour, viscosity, functional and textural properties were obtained.

Sorghum fl our contaminated with β-afl atoxins at a level of 140±7.34 ng/g was extrusion-cooked in a single screw extruder under two different conditions: moderate (ME) and severe (SE). The difference in the processing conditions was in the temperature profi le of the barrel sections of the extruder: 60-80-100°C for ME and 80-150-200°C for SE, respectively. The fl our moisture content (MC) was adjusted at 20, 25 and 30% by means of aqueous lactic acid (LA) at concentrations of 0, 0.5, 1.0, 2.0, 4.0 and 8.0 N. The effect of the three extrusion variables (temperature profi le, MC and LA concentration) was analysed as a completely randomized factorial design 2 ×3 × 6. The barrel temperature profi le, in combination with the MC and LA concentration, signifi cantly affected the extent of afl atoxin reduction in the extruded sorghum. The recovered afl atoxin decreased with an increase in MC and LA concentration, in both temperature-profi les evaluated. The SE condition produced higher afl atoxin degradation rates (from 16.38 to 67.09%) than the ME condition (up to 19.79%).