METHODS TO EVALUATE HYDRATION AND MIXING PROPERTIES OF NIXTAMALIZED CORN FLOURS

ViscoAnalyser (RVA), consistometer, and mixograph methods were develop ed to evaluate the pasting, hydration, and mixing characteristics of c ommercial nixtamalized corn flours (NCF) used for masa production. The effect of moisture level (51-58%) on the mixing characteristics of NC F was evaluated with the mixograph. Masas were subjectively evaluated for machinability properties. Masa with a low moisture level (51%) had reduced mobility and firmer texture, resulting in higher and wider mi xograms. The mixograph was able to differentiate between the various s tages of masa preparation. The first stage involves hydration of NCF p articles, which causes the force to increase. Then masa develops cohes iveness and reaches maximum consistency. Finally, masa develops sticki ness due to overmixing, which makes the curve narrower and lower. At a high moisture level (58%), masa is lubricated and plasticized and yie lds a softer texture with reduced mixing consistency, evident on the m ixograph and in lower subjective hardness readings. Flours with higher water absorption capacities produced thick slurries with increased RV A viscosities and shorter consistometer travel distances. Short consis tometer travel distances were significantly correlated to increased in itial and maximum viscosities in the RVA. The mixograph, RVA, and cons istometer methods can be used in NCF quality control programs.