Effect of ultrasound processing on the physical and powder-flow properties of nixtamalized corn flour and its influence on the quality parameters of tortilla

The objective of this study was to evaluate the effect of ultrasound (US) processing on the physical and powder flow properties of nixtamalized corn flour (NCF) and its influence on the quality parameters of tortillas such as texture, yield, and the presence of amylose-lipid complexes. Nixtamalized corn flour modified by ultrasound (NCFMU) exhibited lower lipid content (3.35%), higher WAI, and higher WSI, as well as higher enthalpy of gelatinization (6.92 J<middle dot>g- 1) and minimum setback viscosity (2934cP). Also, US processing improved the moisture content corresponding to minimum integral entropy (MIE) of adsorption and reduced caking (138.77 N), cohesiveness index (18.03 N<middle dot>m<middle dot>g- 1), and the speed flow dependency values of NCFMU. SEM analysis revealed a rough surface of starch granules in NCFMU. Tortillas prepared from NCFMU exhibited higher values of tensile (2.51 N) and cutting force (23.75 N), as well as flour yield (1.52 kg of tortillas made per kg of flour), than those prepared from NCF. DSC and RVA analyses revealed the formation of amylose-lipid complexes in tortillas prepared from NCFMU. This study provides valuable information on the conditions of US for its employment as an easy, novel, and suitable strategy for obtaining NCF with improved pasting and thermal properties, most desirable moisture-storage conditions, and flow powder behavior, while a better tortilla product is obtained. The effects provided by US could be useful for its application in improvements of NCF with limited functionality, such as those obtained from maize varieties not suitable for the tortilla industry.