Textural and Sensory Characteristics of Milk Protein- Maize Flour-based Extrudates

Sensory and textural characteristics of milk protein-maize-based extrudates were studied as affected by extrusion conditions and milk-proteins Rennet Casein (RC), skimmed milk powder (SMP) and whey protein concentrate (WPC) to maize ratio. Appearance attributes of products decreased significantly (P<0.05) with SMP addition and higher feed moisture content, but improved with WPC-70 and RC. Colour of extrudates was mostly affected by the milk protein- maize ratios, especially with increase in SMP concentration that led to significantly (P<0.05) darker products scoring less than five due to the presence of higher amount of lactose. Feed moisture content decreased mean sensory score for crispness and increased hardness of the extrudates. Overall acceptability of extrudates decreased with the addition of SMP and increase in feed moisture content, except in WPC-70 at 8% level of protein. Extrudate with 8% RC and 12% feed moisture treated at 40 0C inlet and 100 0C outlet cooking zone temperature at screw speed of 340 rpm gave minimum maillard browning, desired textural characteristics, and colour. The correlation of sensory and textural properties showed that textural characteristics can be related with appearance which affected the product most.