Physico-chemical, structural and sensory quality of corn-based flax-snack

Abstract

The effect of incorporating increasing percentage of flaxseed flour on the chemical, physical, microstructure and sensory quality of corn-based snack were studied. A Brabender laboratory single screw extruder was used to prepare the extrudates under fixed extrusion conditions. Feed moisture content was 18%, barrel temperature before the die was 200°C, and screw speed was 200 rpm. Proximate composition, expansion ratio, bulk density, breaking strength, colour, water absorption and soluble indices were examined. Experimental work showed significant difference due to the increased proportion of flaxseed flour. Fiber, fat and protein content were altered in extrudates by the addition of flax. Expansion ratio decreased, bulk density and breaking strength increased almost recilinearly and resulted in a more dense snack. Higher degree of lightness ‘L’ values were obtained in blend containing a lower percentage of flaxseed. Water absorption decreased as the percent of flaxseed increased. Water solubility index showed similar trend. Sensory evaluation by 15 members sensory panel showed that within the observed concentration ranges, total score gradually decreased by increasing proportion of added flaxseed but still acceptable for the panellists. Microscopic examination revealed that increasing the percentage of flaxseed resulted in a denser product, while a lower percent gave a more hollow snack. Consequently, there is a parallelism between the flaxseed percent and the microstructure of the extrudates.