M. BRNCIC1, B. TRIPALO1, S. RIMAC BRNCIC1, S. KARLOVIC1, A. ZUPAN2 and Z. HERCEG1
1 Faculty of Food Technology and Biotechnology1, University of Zagreb, 10000 Zagreb, Croatia
2 City of Zagreb, Office for Health, Labour and Social Protection, 10000 Zagreb, Croatia
BRNCIC, M., B. TRIPALO, S. RIMAC BRNCIC, S. KARLOVIC, A. ZUPAN and Z. HERCEG, 2009. Evaluation of textural properties for whey enriched direct extruded and puffed corn based products. Bulg. J. Agric. Sci., 15: 204-214
Processing of various foodstuffs with extrusion cooking represents a very effective process applicable in biotechnology and food industry while products of extrusion cooking are of major importance today as well. The issue of this work was to incorporate different amount of whey protein concentrate (WPC) in corn flour as raw material during extrusion cooking for achievement extrudates with higher protein content in order to enrich and improve nutritional quality of product and determination of textural-mechanical properties of such a manufactured product. Research was conducted in co-rotating twin screw extruder with setup designed to manufacture direct expanded extrudates based on pure corn flour and enriched with whey protein concentrate. Experimental data were analyzed with multiparameter correlation analysis using software package statistica 6. Achieved textural properties of direct expanded extrudates with addition and without addition of whey protein concentrate as: extrudate diameter (de), expansion ratio (Er), bulk density (BD), extrudate weight equivalent (EWE), hardness and breaking strenght index (BSI) in bending mode, and penetration mode as well were compared with versatile process parameters (feed moisture content and whey protein concentrate intake). Also water apsorption index (WAI), and water solubility index (WSI) were also corelated with empirical models.