THERMAL, TEXTURAL, AND PHYSICOCHEMICAL ANALYSIS OF CORN EXTRUDATES ENRICHED WITH BROCCOLI OR OLIVE PASTE

The growing consumers' demand for healthier snacks is of high importance and is driving research and industry towards developing novel ready to-eat expanded products. Thus, it would be interesting to enrich these products with additives that possibly lead to highly nutrient products. In the present study, extruded snacks based on corn flour enriched with broccoli or olive paste were developed and studied. Although the addition of broccoli or olive paste in extruded snacks can improve their nutritional properties, the final properties of these products must also be considered. Textural analysis (compression tests), thermal analysis (glass transition temperature), and moisture sorption measurements (sorption isotherms) were performed. A Guggenheim-Anderson-de Boer model has been applied to describe moisture sorption isotherms. Moreover, simple mathematical models were developed in order to correlate textural properties (maximum stress, maximum strain, elasticity parameter, number of cracks) with the process conditions during the extrusion (screw speed, temperature) and the raw materials' characteristics (moisture content, concentration of broccoli or olive paste). Regression analysis was used to estimate mathematical models' parameters. The influence of process conditions and raw materials' characteristics on the measured properties of corn-based snacks enriched with broccoli or olive paste was presented based on the alterations of the estimated parameters.