Development of Fortified Guava Pomace and Rice Flour based Extrudates

Abstract

Incorporation of guava pomace (residue) into ready–to–eat expanded product and their effect on functional properties were studied. Guava pomace collected after juice extraction was dried and milled. It was then added to rice flour in predetermined experimental compositions. The samples were processed in a twin–screw extruder with an experimental combination based on central composite rotatable design of response surface methodology (RSM). The independent variables were moisture content (17–21%) on wet basis, temperature (110 – 130⁰C), screw speed (270 –310rpm) and varying proportion of rice: pomace ratio. Results indicated that increasing feed moisture content resulted in extrudates with a higher density, lower expansion, higher WAI, lower WSI and higher hardness. Higher barrel temperature resulted in reduced density, increased expansion and WSI. Addition of guava pomace resulted in increase in WAI, hardness and decrease in bulk density, expansion as well as WSI. The product was optimized at guava pomace content of 10% in rice flour, moisture content of 21%, temperature at 112⁰C and screw speed of 280 rpm.