1Department of Food Engineering and Technology, Sant Longowal Institute of Engineering and Technology (Deemed to be University), Longowal-148106, Sangrur, Punjab
2Department of Agricultural Process Engineering, College of Agricultural Engineering and Technology, Anand Agricultural University, Godhra-389001, Gujarat
*Corresponding author email: navneet.k.agrawal@gmail.com
Online published on 16 October, 2013.
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 four 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 four, moisture content of 21%, temperature at 1120C and screw speed of 280 rpm.
Guava pomace, Bulk density, Lateral expansion, Water absorption index, Water solubility index, Hardness, Response surface methodology
