Optimization of extrusion process of rice flour enriched with pistachio nut flour

Abstract

Response surface methodology deriving by superimposing individual contour plots, was used to investigate the optimum operating conditions for extrusion-cooking of rice flour enriched with pistachio nut flour. The highest barrel temperature (128°C) produced a stiff extrudates (high values of breaking strength i.e. 100 N/mm2 and bulk density i.e. 2.2 g/mL). However, graphical optimization studies showed that the optimal operating conditions involved values of 16-17% water feed content and 70-95°C barrel temperature. This research points out the importance to studythe biopolymer changes that occur during extrusion-cooking processing because of their huge effect on quality characteristics of extrudates.

Keywords

• pistachio nut flour, starch-lipid complexes, optimization response surface methodology, contour plot, breaking strength, bulk density