A laboratory twin-screw, co-rotating extruder was used
in this study. The screw diameter (D) was 12 mm and the total
configured screw length (L) was 36D, which gave an overall L/D
ratio of 36:1. The extruder barrel consisted of four heating/cooling
zones. Barrel temperatures were maintained at 40 C in the
first zone, at 70oC in the second and at 90 C in the fourth zone,
while the temperature in the third zone was varied from 85 to
100 C. Pea starch was fed into the extruder at a rate of 350 g/h
using a MT-1 twin-screw volumetric feeder. Water was injected into the extruder
with a liquid pump at a rate of 85 to 158 g/h, so that the final mixture had a
moisture content in the range of 30–40%. The screws were operated at 100–200 rpm.
Pea starch noodles were extruded through a
circular die with 4 0.80 mm round openings and cut to length
as they exited the extruder die and then dried overnight at
40 C. The dried noodles were kept in sealed plastic bags before
analysis for physical, cooking and textural properties. Part of
the dried noodles were ground into flour using an Udy grinder
with a 0.5 mm sieve and stored at 4 C in sealed plastic bags until
further analysis