Analysis of moisture distribution and texture of quick boil spaghetti

- We revealed moisture distribution of quick boil spaghetti during boiling by MRI.
- Spaghetti with a V-shape groove had a wide low moisture region after boiling.
- Force-strain curves of grooved spaghetti varied according to shearing direction.
- Windmill shape cross section spaghetti had similar texture to that of ordinary one.
- Surface high moisture region hardly influenced on mechanical property of spaghetti.

Lengthwise grooving was adopted to produce quick boil spaghetti with standard thicknesses after boiling. Ordinary dried spaghetti with a 1.6 mm diameter (Sample A, 7 min boiling time) was compared to quick boil spaghetti samples, namely spaghetti with a V-shaped groove (Sample B, 4 min boiling time) and spaghetti with three windmill-shaped grooves (Sample C, 3 min boiling time). The quick boil spaghetti samples had lower moisture content (58-59 g/100 g) than Sample A (63 g/100 g) after cooking. The spin-spin relaxation time (T2) magnetic resonance images during boiling showed that the region around the tips of their grooves absorbed water and swelled particularly rapidly resulting in closure of the grooves. While the region with low moisture content at the core of the strand after boiling was round in Sample A, those in Sample B and C were U-shaped and like a triangle, respectively. The shearing test force-strain curves of boiled Sample B and C varied depending on the shearing direction, which reflected their non-concentric moisture distributions. The high moisture region at the boiled spaghetti surface did not have a large effect on the mechanical properties.