Abstract
Heated extrusion was tested as an alternative process for incorporating "hard-to-cook" beans into food products. A 32 factorial design was used to evaluate extrusion conditions for a 40/60 (w/w) blend of "hard-to-cook" beans and quality protein maize. Tested extrusion variables were temperature (155, 170 and 185 °C) and moisture content (15.5, 17.5 and 19.5 g/100 g). Screw speed was fixed at 130 rpm. The extrudates obtained at 155 and 170 °C with 15.5% moisture had the best physical characteristics and were chosen for comparative analysis of nutritional changes between the unprocessed "hard-to-cook" bean/quality protein maize flour blend and the resulting extrudates. In vitro protein digestibility was higher in the extrudates (80%) than in the flour blend (76%). In vitro starch digestibility was higher at 155 °C (89%) and 170 °C (92%) than in the flour blend (12%). Processing conditions decreased dietary fibre content by 38% at 155 °C and 44% at 170 °C.
Original language | English |
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Pages (from-to) | 1799-1807 |
Number of pages | 9 |
Journal | LWT |
Volume | 41 |
Issue number | 10 |
DOIs | |
State | Published - Dec 2008 |
Keywords
- Extrusion
- Hard-to-cook beans
- Nutritional changes
- QPM