Effects of extrusion variables on the properties of waxy hulless barley extrudates
- 1 January 2004
- journal article
- research article
- Published by Wiley in Molecular Nutrition & Food Research
- Vol. 48 (1), 19-24
- https://doi.org/10.1002/food.200300324
Abstract
The objective of this research was to investigate the extrudability of waxy hulless barley flour under various extrusion conditions. Waxy hulless barley flour was processed in a laboratory-scale corotating twin-screw extruder with different levels of feed moisture content (22.3, 26.8, and 30.7%) and die temperature (130, 150, and 170°C) to develop a snack food with high β-glucan content. The effects of extrusion condition variables (screw configuration, moisture, and temperature) on the system variables (pressure and specific mechanical energy), the extrudate physical properties (sectional expansion index, bulk density), starch gelatinization, pasting properties (cold peak viscosity, trough viscosity, and final viscosity), and β-glucan contents were determined. Results were evaluated by using response surface methodology. Increased extrusion temperature and feed moisture content resulted in decreases in exit die pressure and specific mechanical energy values. For extrudates extruded under low shear screw configuration (LS), increased barrel temperature decreased sectional expansion index (SEI) values at both low and high moisture contents. The feed moisture seems to have an inverse relationship with SEI over the range studied. Bulk density was higher at higher moisture contents, for both low and high barrel temperatures, for samples extruded under high shear screw configuration (HS) and LS. Cold peak viscosities (CV) were observed in all samples. The CV increased with the increase in extrusion temperature and feed moisture content. Although β-glucan contents of the LS extrudates were comparable to that of barley flour sample, HS samples had generally lower β-glucan contents. The extrusion cooking technique seems to be promising for the production of snack foods with high β-glucan content, especially using LS conditions.Keywords
This publication has 25 references indexed in Scilit:
- Effect of Process Conditions on the Physical and Sensory Properties of Extruded Oat‐Corn PuffJournal of Food Science, 2000
- Pasting of Wheat Flour Extrudates Containing Conventional Baking IngredientsJournal of Food Science, 1993
- Effect of Extrusion Variables on Cassava ExtrudatesJournal of Food Science, 1991
- Effect of Temperature on Properties of Extrudates from High Starch Fractions of Navy, Pinto and Garbanzo BeansJournal of Food Science, 1990
- Effects of extrusion cooking on starch and dietary fibre in barleyFood Chemistry, 1989
- Effects of Feed Composition, Feed Moisture, and Barrel Temperature on the Physical and Rheological Properties of Snack‐like Products Prepared from Cowpea and Sorghum Flours by ExtrusionJournal of Food Science, 1988
- The mechanical properties of extruded food foamsJournal of Materials Science, 1988
- RELATIONSHIP BETWEEN ACID EXTRACT VISCOSITY AND TOTAL SOLUBLE AND INSOLUBLE β-GLUCAN CONTENTS OF HULLED AND HULLESS BARLEYCanadian Journal of Plant Science, 1987
- Kinetics of Starch Gelatinization During Extrusion CookingJournal of Food Science, 1987
- Degree of Gelatinisation of Cooked RiceStarch ‐ Stärke, 1973