Evaluation of lentil starches modified by microwave irradiation and extrusion cooking

This study was performed to evaluate the effects of microwave irradiation and extrusion cooking on some physical, chemical, functional, rheological and morphological characteristics of lentil starch. Both treatments caused a decrease (P < 0.05) of moisture, crude protein, crude fibre, water absorption, solubility and swelling power and an increase (P < 0.05) of ash, reducing sugars and absolute density. The extruded starch exhibited the lowest values of water absorption, solubility and swelling power, with some exceptions (P < 0.05). All amylographic viscosities were lower in the modified starches; the extruded sample showed the lowest values. Both treatments reduced the retrogradation tendency of lentil starch, which could be interesting because this is one of the reasons that have limited the commercial use of lentil starches. The extrusion cooking produced the most pronounced modifications in the lentil starch characteristics evaluated, except granular morphology, which was more affected by microwave irradiation. (C) 2002 Elsevier Science Ltd. All rights reserved.