Physico- Chemical Characteristics and Functional Properties of Starch and Dietary Fibre in Grass Pea Seeds

Abstract

Physico-chemical and functional properties of starch and fibre in raw and processed grass pea seeds were evaluated. Whole grass pea seeds were found to contain 41 % starch and 17 % total dietary fibre (2 % soluble and 15 % insoluble) on dry matter basis. Examination by using scanning electron microscopy revealed oval shaped starch granules with an average width of 17 μm and length of 25 μm. Raw sample had a gelatinization onset temperature of 62 °C and two endothermic transition peaks at about 73 °C and 94°C. in addition the starch isolated from grass pea flour was shown to have a transition enthalpy (ΔH) of 10 Jg -1 , The viscosity of the raw sample (using a Brabender amylograph) reached peak maximum at 80-95°C, decreasing during the 30 min holding time (at 95 °C) followed by an increase during cooling to 50 °C. Raw whole seed flour was shown to have a water absorption and water solubility index (WSI) of and 16 %, respectively. Samples that had been cooked for 60 min had a lower WSI than those cooked for 30 min: this was further reduced in the samples cooked after soaking. The carbohydrate extracted from raw flour was found to be mainly high Mwt carbohydrate (55 %), eluted at Kav < 0.2.