Comparative study of three legume starches

Abstract

SummaryStarch content of chickpea (Cicer arietinum), pigeon pea (Cajanus cajan) and bonavist bean (Dolichos lablab) was 58,52 and 50% respectively with recovery of 57.9, 48.1 and 49.0%. The amylose content was 33.5, 27.0 and 31.0%; amylose chain length was 1420,550 and 830 glucose units and amylopectin chain length was 29, 27 and 28 glucose units for chickpea, pigeon pea and bonavist bean respectively. Chickpea starch granules ranged from large oval shaped (21 × 30 pm) to small spherical (13 pm in diameter); pigeon pea from (35 × 42 pm) to 15.2 pm and bonavist bean (35 × 42 pm) to 15.2 pm. The gelatin‐ization temperature range was 67–76°C for chickpea, 71–78°C for pigeon pea and 78–80°C for bonavist bean starch. The swelling power for chickpea, pigeon pea and bonavist bean at 95°C were 17, 18.5 and 22.5% respectively. The legumes showed a single‐stage and somewhat restricted swelling. Solubility curves for legume starches showed a similar pattern and indicated that they have higher solubility at elevated temperatures than wheat starch. The liquefaction characteristics showed that chickpea has the highest resistance to cooking and was the most sensitive to a‐amylase. The three legume starches gave stabilized Brabender hot‐paste viscosity; chickpea had a lower overall viscosity due to its exceptionally long amylose chains.