A study of the properties of starch isolated from three varieties of Lablab purpureus seeds

Starch isolated from three varieties of Lalab purpureus: Rongai white, Rongai brown and Highworth black ranged from 13.2–15.8%. The starch granules were similar in shape (oval) and medium in size (12.51–20.56 μm) but slightly differed in granule size distribution. The starches exhibited a C-type X-ray diffraction pattern with degree of crystallinity ranging from (37.0–46.3%). The apparent amylose ranged from 23.1–26.0% and absolute amylose was 17.5–23.5% and the two were significantly different (p < 0.05). The starches had high onset gelatinization temperatures (To = 73.5–75.7 °C), the gelatinization range and enthalpy change were 12.9–17.7 °C and 12.3–18.8 J/g, respectively. The starches had single stage swelling and amylose leaching patterns. The starch pastes exhibited significant shear thinning, low clarity and poor freeze–thaw stability.