Tepary Bean Starch. Part I. Physico‐chemical Properties

Starch of high purity was isolated by a simple procedure from tepary beans (Phaseolus acutifolius var. latifolius). Granules were spherical to oval with a birefringence pattern similar to that of other legume starches. Under SEM they appeared smooth with no evidence of fissures. They showed a normal distribution of diameters with a range of 15.5–59.8 μ and a mean of 33.5 μ. Tepary starch had an amylose content of 30.7% and a gelatinization temperature range of 70.5–84.0°C. Other properties were also determined. Fractionation provided an amylose fraction with a β‐amyloysis limit of 76.3% and an average DPη of 618. The amylopectin fraction had an average magnified image values of 33, 22 and 10 glucose units respectively.