Supplementary Materials: Influence of Excipients and Spray Drying on the Physical and Chemical Properties of Nutraceutical Capsules Containing Phytochemicals from Black Bean Extract

According to USP 30-NF 25 [1], powder flow with repose angles between 25–30° powder flow is excellent, among 31–35° the flow is good and within 36–40° the flow is fair. For values higher than 41°, the powder has bad flow properties. The best angle of repose was shown by powder obtained from tests 4 and 6 (33 ± 2° and 33 ± 1° in Table S1), whose flow can be considered good. Moreover, the powders obtained from experiments 3 and 7 presented angles of repose of 40°± 1° and 38°± 0°, and, thus, fair flowability. The effect of solids concentration on the angle of repose is in agreement with the results reported by others studies using maltodextrin mixtures as carriers [2]. In previous studies using the angle of repose test, powders with strong structural strength will form a big pile when dispersed in a container resulting in a low bulk density; whereas a structurally weak powder will collapse easily exhibiting a high bulk density [3]. The addition of starch into the powder formulations significantly reduced the angle of repose (Table S2). The test S.6 containing 25.0% maltodextrins, 74.1% starch and 0.9% magnesium stearate exhibited an improved angle of repose of 28 ± 1°, whose flow can be considered good. The improvement in the angle of repose could be attributed to the particle size and shape of the starch and a reduction in the frictional force between the individual particles. The higher particle size of starch could reduce the ability to interact with the glidant and the small particles of the materials affecting the cohesiveness and friction forces [4].