Bulk characteristics of a hulless and two hulled cultivars of oats

Handling and storage properties of one hulless cultivar (AC Belmont), and two hulled cultivars (Robert and AC Marie) of oats (Avena sativa L.) were measured for bulk samples for moisture contents from 10.5% to 19.5%, wet mass basis. The properties were friction coefficients, standard bulk density. pail bulk density, particle density, and filling and emptying angles of repose. Friction coefficients against the four structural materials tested (galvanized steel, plywood, wood-floated concrete, and steel trowelled concrete) ranged from 0.24 at 10.5% moisture content (m.c.) for AC Belmont and Robert oats on galvanized steel, to 0.68 at 19.4% moisture content for AC Belmont on wood-floated concrete. Generally, as the grain moisture content increased, the friction coefficient increased. Standard bulk densities for AC Belmont oals decreased as the moisture content increased. AC Belmont had a mean standard bulk density of 637 kg/m3 . The maximum particle density of AC Belmont was 1409 kg/m3 and the lowest value was 1360 kg/m3 at 19.5% m.c. The Robert oats had a mean standard bulk density of 538 kg/m3 which showed a decreasing trend as the moisture content increased. Particle density dropped steadily from 1378 kg/m3 to 1340 kg/m3 as the moisture content increased. The standard bulk density for AC Marie oats was constant at approximately 445 kg/m3 , except at 19.5% moisture content where it was lower. The average particle density of AC Marie oats was 1305 kg/m3 . AC Belmont had the highest bulk density among the oats at 82% of the bulk density of Columbus wheat, with Robert and AC Marie having densities of 59 and 67% of wheat, respectively. AC Belmont had steadily increasing emptying and filling angles with increasing moisture to a maximum of 35.8° for an emptying angle and 38.6° for a filling angle at 19.5% m.c. Robert oats had a gradual rise in emptying and filling angles with increasing moisture to a maximum of 32.9° for emptying and 29° for filling at the highest moisture content. The emptying and filling angles of AC Marie oats stayed fairly constant until the moisture content increased to 19.5%. The absence of hulls in AC Belmont generally resulted in greater friction coefficients, bulk density, particle density, emptying and filling angles than for the two cultivars with hulls at a given moisture content. The main difference when comparing all the cultivars was a greater particle density for Robert oats. All of the oat cultivars exerted a similar lateral force to galvanized steel walls (4.8 to 5.2 kPa) at 17.0% m.e.. whieh is 6 to 13% less than that for wheat. Key words: oats, hulled, hulless, bulk, physical properties.