Drying soybean seed using air ambient temperature at low relative humidity

Abstract

-Under subtropical and tropical environments soybean seed (Glycine max (L.) Merrill) are harvested early to avoid deterioration from weathering. Careful after-harvest drying is required and is an important step in maintaining the physiological quality of the seed. Soybean seed should be harvested when the moisture content is in a range of 16-20%. Traditional drying utilizes a high temperature air stream passed through the seed mass without dehumidification. The drying time is long because the system is inefficient and the high temperature increases the risk of thermal damage to the seed. New technology identified as heat pipe technology (HPT) is available and has the unique feature of removing the moisture from the air stream before it is passed through the seed mass at the same environmental temperature. Two studies were conducted to evaluate the performance of HPT for dry soybean seed. In the first study the seeds were dried from 17.5 to 11.1% in 2 hours and 29 minutes and in the second sudy the seeds were dried from 22.6 to 11.9% in 16 hours and 32 minutes. This drying process caused no reduction in seed quality as measured by the standard germination, tetrazolium-viability, accelerated aging and seedling vigor classification tests. The only parameter that indicated a slight seed quality reduction was tetrazolium vigor in the second study. It was concluded that the HPT system is a promising technology for drying soybean seed when efficiency and maintenance of physiological quality are desired.

Soybean (Glycine maxL. Merrill) Seed Drying in Fixed Bed: Process Heterogeneity and Seed Quality

“…[1] Soybean seed production also depends on availability of adequate facilities at harvest and processing, such as the adequate conditions for seed drying. [2] Seed quality is defined as a measure of characters or attributes that will determine the performance of seeds when sown or stored. [3] It is a multiple concept encompassing genetic quality, seed health, physical aspects, viability and vigour.…”

Cinética de secagem do nabo forrageiro (Raphanus sativus L.)

“…Recentemente têm sido realizados inúmeros trabalhos com o objetivo de identificar as características de diversos produtos agrícolas durante a secagem de oleaginosas como: soja (FREGOLENTE, et al, 2003;KRZYZANOWSKI;WEST;FRANÇA NETO, 2006), mamona (GONELI, 2008), girassol (SANTOS, 2009) e pinhão manso (ULLMANN et al, 2010). Na literatura, existe carência de informações a respeito das alterações que podem ocorrer nas características das sementes de nabo forrageiro ao longo da secagem, portanto, objetivou-se neste trabalho estabelecer o modelo matemático que melhor descreve a cinética de secagem de sementes de nabo forrageiro, bem como o coeficiente de difusão e a energia de ativação em diferentes condições de ar.…”

Price and Quality of Coffee (Coffea Arabica L.) Dried Using Air Dehumidified by Convection

“…Some authors such as Krzyzanowski et al, (2006a); Krzyzanowski et al, (2006b); Levien et al, (2008); and Avelar et al, (2011), have already tested the heat pipe technology (HPT) and proved its efficiency in drying grains. In coffee, this drying method also showed results that corroborate our findings on the maintenance of grain quality.…”

“…With the advances in drying air dehumidification (e.g., heat pipe technology -HPT), electricity became part of the drying process in a financially competitive scenario. In Brazil, HPT was firstly applied in peanut drying by Krzyzanowski et al, (2006a), as well as in soybean by Krzyzanowski et al, (2006b); Levien et al, (2008); and Avelar et al, (2011). These authors used dehumidified air to dry seeds and found a reduction in drying time and greater maintenance of seed physiological quality.…”