Manufacture of defatted canola meal with enhanced nutritive composition by air classification on an industrial scale

Air classification was used to fractionate canola meal (CM). The effect of combinations of air classification conditions, including rotor speed ranging from 300 to 1200 rpm, air stream rate from 700 to 860 cfpm, and secondary air from 0 to 30%, on particle size and nutritive composition was investigated. Response surface methodology was used to develop response surface equations to estimate these effects.

Protein concentration increased in almost all the fine fractions. Effects of both secondary air and rotor speed of the air classifier were significant at P ≤ 0.1 and P ≤ 0.01, respectively. Almost all the fine fractions contained more oil. Rotor speed, air stream rate, and their interaction were significant at P ≤ 0.01. Both acid detergent fiber (ADF) and neutral detergent fiber (NDF) were shifted to the coarse fractions during the air classification. The rotor speed was significant for both ADF and NDF at P ≤ 0.01.

Protein shifted to the fine fractions. The highest protein concentration in the fine CM fraction was estimated to be 404.2 g kg^-1 , demonstrating an enhancement of 10.7%. ADF and NDF shifted to the coarse CM fractions and were respectively estimated to be 294.8 and 332 g kg^-1 , which were increased by 52.7% and 43.7%. Oil shifted to the fine fractions. The highest concentration was predicted to be 59.7 g kg^-1 , increased by 45.6%. Fine or coarse fraction yields were estimated to be 35-50%, indicating that they are acceptable for an industrial manufacture. © 2019 Society of Chemical Industry.