This study investigates the dry pneumatic separation of wheat flour using a newly designed rotating air classifier to obtain starch- and protein-enriched fractions. The process is based on differences in particle density and size, enabling separation without water or chemical reagents. The influence of key process parameters, including air flow velocity 6–12 m/s, classifier geometry, and particle size distribution, was investigated. Statistical analysis confirmed that the air flow velocity and orifice diameter significantly affect the separation efficiency. The optimal conditions of 9–10 m/s and 1.8 mm resulted in a starch fraction with a purity of about 89% and a protein-enriched fraction containing approximately 45% protein. Regression models (R2 > 0.99) demonstrated a strong relationship between the process parameters and fraction yield. Compared with conventional wet fractionation, the proposed method reduces energy consumption by approximately 28% and eliminates water use. These results confirm the feasibility of dry pneumatic classification as a sustainable and efficient technology for producing functional wheat-based ingredients. All experiments were conducted in triplicate (n = 3), and the results are presented as mean ± standard deviation. The reported yields correspond to the fraction mass, while the composition values indicate component purity within each fraction.
Rzayev et al. (Wed,) studied this question.