Seed germination improves air classification efficiency of pea and faba bean flours

Increasing interest in incorporating pulses into human diets has increased demand for their fractionation into diverse food ingredients. Air classification has relatively low capital and operating costs, uses no water, and preserves the native protein structure. However, its efficiency in separating protein and starch is lower than that of wet fractionation. This study investigated seed germination of pea and faba bean for 24, 48, and 96 h as a pretreatment to improve the air classification efficiency of pulse flours into fine (protein-rich) and coarse (starch-rich) streams.

Scanning electron microscopy revealed that germination disrupted the protein and fiber matrices surrounding starch granules in pea and faba bean seeds, improving subsequent air classification efficiency. Following 24-96 h of soaking and germination, the fine stream yield increased from 251 to 295 g kg⁻¹ for pea and from 274 to 364 g kg⁻¹ for faba bean. Protein retention in the fine stream - the proportion of total protein recovered - also increased, from 620 to 686 g kg⁻¹ for pea and from 702 to 882 g kg⁻¹ for faba bean, both at 48 h of germination. After 96 h, protein retention declined. In contrast, germination had no effect on the starch retention in the coarse stream.

In conclusion, 48 h of germination of pea and faba bean seeds is sufficient to improve the air classification efficiency of the resulting pulse flours. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.