The ash content of air-classified plant protein powder produced via dry fractionation is generally 4.0 – 7.5 % (dry basis), varying by legume source, raw material pre-treatment and separation efficiency.
Key breakdown
- Pea protein (dry air-classified concentrate)
Typical range: 4.5 – 7.0 % db. Minerals mainly come from cotyledon cell salts, seed coat fragments and residual fibre. If dehulling is thorough, ash can drop toward the lower end (4.0–5.0%). Poor dehulling introduces hull minerals and raises ash above 7%. - Chickpea protein (dry air-classified concentrate)
Typical range: 4.8 – 7.5 % db. Chickpea naturally contains higher potassium, calcium and magnesium than peas, leading to slightly higher baseline ash.
Comparison with wet-extracted protein
Wet-isolated protein isolates commonly show ash of 2.0 – 4.0 % db, because soluble minerals are washed away during aqueous extraction. Dry fractionation retains intrinsic minerals from the seed matrix, hence higher ash.
Factors that shift ash value
- Dehulling efficiency: residual seed coat significantly increases ash
- Air classification cut point: finer protein fines carry more mineral-rich fine fibre
- Raw bean moisture, growing soil and crop season
- Post-processing: additional washing or thermal treatment will alter ash
