How does processing legumes into protein concentrates and isolates affect their mineral content and nutritional safety?
This study evaluated the mineral composition, Recommended Dietary Allowance contributions, and Mineral Safety Index of five underutilised legume varieties across three processing stages: defatted flour, protein concentrate, and protein isolate.
The results showed that potassium was the predominant macro-mineral and increased substantially during processing, rising from 654.02–804.61 mg/100 g in defatted flour to 1216.55–1352.50 mg/100 g in protein isolates.
Calcium, phosphorus, iron, zinc, and copper also became more concentrated during protein isolation.
In contrast, manganese decreased markedly, falling from 1.02–2.14 mg/100 g in defatted flour to 0.02–0.25 mg/100 g in protein isolates, suggesting that much of the manganese was lost during aqueous fractionation.
Sodium increased moderately during processing, reaching 280.50–291.99 mg/100 g in the protein isolates.
A 100 g portion of the protein isolates could provide up to 52% of the adult adequate intake for potassium and about 70% of the Recommended Dietary Allowance for both calcium and phosphorus.
The sodium-to-potassium ratio remained favourable at 0.17–0.25, while the calcium-to-phosphorus ratio reached as high as 2.063 in the protein isolates.
Mineral Safety Index assessment showed wide safety margins for the defatted flours and protein concentrates.
However, the increased concentration of trace elements in the protein isolates narrowed the safety margin, particularly for copper.
The findings indicate that these legume protein fractions can serve as nutrient-dense ingredients, but the amount of protein isolate used in food formulations should be carefully controlled.
The authors particularly emphasise the need for careful portion control when these concentrated protein fractions are intended for paediatric formulations.
📖 Read the full article here:
https://doi.org/10.61298/rans.2026.4.2.369
Published in: Recent Advances in Natural Sciences