Dry fractionation as a promising technology to reuse the physically defected legume-based gluten-free pasta

Abstract

Dry fractionation was applied to the legume-based pasta (yellow lentils:whole rice 90:10 w:w) discarded for physical defects. After the air classification, the fine fraction showed a 33% increment of the protein content compared to the raw material, with a 21% yield. The scanning electron micrographs revealed the presence of protein–starch complexes and broken starch granules which led to a low protein separation efficiency. The fine fraction showed interesting nutritional features due to the high concentration of the essential micronutrients Zn (43.3 mg kg−1) and Fe (72.6 mg kg−1). However, also the alpha-galactosides were enriched into the same fraction. The two fractions, fine and coarse, were both characterised by elevated water absorption capacity, with significantly higher values in the fine one. Finally, the gelling capacity varied among the fractions, being influenced by the protein content. Overall, these ingredients could be used to fortify the protein and the essential mineral contents of bakery products, sauces, and creams.