Comparative Analysis of Dry and Wet Fractionated Red Lentil Proteins for Food Applications

Authors: PULIVARTHI, MANOJ - Kansas State University; RAJPUROHIT, BIPIN - Kansas State University; CHAKRABORTY, SNEHASIS - Kansas State University; LI, YONGHUI - Kansas State University; Bean, Scott; SILIVERU, KALIRAMESH - Kansas State University

Submitted to: Sustainable Food Proteins
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/8/2025
Publication Date: 9/4/2025
Citation: Pulivarthi, M., Rajpurohit, B., Chakraborty, S., Li, Y., Bean, S.R., Siliveru, K. 2025. Comparative Analysis of Dry and Wet Fractionated Red Lentil Proteins for Food Applications. Sustainable Food Proteins. https://doi.org/10.1002/sfp2.70030.
DOI: https://doi.org/10.1002/sfp2.70030

Interpretive Summary: Proteins in plants can have important functional roles in food products and be used to develop novel food products. Before being used in food products, plant proteins must first be extracted or concentrated. Extraction of proteins from plants often uses harsh chemicals which can influence the functional properties of the proteins and add substantial cost to the procedure. Dry fractionation is an alternative method for concentrating plant proteins that does not involve the use of a chemical extraction process. This research compared the purity and functional properties of lentil proteins prepared using chemical extraction methods and dry fractionation. Differences in functionality were found between the two processes showing that proteins prepared using dry fractionation had improved properties for some food applications. This research could be applied to the preparation of proteins from other sources such as wheat and sorghum, creating new market opportunities for these crops.

Technical Abstract: Plant proteins are increasingly recognized for their role in sustainable diets, with functional properties being critical for food applications. However, the influence of extraction methods on legume proteins remains under explored. This study compared dry, wet, and mild fractionation for producing protein-rich red lentil fractions and assessing their nutritional and functional properties. Whole red lentils were tempered to 12% moisture, roller-milled and then pin-milled to create a fine parent flour (d90 < 40 µm) suitable for air classification and wet extraction. Air classification at 10,000, 7,000, 6,000, and 4,000 rpm classifier speeds yielded protein-rich fractions, with the 6,000 rpm setting (cut point 22 µm, d90) offering an optimal balance of purity and yield. In wet fractionation, lentil protein isolate (89.2% protein) was produced through alkaline extraction and isoelectric precipitation, while mild extraction produced lentil protein concentrate by just alkaline extraction (64.2% protein). Functional analysis showed wet-extracted isolates performed better in emulsification, water, and oil absorption, while dry-fractionated proteins performed better in foaming, solubility, and gelling. Mild wet-extracted concentrates demonstrated good emulsification and oil absorption but poor foaming stability. Amino acid analysis showed that red lentil protein isolate had higher concentrations of hydrophobic amino acids, particularly isoleucine, leucine, and phenylalanine compared to the dry-fractionated samples, which may contribute to its enhanced emulsifying properties. The dry-fractionated samples maintained a similar amino acid profile as that of lentil flour contributing to its native functionality. In conclusion, dry fractionation offers a sustainable, eco-friendly alternative to wet extraction, preserving native protein integrity while delivering comparable functionality.