Leaf protein concentrate from cauliflower leaves: Effect of filtration and stabilizing solution on extraction and physio-chemical properties

This study aimed to investigate the potential of cauliflower leaf-by-product as a renewable protein source through comprehensive physio-chemical analysis. The objectives were to evaluate the effect of alkaline acid precipitation method along with stabilizing solution (NaCl, ethylenediaminetetraacetic acid [EDTA] and sodium metabisulphite) concentrations (5, 10, and 15 %; 5 % water as control) and sieve filtration (124 μm) on the properties and yield of cauliflower leaf protein concentrates (CAU-LPCs). The fresh cauliflower leaves have a moisture content of 88.74 %. After drying the moisture content of dry leaves reduced to 11.26 % and had a crude protein content of 19.81 %. Particle size distribution of cauliflower leaf juice was influenced by stabilizing solution concentration and sieve filtration. The combination of stabilizing solution and sieve filtration significantly influenced particle size distribution of LPCs. Protein mass balance analysis revealed significant losses during processing, particularly after sieve filtration and centrifugation of alkaline leaf juice. Moisture content of CAU-LPCs ranged from 3 to 4.5 %. Colour analysis showed significant differences based on stabilizing solution and filtration, impacting consumer acceptability. Sieve filtration reduced yield of CAU-LPCs, while stabilizing solution had no significant effect. Protein content was higher in filtered samples (62.44 %), with a plateau observed beyond 5 % stabilizing solution concentration. Zeta potential analysis showed differences between filtered and non-filtered samples. Protein solubility increased with pH, with lower solubility observed in sieve filtered samples. Thermal analysis indicated denaturation peak temperatures ranging from 60.23 to 62.83 °C. SEM images revealed a structured, multi-layered morphology influenced by processing conditions. These insights contribute to understanding of how extraction parameters impact CAU-LPC properties, offering a promising avenue for scalable industrial protein production from underutilized green biomass.