The influence of enzymatic pretreatment of chickpea on properties of protein nanoparticles prepared by heat treatment

Protein nanoparticles from chickpea protein isolates were prepared by heat treatment and their properties were evaluated. Protein was extracted from defatted chickpea seed under alkaline conditions after pretreatment with single arabinofuranosidase or combination of cellulase and xylanase, or without it. Both enzymatic pretreatments delivered protein isolates with enhanced ratio between alpha-helices and beta-sheets/beta-strands in their secondary structure comparing to alkaline isolate. Applied heat treatment was performed for 10 min or 20 min at 90 degrees C, and at pH 7 or pH 9.3. Particle size of prepared nanoparticles varied from 28 to 290 nm, with the smallest particles fabricated from isolate from (cellulase + xylanase)-assisted alkaline extraction at pH 9.3. Protein isolate extracted with the assistance of arabinofuranosidase enabled preparation of nanoparticles with the highest linoleic acid binding capacity - 58% at pH 7, and 69% at pH 9.3. Generally, nanoparticles with smaller particle sizes, and higher linoleic acid binding capacity and ABTS scavenging activity were fabricated from protein extracted by enzyme-assisted alkali protocols and at higher investigated pH. Chickpea protein isolates from enzyme-assisted extractions can be great source for preparation of nanoparticles with advanced properties for the application in food sector.