Bioprocessing strategies to improve the extractability and functional properties of lipids, proteins, and carbohydrates from full-fat chickpea flour

Abstract

Interest in sustainable cost-effective and efficient extraction processes of plant-based matrices has risen due to health, environmental, and social concerns. The concurrent extraction of lipids, proteins, and carbohydrates can be achieved by aqueous and enzymatic extraction processes, addressing low extractability by mechanical pressing and the use of flammable solvents. Being a source of proteins, starch, and fiber, chickpeas can be used as a matrix to generate added value compounds for food, feed, and fuel applications. The application of alkaline protease, preceded or not by carbohydrase pretreatments, was evaluated on the extractability of oil, protein, and carbohydrates from full-fat chickpea flour and protein functionality. Enzymatic extraction increased oil and protein extractability from 49.8 to 72.0–77.1% and 62.8 to 83.5–86.1%, respectively. Although the use of carbohydrase pretreatments, before the addition of protease, did not increase oil and protein extractability, it did increase the carbohydrate content of the extracts from 7.7 to 9.2–9.3 mg/mL, with the release of new oligosaccharides revealed by LC-MS/MS. Enzymatic extraction produced proteins with higher solubility (25.6 vs. 68.2–73.6%) and in vitro protein digestibility (83.8 vs. 90.79–94.7%). Post-extraction -galactosidase treatment of the extracts completely hydrolyzed flatulence-causing oligosaccharides into simple sugars. However, because high water usage is a requirement to maximize extractability in single-stage extractions, a two-stage countercurrent extraction process was developed to reduce water usage without loss in extractability. Countercurrent extraction reduced ~50% of the water used in the extraction while increasing oil and protein extractability to 95.8 and 95.7%, respectively. Techno-economic analysis demonstrated improved annual profitability of the countercurrent process despite its higher operating costs. This study highlights the effectiveness of solvent-free enzymatic strategies to maximize process extractability and feasibility, shedding light on the development of a more competitive process to produce chickpea proteins, lipids, and potential prebiotic oligosaccharides for subsequent industrial applications.