Changes in carbohydrate quality of high-pressure treated aqueous aquafaba

Abstract

Aquafaba is the water residue of cooked chickpeas. Aquafaba's main constituents are carbohydrates and proteins which are responsible for the structural-functional properties in food. The focus of this research was to enhance carbohydrate functionality and digestibility by high pressure (HP) treatment. Specifically, the target was to increase starch digestibility and crystallinity, and formation of resistant starch, and finally to enhance the elastic modulus G′ and consistency coefficient. HP treatment (227–573 MPa for 6–24 min) was applied on aquafaba slurry prepared from different concentrations of freeze dried aquafaba and water (11–29%; w/w). A response surface methodology was used for the experimental design and the results were compared with those from untreated aquafaba. HP treatment increased consistency coefficient as well as G’. The increase in G′ and decrease in tan δ, indicate a structure enhancement by HP treatment resulting in a more cohesive gel network. HP treatment also enhanced starch digestibility and increased resistant starch content significantly from 24.3 to 26.9% (RDS), 0.8–4.1% (SDS), 25.1–31.5% (TDS), and 3.8–4.4% (RS). HP treatment also increased the starch crystallinity as evaluated using both FTIR (as a ratio of 1048/1022 cm−1 bands) and X-ray diffraction (XRD) techniques. Crystallinity increased from 6.9 × 10−1 in control to 8.0–8.4 × 10−1 (FTIR) for pressure treated samples and from 30 to 53% (XRD).