Impact of calcium‐reinforcement on stability, bioavailability, and bioactivity of quercetin‐loaded zein/alginate‐pectin nanoparticles

Cationic calcium ions can crosslink anionic alginate and pectin molecules. It was hypothesized that calcium crosslinking would improve the stability and functionality of biopolymer nanoparticles consisting of zein cores coated by alginate-pectin shells. The effects of calcium ion addition on the structural, physicochemical, and gastrointestinal properties of quercetin-loaded zein/alginate-pectin nanoparticles were therefore investigated. The nanoparticles remained stable to aggregation at calcium ion concentrations of 9 mmol/L or less but aggregated and sedimented at higher concentrations. Calcium ion reinforcement increased the particle dispersion stability even at NaCl concentrations up to 1.4 molL-1. The presence of the calcium ions also reduced quercetin release during the early stages of simulated gastrointestinal digestion but increased its release during the later stages. The relatively high release (56.1%) of quercetin from the calcium-reinforced nanoparticles after digestion resulted in higher intracellular antioxidant activities. The pharmacokinetics of the encapsulated quercetin was measured after its oral administration to rats. The maximal concentration (Cmax) of quercetin in rat plasma for calcium-reinforced nanoparticles was 6.1% higher than non-reinforced nanoparticles; the half-life (t1/2) increased by 17.5%, and the mean retention time (MRT) was 10.0% higher (P < 0.05). These results suggest that calcium ion addition improved the performance and bioavailability of nutraceutical-loaded biopolymer nanoparticles. This might find application in the food and beverage industry. © 2024 Society of Chemical Industry.