Soy protein isolate-pectin from Nicandra Physaloides (Linn.) Gaertn seeds nanogels: A hydrocolloid system for blueberry preservation

Resveratrol (Res) and Phloretin (Pht) are natural compounds with antioxidant and anti-inflammatory activities, yet their practical applications face certain limitations. In this study, nanogels were utilized as carriers to enhance their characteristics and bioactivities. Soy protein isolate (SPI) and pectin (NPGP) derived from <i>Nicandra physaloides</i> (Linn.) Gaertn seeds were successfully prepared using a two-step method involving Maillard dry heat and heated self-assembly. SPI-NPGP nanogels (NGs) of were determined to be 2 mg/mL SPI-NPGP grafts, heat-treated at 90 °C for 40 min at pH = 4.6. The loading efficiency of NGs containing Res and Pht reached 4.03% and 8.15%, respectively, and Res/Pht-NGs were spherical in shape, uniformly distributed, and hydrophilic. Stability studies confirmed their good pH tolerance, storage stability, <i>in vitro</i> stability, along with strong antioxidant activity. Additionally, Res/Pht-NGs showed significant inhibitory effect against <i>Staphylococcus aureus</i> (<i>S. aureus).</i> The application of Res/Pht-NGs in blueberry preservation effectively reduced weight loss and decay incidence by slowing respiratory rates, preserving anthocyanin content, antioxidant capacity, and flavonoid levels, while inhibiting the degradation of volatile organic compounds. In conclusion, Res/Pht-NGs exhibit excellent stability and effective blueberries preservation, offering a novel approach for food preservation and the application of NPGP.