Wild blueberry polyphenol-protein food ingredients produced by three drying methods: Comparative physico-chemical properties, phytochemical content, and stability during storage

Particulate colloidal aggregate food ingredients were prepared by complexing wheat flour, chickpea flour, coconut flour and soy protein isolate with aqueous wild blueberry pomace extracts, then spray drying, freeze drying, or vacuum oven drying to prepare dry, flour-like matrices. Physico-chemical attributes, phytochemical content and stability during storage were compared. Eighteen anthocyanins peaks were identified for samples. Spray dried matrices produced with soy protein isolate had the highest concentration of polyphenols (156.2 mg GAE/g) and anthocyanins (13.4 mg/g) and the most potent DPPH scavenging activity (714.1 μmoles TE/g). Spray dried blueberry polyphenols complexed with protein were protected from degradation during 16 weeks at 4 °C and 20 °C. Soy protein isolate more efficiently captured and stabilized wild blueberry pomace phytochemicals than other protein sources. Overall, spray drying the blueberry extracts complexed with protein proved to be an environment-friendly strategy to produce stable functional ingredients with multiple applications for the food industry.