An Improved pH-Driven Method for Upcycling Polyphenols from Plants or Byproducts into Foods

The incorporation of polyphenols into food systems provides various health benefits, yet their stability and bioactivity are often compromised by processing conditions. In this study, we advanced the pH-driven method for processing highly pH-sensitive polyphenols, such as quercetin, by optimizing operating conditions, including minimizing oxygen exposure and reducing operating times. As a result, an improved post-pH-driven (PPD) method was developed to encapsulate pH-sensitive quercetin into nanoemulsions with an encapsulation efficiency exceeding 95%, indicating that this method could be broadly applicable for incorporating various polyphenols. For example, it has been successfully applied to upcycle plant polyphenols from peanut skin into nanoemulsions, serving as a representative food model. The PPD method demonstrated superior performance compared to a conventional water-based method, achieving 1.8 times higher remaining percentage of total polyphenolic content. Additionally, the PPD-based nanoemulsions exhibited significantly enhanced antioxidant properties, with DPPH and ABTS radical scavenging activities increasing by 3.7 and 2.8 times, respectively, compared to the water-based method. These findings underscore the potential of the PPD method as a versatile and efficient approach for developing polyphenol-powered foods by upcycling plant byproducts and improving processing efficiency.