Acid-Adapted Polyphenol Oxidases from Agricultural Wastes: Extraction, Characterization, and Application in Plant Protein Crosslinking

Polyphenol oxidases (PPOs) are enzymes that oxidize mono- and diphenolic compounds to o-quinones, facilitating pigment formation and protein crosslinking in food systems, thereby improving their techno-functional properties. However, most PPOs function op- timally near neutral pH, limiting their application in acidic food products. This study aimed to extract acid-adapted PPOs from various fruit by-products, including Hass avo- cado seeds (pH 5.9), Anjou pears (pH 4.0), Bartlett pears (pH...