Collard Green Extracts as Potential Inhibitors of Enzymatic Browning

/is study seeks to assay the phenolic extract of collard greens (CGs) as a new source of inhibitor for polyphenol oxidase (PPO), the primary enzyme responsible for enzymatic browning. The extract of CGs obtained under optimized extraction conditions had a total phenolic content (TPC) and a ferric-reducing antioxidant power (FRAP) value of 2.35 ± 0.23 mmol gallic acid equivalent/L and 3.35 ± 0.06 mmol Trolox equivalent/L, respectively. To enhance the extracts’ inhibitory activity, an acid hydrolysis treatment (0.3–0.6M HCl, 2 h at 80°C) was applied to convert glycosidic phenolic compounds into aglycones. /is treatment signiCcantly increased the concentration of Davonoids, including catechin and its derivatives, as well as the cupric chelating activity of the extract (p 0.05). /e acid-hydrolyzed and nonhydrolyzed extracts were tested as natural inhibitors of PPO, sourced from Jerusalem artichoke tubers (JAT), with ascorbic acid (AA) as a reference inhibitor. Kinetic analysis indicated that the nonhydrolyzed extract and AA performed as competitive inhibitors (increased Michaelis–Menten constant [Km] and stable maximum velocity [Vmax]), whereas the acid-hydrolyzed extract exhibited mixed-type inhibition (increased Km and decreased Vmax). To validate the eHect of the extracts on the real food models, the eHect of the inhibitors was tested on the fresh-cut slices of JAT by measuring colorimetric parameters, and the results revealed that the acid-hydrolyzed extract had a signiCcantly higher browning inhibition compared to nonhydrolyzed extract and AA. /ese Cndings highlight the potential of extracts of CGs, particularly in their hydrolyzed form, as eHective natural inhibitors of enzymatic browning in food applications.