Characterization of chlorophyll breakdown in green prickleyashes (Zanthoxylum schinifolium Zucc.) during slow drying

To investigate the possible mechanism of color degradation of green prickleyashes (Zanthoxylum schinifolium Zucc.) in slow drying, changes in their peel colors, enzyme activities, content of chlorophylls (Chls) and derivatives were evaluated. The results showed the peel color changed from brilliant green to black-brown and Chls underwent a rapid degradation. Enzyme activities changed as follows: chlorophyllase activity decreased; chlorophyll-degrading peroxidase (Chl-POD) activity as well as pheophorbidase (Pheidase) exhibited a biphase trend displaying an inverted “V” phase, and the increase in Chl-POD resulted in the accumulation of C13²-hydroxy-chlorophyll a. Based on the study of enzyme activities and Chl degradation, conclusions were drawn that Chl-POD and Pheidase were considered as the key enzymes to promote chlorophyll breakdown. Compared with slow drying, fast drying could inhibit the two key enzyme activities and blockade the chlorophyll-degrading pathway, which was proposed to process green prickleyashes.