S.J.R. Underhill, D.H. Simons, C. Critchley
Lychee (Litchi chinensis Sonn.) is a non climacteric subtropical fruit indigenous to Southern China. Once harvested the brilliant red pericarp colour deteriorates rapidly, with the pericarp appearing brown within 24 to 48 hours after harvest. Although browning can be effectively controlled commercially, little is known of the browning mechanism involved. Browning in lychee is considered to occur through polyphenol oxidase and peroxidase degradation of the anthocyanin pigments. Although the proposed role of polyphenol oxidase activity in lychee browning is widely accepted, little direct evidence exists to confirm this.

Current work on lychee postharvest browning under ambient storage condition questions the importance of enzyme mediated pigment degradation. Polyphenol oxidase activity was shown to decrease after harvest, with little change in total anthocyanin content of the pericarp. Results from in vivo work have highlighted the importance of vacuolar pH and its effect on pigment structure and stability. By lowering the pericarp pH in vivo it is possible to reverse already established pericarp browning.

Underhill, S.J.R., Simons, D.H. and Critchley, C. (1992). POSTHARVEST PERICARP BROWNING OF LYCHEE (LITCHI CHINENSIS SONN.) FRUIT. Acta Hortic. 321, 718-725
DOI: 10.17660/ActaHortic.1992.321.90

Acta Horticulturae