Changes in bioactive compounds and microstructure in persimmon (Diospyros kaki L.) treated by high hydrostatic pressures during cold storage

High hydrostatic pressure (HHP) processing modifies the localization, concentration, and activity of the bioactive compounds of plant foods. The aim of this study was to evaluate changes in carotenoids and total phenolics of persimmon (astringent fruits, cv. Rojo Brillante) pieces submitted to high pressures and stored at 4oC during 28days. A microstructure study was conducted by Light Microscopy (LM) and Cryo Scanning Electron Microscopy (Cryo-SEM). Individual carotenoids were analyzed by HPLC, total phenolic content by Folin-Ciolcateau and antioxidant activity by DPPH methods, respectively. HHP treatment produced a significant increase in the extractability of carotenoids (23%-28%) but a decrease in total phenolics (20%). During cold storage, there was a progressive release of cell content toward the apoplast due to the damages in membranes and cell walls produced by HHP treatments. This fact produced a significant decrease in carotenoid and phenolic contents and in antioxidant capacity in all persimmon samples.