Abstract
Broccoli heads stored at 20°C soon after harvest (non-heat treatment) showed a decrease in soluble protein content and a rapid increase in free amino acid content, whereas broccoli heads dipped in 45°C water for 14 minutes did not show changes during storage in soluble protein content or free amino acid content.
On PAGE patterns of soluble proteins of broccolis, three protein components (a, b and c) were observed soon after harvest. The main component (c) of non-heat treated broccolis decreased during storage, whereas this component in heat treated samples did not change. On SDS-PAGE patterns of soluble proteins of broccolis, the main component (48.5 kDa) of non-heat treated samples decreased during storage, whereas this component in heat treated specimens did not change.
The proteinase activity of non-heat treated broccolis increased rapidly, whereas the activity of heat treated samples was low during storage. PCMB and leupeptin strongly inhibited the proteinase activity of non-heat treated broccolis after 5 days storage. Iodoacetic acid and iodoacetamide inhibited the proteinase activity of non-heat treated samples, whereas they did not inhibit the activity of heat treated specimens. These results suggest an increase in cysteine proteinase activity in non-heat treated broccolis during storage.
