Peroxidase broccoli

Avoid rare red meat and vegetables with peroxidase activity (turnips, broccoli, cauliflower, and radishes) for 3 days prior to testing... 

Enzyme Purification. Broccoli contained sufficient levels of peroxidase, lipase and cystine lyase to permit their isolation in the amounts needed. Only traces of lipoxygenase and catalase were present. Activities (units/g vegetable see assay methods below) were peroxidase, 220 lipase, 12 lyase, 0.26. Catalase was M) units/g in broccoli compared to 19 in English green peas lipoxygenase was 2 units/g in broccoli compared to 110 in English green peas. Peroxidase, lipase and cystine lyase were purified by... 

Aroma Analysis. Isolated peroxidase, lipase and cystine lyase were added singly and in various combinations to homogenates of blanched broccoli (free of enzyme activities) at the same activity level they were present in the unblanched broccoli. The samples were incubated at 30°C for three hours in a water bath and then cooked on hot plates for 20 min at 93°C. A teaspoon of sample was put into each of several wine glasses, the glasses covered and the samples incubated at room temperature (23 1°C) for at least 15 min before evaluation by the panel. 

Figure 1. Schematic diagram of the purification of peroxidase, cystine lyase and lipase from broccoli. PVP, polyvinylpyrrolidone PALP, pyridoxal-5 -phosphate.

Figure 2. Average aroma intensity differences from the blanched reference of broccoli puree, a, Samples are control, added peroxidase, added lipase, and added lyase. Aroma descriptors designated with shaded bars are statistically different from the blanched reference sample at p < 0.05. Continued on next page.

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