Evolution of ascorbic acid and peroxidase during industrial processing of broccoli
2000
Murcia, M.A. | Lopez-Ayerra, B. | Martinez-Tome, M. | Vera, A.M. | Garcia-Carmona, F.
The ascorbic acid content and peroxidase activity of raw, canned and frozen (after blanching times of 60, 90, 120 and 150 s) broccoli florets and stems were determined. The ascorbic acid content represented 1.12 and 0.78 g kg-1 fresh weight in raw florets and stems respectively. After blanching (for different times) and freezing, the ascorbic acid content decreased to values of 0.55-0.56 g kg-1 fresh weight in florets and 0.35-0.36 g kg-1 fresh weight in stems. The industrial processing involved in canning decreased the ascorbic acid content to 0.18 g kg-1 fresh weight in florets. The peroxidase activity observed in the florets and stems of raw broccoli was 308.8 and 278.6 micromole min-1 per 100 g fresh weight respectively. The peroxidase activity remaining in frozen florets varied from 0.9 to 0.2%, while that in stems showed values of between 7.5 and 8.4%. These values for stems were within the range recommended for residual activity after blanching and freezing. The peroxidase activity of canned broccoli florets was practically undetectable.
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