Degradation Kinetics of Peroxidase Enzyme, Phenolic Content, and Physical and Sensorial Characteristics in Broccoli (Brassica oleracea L. ssp. Italica) during Blanching

• Published in: Journal of agricultural and food chemistry Vol. 57; no. 12; pp. 5370 - 5375
• Main Authors: Gonçalves, Elsa M, Pinheiro, Joaquina, Alegria, Carla, Abreu, Marta, Brandão, Teresa R. S, Silva, Cristina L. M
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 24.06.2009
• Subjects: Biological and medical sciences; Brassica - chemistry; Brassica - enzymology; Chemical Changes Induced by Processing/Storage; Food Handling; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; Hot Temperature; Kinetics; Peroxidase - chemistry; Phenols - analysis; Plant Proteins - chemistry; blanching; kinetics modeling; Broccoli; quality parameters; Vegetables; Enzyme; Modeling; Degradation; Brassica oleracea; Peroxidases; Cruciferae; Dicotyledones; Quality; Angiospermae; Phenols; Spermatophyta; Peroxidase; Oxidoreductases; Kinetics; Blanching
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf900314x

The effects of water blanching treatment on peroxidase inactivation, total phenolic content, color parameters [−a*/b* and hue (h°*)], texture (maximum shear force), and sensory attributes (color and texture, evaluated by a trained panel) of broccoli (Brassica oleracea L. ssp. Italica) were studied at five temperatures (70, 75, 80, 85, and 90 °C). Experimental results showed that all studied broccoli quality parameters suffered significative changes due to blanching treatments. The vegetal total phenolic content showed a marked decline. Degradation on objective color and texture measurements and alterations in sensorial attributes were detected. Correlations between sensory and instrumental measurements have been found. Under the conditions 70 °C and 6.5 min or 90 °C and 0.4 min, 90% of the initial peroxidase activity was reduced. At these conditions, no significant alterations were detected by panelists, and a small amount of phenolic content was lost (ca. 16 and 10%, respectively). The peroxidase inactivation and phenolic content degradation were found to follow first-order reaction models. The zero-order reaction model showed a good fit to the broccoli color (−a*/b* and h°*), texture, and sensory parameters changes. The temperature effect was well-described by the Arrhenius law.