Effect of Different Blanching Methods on the Activity of the ‎Peroxidase Enzyme and the Quality Characteristics of Frozen ‎Carrot Slices

Batool Alansari*(1) and Abdulrahman Hasan Laftah(1)

(1). Department of Food Science, Faculty of Agriculture, University of Basrah, Basra, Iraq.

(*Corresponding author: Dr. Batool Alansari. E-Mail: batool.Mahmod6@gmil.com).

Received: 04/04/2020                               Accepted: 03/06/2020


This study was carried out between January to February 2019 in Basra University, Faculty of Agriculture, at laboratory of Food Science Department  to determine the effect of different blanching methods (boiling water immersion T1, steam T2 and microwave T3) for 5 minutes on the activity of the peroxidase enzyme and the quality characteristics of the carrot slices stored in freezing for a period of 30 days. The activity of the peroxidase enzyme was measured for all treatments and some chemical and sensory tests of carrot slices were performed before and after freezing. The results showed that there were significant differences at the probability level (P <0.05) between T3, T2, and T1 treatments compared to the T0 control treatment (un blanched carrots), as the enzyme activity decreased gradually as the storage period progressed. It is noted from the results that banching time was insufficient to stop the activity of the enzyme, which is evidence of the efficiency of the blanching process, while the percentage of moisture and pH increased, while the ratio of dry matter, the percentage of total acidity and the content of ascorbic acid to the treatments T3, T2, T1 decreased compared with T0 (control treatment). The results of the sensory tests showed that there were no significant differences at the probability level (P <0.05) between the T3, T2, and T1 treatments compared to the T0 (control treatment). The best treatment was the blanching method with boiling water immersion and microwave blanching in terms of color and texture, whereas there were no differences in taste and smell for all treatments after the end of the freezing storage period.

Key words: Peroxidase, Freeze storage, Carrot, Blanching, Ascorbic acid.

Full paper in Arabic: PDF