Document Type : Research Article
Authors
1 Ferdowsi University of Mashhad
2 Department of Food Science and Technology, Ferdowsi University of Mashhad, Mashhad, Iran.
Abstract
Barberry is an agricultural product, which is cultivated in large amounts, only in Iran. Its popularity as an ingredient for many by-products has grown recently. It contains anthocyanins which can be used as natural food colorants. These compounds are useful for human health and have high economic value. Magnitude and duration of heating has a strong influence on anthocyanin stability. Temperature degrades the anthocyanins and the rates of degradation depend on the presence of oxygen, pH and their chemical structure. In this study the effect of temperature and solid content on degradation kinetic of anthocyanins in Berberis vulgaris var asperma were determined over a temperature range of 70-90◦C. Analysis of kinetic data suggested a first-order reaction for the degradation of barberry juice and concentrate anthocyanins. The half-life values were calculated 6.02, 3.32 and 1.06h for juice, 3.32, 1.84 and 0.76h for concentrate of 30 Brix and 3.19, 1.31 and 0.49h for concentrate of 50 Brix between 70 and 90◦C, respectively.The temperature-dependent degradation was modeled using Arrhenius equation. By increasing solid content, the activation energy value was increased but D-value and Z-values were reduced. The results shows that the degradation of anthocyanins in concentrates occurred at a faster rate than in juice. By increasing the temperature degradation rates were increased both in juice and concentate.
Keywords
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