Document Type : Original Article
Authors
1 Mechanical Engineering of Biosystems Tarbiat Modares University, Tehran
2 Department of Biosystem Engineering, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
3 Department of Food Science and Technology, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
Abstract
In this study, the effect of the ohmic heating process with different voltage gradients (5, 7.5, and 10 V/cm) on the physicochemical and color properties of sour orange juice at various weight loss levels (10%, 20%, and 30%) was investigated. Principal Component Analysis (PCA) was used to analyze the data and differentiate quality characteristics among the samples. Parameters such as flavonoids, total phenols, color indices (L*, a*, b*), pH, soluble solids, browning index, and total color change were measured as key quality indicators. The results showed that a 10% weight loss under a 5 V/cm voltage gradient led to better preservation of bioactive compounds and the natural color of the product. In contrast, higher weight loss and the application of higher voltage gradients (especially 10 V/cm) caused degradation of bioactive compounds, increased soluble sugars, and intensified browning. The 7.5 V/cm voltage gradient showed a more balanced performance compared to the other two. These findings indicate that the optimal combination of a low voltage gradient with limited weight loss yields the best results in maintaining the nutritional and visual quality of sour orange juice. Therefore, this method can be used as an efficient approach in the industrial processing of natural extracts to preserve nutritional value and visual appeal.
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