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Carrot juice obtained by hydraulic press with wooden set-up was subjected to pretreatments (temperature, time and pH) prior to extraction process. Their effects on the most important quality parameters of carrot juice, such as beta-carotene, reducing sugars, pectin, vitamin C, viscosity, pH and acidity were studied. Response surface methodology was employed, where the experiment was carried out according to a central composite rotatable design. The variables ranges used were 61.50-98.50°C (temperature), 124.55-595.45 s (time) and 2.31-6.69 (pH -concentration of citric acid). The results showed that beta-carotene extraction was significantly increased (52.9%) with these pretreatments in comparison to control samples. All the derived mathematical models for the responses were found to be fit significantly to predict the data. The responses were optimised by numerical method and were found to be 7190 lg per 100 g beta-carotene, 3.41% reducing sugars, 4.96 mg per 100 g vitamin C, 0.59% pectin, 1.64 · 10 3 Ns m )2 viscosity, 5.26 pH and 4.97% acidity at optimum input variables of 75.26°C (temperature), 349.89 s (time) and 3.2 (pH). The desirability for all the responses was found to be 83.8%.

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