Optimization of the foam-mat drying process to develop high-quality tomato powder: A response surface methodology approach

This research aimed to estimate the optimum formulation of process parameters in making tomato powder with optimal physicochemical properties using foam-mat drying. The egg albumin (EA) concentration (1–5%), carboxymethyl cellulose (CMC) concentration (1–1.5 %), and drying temperature (60–70 °C) were employed as independent variables in optimizing through Response Surface Methodology (RSM) in combination with Box-Behnken experimental design (BBD). Based on the total 17 runs of BBD, foam-mat dried powder showed physicochemical properties such as 0.18–0.33 g/cm(3) foam density, 178.54–350 % foam expansion, 40–94 % foam stability, 46.80–62 % water soluble index (WSI), 1.13–2.96 water absorption index (WAI), 1.51–2 °Brix TSS, 2.30–3.98 mg/100 mL ascorbic acid, 0.22–0.38 % titratable acidity, and color (L∗: 29.26–48.07, a∗: 9.73–16.86, and b∗: 6.81–21.56). Furthermore, the ANOVA findings revealed the correlation of determination (R(2)) exceeding 85 % for the models, suggesting that the interaction between the responses and the prediction of the implied model is suitable. The optimal formulation from RSM was 4.59 % EA, 0.70 % CMC, and 60 °C drying temperature. Under the optimized conditions, the experimental values were 0.19 ± 0.03 g/cm(3) foam density, 346.60 ± 3.35 % foam expansion, 89.05 ± 2.80 % foam stability, 55.56 ± 3.22 % WSI, 2.49 ± 0.09 WAI, 1.84 ± 0.15 °Brix TSS, 2.93 ± 0.10 mg/100 mL ascorbic acid, 0.39 ± 0.02 % titratable acidity, 46.95 ± 6.35 L∗, 17.54 ± 1.50 a∗, and 21.85 ± 0.74 b∗. The optimized parameters were verified, and there was good agreement between the experimental results and the predicted values (residual standard error (RSE) ≤ 5).