Microwave-assisted extraction of phenolic acids and flavonoids and production of antioxidant ingredients from tomato: A nutraceutical-oriented optimization study

• A 5-level full factorial design was successfully implemented for MAE optimization.
• Time, temperature, ethanol concentration and solid/liquid ratio were relevant variables.
• Antioxidant extracts rich in functional phenolic acids and flavonoids were obtained.
• Non-significant differences between experimental and predicted values were found.
• Tomato extracts presented potential as ingredients in the design of functional foods.

The production of natural extracts requires suitable processing conditions to maximize the preservation of the bioactive ingredients. Herein, a microwave-assisted extraction (MAE) process was optimized, by means of response surface methodology (RSM), to maximize the recovery of phenolic acids and flavonoids and obtain antioxidant ingredients from tomato. A 5-level full factorial Box–Behnken design was successfully implemented for MAE optimization, in which the processing time (t), temperature (T), ethanol concentration (Et) and solid/liquid ratio (S/L) were relevant independent variables. The proposed model was validated based on the high values of the adjusted coefficient of determination and on the non-significant differences between experimental and predicted values. The global optimum processing conditions (t = 20 min; T = 180 °C; Et = 0%; and S/L = 45 g/L) provided tomato extracts with high potential as nutraceuticals or as active ingredients in the design of functional foods. Additionally, the round tomato variety was highlighted as a source of added-value phenolic acids and flavonoids.

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