Ultrasound assisted phytochemical extraction of red cabbage by using deep eutectic solvent: Modelling using ANFIS and optimization by genetic algorithms

The present investigation studied the effect of process parameters on the extraction of phytochemicals from red cabbage by the application of ultrasonication and temperature. The solvent selected for the study was deep eutectic solvent (DES) prepared by choline chloride and citric acid. The ultrasound assisted extraction process was modeled using adaptive neuro-fuzzy inference system (ANFIS) algorithm and integrated with the genetic algorithm for optimization purposes. The independent variables that influenced the responses (total phenolic content, antioxidant activity, total anthocyanin activity, and total flavonoid content) were ultrasonication power, temperature, molar ratio of DES, and water content of DES. Each ANFIS model was formed by the training of three Gaussian-type membership functions (MF) for each input, trained by a hybrid algorithm with 500 epochs and linear type MF for output MF. The ANFIS model predicted each response close to the experimental data which is evident by the statistical parameters (R2>0.953 and RMSE <1.165). The integrated hybrid ANFIS-GA algorithm predicted the optimized condition for the process parameters of ultrasound assisted extraction of phytochemicals from red cabbage was found to be 252.114 W for ultrasonication power, 52.715 °C of temperature, 2.0677:1 of molar ratio of DES and 25.947 % of water content in DES solvent with maximum extraction content of responses, with fitness value 3.352. The relative deviation between the experimental and ANFIS predicted values for total phenolic content, antioxidant activity, total anthocyanin activity, and total flavonoid content was found to be 1.849 %, 3.495 %, 2.801 %, and 4.661 % respectively.

Ultrasound assisted extraction of red cabbage and encapsulation by freeze-drying: moisture sorption isotherms and thermodynamic characteristics of encapsulate

In the present study encapsulation of ultrasound assisted red cabbage extract was carried out using four different carrier agents such as maltodextrin, gum arbic, xanthan gum, and gellan gum. Among the four hydrocolloids investigated, maltodextrin was found to have the least destructive effect on anthocyanin content (14.87 mg C3G/g dw), TPC (54.51 ± 0.09 mg GAE/g dw), TFC (19.82 Mg RE/g dw) and antioxidant activity (74.15%) upon freeze-drying. Subsequently a storage study was conducted using maltodextrin as carrier agent at 25-50 °C. The Clausius-Clapeyron equation was used to evaluate the net isosteric heat (qst) of water adsorption. The differential entropy (ΔS) and qst decreased from 82.298 to 38.628 J/mol, and 27.518 kJ/mol to 12.505 kJ/mol, respectively as the moisture content increased from 2 to 14%. The value of isokinetic energy and Gibb's free energy were found to be 364.88 and - 1.596 kJ/mol for freeze dried red cabbage.

Graphical abstract