Encapsulation and drying methods in the production of powdered red cabbage (Brassica oleracea L.): Chemometrics and Fourier transform infrared spectroscopy.

In this study, powder colorant was obtained from red cabbage (Brassica oleracea L.). The stability of the colorants obtained by spray and freeze drying was investigated in terms of antioxidant capacity and anthocyanin content. The yield of the products increased with the encapsulation for both drying methods and encapsulation application. Drying method and encapsulation application had a significant effect on most of the physical properties of powders except for flowability and adhesiveness values. An increase in L*, a*, and C values was observed with the encapsulation process. Antioxidant activity of the samples increased with the encapsulation process by 13.44% in the spray-dried samples, while it increased by 9.75% in the freeze-dried samples. Total monomeric anthocyanin content was detected as 9039.21 mg/kg for encapsulated freeze-dried samples and 7811 mg/kg for encapsulated spray-dried ones. Nine anthocyanins were detected in the samples by using high-performance liquid chromatography. To discriminate samples according to drying methods with/without encapsulation principal component analysis (PCA) was used based on the Fourier transform infrared (FTIR) data. Four groups were observed for the PCA. The chemometric evaluation was done to predict the antioxidant capacity, anthocyanin content, and individual anthocyanins using FTIR spectra. High correlations were observed between the calculated and reference values for partial least square regression analysis.

Recovery of phenolic compounds from peach pomace using conventional solvent extraction and different emerging techniques.

The study compared high-pressure, microwave, ultrasonic, and traditional extraction techniques. The following extraction conditions were implemented: microwave-assisted extraction (MAE) at 900 W power for durations of 30, 60, and 90 s; ultrasonic-assisted extraction (UAE) at 100% amplitude for periods of 5, 10, and 15 min; and high-pressure processing (HPP) at pressures of 400 and 500 MPa for durations of 1, 5, and 10 min. The highest yield in terms of total phenolic content (PC) was obtained in UAE with a value of 45.13 ± 1.09 mg gallic acid equivalent (GAE)/100 g fresh weight (FW). The highest PC content was determined using HPP-500 MPa for 10 min, resulting in 40 mg GAE/100 g, and MAE for 90 s, yielding 34.40 mg GAE/100 g FW. The highest value of antioxidant activity (AA) was obtained by UAE in 51.9% ± 0.71%. The PCs were identified through the utilization of Fourier transform infrared (FTIR) spectroscopy and high-performance liquid chromatography (HPLC). Utilizing multivariate analysis, the construction of chemometric models were executed to predict AA or total PC of the extracts, leveraging the information from IR spectra. The FTIR spectrum revealed bands associated with apigenin, and the application of HPP resulted in concentrations of 5.41 ± 0.25 mg/100 g FW for apigenin and 1.30 ± 0.15 mg/100 g FW for protocatechuic acid. Furthermore, HPLC analysis detected the presence of protocatechuic acid, caffeic acid, p-coumaric acid, and apigenin in both green extraction methods and the classical method. Apigenin emerged as the predominant phenolic compound in peach extracts. The highest concentrations of apigenin, p-coumaric acid, and protocatechuic acid were observed under HPP treatment, measuring 5.41 ± 0.25, 0.21 ± 0.04, and 1.30 ± 0.15 mg/kg FW, respectively.