Optimization of Extraction of Bioactive Compounds from Black Carrot Using Response Surface Methodology (RSM)

Valorization of Sour Cherry Kernels: Extraction of Polyphenols Using Natural Deep Eutectic Solvents (NADESs)

The objective of this research was to optimize the natural deep eutectic solvent (NADES) extraction process from sour cherry kernels (Prunus cerasus L.). For polyphenol isolation, conventional solid-liquid extraction was employed using different concentrations of ethanol (0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 96%), as well as the innovative NADES extraction technique. In the initial phase of the research, a screening of 10 different NADESs was conducted, while extraction was carried out under constant parameters (50 °C, 1:20 w/w, 60 min). NADES 4, composed of lactic acid and glucose in a molar ratio of 5:1, exhibited the highest efficiency in the polyphenol isolation. In the subsequent phase of the research, response surface methodology (RSM) was utilized to optimize the extraction process. Three independent variables, namely temperature, extraction time, and solid-liquid (S/L) ratio, were examined at three different levels. The extracted samples were analyzed for total phenol (TP) and antioxidant activity using the DPPH, ABTS, and FRAP assays. ANOVA and descriptive statistics (R2 and CV) were performed to fit the applied model. According to RSM, the optimal extraction conditions were determined as follows: temperature of 70 °C, extraction time of 161 min, and S/L ratio of 1:25 w/w.

Response surface methodology as a tool to optimize the extraction of bioactive compounds from plant sources

Response surface methodology (RSM) is a widely used mathematical and statistical technique for modeling and optimizing the process for the extraction of bioactive compounds. This review explains the optimization approach through the use of experimental design and empirical models for response prediction and the utilization of the desirability function for multiple response optimization. This paper also reviews recent studies on the application of RSM to optimize bioactive compound extraction processes such as conventional solvent extraction, microwave-assisted extraction, supercritical fluid extraction, and ultrasound-assisted extraction. Finally, the challenges associated with the use of RSM and the efforts made to improve RSM in the extraction process are also highlighted. Overall, this review informs many aspects of RSM that are occasionally ignored or insufficiently discussed with regard to the optimization of bioactive compound extraction processes, and it summarizes significant applications where RSM proved suitable. © 2022 Society of Chemical Industry.

Simultaneous Hydrolysis of Ellagitannins and Extraction of Ellagic Acid from Defatted Raspberry Seeds Using Natural Deep Eutectic Solvents (NADES)

Defatted raspberry seeds were used as an alternative source of antioxidants and ellagic acid (EA) extracted using Natural deep eutectic solvents (NADES). In the preliminary study, the best NADES combination (citric acid-betaine) and the most influential variables (temperature, time, and NADES/plant ratio) were selected for the further optimization process. All samples were analyzed in terms of total polyphenol, EA content, and antioxidant activity. Two sets of optimal conditions were generated by response surface methodology. The first set (Opt1) was designed for higher conversion of ellagitannins to EA while the latter set (Opt2) for higher EA content/100 g extract. Opt1 and Opt2 had higher values for all investigated responses compared to 80% ethanolic extract but had a lower conversion rate of ellagitannins to EA compared to acidified methanol extract. The third set of parameters (Opt3) selected beyond the initial experimental domain was used to obtain a sample with the highest EA content/100 g extract. Due to their nature, NADES extracts are ready to use and could have various technological roles in products since they are antioxidants, acidifiers, and colorants. NADES raspberry extracts exhibited higher anti-proliferative activity compared to ethanolic extracts in terms of EC50 values. However, the main contributor of anti-cancer activity in NADES raspberry extracts were individual NADES compounds and/or their newly formed NADES structure.

Extraction of flavonoids from Citri Reticulatae Pericarpium Viride using a deep eutectic solvent

Flavonoids are the main active ingredient in Citri Reticulatae Pericarpium Viride (CRPV). In this study, a deep eutectic solvent (DES) was explored to extract the main flavonoids from CRPV, including narirutin (NAR) and hesperidin (HES). A total of 30 DESs were prepared, and DES-20 (proline : urea) was selected as the optimal solvent. According to the single factor and response surface methodology experiments, the optimal extraction conditions for the flavonoids included a molar ratio of 1 : 2, water content of 30%, extraction time of 28 min, extraction power of 240 W, and a liquid-to-solid ratio of 70 mL g⁻¹ and the optimal extraction yields of NAR and HES were 21 ± 2 mg g⁻¹ and 60 ± 2 mg g⁻¹, respectively. The recovery rate of NAR and HES with macroporous resin SP825 were 88 ± 3% and 86 ± 4%, respectively. Compared with traditional extraction methods, this novel method greatly improved extraction efficiency and saved time. Scanning electron microscopy results showed that this novel method could destroy the plant cell wall to enhance the extraction efficiency. Then, 21 flavonoids were identified through an ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) technique and nine of them were discovered for the first time in CRPV extracts. Furthermore, a high-performance liquid chromatography (HPLC) method was simultaneously used to determine NAR and HES in CRPV extracts upon methodological validation. Finally, antioxidant and cytotoxic experiments in vitro showed that the flavonoids extracted from the CRPV exhibited certain antioxidant and cytotoxic activities. The above results indicated that the DES was a green solvent, which can effectively extract NAR and HES from CRPV.

Flavonoids are the main active ingredient in Citri Reticulatae Pericarpium Viride (CRPV).

Ascorbic acid-induced degradation of liposome-encapsulated acylated and non-acylated anthocyanins of black carrot extract

BACKGROUND

In the presence of ascorbic acid, the degradation of acylated (sinapic, ferulic and p-coumaric acid derivatives of cyanidin-3-xylosylglucosylgalactoside) and non-acylated anthocyanins of black carrot extract (BCE) encapsulated in liposomes was studied. BCEs (0.2% and 0.4% w/w) were encapsulated in liposomes using different lecithin concentrations (1%, 2% and 4% w/w).

RESULTS

The liposomes were prepared with particle diameters of less than 50 nm and zeta potentials of about -21.3 mV for extract-containing liposomes and -27.7 mV for control liposomes. The encapsulation efficiency determined using high-performance liquid chromatography (HPLC) showed that increasing lecithin levels increased the efficiency to 59% at the same extract concentration. The concentrations of total anthocyanins and individual anthocyanins were determined for ascorbic acid (0.1% w/w)-degraded extract and liposomes (containing 0.2% w/w extract). Anthocyanin quantification of both liposomal and extract samples was performed by HPLC using cyanidin-3-O-glucoside chloride as standard. Five anthocyanins in the extract and encapsulated liposomes were quantified during 24 h (0-24 h): cyanidin-3-xylosylglucosylgalactoside 1.0-0.51 and 0.82-0.58 mg g^-1 , cyanidin-3-xylosylgalactoside 2.5-1.1 and 2.2-1.7 mg g^-1 , cyanidin-3-xylosyl(sinapoylglucosyl)galactoside 0.51-0.14 and 0.35-0.28 mg g^-1 , cyanidin-3-xylosyl(feruloylglucosyl)galactoside 1.37-0.41 and 1.06-0.98 mg g^-1 , and cyanidin-3-xylosyl(coumaroylglucosyl)galactoside 0.28-0.08 mg g^-1 for extract and 0.27-0.26 mg g^-1 for liposomes, respectively.

CONCLUSIONS

This study demonstrates the potential beneficial effect of liposomal encapsulation on individual, particularly acylated, anthocyanins after addition of ascorbic acid during a storage time of 24 h.

Recovery of anthocyanins from sour cherry (Prunus cerasus L.) peels via microwave assisted extraction: monitoring the storage stability

Utilization of economical and environmental methods as an alternative process to recover the industrial crops and food products into high-added value compounds is of great significant. In the current study, microwave assisted extraction (MAE) was optimized by response surface methodology (RSM) in order to evaluate the waste of sour cherry as a source of phenolic compounds rich in anthocyanins. The process parameters (microwave power, irradiation time and ethanol solvent concentration) of MAE method were optimized by face centered composite design of RSM. Responses such as total phenolic componds (TPC), total anthocyanin (TA) contents and antioxidant capacity (DPPH) of extracts were measured spectrophotometrically after extractions of samples. The optimized result of MAE was 500 W of microwave power, 90 s of irradation time and 80% ethanol solvent concentration. Antioxidant capacity was tested using by 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical. Chromatographic analysis (HPLC) was also used to measure the concentration of major anthocyanin (cyanidin-3-glucoside) of the samples. Maximum predicted TPC, TA and DPPH yields on optimized conditions were 44.15 mg-GAE/g-FM (mg- gallic acid equivalent per g- fresh matter), 12.47 mg-cyanidin-3-glucoside/g-FM and 69.90 (%, inhibition), respectively. A stability assay under different conditions (light, dark, ambient condition, refrigerator and deep freezer) has been also performed in order to display the stability of bioactivity profile. All of the process parameters were significant at the level of p < 0.0001.

Preparation of Oligosaccharides by Degradation of Polysaccharides from Chinese Jujube and Its Biological Activity

This study examined the degradation of polysaccharides to oligosaccharides in Chinese jujube fruits. Using a response surface model, the degradation conditions of polysaccharides under acid hydrolysis and enzymatic hydrolysis were optimized in laboratory conditions. A degradation rate of 66.9% was obtained under optimum acid hydrolysis conditions: 0.6 mol/L hydrochloric acid, 3% substrate concentration, and 1 h reaction time. A degradation rate of 41.4% was obtained under optimum enzyme hydrolysis conditions: 4.0 mL cellulose solution (10 mg/mL), 0.3 mL substrate solution (20 mg/mL), 0.7 mL citric acid buffer solution (pH 5), and 7.3 h reaction time. Using the stimulation effect for strain J-4 intestinal probiotic proliferation, the biological activity of oligosaccharides was determined. The results showed that the oligosaccharides from enzyme hydrolysis encouraged intestinal probiotic proliferation.