Ultrasound-Assisted Aqueous Extraction of Phenolic, Flavonoid Compounds and Antioxidant Activity of Mucuna macrocarpa Beans: Response Surface Methodology Optimization.

OBJECTIVE: This investigation was undertaken to optimize the effective extraction of total phenolics content (TPC), total flavonoids content (TFC), and antioxidant activity from the Mucuna macrocarpa (MM) beans. An ultrasound-assisted extraction (UAE) technique with water as an effective solvent was proposed for the response surface methodology (RSM) optimization. METHODS: A three-level, two-factor central composite design (CCD) was employed to reveal the optimal points of variables. Different extraction times (5, 10, 15 minutes) and ultrasonic power levels (10, 20, 30 W) were used for the optimization. The experimental runs given by the RSM were evaluated for TPC, TFC, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (RSA), and N,N-dimethyl-p-phenylenediamine (DMPD) RSA and ferric reducing antioxidant power (FRAP). RESULTS: The predicted times for maximum extraction of TPC (186.61 mg GAE g-1), TFC (148.87 mg QUE g-1), and DPPH RSA (99.37%), and DMPD RSA (50.58%) and FRAP (2.38 O.D. at 593 nm) were 12.57, 12.84, 12.43, 12.97, and 13.24 min, and ultrasonic power levels were found to be 27.30, 26.76, 26.22, 27.03, and 27.84 W, respectively. Reverse-phase high-performance liquid chromatography (RP-HPLC) analysis of phenolics compounds from the RSM optimized sample showed tannic acid (48.09 ± 1.92 mg/g), gallic acid (1.17 ± 0.19 mg/g), p-coumaric acid (0.56 ± 0.03 mg/g), and p-hydroxybenzoic acid (0.049 ± 0.01 mg/g) content. CONCLUSION: Water and ultrasonication were found to be an effective extraction solvent and technique. RSM was effectively employed to investigate the optimal process conditions for the maximum extraction of TPC, TFC, and antioxidant compounds from the MM beans. Further, MM beans can be explored as a prominent antioxidant source for the treatment of several disorders.

Response surface methodology optimization for sorption of malachite green dye on sugarcane bagasse biochar and evaluating the residual dye for phyto and cytogenotoxicity.

In the present study, sorption and detoxification of malachite green (MG) dye was executed using biochar resulting after pyrolysis of agro-industrial waste at 400, 600 and 800 °C. Maximum sorption of MG dye (3000 mg/L) was observed on the sugarcane bagasse biochar (SCB) prepared at 800 °C. The interactive effects of different factors like dye concentration, time, pH and temperature on sorption of MG dye were investigated using response surface methodology (RSM). Optimum MG dye concentration, contact time, temperature and pH predicted through Box-Behnken based RSM model were 3000 mg/L MG dye, 51.89 min, 60 °C and 7.5, respectively. ANOVA analysis displayed the non-significant lack of fit value (0.4566), whereas, the predicted correlation coefficient values (R2 0.8494) were reasonably in agreement with the adjusted value (R2 0.9363) demonstrating highly significant model for MG dye sorption. The applicability of this model was also checked through F- test (30.39) with lower probability (0.0001) value. Furthermore, the characterization of SCB was performed using fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), Brunauer-Emmett-Teller surfaces (BET), total organic carbon (TOC) and atomic absorption spectroscopy (AAS). Phyto-toxicity and cytogenotoxicity studies showed successful removal of MG dye using SCB. In addition, the batch sorption studies for reutilization of SCB revealed that the SCB was effective in removal of MG for five repeated cycles. This technology would be effective for treating the toxic textile effluent released from the textile industries.