Ultrasound-assisted extraction of pectin from Citrus limetta peels:Optimization,characterization,and its comparison with commercial pectin

With an aim of complete reuse and recycling of citrus by-products,this study investigated the pectin extraction from Citrus limetta peels employing the ultrasound-assisted extraction(UAE)technique.The extraction process was optimized using Box-Behnken Design and a maximum pectin yield of 28.82%was obtained under the optimal conditions of 40℃ temperature,37%amplitude,and 1.9 pH after 24 min sonication time,which was validated by the experimental results(28.73±0.12%).The pectin extracted under optimum conditions was characterized for its physicochemical,antioxidant,functional,structural,thermal,apparent viscosity and was compared with commercial pectin.Both commercial(CP)and ultrasound extracted pectin(UAEP)were highly esterified with degree of esterification of 59.71±0.12%and 55.29±0.51%,respectively and methoxyl content of 7.06±0.10%and 7.19±0.15%,respectively.In addition,UAEP exhibited high antioxidant and similar water/oil holding capacities and emulsifying properties as compared to CP.XRD patterns of pectin samples suggested high crystallinity of UAEP than CP,SEM exhibited smoother surface of UAEP as compared to CP,and FT-IR spectra proved the presence of GalA units in both samples.The thermal analysis by DSC and TGA showed high thermal stability of UAEP than CP.A detailed comparative study on properties of ultrasound extracted pectin from C.limetta peels and commercial pectin confirmed that the extracted pectin was of good quality as can be potentially utilized as food ingredient in food sector.

Optimization of ultrasound assisted extraction of six major compounds from Cimicifugae Rhizome

Cimicifugae Rhizome （RC） is one of many commonly used traditional Chinese medicines. This study used Box-Behnken Design （BBD）, a widely used form of response surface methodology （RSM）, to optimize the conditions of the ultrasound-assisted extraction （UAE） for the extraction of phenolic compounds from CimicifugaeRhizome. The influence of three independent variables, including ethanol concentration （%）, extraction time （min） and solvent-to-material ratio （mL/g）, on the extraction yields of phenolic compounds were examined. The results demonstrated that the optimal ultrasound-assisted extraction （UAE） conditions were as follows： ethanol concentration of 68%, an extraction time of 19 min, and solvent-to-material ratio of 30 mL/g for the extraction of caffeic acid, cimicifugoside, ferulic acid, isoferulicacid, cimifugin, 4′-O-β-glucopyranosyl-5-O-methylvisamminol. These results demonstrated the suitability of UAE for the extraction of phenolic compounds from CimicifugaeRhizome.

Optimization of ultrasound assisted extraction of celastrol from Celastrus monospermus Roxb.using response surface methodology

In the present study, we aimed to investigate the effects of key extraction parameters including extraction time（10–20 min）, extraction temperature（30–60 °C）, ultrasonic power（60–90 W） and solvent-to-solid（S/S） ratio（10–30 m L/g） on yield of celastrol from Celastrus monospermus Roxb. To optimize the conditions, we investigated the effects of parameters on the ultrasound assisted extraction（UAE） with the Box-Behnken Design（BBD）, one widely used form of Response Surface Methodology（RSM）. In all tested solvents, ethanol was the most effective for celastrol extraction, followed by methanol, ethanol, ethyl acetate, n-butanol and water. A second order polynomial model was fitted well to the extraction experimental data with R2 of 0.9928. Extraction yield of 3.116 mg/g was obtained for celastrol under the optimized extraction conditions of extraction time（20 min）, extraction temperature（46 °C）, ultrasonic power（60 W） and S/S ratio（30 m L/g）. Experimental validation was performed, and the experimental values agreed well with the predicted values. The results indicated that the UAE was good extraction material for celastrol from C. monospermus Roxb.