土壤中酚的超声波提取

以合成土样为对象,研究了超声波辅助提取苯酚的条件及其提取效率。用中档超声波场辐射试样2×30s,30ml丙酮-正己烷(体积比1:1)分两次萃取10.0g合成土样中的苯酚,这时所获收率最高。在选定条件下用于实际土样分析,以索氏萃取4h的结果为对照基准,本方法的平均回收率为97.8％,RSD为1.5％。     

Ultrasonic enhancement of the supercritical extraction from ginger

This work examines the concurrent use of power ultrasound during the extraction of pungent compounds from a typical herb (ginger) with supercritical CO₂. A power ultrasonic transducer with an operating frequency of 20 kHz is connected to an extraction vessel and the extraction of gingerols from freeze-dried ginger particles (4–8 mm) is monitored. In the presence of ultrasound, we find that both the extraction rate and the yield increase. The higher extraction rate is attributed to disruption of the cell structures and an increase in the accessibility of the solvent to the internal particle structure, which enhances the intra-particle diffusivity. While cavitation would readily account for such enhancement in ambient processes, the absence of phase boundaries should exclude such phenomena above the critical point. Possible alternate mechanisms for the cell structure damage are discussed.     

Ultrasonic extraction of resins from an historic textile

Ultrasound assisted extraction was applied on the historical textile as the most appropriate sample preparation step for the identification of the resinous binder. Fragile silk banner from the 19th century was analyzed for the presence of different resins. After the ultrasonic extraction with ethyl acetate in the ultrasonic bath, resinous materials and unknown sample from the banner were separated by thin layer chromatography. The multiple developments in benzene-methanol (95:5) system as mobile phase and silica gel layer as stationary phase were applied, and afterwards the video densitometry determination of the components was performed by means of video camera HV-C20. The shellac resin was determined as an important part of the complex binder.     

Ultrasonic hop extraction

Ultrasonic hop extraction improves the quality of beer and reduces the cost of materials in the process. Although Ultrasonics does not convert non-bittering resins to bitter isohumulones, it increases the supply of essential oils.     

Ultrasonic extraction of steroidal alkaloids from potato peel waste

Potato processors produce large volumes of waste in the form of potato peel which is either discarded or sold at a low price. Potato peel waste is a potential source of steroidal alkaloids which are biologically active secondary metabolites which could serve as precursors to agents with apoptotic, chemopreventive and anti-inflammatory properties. The present study investigated the relative efficacy of ultrasound assisted extraction (UAE) and solid liquid extraction (SLE) both using methanol, to extract steroidal alkaloids from potato peel waste and identified optimal conditions for UAE of α-solanine, α-chaconine, solanidine and demissidine. Using response surface methodology optimal UAE conditions were identified as an amplitude of 61 μm and an extraction time of 17 min which resulted the recovery of 1102 μg steroidal alkaloids/g dried potato peel (DPP). In contrast, SLE yielded 710.51 glycoalkaloid μg/g DPP. Recoveries of individual glycoalkoids using UAE yielded 273, 542.7, 231 and 55.3 μg/g DPP for α-solanine, α-chaconine, solanidine and demissidine respectively. Whereas for SLE yields were 180.3, 337.6, 160.2 and 32.4 μg/g DPP for α-solanine, α-chaconine, solanidine and demissidine respectively. The predicted values from the developed second order quadratic polynomial equation were in close agreement with the experimental values with low average mean deviation (E < 5%) values. Predicted models were highly significant (p < 0.05) for all parameters studied. This study indicates that UAE has strong potential as an extraction method for steroidal alkaloids from potato peel waste.     

超声法提取余甘树皮中单宁的研究

本文研究了以水替代有机溶剂作为提取剂，利用超声技术提取余甘树皮中单宁的最佳条件。研究结果表明：当超声频率为40kHz，功率为100W，作用时间为15-20min，固液比为1：24时，可一次性提取得到含量较高的缩合型单宁，同时达到节约有机提取剂和减少污染的双重效果。     

Ultrasonic extraction and separation of anthraquinones from Rheum palmatum L

The ultrasonic nebulization extraction (UNE) was developed and applied to extract anthraquinones (emodin, aloe-emodin and rhein) from Rheum palmatum L. Several parameters of UNE, including type of extraction solvent, concentration of extraction solvent, volume of extraction solvent, extraction time and ultrasonic power, were studied and the optimized parameters were selected. The operation conditions of micellar electrokinetic capillary chromatography (MEKC) were also studied. Under the selected conditions, contents of emodin, aloe-emodin and rhein obtained from different cultivated areas of R. palmatum L. were 1.08–2.04 mg/g, 0.65–1.16 mg/g and 0.70–2.90 mg/g, respectively. The relative standard deviations (RSDs) for emodin, aloe-emodin and rhein were 1.3–2.4%, 1.9–4.7% and 1.3–3.9%, respectively. Compared with maceration extraction (ME), reflux extraction (RE), stirring extraction (SE) and ultrasonic extraction (UE), the proposed method was more efficient, faster and easier to be operated and lower equipment costs and lower extraction temperature were required. The results indicated that UNE was a good alternative method for extracting anthraquinones from R. palmatum L. Compared with traditional extractions, the proposed extraction has a potential in on-line sampling, especially when the gas is used as the carrier of sample.     

超声波在多糖降解及提取中的应用

本文支综合介绍了超声波在多糖降解和提取中应用的研究进展．着重对超声波在淀粉，壳多糖，细菌多糖的降解和真菌多糖的提取中的应用作了较详细的阐述．     

Ultrasonic extraction of oil from tobacco (Nicotiana tabacum L.) seeds

The ultrasonic extraction (UE) of oil from the seeds of a semi-oriental tobacco (Nicotiana tabacum L.) plant strain by using n-hexane and petroleum ether was studied at different temperatures and seeds-to-solvent ratios. The oil yield depended on the seed comminution, the extraction temperature, the seeds-to-solvent ratio and the type of solvent. The oil yield was much higher if the seeds were ground before extraction. The oil yield increased with increasing the extraction temperature and with decreasing the seeds-to-solvent ratio. n-Hexane was somewhat more efficient in the oil extraction than petroleum ether. In recovering the tobacco seed oil (TSO), the UE was less efficient than the Soxhlet extraction. The advantage of the UE was a relatively high oil yield at 25 degrees C in a shorter time. The kinetics of UE of TSO was described using the model of unsteady diffusion through plant material.     

Ultrasonic pre-irradiation effect upon aqueous enzymatic oil extraction from almond and apricot seeds

The present work evaluates the benefit of using ultrasonic pre-irradiation before extracting oil from almond and apricot seeds by aqueous enzymatic oil extraction (AEOE) process. The use of a commercial preparation which is a mixture of three proteases in AEOE gave 75% w/w oil yield from almonds at pH 4.0 in 18 h at 40 °C. The ultrasonic pre-irradiation at 70 W for 2 min increased the yield to 95%, w/w and reduced the extraction time to 6 h. The effect of ultrasonic pre-irradiation on meal morphology could be visually seen by scanning electron micrographs. It indicates development of of microfractures and disruption of cell walls in almond powder. With apricot, also, ultrasonic pre-irradiation also marginally increased the oil yield obtained by AEOE to 77% w/w and reduced the extraction time to 6 h. Thus, ultrasonic pre-irradiation step may reduce time required to extract oil from edible oils from plant sources and hence can improve through put in commercial oil production process.