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Ultrasound assisted extraction (UAE) of saikosaponins from Radix Bupleuri (Bupleurum Chinense DC) was studied. The effects of various factors such as time (t), temperature (T), ultrasound power (I), particle size (S), solvent to solid ratio (R) and solvent concentration (C) on the yield of target components were investigated. The experimental results indicated that the extraction by UAE is six times faster than those by conventional thermal extraction. It is also found that fast extraction rate was obtained in the first 30 min of sonication. Prolonged sonication did not give a proportional increase in the yield. For the effect of ultrasound power, the maximum yield was obtained at the power level of around 21 W. Scanning electron microscope (SEM) images of the plant cells after UAE treatment were obtained to provide visual evidence of the sonication effect. The effects of particle size, solvent to solid ratio and solvent concentration on the yield are also discussed. The preliminary optimum conditions for UAE of saikosaponins were found at time of 30 min, temperature of 80 • C, power of 21 W, particle size <0.3 mm, solvent to solid ratio of 25 ml/g and solvent concentration of 50%.

Oil and coixenolide are important components of adlay seed (Coix lachrymal-jobi L. var. Adlay) with many beneficial functions to human health. In this work, a novel extraction technique--ultrasound assisted supercritical fluid extraction (USFE)--was studied. Effects of operating conditions on the extraction, including extraction temperature (T), pressure (P), time (t), CO(2) flow rate (F) and ultrasonic power (I) were investigated. There are optimum temperatures which gives the maximum extraction yields (EYs) for the supercritical fluid extractions with and without ultrasound. The effect of pressure on EYs for is similar to that of pressure on CO(2) density. Based on the yield of extraction, the favorable conditions for supercritical fluid extraction (SFE) were: T at 45 degrees C, P at 25 MPa, t at 4.0 h and F at 3.5L/h. While ultrasound was applied as in USFE, the following parameters were preferred: T at 40 degrees C, P at 20 MPa, t at 3.5h and F at 3.0 L/h, respectively. The results show that supercritical fluid extraction with the assistance of ultrasound could reduce the temperature, pressure, CO(2) flow rate, as well as time used in the process. Compared with SFE, USFE could give a 14% increase in the yield for extracting oil and coixenolide from adlay seed with less severe operating conditions.

Soymilk was subjected to various heat treatments at 95, 121 and 140 • C for various lengths of time. The contents of the aglycones of isoflavone (daidzein, glycitein and genistein) of the soymilk were determined using C 18 reversed-phase high-performance liquid chromatography. Genistein showed greater stability to heat treatment than daidzein and glycitein. Both the daidzein and glycitein contents decreased rapidly during the early stage of heating, but on continued heating the rates of decrease were much slower. Heating may cause an increase or decrease in the genistein content of soymilk depending on the temperature and time used. Upon heating at 95 and 121 • C, there was an increase in the genistein content in the early stage of heating, possibly due the conversion of genistin to genistein. Heating at 140 • C for more than 15 s and prolonged heating at 95 and 121 • C, however, caused a slow decline in the genistein content.

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