Tang D.-S., Tian Y.-J., He Y.-Z., Li L., Hu S.-Q., Li B. (2010): Optimisation of ultrasonic-assisted protein extraction from brewer's spent grain. Czech J. Food Sci., 28: 9-17, Response surface methodology was employed to optimise the ultrasonic-assisted extraction of protein from brewer's spent grain. Three variables, namely the extraction time (min), ultrasonic power (W/100 ml of extractant), and solid-liquid ratio (g/100 ml) were investigated. Optimal conditions were determined and tri-dimensional response surfaces were plotted using mathematical models. The ANOVA analysis indicated that all the quantities determined, i.e. the extraction time, ultrasonic power, and solid-liquid ratio, had significant positive linear and negative quadratic effects on the protein yield. Optimum conditions for the extraction of protein were found to be: the extraction time of 81.4 min, ultrasonic power of 88.2 W/100 ml of extractant, and solid-liquid ratio of 2.0 g/100 ml. The optimal predicted protein yield obtained was 104.2 mg/g BSG while the experimental yield of protein was in agreement with the predicted value.

Meng, et al.: Evaluation of DPPH Free Radical Scavenging Activity of Ligularia fischeriA comparison study of the antioxidative activities was conducted in vitro on the different extracts from the different origins, harvest seasons, solvents and plant parts of Ligularia fischeri grown in Shaanxi. Different parts of L. fischeri, such as roots and rhizomes, stems, leaves, scapes and fruits, were extracted by an ultrasonicassisted extraction method with water, 95% ethanol, n-butanol, ethyl acetate and chloroform, respectively. Diphenyl picryl hydrazyl method was used to evaluate the antioxidative activities of these extracts. The result of antioxidative study showed that L. fischeri picked in September showed higher activities than that those picked in October. The extracts of L. fischeri from different solvents presented different free radical scavenging activities: water>95% ethanol>n-butanol>ethyl acetate>chloroform. The different herbal parts also showed the different antioxidative activities. The present work will provide a reference for the further research and exploitation of L. fischeri. Key words: Ligularia fischeri, extracts, antioxidative activities, DPPH method, radical scavenging activitiesLigularia fischeri (Ledebour) Turcz., a perennial herbaceous plant, belongs to the Compositae family. It is consumed as an important wild vegetable in Korea [1] and Jilin Province of China [2] , and also the area of cultivation has increased gradually year by year. With the function of analgesia and cough expectorant, it has also been used for the treatment of traumatic injury, lumbocrural pain, whooping cough and other diseases [3] . The herbs, whose medicinal part is normally regarded as roots and rhizomes, are mainly distributed in Gansu, Shaanxi, Sichuan, Hubei, Henan, Anhui, Zhejiang and northeast of China. In Shaanxi province, it was harvested in the Qinling and Daba Mountain [4,5] .Free radicals, which are produced by the chemical reaction of organic compounds, could damage the body's tissues and cells, leading to human aging and causing a variety of diseases. Therefore, it is very important to find the antioxidants for scavenging these free radicals. Various in vitro and in vivo methods have been developed for the assessment of antioxidative activities.. From the standpoint of in vitro, several methods have been proposed for evaluating the antioxidative activity, such as 1,1-diphenyl-2-pierylhydrazyl (DPPH) method, 2,2'-azino-bis-(3-ethylbenzo thiazolin-6-sulfonic acid) diammonium salt (ABTS) method, ferric reducing antioxidant power (FRAP) method and so on [6][7][8][9] . DPPH method is one of the universal tools for estimating the antioxidative activities of the different products. DPPH radical, a very stable nitrogen-centered radical, can be used to determine the free radical scavenging ability, which is related to their antioxidative activities. The method is based on the spectrophotometric measurement of DPPH• concentration changes resulting from the DPPH• reaction with an antioxidant.Up to now, some studi...

Antioxidant and antimicrobial activities of the essential oil and n-hexane (HEE), chloroform (CHE), ethyl acetate (EAE), and methanol (MEE) extracts, respectively, from the root of Saurauia lantsangensis Hu were investigated. The GC-MS analysis revealed 39 compounds representing 96.41% of the oil containing T-muurolol (13.85%), acetophenone (7.46%), α-cadinol (6.26%), methyl palmitate (5.36%), n-hexadecanoic acid (4.31%), torreyol (3.69%), and isospathulenol (3.48%) as major components. Antioxidant activities determined by three various testing systems, i. e. DPPH radical scavenging, superoxide anion radical scavenging, and reducing power assay, increased in the order: HEE < CHE < oil < MEE < EAE. CHE, EAE, MEE and oil exhibited a promising antimicrobial effect determined as the diameter of zones of inhibition (13.3 -16.2, 16.5 -20.4, 13.5 -16.6, and 16.5 -22.7 mm), respectively, along with their respective MIC values (500 -1000, 125 -500, 250 -500, and 250 -500 μg/ml) against Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli), Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus), and a yeast (Hansenula anomala).

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