Extraction itérative de requêtes fréquentes
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Most approaches to knowledge discovery in databases consider extractions one at a time. However it is well known that, in practice, any extraction process is interactive and iterative. In this paper, we introduce an approach that can take benefit from previously computed extractions in the computation of the current extraction. To do so, we assume that the answers to previous extractions are stored and we use properties of query containment for pruning candidate queries. First, we introduce our approach in the context of deductive databases. Then, we show that restricting our framework to the case of relational queries allows for reducing the complexity of query containment tests. The experimental results reported in this paper show a significant reduction of computation time when taking into account the iterative aspects mentioned above.Jellyfish is a potential resource for collagen extraction. In this paper, two methods named as acid extraction and pepsin extraction were used to extract collagen from Jellyfish, the effects of different sorts of acid solution, pepsin concentration, ratio of material to liquid and extraction time on extraction yield were researched, and the optimization of extraction conditions were examined. The results showed the optimal condition of acid extraction was using hydrochloric acid, ratio of material to liquid 1:2.0, extraction time 84h, and that of pepsin extraction was using 3.0 % of pepsin, ratio of material to liquid 1:2.0, extraction time 48h. Meanwhile, the extraction yield of pepsin extraction was higher than acid extraction.
Pepsin
Hydrochloric acid
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In this paper,we studied on orthogonal extraction technology of curcumin pigment.When temperature was 55°C,the influence of the material liquid extract concentration,solid-liquid ratio,and extraction time on curcumin extraction rate were explored.Through orthogonal test L9(34),the optimum extracted process conditions of curcumin were that: ethanol concentration for 75%,materials for 1∶10,and extracting time than for 2.5h,extraction rate 4.48%.Acetone concentration as 70%,materials,than for extracting time for 2h as extraction rate was 4.94%.Acetone extraction of curcumin was higher than ethanol,and extraction time was shorter.,Extract usage of acetone was larger.The experimental results provided a reference for industrial extraction of curcumin.
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OBJECTIVE To optimize the extraction of the free anthraquinone from the rhubarb with alkali extraction.METHODS Impregnation method,recirculating method and supersonic waves method were compared.Taking content of the free anthraquinone as parameters,the optimum extraction process was selected with the L_9(34)orthogonal design,and factors and levels of extraction technology on influencing the free anthraquinone with alkali extraction was studied.RESULTS The optimum extraction process with alkali extraction was:in 20℃,adding 15-fold times of 2% Na_2CO_3 solution and extracting for 30 minutes for 2 times.CONCLUSION Extracting the free anthraquinone with alkali extraction was feasible.
Anthraquinones
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Extraction of a pigment from the flower of Pyrostegiaignea Presl.was studied by single factor experiment and L9(33) orthogonal test.The results showed that the best extraction solvent was determined as acetone and the optimum acetone-extraction conditions were as follows:material-extraction solution ratio of 1:10(g/mL),extraction temperature 60 ℃,and extraction time 10 h.The obtained pigment had good thermo-stability,high anti-oxidation and deoxidizing agent-resisting properties.Besides,it was stable under weak acid and alkli conditions.Most of the tested food addiitive and metallic ion had little effects on the pigment,but it could be obviously influence by Fe3+,starch and sunlight.
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When extracting the pigment of Globeflower by water, temperature, pH, and extraction frequency were respectively tested, based on it, the orthogonal test was conducted; the temperature and frequency of acetone extraction were also studied; furthermore the extracting ways were compared, the stability of pigment was explored. Under this experiment, the better factors for water extraction were 95 ℃~100 ℃, pH 7.0, one time for 30 min, for acetone extraction, at 54 ℃, one time lasting 30 min. The way of water- acetone extraction was superior to acetone-water extraction and single solvent. The pigment was steady under normal temperature, pH 3.0~7.0, saccharine medium. NaCl limited, low concentrations of Ca2+ and Mg2+ couldn't influence the pigment, Fe3+, strong sunlight and H2O2 could destroy pigment.
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Effects of temperature,time and solid-liquid ratio on the extraction of β-carotene from Rhodotorula benthica(HN-3) were studied by DMSO method to find out the optimum extraction technology and provide a reliable theoretical basis for industrial production of β-carotene from Rhodotorula benthica.The results showed that the optimum conditions included solid-liquid ratio 1∶25,extraction time 60 min and extraction temperature 30℃,the amount of β-carotene could be up to 345.7μg/g,10.93% higher than that extracted under single factor condition(307.9μg/g).The optmium extraction technology laid the foundation for efficient extraction of β-carotene from Rhodotorula benthica.
Rhodotorula
Carotene
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Research has been carried out on the alkaline extraction of resveratrol from the red skin of peanuts.The pH value,extraction temperature,extraction time and extraction times were studied respectively by single factor and orthogonal experiment.The result showed the optimum conditions were as follows:pH value 10.0,extraction temperature 40℃,extraction time 2h and the number of extraction times 4,under this condition,the extraction yield of resveratrol could reach as high as 0.196%.
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The extraction of lipophilic compounds in shrimp head by organic solvent was investigated in this paper. The results showed that: After the protein in shrimp head was hydrolyzed by proteinase and separated, 94.81% lipophilic compounds was extracted out by direct extraction methods. Cyclohexane was suitable as extraction solvent. At the first extraction, the extracting speed was up to 14.63mg/min, and after 1 hour, about 80% lipophilic compounds was extracted out. At the second extraction, after of extraction 1 hour, about 13% lipophilic compounds was extracted out. If the extracting time was 1 hour for every extraction, the content of lipophilic compounds remained in shrimp head was reduced down to less than 5% after three extractions. To get higher extraction ratio, the water content of the shrimp head materials should be in the range from 10% to 14%, and the material/solvent was 1∶5. When the extracting temperature was about 80℃, it was advantageous to the extraction.
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A new technique for extraction of curcumin in curcuma aromatica has been developed, which is based on cellulose enzymolysis. The influences of cellulose amount, treatment time, temperature, pH value, number of extraction and extraction time on the extraction rate of curcumin were studied. The optimum extraction conditions are as the fo1llowing, enzymolysis temperature 50℃, enzyme amount 180 U for 10 g curcuma aromatica, enzymic treatment 120 min, pH value 3.5, number of extraction 2, extraction time 90 min. The extraction rate of curcumin is obviously increased by the cellulose treatment.
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Phenolic compounds, obtained from plants are important in the food, biomaterial and pharmaceutical industries; however current extraction methods, such as Soxhlet (solid-liquid) extraction, liquid-liquid extraction, microwave-assisted extraction, and ultrasonic extraction (USE), have the disadvantages of large processing times, contamination by solvents, and degradation of analytes. This study demonstrates that shock wave-assisted extraction can be used as a more efficient, eco-friendly and rapid method. Extraction of powdered samples of Eysenhardtia polystachia heartwood, a plant with high concentration of phenolic compounds, exposed to different doses of underwater shock waves, was compared with the conventional methods. Our results revealed that shock wave-assisted extraction (1500 shock waves with a peak positive pressure of approximately 88 MPa) produced 34.54% and 31.95% higher contents than Soxhlet and USE, respectively. Extraction times using shock waves were much shorter than with all other methods tested, proving that it is an attractive method to obtain both phenolic acids and flavonoids without the need for organic solvents. Furthermore, shock waves produced a significantly higher content of total reducing sugars than Soxhlet extraction and less phenolic acids which gives the insight of a more selective extraction of components.
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