جستجوی مقالات مرتبط با کلیدواژه "extraction" در نشریات گروه "جنگلداری"

Abstract1 Comon Ash is a forest species with versatile biological and medicinal activities that extracts of its various organs are used as a model for making new compounds in the treatment of various human diseases. There is a high correlation between the geographical origin of medicinal plants and the active compounds produced in them. Therefore In this study, using this correlation, the most suitable habitat in terms of production of secondary metabolites is introduced For this research, selected eight habitats from an altitude range of 200 to 1600 meters (Perchink, three parcels of Panj Amreh series, Alandan, Lala, Qarnsara and Ilal) in Tajan and Siahroud watersheds located in Mazandaran province. In each habitat, 3 tree that were similar to each other in terms of quality characteristics were selected (tree diameter and height, leaf freshness and health, canopy density). Leaf samples from the middle part of the branches. The canopy was harvested in four directions in order to eliminate the effect of geographical direction in sampling. The leaf samples were dried in the open air and after grinding and preparing the extract with absolute ethanol, the leaf extracts were prepared for injection by gas chromatography. In order to study the physical and chemical properties of the soil, a soil sample was taken in combination around each tree base from a depth of 0-15 cm. Then physicochemical properties of soil such as bulk density, acidity, organic crane, total nitrogen, available phosphorus, potassium and calcium were measured in the laboratory. One-way analysis of variance was used to investigate the differences between the sampling areas in terms of secondary chemical composition in the leaves. Pearson double correlation was also used to find out how environmental and soil parameters relate to these chemical compounds. The results showed that the characteristics of the sampling location had an effect on the values of the identified secondary compounds. All identified compounds (except Vitamin E and Ferruginol) had a positive correlation with altitude factor. The highest levels of Neophytadiene (27.7%), Squalene (21.7%), n-Hexadecanoic acid (26.8%), Octadecatrinoic acid (28.3%), Phytol (6.35%) and Benzeneethanol (10.39%) were observed in ilal. There was no significant relationship between soil physical properties such as moisture content, bulk density and soil texture with chemical compounds in the leaves. Also, in all studied habitats, there was a significant negative relationship between soil nutrients and identified compounds. Also, a number of identified compounds were observed in only one or more habitats and were not common in all habitats studied. The results of this study showed with increasing altitude, the amount of metabolites in the leaves increased and most of the soil nutrients had a negative correlation with the identified chemical compounds. In other words, reducing soil nutrients can cause some kind of stress and increase the production of secondary metabolites in the plant.

In this study, hot water pre-extraction of barley straw followed with soda and monoethanolamine pulping was investigated. Pre-extraction that resulted in removal of 28 % of barley straw hemicelluloses and pre-extraction yield of 72.7 % was selected as the optimum pre-extraction treatment. The pulping results show that among the pulps from pre-extracted barley straw and barley straw without pre-extraction, monoethanolamine pulps have the highest yields. Also, the yields of pulps were drastically dropped after hot water pre-extraction. At the same pulping conditions, the kappa numbers of pulps that produced from pre-extracted barley straw were decreased more than that of from barley straw without pre-extraction in soda pulping, but this effect is not seen in the case of monoethanoleamine pulps. Pre-extraction of barley straw followed with soda pulping resulted in pulps with higher tensile, burst and tear indices in comparison to untreated samples. In the case of monoethanoleamine pulp the similar trend can be seen in except of tensile index. The brightness of pulps from pre-extracted barley straw is decreased while the pre-extraction has no effect on pulp opacities.

Optimization of the isolation methods and utilization of the sugars present in the hydrolysates obtained from pre-hydrolyses of various lignocellulosic materials for production of new chemicals and energy is currently accounted for novel methods of biorefinery all over the world. In this study, effect of temperature (90 and 100 oC), KOH concentration (2, 4 and 6 %) and Polyoxyethylene (80) sorbitan monooleate (Tween 80) (0.3 and 0.5 %) was investigated in alkaline pre-extraction of wheat straw on its extracted compounds. To hydrolyze the oligomers in the extracted liquor into monomeric sugars, a vial containing 1 mL of the extracted liquor and 20 ml 4% sulfuric acid was kept in an autoclave at 121◦C for one hour. Results indicated that both weight loss of wheat straw chips and dissolved solids content in the extracted liquor increased by increasing temperature and KOH concentration, meaning that sugars removal from wheat straw and total sugars in hydrolysate increased by increasing temperature and KOH concentration. Also, the sugars removal from wheat straw chips increased by addition of Tween 80, in a manner that in equal concentration of KOH, addition of Tween 80 led to an increase in total sugars content. It is therefore concluded that addition of Tween 80 can improve yield of sugars derived from hemicelluloses extraction without increasing alkali concentration, whereby environmental pollution may decline.

The effect of Soxhlet and simple immersion extraction methods on the amount and type of bioactive phenolic compounds of C. arizonica woodknots were studied. Lipophilic and hydrophilic compounds were Soxhlet extracted according to T280 pm-99 standard method with hexane and acetone solvents, respectively. Also, in the immersion method woodknot samples were dipped in hexane to remove the lipophilic moieties and then treated with ethanol: H2O (1: 9, v/v) solvent to isolate the hydrophilic compounds. Also, an alkaline hydrolysis step with one molar NaOH solution was performed to remove sugar impurities from the ethanolic extract of the immersion method. GC-MS was used to identify the extractives components of different procedures. The results of analysis indicated the efficiency of bioactive components extraction with ethanol: H2O (1: 9, v/v) solvent comparing to acetone procedure. Moreover, the simple immersion method was showed to be a suitable method in extraction of bioactive extractives. Contribution of matairesinol (MR), dienestrol and curumine in the extract of EtOH: H2O were 11.2, 0.4 and 0.9%, respectively. Alkaline hydrolysis led to a partial degradation of phenolics according to the results of GC-MS analysis.

In this study، the effect of using cellulose nanofibers and cationic starch on the mechanical properties of soda anthraquinone (Soda-AQ) pulp prepared from un-extracted/ alkaline pre-extracted rice straw using conventional hand sheet paper making system with standard wire was investigated. Cellulose nanofibers were added at three ratios of 2، 5 and 10 wt%، mixed with pulps from un-extracted/ alkaline pre-extracted rice straw over 2، 5 and 10 minutes. The consumption ratio of cationic starch was also tuned at 1. 5 percent based on dry weight of pulp. The results show that in spite of using conventional hand sheet paper making system، the mechanical strength of paper containing cellulose nanofibers linearly increased. The use of cationic starch had a positive significant effect on the paper properties due to better retention of cellulose nanofibers. The results indicate the success of using cellulose nanofibers with cationic starch in improving the mechanical characteristics of soda-AQ pulp in conventional hand sheet paper making system.

The effect of partial pre-extraction of hemicelluloses on the properties of rice straw soda AQ pulp to produce valuable by products from this pre-extraction was investigated. The pre-extraction conditions were conducted using 10% sodium hydroxide (based on dry weight of the rice straw), at 50 °C for 90 minutes to reach the extraction rate of 48.1% of the hemicelluloses. Soda-AQ pulping was performed under different conditions at pre-determined pulping time and liquor to straw ratios. The optimum pulping conditions was found as 14% active alkali, 160 °C and 45 minutes pulping time. Comparasion of per-extracted materials with the normal rice straw indicated that to achieve the same kappa number and yield, the pretreated material requires less alkali and cooking time. The results showed that pre-extraction marginally reduced the tensile strength index of the pulp which the difference was not statistically significant with control pulping condition. However, the burst strength index of pre-extracted pulp and control was identical. The overall mechanical properties of pretreated pulp were the same as the control.

Biomass pretreatment plays a crucial role in a lignocelluloses feedstock-based biorefinery for processing of three major output streams (cellulose، hemicelluloses and lignin) into chemicals and biofuels. Biomass pretreatment includes processing of lignocellulosic material under aqueous، dilute acid or alkaline media to obtain a cellulosic fraction، which in then produce added-value products. In this study، the effect of pre-extraction on alkaline pulping (soda) and papermaking properties of Bagasse was investigated. Samples of sugar cane bagasse were hydrolysed by auto hydrolysis with hot-water. Results showed that pre-extraction optimum conditions were 30 min، 135OC and 10 min 170OC، resulted in extraction yield and holocellulose removal of 86% and 11%، respectively. Also، the pulping optimum conditions were alkali charge 17%، 165 OC for 1h. The results indicated that for unbleachable pulp production the pulping yield from the extracted bagasse is higher than the unextracted bagasse but the bleached pulp from unextracted bagasse have higher yield compared to the extracted bagasse. Pulp strength properties such as the tensile index and the burst index were found to be lower when pre-extraction was applied.

In the present research, kenaf chips have been pre-extracted to weight loss levels of about 8.5, 11.5 and 14.5%, based on oven dried Kenaf chips by hot water and acid catalyzed hot water prior to pulping process. Pre-extracted and un-pretreated (control sample) Kenaf chips were converted to pulp by soda-AQ process at three cooking times 60, 90 and 120 minutes. The results of pre-extraction stage indicated that pre-extraction time to achieve a specified weight loss has been reduced with addition acid catalysis (Sulphric Acid). The results of pulping indicated that pulp yield reduced by increasing cooking time as well as weight loss of Kenaf chips in pre-extraction stage. In terms of the average pulp yield and kappa number at constant cooking time, there were significant differences at 1% error level between un-extracted (control sample) and the chips pre-extracted to 8.5, 11.5 and 14.5% weight loss. As, control pulp had highest yield and kappa number and pre-extracted pulp, at 14.5% weight loss, had lowest yield. In addition, in terms of pulp yield there were significant differences at 1% error level between un-preextracted (control) Kenaf chips and samples extracted with pure hot water and acid catalyzed hot water at any weight loss levels of 8.5, 11.5 and 14.5%. Control pulp had highest and hot water pre-extracted pulp had lowest yield. Significant differences at 1% error level were observed between control sample and pre-extracted Kenaf chips at similar amounts of weight loss in terms of average pulp kappa but there were no significant differences for average kappa number between pulps pre-extracted from hot water and acid catalyzed treatments. The results of physical and strength properties of hand sheets showed that different strength amounts were reduced by increasing the amounts of pre-extracted weight loss from 8.5 to 14.5% for all second pre-extraction methods. On the other hands, strength amounts of pulp from hot water pre-extracted Kenaf chips were often lower than pulp samples pre-extracted by acid catalyzed hot water.