Isolation and structural characterization of hemicelluloses from palm of Phoenix dactylifera L

Statistics-based optimization of the extraction process of kelp polysaccharide and its activities

Statistics-based response surface methodology (RSM) was used to optimize the extraction process of kelp polysaccharide and its activities were evaluated. Single factor experiment was first designed for determining the optimal range of each of four factors and these factors were further optimized using RSM with a CCD design. The optimal conditions were as follows: pH 3.4, temperature 83 °C, extraction time 3.95 h and ratio of water to kelp 1:23. Under the above conditions, the yield of kelp polysaccharide obtained was 1.26%. Scavenging percentages of free radicals OH, O(2)(-) and DPPH by kelp polysaccharide were up to 90.8% (1.6 mg/mL), 85% (1 mg/mL) and 23.8% (1 mg/mL), respectively. An increase of 86% in the biosynthetic activity of collagen was obtained at a kelp polysaccharide concentration of 0.25%. All these results indicate that kelp polysaccharide may be a good candidate as an effective ingredient of cosmetics for future use.

The structural changes of the bagasse hemicelluloses during the cooking process involving active oxygen and solid alkali

This work describes the structural changes of bagasse hemicelluloses during the cooking process involving active oxygen (O(2) and H(2)O(2)) and solid alkali (MgO). The hemicelluloses obtained from the bagasse raw material, pulp, and yellow liquor were analyzed by high-performance anion-exchange chromatography (HPAEC), gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR), and (1)H-(13)C 2D hetero-nuclear single quantum coherence spectroscopy (HSQC). The results revealed that the structure of the bagasse hemicelluloses was L-arabino-(4-O-methylglucurono)-D-xylan. Some sugar units in hemicelluloses were oxidized under the cooking conditions. Additionally, the backbones and the ester linkages of hemicelluloses were heavily cleaved during the cooking process.

Extraction optimization of water-extracted mycelial polysaccharide from endophytic fungus Fusarium oxysporum Dzf17 by response surface methodology

Water-extracted mycelial polysaccharide (WPS) from the endophytic fungus Fusarium oxysporum Dzf17 isolated from Dioscorea zingiberensis was found to be an efficient elicitor to enhance diosgenin accumulation in D. zingigerensis cultures, and also demonstrated antioxidant activity. In this study, response surface methodology (RSM) was employed to optimize the extraction process of WPS from F. oxysporum Dzf17 using Box-Behnken design (BBD). The ranges of the factors investigated were 1–3 h for extraction time (X₁), 80–100 °C for extraction temperature (X₂), and 20–40 (v/w) for ratio of water volume (mL) to raw material weight (g) (X₃). The experimental data obtained were fitted to a second-order polynomial equation using multiple regression analysis. Statistical analysis showed that the polynomial regression model was in good agreement with the experimental results with the determination coefficient (R²) of 0.9978. By solving the regression equation and analyzing the response surface contour plots, the extraction parameters were optimized as 1.7 h for extraction time, 95 °C for extraction temperature, 39 (v/w) for ratio of water volume (mL) to raw material weight (g), and with 2 extractions. The maximum value (10.862%) of WPS yield was obtained when the WPS extraction process was conducted under the optimal conditions.

Date fruits (Phoenix dactylifera Linn): an emerging medicinal food

Date palm is one of the oldest trees cultivated by man. In the folk-lore, date fruits have been ascribed to have many medicinal properties when consumed either alone or in combination with other herbs. Although, fruit of the date palm served as the staple food for millions of people around the world for several centuries, studies on the health benefits are inadequate and hardly recognized as a healthy food by the health professionals and the public. In recent years, an explosion of interest in the numerous health benefits of dates had led to many in vitro and animal studies as well as the identification and quantification of various classes of phytochemicals. On the basis of available documentation in the literature on the nutritional and phytochemical composition, it is apparent that the date fruits are highly nutritious and may have several potential health benefits. Although dates are sugar-packed, many date varieties are low GI diet and refutes the dogma that dates are similar to candies and regular consumption would develop chronic diseases. More investigations in these areas would validate its beneficial effects, mechanisms of actions, and fully appreciate as a potential medicinal food for humans all around the world. Therefore, in this review we summarize the phytochemical composition, nutritional significance, and potential health benefits of date fruit consumption and discuss its great potential as a medicinal food for a number of diseases inflicting human beings.

Novel hydrophobic hemicelluloses: synthesis and characteristic

Novel hydrophobic hemicelluloses possessing hydrophobic groups were prepared by the benzylation of wheat straw hemicelluloses with benzyl chloride under the presence of catalyst in an ethanol/water system. In particular, the progress of the benzylation reaction was studied as a function of the volume ratio of ethanol/water from 4:1 to 6:4, the molar ratio of NaOH/anhydroxylose unit in hemicelluloses from 0.6:1 to 1.5:1, the molar ratio of benzyl chloride/anhydroxylose unit in hemicelluloses from 0.5:1 to 2.0:1, reaction temperature 50-80 °C, and reaction time 4-20 h Benzylated hemicelluloses with the low degree of substitution from 0.09 to 0.35 were obtained depending on the experimental conditions. The incorporation of benzyl groups into the backbone of hemicelluloses was confirmed by FT-IR and (13)C NMR spectroscopies. The thermal stability increased after the modification of hemicelluloses due to the introduction of benzyl groups. The introduction of benzyl groups endows hemicelluloses with the hydrophobicity, which could be potentially applied in plastic industries.

Structural and thermal characterization of hemicelluloses isolated by organic solvents and alkaline solutions from Tamarix austromongolica

Three organosolv and three alkaline hemicellulosic fractions were prepared from lignocellulosic biomass of the fast-growing shrub Tamarix austromongolica (Tamarix Linn.). Sugar analysis revealed that the organosolv-soluble fractions contained a higher content of glucose (33.7-6.5%) and arabinose (14.8-5.6%), and a lower content of xylose (62.2-54.8%) than the hemicellulosic fractions isolated with aqueous alkali solutions. A relatively high concentration of alkali resulted in a decreasing trend of the xylose/4-O-methyl-D-glucuronic acid ratio in the alkali-soluble fractions. The results of NMR analysis supported a major substituted structure based on a linear polymer of β-(1→4)-linked d-xylopyranosyl residues, having ramifications of α-L-arabinofuranose and 4-O-methyl-D-glucuronic acid residues monosubstituted at O-3 and O-2, respectively. Thermogravimetric analysis revealed that one step of major mass loss occurred between 200-400°C, as hemicelluloses devolatilized with total volatile yield of about 55%. It was found that organosolv-soluble fractions are more highly ramified, and showed a higher thermal stability than the alkali-soluble fractions.

Twin-screw extrusion for hemicellulose recovery: influence on extract purity and purification performance

A twin-screw extruder was used for the extraction of wheat bran hemicelluloses by the co-extrusion of wheat straw and bran. As compared with a stirred reactor extraction, a twin-screw extruder resulted in a lower extraction rate (only about 24% of hemicelluloses in the wheat bran), but it has the advantages of a shorter residence time for the vegetable matter and a lower chemical and water consumption. Hemicellulose powder production is usually effected via an expensive alcoholic precipitation step after concentration. Ultrafiltration was investigated as a means to reduce the alcohol consumption. Trials were made with hollow fiber polyethersulfone membranes with a molecular weight cut-off of 30 kDa. Ultrafiltration mainly concentrated the extract and removed small molecules such as monosaccharides and minerals. The combination of the anion-exchange chromatography and ultrafiltration allowed for the removal of colored compounds.

Synthesis and antioxidant activity of hydroxycinnamic acid xylan esters

Naturally occurring hydroxycinnamic acids, such as ferulic and sinapic acids, are known to possess antioxidant activity. In this study, ferulic acid and sinapic acid were covalently attached to oat spelt arabinoxylan and birch wood glucuronoxylan by esterification in a two-step feasible synthesis to generate modified xylans with various degrees of substitution. The obtained derivatives were fully analyzed by FT-IR, NMR, and HPSEC experiments to confirm the esterification of xylans and the degree of substitution. The antioxidative potential of the conjugates was evaluated using the emulsion lipid oxidation test. The results demonstrate that the derivatized xylans inhibited lipid oxidation notably better than the native oat spelt and birch wood xylans. It was found that ferulic acid esters of glucuronoxylan were more efficient antioxidants than those of arabinoxylan and that sinapic acid xylan esters were more efficient than their ferulic acid counterparts.

Rapid esterification of wheat straw hemicelluloses induced by microwave irradiation

Esterification of wheat straw hemicelluloses with acetyl chloride, propionyl chloride, n-octanoyl chloride, lauroyl chloride, palmitoyl chloride, stearoyl chloride, and oleoyl chloride, respectively, using N-bromosuccinimide (NBS) as a catalyst was achieved in DMF/LICl medium by microwave irradiation. The effects of various acyl chlorides and the molar ratios of xylose units in hemicelluloses/acyl chloride on the degree of substitution (DS) were investigated and DS reached up to 1.34 by a few minutes. (13)C NMR studies showed that the esterification occurred preferentially at the C-3 and C-2 positions. On the other hand, microwave irradiation brought a partial degradation of the polymer, and therefore resulted in a slight decrease in thermal stability of the hemicellulosic derivatives in comparison with conventional heating technique.