23 research outputs found

    Characterizations of saponin and phenolic bioactive compounds extracted from fenugreek seed and aloe vera leaves via microwave-assisted extraction method

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    In this study, the potential of fenugreek seed and Aloe vera leaves as a source of saponins, phenolics and antioxidants were investigated. Microwave-assisted extraction (MAE) and Soxhlet extraction (SE) were used to obtain the extracts. The effects of experimental factors in MAE such as extraction time (2-12 min), microwave power (300-700 W), ethanol concentration (20-100%), feed-to-solvent ratio (1:8-1:16 and 1:18-1:22 g/mL) and extraction temperature (40-80 °C) were evaluated using one-factor-at-a-time (OFAT), respectively. The SE factors including extraction time (1-5 h), ethanol concentration (20-100%) and feed-to-solvent ratio (1:14-1:24 g/mL) were also investigated. Results indicated the higher extraction yield, total saponin content (TSC) and Total phenolic content (TPC) were obtained via MAE compared to SE in a time saving process. The maximum yields in SE were obtained at 3 h of extraction time, 60 % ethanol concentration and 1:20 g/mL F:S ratio which were 19.35±0.75%, 125.04±1.55 mg DE/g d.w. and 60.13±2.04 mg GAE/g d.w. for fenugreek seed and 22.45±0.76%, 44.78±1.01 mg OAE/g d.w. and 49.99±0.56 mg GAE/g d.w. for Aloe vera leaves, respectively. Further screening of the factors via two-level factorial design was carried out for MAE parameters. Results indicated that ethanol concentration and extraction temperature were the most and least significant factors in achieving maximum recoveries of the yields, respectively. The selection of factor levels for optimization process was obtained based on the pre-evaluation of factors (OFAT). The best points for optimizing the factors were extraction time (2-4 min), microwave power (500-700 W and 400-600 W), ethanol concentration (40-80% and 20-60%), feed-to-solvent ratio (1:8-1:12 and 1:18-1:22 g/mL) and constant temperature of 70 °C, respectively. The optimal MAE conditions for fenugreek seed and Aloe vera leaves extraction yield, TSC and TPC were at 2.84 min, 572.50 W, 63.68%, and 1:9 g/mL. Based on the optimum condition, the responses of extraction yield, TSC and TPC of fenugreek seed were 26.04 ± 0.88%, 195.89 ± 1.07 mg DE/g d.w., 81.85 ± 0.61 mg GAE/g d.w, and for Aloe vera leaves extracts in MAE were 2.79 min, 478.95 W, 43.38% ethanol, and 1:19 g/mL. Where, based on these conditions, the extraction yield, TSC and TPC of Aloe vera leaves extract were 36.17 ± 1.13%, 65.89 ± 0.77 mg OAE/g d.w and 73. 05 ± 1.05 mg GAE/g d.w, respectively. The extracts obtained via MAE and SE were also tested for its antioxidant capacity via 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,20-azino- bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), structure and bonding using Fourier transform infrared (FTIR) and morphological studies using SEM. Results indicated that extracts obtained via MAE showed higher antioxidant capacity with low IC50 values of (195.27 ± 0.56 μg/mL; DPPH), (157.92 ± 1.11 μg/mL; ABTS), 12 identified peaks in FTIR for fenugreek seed and (275 ± 1.45 μg/mL; DPPH) (215.58 ± 0.57 μg/mL; ABTS), 11 peaks in FTIR and more wrapped and opened texture via scanning electron microscope (SEM), respectively. However, in SE it was (224.47 ± 0.77 μg/mL; DPPH), (199.67 ± 0.96 μg/mL; ABTS) for fenugreek seed and (305.79 ± 0.66 μg/mL; DPPH), (263.29 ± 1.21 μg/mL; ABTS), with 6 identified peaks via FTIR and closed pores showed via SEM in both plants, respectively. kinetic studies and dielectric properties for MAE were also carried out. The LC-QTOF-MS result of optimized extracts also confirmed the presence of 58 saponins and 27 phenolic compounds in fenugreek seed and 29 saponin with 32 phenolic compounds in Aloe extract. The optimized extracts also indicated surfactant properties such as wetting, reduction of water surface tension, foaming and emulsification properties. Thus, these extracts can be a promising source of saponins, phenolics, antioxidants and natural co-emulsifier for food, cosmetics and pharmaceutical products

    A review on production of biodiesel from waste cooking oils

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    Nowadays, preservation of natural resources on earth is one of the most important concerns of humanity. In this regard, increasing the consumption of energy is one of the most critical challenges that humans are facing. Because, on the one hand, the untapped use of different sources of energy from fossil fuels can destroy this natural resource and, on the other hand, pollution from the use of these resources is a serious threat to the environment. Recent research suggests that affordable, sustainable and environmentally friendly fuels, which can be a good alternative to fossil fuels, have become more important. Therefore, biodiesel has made it possible to release less greenhouse gas emission and low toxicity emissions, which can partly meet fuel requirements and is the best alternative for petroleum diesel. In addition, the waste cooking oils are a major source of biodiesel for their essential compounds, such as glycerol. The use of waste cooking oils can reduce biodiesel production cost by 60 to 90 percent. Therefore, the main objective of this review is to study the production of biodiesel using transesterification reaction of waste cooking oil as an alternative fuel to petroleum diesel that can be used easily in diesel engines

    Stabilization of crude oil emulsions using different surfactants

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    Emulsions can be found in different industries such as petroleum, food, cosmetic and pharmaceutics. Generally, there are two types of emulsions in petroleum industries: water-in-oil (W/O) and oil-in-water (O/W). The aim of this research was to evaluate the stability of W/O emulsions using different emulsifiers such as Span 80, Span 83, Triton-x-100, DEA, and LSWR with different concentrations (1.5 and 2.5) vol%. All the emulsions were prepared at (20-80) vol% and 2000 rpm. The result of this study showed that the most stable emulsions were prepared by Span 80. However, LSWR formed the most unstable emulsions. In addition, it was also found that the concentration of emulsifier can significantly affect the emulsion stability

    Emulsion types, stability mechanisms and rheology: A review

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    Emulsions have been widely used in different industrial processes. The development and production of good quality emulsions depend on the knowledge of emulsion preparation, stability mechanisms and rheological studies. To form stable emulsions, an emulsifier is required to reduce the droplet sizes of the emulsions and enhance the emulsion stability. The purpose of this review article is to provide information about types of emulsions, stability mechanisms and rheological studies as well as factor affecting the stability of emulsions

    Analysis of Microwave Heating Process for Demulsification of Water-in-Crude Oil Emulsions

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    In this investigation, the process of microwave heating technology was evaluated to measure the effect of some important parameters such as dielectric properties (έ and ɛʺ), rate of temperature increase (dT/dt), volume rate of heat generation (Qmw), wavelength (λ) and penetration depth (Dp) during the microwave irradiation on crude oil emulsions. Two types of Malaysian crude oil mixed together at a volume ratio of 50-50% and applied for further investigations. In order to ensure the efficiency of the process, the improvement of existing techniques and the development of new technology different ratios of water and oil were utilized to prepare the emulsions of water-in-crude oil (W/O). The emulsion samples were heated under 360 watt and 540 watt for 3 to 5 minutes. The findings of the microwave heating demulsification showed that higher microwave power (540 watt) along with the radiation time (5 min) were not much effective for water separation. This is because of the over boiling of the samples. Consequently, for microwave heating demulsification the best water separation efficiency was achieved at 3 (minutes), 360 (watt). Based on the result of microwave parameter’s calculations, it was found that parameters such as; dT/dt, Qmw, έ and ɛʺ, were inversely proportional to the radiation time. However, parameters such as λ and Dp were directly proportional to the time of the radiation

    Effect of co2 partial pressure on dry reforming of ethanol for hydrogen production

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    The effect of CO2 partial pressure on ethanol dry reforming was evaluated over 5%Ce-10%Co/Al2O3 catalyst at = PCO2 = 20-50 kPa, PC2H5OH = 20 kPa, reaction temperature of 973 K under atmospheric pressure. The catalyst was prepared by using impregnation method and tested in a fixed-bed reactor. X-ray diffraction measurements studied the formation of Co3O4, spinel CoAl2O4 and CeO2, phases on surface of 5%Ce-10%Co/Al2O3 catalyst. CeO2, CoO and Co3O4 oxides were obtained during temperature–programmed calcination. Ce-promoted 10%Co/Al2O3 catalyst possessed high BET surface area of 137.35 m2 g-1. C2H5OH and CO2 conversions was improved with increasing CO2 partial pressure from 20-50 kPa whilst the optimal selectivity of H2 and CO was achieved at 50 kPa

    Optimization of saponins, phenolics, and antioxidants extracted from fenugreek seeds using microwave-assisted extraction and response surface methodology as an optimizing tool

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    Fenugreek is a multiregional plant mostly found in Asia, the Middle East, and some European countries. Thus, this study aimed to optimize the microwave-assisted extraction (MAE) process parameters such as irradiation time (2–4 min), ethanol concentration (40–80%), microwave power (500–700 W), solid-to-liquid ratio (1:8–1:12 g/mL), and a fixed extraction temperature (70 °C) for fenugreek seed powder. Response surface methodology (RSM) was applied to optimize MAE process parameters to achieve optimal total saponin content (TSC), total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) antioxidant capacities of fenugreek seed extract. The levels of independent variables were first evaluated using one-factor-at-one-time method, after which the suitable levels (−1, 0, and +1) were selected for the optimization process. The optimal conditions of MAE parameters were found to be 2.84 min, 572.50 W, 63.68%, and 0.09 g/mL. Based on the suggested optimum conditions, the obtained responses were 195.89 ± 1.07 (mg diosgenin equivalent/g d.w.), 81.85 ± 0.61 (mg gallic acid equivalent/g d.w.), 92.86 ± 0.56%, and 95.85 ± 0.81%. Analysis of variance revealed that all the responses including TSC, TPC, DPPH, and ABTS antioxidant capacities were significantly influenced (P < 0.05) by irradiation time, solvent concentration, microwave oven power, and feed-to-solvent ratio. Hence, the results obtained from liquid chromatography–quadrupole–time-of-flight mass spectrometry indicated the presence of steroid saponins, triterpenoid saponins, phenolics, and other natural antioxidants

    Potential of fenugreek seed extract for health, the environment and the economy

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    Bioactive compounds extracted from natural sources and plants have received potential interest in food, cosmetic and pharmaceutical industries. Recently, the use of synthetic antioxidants such as BHT and BHA are not very encouraged to be used in food, pharmaceutical and cosmetic products. Beside the application of synthetic surfactants at high volume in health-related products are prohibited by world health organization (WHO) due to their risks and side effects. In this research, fenugreek seed has been used to produce a multifunctional bioactive extract containing saponin, phenolic and antioxidant compounds via microwave-assisted extraction technology. Fenugreek seed is a low price and abundantly found material with many health benefits. The extract characterized using LC-QTOF-MS, FTIR, SEM, and also determined the total saponin, total phenolic compounds inside the extract. Due to the high amount of saponin inside the extract, it has been tested for emulsification and wettability properties. In addition, the properties of saponin makes it a good biosurfactant for food, cosmetic, pharmaceutical, water and soil treatment industries. It has been reported that biosurfactant are efficiently used for removal of heavy metals from water and soil

    Iridoids of fenugreek (Trigonella-foenum-graecum L.) seed extract detected via LC-QTOF-MS analysis

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    Fenugreek seed is a traditional medicinal plant with a wide biological activity. In this study, iridoids (Asperulosidic acid (1), 7-O-Methylmorroniside (2), Gentiopicroside (3), Rehmannioside A (4), Loganic acid-6′-O-β-Dglucoside (5), Sweroside (6), Penstemoside (7), 6′-O-β-D-Glucosyl Gentiopicroside (8), Oleuropein (9)) in optimized microwave-assisted extract of fenugreek seed were detected for the first time. The identification of iridoid compounds was carried out by liquid chromatography quadrupole time-of-flight mass spectrometry coupled with electrospray ionization (LC-QTOF-MS-ESI) in positive ion modes and Fourier Transform Infrared Spectroscopy (FTIR) analysis. More than 400 compounds were detected via LC-QTOF-MS, while among them only 9 were iridoids. The presence of iridoid compounds was also confirmed with FTIR analysis. In positive ion mode, iridoids with formic acid as mobile phase associated in formation of three adducts [+ H, + Na + K]. However, in the case of negative ion no iridoid compound was observed in the extract
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