Microwave-assisted solvent extraction of castor oil from castor seeds

This study was aimed at evaluating the physicochemical properties and oxidation stability of castor oil using microwave-assisted solvent extraction (MAE). MAE was performed using 5% ethanol in hexane as solvent at different extraction times, power intensities and solvent-to-feed (S/F, ml of solvent to gram of feed) ratios. The process parameters were optimized by statistical approach using historical data design of response surface method (RSM). The oils were characterized for yield, physicochemical properties, dielectric properties and oxidation stability, and comparison was also made with oil extracted using Soxhlet method. Results show that the maximum oil yield of 37% was obtained at 20 min with microwave power intensity of 330 W and S/F ratio of 20. The main fatty acid composition of castor oil is ricinoleic acid. The density, refractive index, dielectric properties and oxidation stability of oils are not affected by the extraction methods and extraction parameters of MAE. However, the MAE-extracted oil is more viscous compared to that by Soxhlet method. With extra caution on oil oxidation, MAE could be a promising solvent extraction method with an 86% less in processing time and a higher yield.     

Water-based extraction of pectin from flavedo and albedo of orange peels

The extraction of pectin from orange peels has been studied at different sample to solvent ratios, different pHs and with different extraction techniques using water. The highest pectin and total nitrogen was produced by a sample to solvent ratio of 1:12.5. The amount of pectin extracted reduces as the pH increased, while the extractability of crude protein is not affected so significantly. Previous workers have found similar results. Considerably more pectin was obtained by the Soxhlet method than by microwave extraction by a factor of two, with a longer extraction duration than the microwave extraction by a factor of 240, so microwave extraction showed a much higher extraction rate (per unit time) by a factor of 120. Pectin existed mainly in the albedo, but the flavedo still contained 27% of the amount of pectin in the total extract. The total pectin yield from the dried peel was 2.2%. The combination of hand-pressure and microwave on pectin yield from flavedo was 12% better than hand-pressure alone, which was also better than microwave extraction alone.     

Supercritical carbon dioxide extraction of triglycerides from Jatropha curcas L. seeds

This study examines the effects of pressure, temperature and solvent to solid ratio (SSR) on extraction efficiency of triglycerides from powdered Jatropha seeds by using supercritical carbon dioxide extraction. Supercritical extractions were designed for pressures ranging from 250 to 350 bar, temperatures ranging from 313 to 333 K and SSR values ranging from 65:1 to 125:1. All values were selected using response surface methodology in order to determine their effects on the concentration of triglycerides from the extracted oil. Using 3750 g of carbon dioxide over 5 h, a supercritical carbon dioxide extraction (at 350 bar, 333 K and an SSR value of 125:1) yielded 43.51% oil. The concentration and extraction efficiency (i.e. recovery) of triglycerides in the extract reached 657.1 mg/g and 97.62%, respectively. Changes in pressure presented more effective in increasing the recovery of triglycerides, but both temperature and the SSR value are important in obtaining high concentration of triglycerides from the Jatropha seeds that are useful for biodiesel materials.     

The effect of extraction techniques on yield,extraction kinetics,and antioxidant activity of aqueous-methanolic extracts from nettle (Urtica dioica L.) leaves

Five extraction techniques, maceration, reflux, Soxhlet, Tillepape, and ultrasonic extraction, were used to obtain the extractive matter from nettle leaves. The antioxidant activity of extracts was assessed by DPPH, FRAP, and H₂O₂ test, while the total phenolic and total flavonoid content was determined according to the Folin–Ciocalteu and aluminium chloride methods, respectively. Model Ponomarev and a non-stationary diffusion model through the plant material were used for modelling extraction process. The extract obtained by Soxhlet extraction, containing higher amounts of extractive matter as well as phenolic and flavonoid compounds, showed better antioxidant activity than those obtained by other extraction techniques.     

A novel process for extraction of tea oil from Camellia oleifera seed kernels by combination of microwave puffing and aqueous enzymatic oil extraction

The objective of this study was to extract the oil from Camellia oleifera seed kernels by aqueous enzymatic oil extraction (AEOE). We describe a novel process for extraction of tea oil preceded by tea saponin extraction from C. oleifera seed kernels. The extraction efficiency obtained with microwave‐assisted extraction (MAE) is very high, which the recovery yield is up to 83% in 30 s and the saponins in camellia seed kernels can be completely removed by the second MAE. Moreover, an important step in the process development has been the pretreatment by microwave puffing of camellia seed kernel residues followed by AEOE increased oil extraction yield from 53% to 95%, which will is comparable to hexane oil extraction yields from plant materials.     

Experimental and modelling of supercritical oil extraction from rapeseeds and sunflower seeds

The supercritical oil extraction from oleaginous seeds (sunflower and rapeseeds) is presented here through experimental and modelling results. The experimental setup allows an accurate following of the mass of the oil extracted and to derive the experimental influences of pressure, temperature and supercritical CO₂ flowrate on the extraction curves. These parameters are very sensitive and highlight the necessity of precise optimisation of experimental conditions. In order to complete the behaviour of supercritical fluids extraction, an improved modelling is proposed. The modelling basic equations are based on others modelling published previously. In this work, the determination of several parameters comes from correlations and the other constants are fitted with all the experimental results. Thus the modelling is more representative and predictive as other ones. The modelling results present a good agreement with the experimental results, and hence it can be used for the dimensioning of some extraction autoclaves.     

微波辅助提取山竹夹层中黄酮化合物的研究

研究微波辅助提取山竹夹层中黄酮类化合物的提取工艺与条件。采用正交试验法确定提取优化条件为:90%甲醇为提取溶剂,原料与提取剂的固液比1∶100,微波功率800 W,微波提取时间15 s,提取次数两次。对比传统溶剂提取法,微波辅助提取的一次提取量是传统溶剂提取法的1.65倍,提取时间则是后者的1/80。     

Supercritical CO2 extraction of oil from seeds of six grape cultivars: Modeling of mass transfer kinetics and evaluation of lipid profiles and tocol contents

The current study focuses on the recovery of grape seed oil by supercritical CO₂ extraction. Grape seeds from six grape cultivars were extracted in two subsequent harvesting years, and the resulting oils were characterized for the relative amount of: (a) lipid classes; (b) lipid acyl chains; and (c) tocopherols and tocotrienols. Comparative extractions were performed by utilizing n-hexane as solvent and by mechanical pressure. A well-established modeling approach was applied to evaluate the mass transfer parameters affecting the kinetics of supercritical CO₂ extraction: with these parameters, process scale-up can be addressed. The results reported in this study testify the potentiality of grape seed oil as a source of unsaturated fatty acids and tocols. Moreover, they offer a clear picture of the similarities and differences among oils from different grape cultivars and obtained through different extraction techniques.     

飞天蜈蚣七皂苷提取动力学研究

采用球形模型,以Fick第二定律为基础,建立飞天蜈蚣七皂苷的提取动力学模型.对飞天蜈蚣七皂苷进行乙醇回流提取,在不同的液料比(体积质量比)、提取温度及提取时间等条件下,对提取液中皂苷的质量浓度进行检测.再根据该球形模型方程分别推算出了提取速率常数、活化能、相对萃余率、有效扩散系数等动力学函数值.根据该模型方程推算出的提...     

Multi response optimisation of polyphenol extraction conditions from grape seeds by using ultrasound assisted extraction (UAE)

Multi response optimisation conditions were investigated in grape seeds’ phenolic compounds extraction by using ultrasound-assisted extraction (UAE) methodology. The effect of independent process variables such as EtOH concentration (0–100%), extraction time (0–40 min), solvent:solid ratio (4.5–38.5 mL/g) and extraction temperature (20–60°C) on total phenolic content (TPC) and total antioxidant activity (TAA) of the extracts were studied. The optimum conditions of UAE were determined as follows: EtOH concentration, 61.76%; extraction time 20 min., solvent:solid ratio, 30 mL/g; extraction temperature 50°C. The estimation results of the model and the experimental results for TPC and TAA showed a great similarity.     

不同溶剂的索式法提取酸浆果籽中油脂及成分分析

分别以乙醚、乙酸乙酯、正己烷为萃取溶剂,采用索氏萃取法提取黑龙江省产酸浆果籽获得了油脂,得油率分别为乙醚19.70%(质量分数,以下同)、乙酸乙酯19.53%、正己烷18.83%.用气质联机(GC/MS)对籽油成分进行分析的结果显示,酸浆籽油脂成分主要由亚油酸,油酸,十六烷酸和十八烷酸构成.     

飞天蜈蚣七多糖提取动力学研究

根据中草药浸提机制和扩散理论对飞天蜈蚣七多糖浸提的动力学进行初步研究。以Fick第二定律为基础,采用球形模型讨论液料比、提取时间、提取温度与飞天蜈蚣七中多糖浸出量之间的关系,从而建立提取过程中动力学模型,并由此推算出浸提多糖过程中的速率常数、活化能、相对萃余率、有效扩散系数等动力学参数。飞天蜈蚣七中多糖的浸出量随着温度的升高而增加、随着液料比的变化而变化、随着提取时间的增长而逐渐增加并最终趋于平衡;浸提多糖的相对萃余率符合指数模型;有效扩散系数也随着温度升高而增加并受到液料比的影响。研究得到的动力学模型可为飞天蜈蚣七多糖提取的工艺条件优化和深层次研究奠定理论基础。     

Microwave-assisted extraction of chlorogenic acid from flower buds of Lonicera japonica Thunb.

An efficient microwave-assisted extraction (MAE) technique has been developed to recover chlorogenic acid from flower buds of Lonicera japonica Thunb. The yield of chlorogenic acid rapidly reached 6.14% within 5 min under the optimal MAE conditions, i.e. 50% ethanol as extraction solvent, 1:10 (w/v) of the solid/liquid ratio and 60 °C of extraction temperature. The MAE showed obvious advantages in terms of short duration and high efficiency to recover chlorogenic acid from raw plant materials in comparison with conventional heat-reflux extraction. The mechanism of the enhanced extraction by microwave assistance was discussed by observing cell destruction of plant material after MAE treatment by scanning electron microscopy. The results showed that the plant materials were significantly destroyed due to the cell rupture after MAE treatment.     

Supercritical fluid extraction and characterisation of oil from hazelnut

Hazelnut (Corylus avellana L.) oil was extracted with compressed carbon dioxide in the temperature range of 308—321 K and in the pressure range of 18—23.4 MPa. In addition the influence of the superficial velocity, within a tubular extractor was studied. Physical and chemical characteristics of the oil were obtained. The results including contents of free fatty acids, sterols, triacylglycerols and tocopherols were compared with those obtained when n‐hexane was used as solvent. No significant differences were found when the oils extracted by both methods were analysed. The main fatty acid was the oleic acid (83—85%), followed by linoleic acid (6—8%) and palmitic acid (5—6%). The main triglyceride found in hazelnut oils was the trioleylglycerol (OOO) (63.4—69.6%), followed by the linoleyl‐dioleylglycerol (LOO) (11.6—15.5%) and palmitoyl‐dioleylglycerol (POO) (9.9—10.4%). In terms of sterols, the main component was β‐sitos‐terol (∼83%) followed by campesterol (∼6%). The amount of cholesterol was very low (∼0.2%). The CO₂ extracted oil contained about 17% more tocopherols (458.7 μg/g oil) than the oil extracted by n‐hexane (382.8 μg/g). Oxidative stability was studied by using the induction time determined by the Rancimat method. The oil obtained by supercritical fluid extraction (SFE) was slightly more protected against oxidation (8.7 h for SFE extracted oil and 6.7 h for the hazelnut oil extracted with n‐hexane). Both oils presented high stability index values (7.81 for the oil extracted by n‐hexane and 8.7 for the oil extracted with supercritical CO₂). Oil extracted by supercritical CO₂ was clearer than the one extracted by n‐hexane, showing some refining. Besides, the acidity index was 1.6 for the n‐hexane extracted oil and 0.9 for the oil extracted with supercritical carbon dioxide. The central composite non‐factorial design was used to optimise the extraction conditions, using the Statistica, version 5 software (Statsoft). The best results, in terms of recoveries of hazelnut oil by SFE, were found at 22.5 MPa, 308 K and superficial velocity of 6.0 × 10^—4 ms^—1.     

Subcritical co‐solvents extraction of lipid from wet microalgae pastes of Nannochloropsis sp.

In this paper subcritical co‐solvents extraction (SCE) of algal lipid from wet pastes of Nannochloropsis sp. is examined. The influences of five operating parameters including the ratio between ethanol to hexane, the ratio of mixed solvents to algal biomass (dry weight), extraction temperature, pressure, and time were investigated. The determined optimum extraction conditions were 3:1 (hexane to ethanol ratio), 10:1 ratio (co‐solvents to microalgae (dry weight) ratio), 90°C, 1.4 MPa, and 50 min, which could produce 88% recovery rate of the total lipids. In addition, electron micrographs of transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were conducted to show that the algal cell presented shrunken, collapsed with some wrinkles and microholes after SCE extraction. The main composition of total lipids extracted under the optimum conditions was TAG which represented more than 80%. And the fatty acid profile of triglycerides revealed that C16:0 (35.67 ± 0.2%), C18:1 (26.84 ± 0.044%) and C16:1 (25.96 ± 0.011%) were dominant. Practical applications: The reported method could save energy consumption significantly through avoiding deep dewatering (for example drying). The composition of the extracted lipid is suitable for the production of high quality biodiesel.     

Solvent-assisted extraction of oil from papaya (Carica papaya L.) seeds: evaluation of its physiochemical properties and fatty-acid composition

ABSTRACT

The present work reports the solvent-assisted extraction of oil from papaya (Carica papaya L.) seeds. Various operating parameters such as solid solvent ratio, temperature and time on oil yield, and its effects have been investigated using response surface methodology. The experimental oil yield (20.30 ± 0.03%) at optimal condition was well agreed with the predicted value. The compositions from GC-FID results showed saturated fatty acid (20.94%), monounsaturated fatty acid (73.12%), and polyunsaturated fatty acid (4.96%). It was also found that the solvent-assisted extraction is a simple and effective method for extraction of oil from papaya seeds.     

Optimization of oil extraction from Pitanga (Eugenia uniflora L.) leaves using simplex centroid design

Simplex centroid design (SCD) was employed to optimize the mixing of petroleum ether, n-hexane, methanol and ethanol for the extraction of oil (PLO) from Pitanga (Eugenia uniflora L.) leaves, via Soxhlet extraction. The highest yield (54%) of Pitanga leaf oil (PLO) was obtained with 100% ethanol and the lowest yield (16%) from the mixture of methanol (33.3%)/hexane (33.3%)/ethanol (33.3%). The coefficient of determination (R²) of the model equation obtained was 0.91, while the adjusted R² and predicted R² were 0.8729 and 0.951, respectively. The saponification value (S.V.), iodine value, acid value and free fatty acid (FFA) are 35.34 mgKOH/g, 72.97 mgI₂/g oil, 32.41 and 16.30 mgKOH/g, respectively.