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Anthocyanins are one of the bioactive compounds in roselle that has many medicinal proposes. Anthocyanins are placed in the inner part of the roselle; therefore, combinations of two methods were applied to extract the anthocyanins. The first stage is employing supercritical carbon dioxide (ScCO2) to break the particle surface or outer layer of the roselle based on the total phenolic compounds (TPC) recovery, and the second step was to apply subcritical water extraction (SWE) for the extraction of anthocyanins. The objective is to determine the best conditions to obtain high yields of total anthocyanins compounds (TAC) from the roselle (Hibiscus sabdariffa) by employing a combination of ScCO2 and SWE. The optimal conditions of ScCO2 (first stage) were 19.13 MPa, 60 °C, and 4.31 mL/min, yielding 18.20%, and 80.34 mg/100 g TPC, respectively. The optimum conditions of SWE (second stage) were 9.48 MPa, 137 °C, and 6.14 mL/min, yielding 86.11% and 1224.61 mg/100 g TAC, respectively. The application of integrated ScCO2 and SWE proved successful in achieving high anthocyanins production and yield as compared to previous extraction methods. This approach may be used to extract the roselle with a greater anthocyanin's concentration than the prior method. [ABSTRACT FROM AUTHOR]

The optimization of red pigment anthocyanin from roselle (Hibiscus sabdariffa) by subcritical water extraction (SWE) has not been the topic of a scientific investigation. Therefore, the objective of this paper was to establish the optimal parameters for obtaining the maximum yield, total anthocyanin compounds (TAC), total phenolic compounds (TPC), and total flavonoid compounds (TFC) by SWE utilizing a response surface methodology. The optimal conditions were 8.75 MPa, 393.54 K, and 4.89 mL/min, with a yield of 0.69 g/g, TAC of 927.74 mg/100 g, TPC of 39.54 mg/100 g, and TFC of 614.57 mg/100 g. High temperatures and flow rates are favorable for achieving a maximum yield. In contrast, a high temperature is suitable for obtaining high concentrations of anthocyanin, flavonoid, and phenolic compounds. This technique (SWE) recovers anthocyanin at a greater extraction rate than traditional methods; hence, SWE may be substituted for conventional methods for extracting anthocyanin. [ABSTRACT FROM AUTHOR]

Garlic (Allium sativum L.) is an herbaceous plant and is recognised for its numerous medicinal and culinary properties, and it is used in diverse food preparations for its characteristic flavour and aroma. High alliin content increases the formation of allicin, a bioactive compound of garlic. Therefore, this research aimed to compare different extraction methods for garlic (Allium sativum L.) between subcritical water extraction (SWE) and Soxhlet extraction to obtain a high extraction yield and alliin content. The SWE conditions were 120 °C and 180 °C temperatures and 2 mL/min and 6 mL/min flow rates at a constant pressure of 15 MPa for a 10 min extraction time, respectively. In the meanwhile, the extraction time for Soxhlet extraction with various solvents, namely, distilled water, ethanol–water (1:1), and 100% ethanol, was two hours. High-performance liquid chromatography (HPLC) was used to analyse alliin. Soxhlet extraction had the best yield (1.96 g) using ethanol–water (1:1) as the solvent in comparison to SWE extraction (1.28 g) at 180 °C and 6 mL/min. In contrast, SWE yielded a greater concentration of alliin (136.82 mg/g) at 120 °C and 2 mL/min than the Soxhlet method when using distilled water as the solvent (65.18 mg/g). Therefore, SWE may replace Soxhlet extraction as the conventional method for extracting alliin from garlic at a high concentration, and SWE has advantages that favour garlic extracts. [ABSTRACT FROM AUTHOR]

This study aims to develop a new semi-empirical model to fit solute solubility in a mixture of solvents, viz. supercritical carbon dioxide, ethanol, and water, as well as to evaluate the effects of competing solvents on solubility. Therefore, the model was assessed by fitting the published solubility data and comparing it with the established semi-empirical models. The findings revealed that the new model gave the highest coefficient of determination, R2 of 0.96 and had the lowest AARD (i.e., 3.88%), compared to other models. To conclude, the new model is feasible in determining three solvents' solvation effects in one system. [ABSTRACT FROM AUTHOR]

Rosmarinic acid (RA) is present in a broad variety of plants, including those in the Lamiaceae family, and has a wide range of pharmacological effects, particularly antioxidant activity. To extract RA from Orthosiphon stamineus (OS) leaves, a Lamiaceae plant, a suitable extraction process is necessary. The present study used a green extraction method of supercritical carbon dioxide (SCCO2) extraction with the addition of ethanol as a modifier to objectively measure and correlate the solubility of RA from OS leaves. The solubility of RA in SCCO2 was determined using a dynamic extraction approach, and the solubility data were correlated using three density-based semi-empirical models developed by Chrastil, del Valle-Aguilera, and Gonzalez. Temperatures of 40, 60, and 80 °C and pressures of 10, 20, and 30 MPa were used in the experiments. The maximum RA solubility was found at 80 °C and 10 MPa with 2.004 mg of rosmarinic acid/L solvent. The RA solubility data correlated strongly with the three semi-empirical models with less than 10% AARD. Furthermore, the fastest RA extraction rate of 0.0061 mg/g min−1 was recorded at 80 °C and 10 MPa, and the correlation using the Patricelli model was in strong agreement with experimental results with less than 15% AARD. [ABSTRACT FROM AUTHOR]

The purpose of this work was to determine the optimal conditions for recovering high yields of total phenolic compounds (TPC), total flavonoid compounds (TFC), and antioxidant activity (AA) from roselle (Hibiscus sabdariffa) by employing supercritical carbon dioxide (ScCO2). The solubility of yield, phenolic, and flavonoid in ScCO2 was estimated using solubility models. Pressure (10 to 20 MPa), temperature (40 to 60°C), and flow rate (3 to 5 ml/min) were used as factors in this investigation. According to the response surface methodology (RSM), the optimal conditions were 20 MPa, 40°C, and 4.875 ml/min, yielding 14.11%, 935.48 mgGAE/L TPC, 812.16 mgQUE/L TFC, and 98.59% antioxidant activity, respectively. With 5.29%, 1.28%, and 1.34% of average absolute relative deviation (AARD), the Putra model provided the best connection to the yield extract, phenolic, and flavonoid solubility. The use of RSM and modeling was effective in attaining a high production and concentration of phenolic compounds. Practical applications: Roselle (Hibiscus sabdariffa) comprises several beneficial components, including phenolic, flavonoid, and antioxidant substances. It is used to treat pyrexia, liver damage, hypertension, and leukemia, among other conditions. Toxic and conventional solvents, on the other hand, have often been utilized to recover these valuable compounds. To alleviate these disadvantages, the important chemicals in roselle are extracted using supercritical carbon dioxide (ScCO2). The solubility behavior of oil yield, phenolic, and flavonoid compounds was determined in this work using a semi‐empirical model. The data indicate that an endothermic process occurred to enhance the solubility of yield extract and the exothermic process is suitable for the phenolic and flavonoid recovery. [ABSTRACT FROM AUTHOR]

An accurate and suitable semi-empirical model is crucial to determine the solubility of plant extracts in supercritical carbon dioxide (SC-CO2) assisted by ethanol as a co-solvent. In this paper, a new solubility model was proposed to correlate the plant solubility to SC-CO2 and ethanol. The accuracy and capability of the new model were evaluated by fitting it with published solubility datasets. The overall percentage of average absolute relative deviation was 12.13%, and the average coefficient of determination (R2) was 0.89. Comparisons between the results of the new model and the published models showed an excellent capability and accuracy in fitting solute solubility in SC-CO2 in the presence of ethanol as a co-solvent. [ABSTRACT FROM AUTHOR]

Peanut skin is a waste by-product from peanut industries. It is rich in antioxidants and bioactive compounds. Therefore, the objective of this study was to empirically model and optimize supercritical CO2 extraction of oil from peanut skin. The extraction conditions were pressure (100, 200 and 300 bar), temperature (313, 328 and 343 K) and rate of modifier ethanol (0.075, 0.15 and 0.225 mL/min). The extraction process was subsequently examined using modified Brunner and Esquivel models. The optimum conditions for extraction peanut skin oil were 279 bar, 70°C and rate of modifier of 7.5% with a maximum yield of peanut skin oil of 0.83 g and initial slope of 0.568 g/min. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the extraction of peanut skin using supercritical carbon dioxide extraction and soxhlet extraction in terms of oil yield and catechin. For supercritical fluid extraction, the temperatures used were 40 and 70°C, while pressure used was 10 and 30 MPa, the flow rate was CO2 3 mL/min, and the concentration of co-solvents was 0 and 5%. Meanwhile, for soxhlet extraction, the extraction time was 6 hr with ethanol, hexane and water as the solvents. The results showed that soxhlet extraction gave the highest yield of extract (36.282%) using ethanol as solvent as compared with supercritical CO2 extraction (15.47%) at pressure 30 MPa, temperature 70°C and 5% concentration of co-solvent. This study reveals that the extracts from SC-CO2 extraction yielded the highest amount of catechin (208.73 µg/g sample) compared with that yielded in the soxhlet extraction (42.24 73 µg/g sample) with distilled water as a solvent analysed with High Performance Liquid Chromatography (HPLC). [ABSTRACT FROM AUTHOR]

In this work, the effect of extraction parameters on catechin extraction from betel nuts was studied. The supercritical carbon dioxide extraction parameters were pressure, temperature, and solvent flow rate while using average particle size of 177.5 μm and 5% (v/v) methanol as modifiers. Detection and quantification of catechin were achieved using HPLC analysis. The highest amount of extract and catechin concentration were 34.00 mg extract/g sample and 565.38 ppm of catechin obtained at 30 MPa, 70°C, and 4 mL/min. The results given by optimization tools suggest the same operating conditions with less than 3% difference. [ABSTRACT FROM PUBLISHER]

ABSTRACT Catechin that is known for its antioxidant, antihypertension and anticancer properties can be obtained from Areca catechu. In this study, accelerated water extraction (AWE) method was used to extract catechin from A. catechu seeds. The extraction parameters tested were temperature (120, 140 and 160 °C), static time (5, 10 and 15 min) and static cycle (1, 2 and 3 cycles). A. catechu extracts were analysed using liquid chromatography time-of-flight mass spectrometry to quantify the amount of catechin. Highest oil yield of 390.00-mg oil/g sample was obtained at temperature of 140 °C, 15 min of extraction time and 3 cycles. On the other hand, the highest catechin amount of 0.0716-mg catechin/g sample was obtained at 140 °C, 10 min and 2 cycles. The effect of extraction temperature was studied using the second-order kinetic model, and it showed good regression coefficient of more than 0.99. It suggests that the model could be applied to describe the extraction of catechin from A. catechu seeds. Based on the model, the initial extraction rate, the equilibrium extraction capacity and the extraction rate coefficient were evaluated to explain the AWE process at temperatures ranging from 120 to 160 °C. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Dry powder of red color from roselle calyces, which can be used as natural colorant and functional food ingredient, was produced using microencapsulation technique. Four different matrices, i.e., maltodextrin, gum Arabic, combination of maltodextrin and gum Arabic, and soluble starch were used for encapsulation study. Identification and measurement of anthocyanins in encapsulated roselle was made by high-performance liquid chromatography. Encapsulation efficiencies were determined and compared with storage analysis data. The stability of encapsulated pigments was investigated during storage under three different storage temperatures (4, 25 and 37C) until 105 days. The four type of matrices largely increased the half-life of the pigments during storage especially at 37C (P < 0.05) compared with the non-encapsulated roselle extract. Storage temperature did not significantly (P > 0.05) effect the L*, a* and b* values. However, type of encapsulation agent and storage time significantly (P < 0.05) affected the color changes. The L* and a* values were decreased during storage whereas the b* value was increased. Combination of maltodextrin and gum Arabic showed the highest encapsulation efficiencies (99.87 ± 0.04%), lower degradation rate in 4C (3.7 ± 0.3) and had smaller changes in a* and b* values among the four matrices. PRACTICAL APPLICATIONS A spectrum of natural, red-hue primer colorants derived from roselle plant extracts, substantially free of alkaloids, enzymes, aroma or solvent residuals, and microencapsulated to ensure good stability and shelf life. This study measures the storage stability and suitability of the microencapsulated natural colorants. The colorants are for functional use in the food, pharmaceuticals, cosmetics and other industries. [ABSTRACT FROM AUTHOR]

ABSTRACT The stability of roselle anthocyanins was investigated under three different heat treatments (60, 80 and 98C). The dry red powder from roselle calyces was produced using spray-drying technique using four different encapsulating agents, i.e., maltodextrin, gum arabic, a combination of maltodextrin and gum arabic, and soluble starch. The four types of matrices increased the half-life of the pigments during heat treatment, especially at 98C ( P < 0.05), compared with the roselle extract as the control. Heat treatment results showed that the combination of maltodextrin and gum arabic had the lowest degradation kinetic rates at 60 and 80C. Arrhenius parameters' results further confirmed that the degradation of anthocyanins was strongly dependent on the operating temperatures during heat treatment. In this study, all encapsulating agents, except the soluble starch, largely elongated the half-life of roselle anthocyanins compared with the nonencapsulated anthocyanins. PRACTICAL APPLICATIONS A spectrum of natural, red-hue primer colorants is derived from roselle plant extracts, which is substantially free of alkaloids, enzymes, aroma or solvent residuals, and is microencapsulated to ensure good stability and shelf life. This study measured the thermal stability and suitability of the microencapsulated natural colorants. The colorants are for functional use in the food, pharmaceuticals, cosmetics and other industries. [ABSTRACT FROM AUTHOR]

The objective of this study was to study and compare the effect of particle size on the modified supercritical carbon dioxide and soxhlet extraction in terms of oil yield and antioxidant activity. The mean particle sizes of 300, 355, 425, and 500 µm for modified supercritical carbon dioxide extraction, the temperatures of 40 and 70 °C, pressure of 10 and 30 MPa, flow rate of CO2 3 mL/min, and rate of co‐solvent 5% were used in this study. Meanwhile, for soxhlet extraction, the extraction time was 6 hr with ethanol, hexane, and water as the solvent. DPPH method was used to analyze the antioxidant activity of the extract. The results showed that 425 µm gave the highest yield extract on the modified supercritical carbon dioxide extraction (15.53%), soxhlet extraction (36.28%), antioxidant activities for modified supercritical carbon dioxide (93.43%), and soxhlet extraction (62.21%). Single sphere model has successfully fitted the experimental data of modified supercritical carbon dioxide with error below 5% with the highest diffusivity coefficient was 6.794E‐12 m2/s at operating conditions was 10 MPa, 40 °C and particle size 425 µm. Practical applications: Peanut skin as waste of peanut industries has many bioactive compounds and high antioxidant activities. Therefore, supercritical carbon dioxide extraction as a green technologhy carry out the extract from peanut skin. Addition of ethanol as modifier is needed to enhance the polarity of supercritical carbon dioxide to extract polar compounds inside of peanut skin. To begin with, the extract of peanut skin using modified supercritical carbon extraction is compared with soxhlet extraction as conventional extraction. Although soxhlet extraction obtained high yield extract, modified supercrirical carbon dioxide gave higher antioxidant activities. The antioxidant activity of modified supercritical carbon dioxide extraction was more than 90%. Furthermore, effect of particle size in the extraction processes was determined to obtain high extract yield and antioxidant activity. the result shows that 425 µm gave the maximum yield extract and antioxidant activity on the modified supercritical carbon dioxide and soxhlet extraction. [ABSTRACT FROM AUTHOR]