Effect of solution on starch structure: New separation approach of amylopectin fraction from gelatinized native corn starch

The complete dissolution of starch without degradation are necessary prerequisites for starch fractionation to obtain amylose or amylopectin (AP). With the recent, continuous progress in finding efficient and eco-friendly starch-dissolving solutions, applying new solvents for starch fractionation is important. In this study, the effects of dimethyl sulfoxide (DMSO), NaOH, and CaCl2 solutions on starch structure and AP product parameters during starch fractionation were compared with respect to the starch deconstruction effect. This study proved that the CaCl2 solution could effectively dissolve corn starch (50 °C, solubility of 98.96 %), and promote the regeneration of starch into uniform and fine particles. Furthermore, the three solvents (DMSO, NaOH, and CaCl2) changed the crystal structure of corn starch, but they were all non-derivatizing solvents. The effect of the CaCl2 solution on the molecular structure of corn starch was the least significant of the three solvents. Finally, the extraction rate of AP from the CaCl2 solution reached 69.45 %. In conclusion, this study presents a novel and effective method for AP extraction.

Ultrasound-assisted extraction conditions optimisation using response surface methodology from Mitragyna speciosa (Korth.) Havil leaves

The optimisation of the Ultrasound-Assisted Extraction (UAE) method was investigated by employing the Central Composite Rotatable Design (CCRD) of Response Surface Methodology (RSM). The UAE method was based on a simple ultrasound treatment using methanol as the extraction medium to facilitate the cell disruption of Mitragyna speciosa leaves for optimum extraction yield and Total Phenolic Content (TPC). Three different parameters comprising extraction temperature (X1: 25-50 °C), sonication time (X2: 15-50 min), and solvent to solid ratio (X3: 10-30 mL/g), and were selected as the independent variables, while two response variables were selected, namely extraction yield (Y1) and TPC (Y2). Based on the results, the developed quadratic polynomial model correlated with the experimental data is based on the coefficient of determination (R2) of extraction yield (0.9972, p < 0.0001) and TPC (0.9553, p < 0.0001). At 25 °C, 15 min sonication time, and 10 mL/g of solvent to solid ratio, the optimal conditions recorded an extraction yield and TPC of 22.69% and 143.51 mg gallic acid equivalent (GAE)/g, respectively. Furthermore, the actual response and the predicted values of the developed models correlated with each other as the Residual Standard Error (RSE) values were <5%. Meanwhile, the Liquid Chromatography- tandem Mass Spectrometry (LC-MS/MS) was employed to characterise the optimised M. speciosa extract and revealed the presence of major phytochemicals, including catechin, rutin, kaempferol, coumarin, gallic acid, chlorogenic acid, and caffeic acid. These compounds could exhibit certain therapeutic effects, such as anti-inflammatory, antibacterial, and antioxidant. Therefore, the findings in this study supported the suggestion that the various available bioactive compounds besides alkaloids contributed to the bioactive properties in M. speciosa, making it an effective traditional herbal medicine to treat various illnesses.

Supercritical CO2-ethanol extraction of oil from green coffee beans: optimization conditions and bioactive compound identification

In this research, a supercritical CO₂-ethanol extraction was optimized to obtain a green coffee oil rich in bioactive compounds. A face-centered central composite design was used to evaluate the effect of temperature (50-70 °C), extraction pressure (15.0-30.0 MPa), and cosolvent content (5-20%) on the extraction yield and total phenolic compound content of green coffee supercritical extract (GCSE). The experimental data were fitted to a second-order polynomial model. According to the statistical analyses, the lack of fit was not significant for either mathematical model. From the response surface plots, the extraction pressure and cosolvent content significantly impacted the extraction yield, while the total phenolic compound content was impacted by temperature and cosolvent content. The optimal conditions were a 20% cosolvent content, a pressure of 30 MPa, and a temperature of 62 °C, which predicted an extraction yield of 7.7% with a total phenol content of 5.4 mg gallic acid equivalent g GCSE^-1. The bioactive compounds included 5-caffeoylquinic acid (11.53-17.91 mg g GCSE^-1), caffeine (44.76-79.51 mg g GCSE^-1), linoleic acid (41.47-41.58%), and palmitic acid (36.07-36.18%). Our results showed that GCSE has the outstanding chemical quality and antioxidant potential, suggesting that GCSE can be used as a functional ingredient.

Ultrasound: a suitable technology to improve the extraction and techno-functional properties of vegetable food proteins

Vegetable-based proteins may be extracted from different sources using different extraction methods, among them, ultrasound-assisted extraction stands out. This review presents the current knowledge on ultrasound-assisted extraction (UAE) and the functional properties of extracted vegetable proteins. Ultrasound generates cavitation in a liquid medium, defined as gas and vapor microbubbles collapse under pressure changes large enough to separate them in the medium. Cavitation facilitates the solvent and solid interaction, increasing yield and reducing extraction periods and temperature used. Moreover, ultrasound treatment changed extracted protein properties such as solubility, hydrophobicity, emulsifying and foam, water and oil absorption capacity, viscosity, and gelatinization. Ultrasound-assisted extraction is a promising technique for the food technology sector, presenting low environmental impact, lower energy and solvent consumption, and it is in accordance with green chemistry technology and sustainable concepts.

Novel insights in dimethyl carbonate-based extraction of polyhydroxybutyrate (PHB)

BACKGROUND

Plastic plays a crucial role in everyday life of human living, nevertheless it represents an undeniable source of land and water pollution. Polyhydroxybutyrate (PHB) is a bio-based and biodegradable polyester, which can be naturally produced by microorganisms capable of converting and accumulating carbon as intracellular granules. Hence, PHB-producing strains stand out as an alternative source to fossil-derived counterparts. However, the extraction strategy affects the recovery efficiency and the quality of PHB. In this study, PHB was produced by a genetically modified Escherichia coli strain and successively extracted using dimethyl carbonate (DMC) and ethanol as alternative solvent and polishing agent to chloroform and hexane. Eventually, a Life Cycle Assessment (LCA) study was performed for evaluating the environmental and health impact of using DMC.

RESULTS

Extraction yield and purity of PHB obtained via DMC, were quantified, and compared with those obtained via chloroform-based extraction. PHB yield values from DMC-based extraction were similar to or higher than those achieved by using chloroform (≥ 67%). To optimize the performance of extraction via DMC, different experimental conditions were tested, varying the biomass state (dry or wet) and the mixing time, in presence or in absence of a paper filter. Among 60, 90, 120 min, the mid-value allowed to achieve high extraction yield, both for dry and wet biomass. Physical and molecular dependence on the biomass state and solvent/antisolvent choice was established. The comparative LCA analysis promoted the application of DMC/ethanol rather than chloroform/hexane, as the best choice in terms of health prevention. However, an elevated impact score was achieved by DMC in the environmental-like categories in contrast with a minor contribution by its counterpart.

CONCLUSION

The multifaceted exploration of DMC-based PHB extraction herein reported extends the knowledge of the variables affecting PHB purification process. This work offers novel and valuable insights into PHB extraction process, including environmental aspects not discussed so far. The findings of our research question the DMC as a green solvent, though also the choice of the antisolvent can influence the impact on the examined categories.

Effect of acid treatment on extraction yield and gel strength of gelatin from whiptail stingray (Dasyatis brevis) skin

Chemical properties of fish gelatins differ from those of conventional mammalian sources, representing an attractive technological alternative for the food industry. Ray filleting generates a considerable amount of skin waste that can be used as a collagen source for gelatin extraction. Thus, this research evaluated the HCl and CH₃COOH effect, at 0.01, 0.025, 0.05, 0.075, 0.1, 0.15, and 0.2 M, on extraction yield, molecular weight distribution, and gel strength (GS) of whiptail stingray (Dasyatis brevis) skin gelatins. Results showed differences (P < 0.05) between acid type and concentration used. CH₃COOH (0.15 M) gave the highest extraction yield (7.0% vs. 5.5% at 0.15 M HCl) and GS (653 ± 71 g vs. 619.5 ± 82 g at 0.2 M HCl). Gelatin electrophoretic profile from CH₃COOH revealed α-/β-components and high molecular weight (> 200 kDa) polymers. Ray gelatin GS was higher than commercial bovine gelatin, suggesting its possible use for technological food applications.

Puffing of Rehmannia glutinosa enhances anti-oxidant capacity and down-regulates IL-6 production in RAW 264.7 cells

The roots of Rehmannia glutinosa (RG) have been widely used for medicinal purposes in Asia. The traditional processing of RG involves repetitive steaming and drying, and 9-time-steamed RG (NSRG) is the most commonly consumed form. For a development of a convenient processing method, RG was puffed at various pressures resulting in significantly increased solid extraction yield by up to 14%. The amount of the Maillard reaction product 5-hydroxymethylfurfural and the antioxidant capacities determined by the ABTS and DPPH radical scavenging assays were enhanced at increasing puffing pressure. Treatment of lipopolysaccharide-stimulated RAW 264.7 macrophages with RG extracts revealed that puffing of RG enhanced its suppression of the pro-inflammatory cytokine IL-6 by up to 37%. The 5-hydroxymethylfurfural contents, ABTS/DPPH radical scavenging capacities, and IL-6 regulatory effects of puffed RG samples were greater than those of the NSRG control, indicating that puffing is a desirable processing technique for development of nutraceuticals using RG.

Microwave-assisted extraction for Hibiscus sabdariffa bioactive compounds

H. sabdariffa has demonstrated positive results against chronic diseases due to the presence of phytochemicals, mainly phenolic compounds. The extraction process of bioactive compounds increases the efficient collection of extracts with high bioactivity. Microwave-Assisted Extraction (MAE) constituted a "green technology" widely employed for plant matrix. In this work, the impact of temperature (50-150 °C), composition of extraction solvent (15-75% EtOH) and extraction time (5-20 min) on the extraction yield and individual compounds concentrations were evaluated. Furthermore, the characterization of 16 extracts obtained was performed by HPLC-ESI-TOF-MS. The results showed that 164 °C, 12.5 min, 45% ethanol was the best extraction condition, although glycoside flavonoids were degraded. Besides that, the optimal conditions for extraction yield were 164 °C, 60% ethanol and 22 min. Thus, temperature and solvent concentration have demonstrated to be potential factors in MAE for obtaining bioactive compounds from H. sabdariffa.

Ultrasound synergized with three-phase partitioning for extraction and separation of Corbicula fluminea polysaccharides and possible relevant mechanisms

Ultrasound and three-phase partitioning (USTPP) were combined to extract and separate polysaccharides (PS) efficiently from Corbicula fluminea crude extracts. The following optimum experimental conditions were established: 20% (w/v) ammonium sulfate concentration, 1:1 (v/v) t-butanol to crude extract ratio, 180W ultrasonic power, 40kHz frequency, 100% duty cycle, 10min irradiation time, and 35°C. The maximum extraction yield of PS obtained from USTPP was approximately 11.22%, which was higher than the maximum yields from conventional three-phase partitioning (TPP; 9.32%) and ultrasound extraction (USE; 6.05%). The extraction time for USTPP was significantly reduced to 10min from 30 and 60min for TPP and USE methods, respectively. The primary chemical structures of PS collected through the three extraction protocols were basically conserved. The synergistic effects of ultrasound and TPP on PS extraction were also determined. Results revealed that USTPP is an effective technique to extract and separate PS from C. fluminea potentially applied in food, cosmetics, and medicines.

Improved collagen extraction from jellyfish (Acromitus hardenbergi) with increased physical-induced solubilization processes

Efficiency and effectiveness of collagen extraction process contribute to huge impacts to the quality, supply and cost of the collagen produced. Jellyfish is a potential sustainable source of collagen where their applications are not limited by religious constraints and threats of transmittable diseases. The present study compared the extraction yield, physico-chemical properties and toxicology in vitro of collagens obtained by the conventional acid-assisted and pepsin-assisted extraction to an improved physical-aided extraction process. By increasing physical intervention, the production yield increased significantly compared to the conventional extraction processes (p < .05). Collagen extracted using the improved process was found to possess similar proximate and amino acids composition to those extracted using pepsin (p > .05) while retaining high molecular weight distributions and polypeptide profiles similar to those extracted using only acid. Moreover, they exhibited better appearance, instrumental colour and were found to be non-toxic in vitro and free of heavy metal contamination.

The suitability of extraction solutions to assess bioaccessible trace metal fractions in airborne particulate matter: a comparison of common leaching agents

The determination of bioaccessible metal concentrations and/or fractions is a prerequisite for reliable assessment of the hazardous potential of toxic trace metals present in airborne particulate matter (APM). For this purpose, the use of various leaching agents has been reported in literature. The applied reagents reveal severe differences in composition. Therefore, variations in the amounts of trace metals released from APM samples could be expected with the use of these agents, hampering comparison of literature data. In this work, bioaccessible metal fractions were determined in PM10 samples from Graz, Austria, and Karachi, Pakistan, using synthetic gastric juice (SGJ), artificial lysosomal fluid (ALF), Gamble's solution, aqueous solutions of sodium chloride, ammonium acetate, ammonium citrate, and water for sample extraction. Investigated trace metals showed distinct differences in extractable fractions for the same extractant. For example, bioaccessible contents ranged from 34.8 ± 13.3% for Ni (n = 12) to 77.9 ± 14.8% for Cd (n = 12) when SGJ was used for extraction. Furthermore, extraction yields for the applied leaching agents were determined, indicating for all investigated elements two to four times more efficient extraction with SGJ, ammonium citrate buffer, and ALF as compared to water and simple inorganic salt solutions, indicating that ammonium citrate buffer could be used as an alternative for synthetic body fluids with rather complex composition.

New method to enhance the extraction yield of rutin from Sophora japonica using a novel ultrasonic extraction system by determining optimum ultrasonic frequency

A new method has been proposed for enhancing extraction yield of rutin from Sophora japonica, in which a novel ultrasonic extraction system has been developed to perform the determination of optimum ultrasonic frequency by a two-step procedure. This study has systematically investigated the influence of a continuous frequency range of 20-92 kHz on rutin yields. The effects of different operating conditions on rutin yields have also been studied in detail such as solvent concentration, solvent to solid ratio, ultrasound power, temperature and particle size. A higher extraction yield was obtained at the ultrasonic frequency of 60-62 kHz which was little affected under other extraction conditions. Comparative studies between existing methods and the present method were done to verify the effectiveness of this method. Results indicated that the new extraction method gave a higher extraction yield compared with existing ultrasound-assisted extraction (UAE) and soxhlet extraction (SE). Thus, the potential use of this method may be promising for extraction of natural materials on an industrial scale in the future.

Characterization of fructan extracted from Eremurus spectabilis tubers: a comparative study on different technical conditions

The fructans, inulin and oligofructose, were known to possess many physiologic properties. In the present study, the Box-Behnken design was used to determine the optimum extraction conditions of fructan from Eremurus spectabilis root powder (Serish) with water extraction, direct and indirect ultrasound assisted extraction methods that gave the maximum yield. Sonication amplitude (20-100 %), sonication temperature (30-70 °C) and sonication time (5-40 min) were considered variables of direct and indirect ultrasound extractions while for conventional extraction the following variables were water to solid ratio (30-50 v/w), temperature (40-90 °C) and time (5-40 min). A second-order polynomial model was fitted to each response and the regression coefficients were determined using least square method. There was a good agreement between the experimental data and their predicted counterparts. In addition to establishing the difference of these extraction methods, the scanning electron microscopy, Fourier-transform infrared spectroscopy, zeta potential and particle size analysis have been shown to be useful tools to investigate, approximate and predict characteristics of extracted fructan. Moreover, comparison of conventional extraction, direct sonication extraction, indirect sonication extraction showed the indirect sonication extraction is a suitable method for fructan extraction.

Optimisation of ultrasound-assisted extraction of oil from papaya seed by response surface methodology: oil recovery, radical scavenging antioxidant activity, and oxidation stability

The present study aimed to investigate the effects of ultrasound-assisted extraction (UAE) condition on the yield, antioxidant activity and stability of the oil from papaya seed. The studied ultrasound variables were time, temperature, ultrasound power and solvent to sample ratio. The main goal was to optimise UAE condition providing the highest recovery of papaya seed oil with the most desirable antioxidant activity and stability. The interaction of ultrasound variables had the most and least significant effects on the antioxidant activity and stability, respectively. Ultrasound-assisted extraction provided a relatively high oil recovery (∼ 73%) from papaya seed. The strongest antioxidant activity was achieved by the extraction at the elevated temperature using low solvent to sample ratio. The optimum ultrasound extraction was set at the elevated temperature (62.5 °C) for 38.5 min at high ultrasound power (700 W) using medium solvent to sample ratio (∼ 7:1 v/w). The optimum point was practically validated.

Effect of gamma irradiation on the extraction yield, total phenolic content and free radical-scavenging activity of Nigella staiva seed

In the present study, the radiation processing of Nigella sativa seed samples was carried out at dose levels of 2, 4, 8, 10, 12 and 16kGy. The extraction yield, total phenolic content and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging activity of both control and irradiated samples extracted in acetone, methanol and water were assessed. The results showed that the extraction yields increased with an increase in radiation dose for all the test solvents. At 16kGy the increases were 3.7%, 4.2%, 5.6% and 9.0% for hexane, acetone, water and methanol extracts, respectively. The phenolic content in the acetone extract was found to be increased from 3.7 for the control sample to 3.8mg/g for the 16kGy radiation-processed sample. No significant change was observed for the phenolic content of the methanolic extract, while the aqueous extract showed a decrease at dose levels of 12 and 16kGy. In the control samples, the DPPH radical-scavenging activity was 79.4%, 79.1% and 92.0% for water, acetone and methanol extracts, respectively, at 5mg/ml concentration. Gamma irradiation enhanced the scavenging activity in acetone and methanol extracts by 10.6% and 5.4%, respectively, at 16kGy. In summary, gamma irradiation increased the extraction yield and total phenolic content, as well as enhancing the free radical-scavenging activity. In addition, the type of solvent used for extraction also affected the impact of irradiation on antioxidant activity and total phenolic content of N. sativa seed.