Negative pressure cavitation based ultrasound-assisted extraction of main flavonoids from Flos Sophorae Immaturus and evaluation of its extraction kinetics

Evaluation of multiscale mechanisms of ultrasound-assisted extraction from porous plant materials: Experiment and modeling on this intensified process

Ultrasound-assisted extraction (UAE) is an intensified mass transfer process, which can utilize natural resources effectively, but still lacks detailed mechanisms for multiscale effects. This study investigates the mass transfer mechanisms of UAE combined with material's pore structure at multiscale. Porous material was prepared by roasting green coffee beans (GCB) at 120 °C (RCB120) and 180 °C (RCB180), and their UAE efficiency for phytochemicals (caffeine, trigonelline, chlorogenic acid, caffeic acid) were evaluated by experiment and modeling. Besides, the physicochemical properties, mass transfer kinetics, and multi-physical field simulation were studied. Results indicated that positive synergy effects on extraction existed between ultrasound and material's pore structure. Higher mass transfer coefficients of UAE (GCB 0.16 min-1, RCB120 0.38 min-1, RCB180 0.46 min-1) was achieved with higher total porosity (4.47 %, 9.17 %, 13.52 %) and connected porosity (0 %, 3.79 %, 5.98 %). Moreover, simulation results revealed that micro acoustic streaming and pressure difference around particles were the main driving force for enhancing mass transfer, and the velocity (0.29-0.36 m/s) increased with power density (0.64-1.01 W/mL). The microscale model proved that increased yield from UAE-RCB was attributed to internal convection diffusion within particles. This study exploited a novel benefit of ultrasound on extraction and inspired its future application in non-thermal food processing.

Pectin extracted from Premna Microphylla Turcz for preparation of a "sandwich" multi-property sensor film involved with deep eutectic solvent

An acidic deep eutectic solvent (DES, choline chloride/citric acid) was used to efficiently extract edible pectin from Premna microphylla Turcz (PMTP) and further prepare the film sensor with the purpose of "four birds with one stone" with the roles of extractant, coalescent, conductivity promoter and bacteriostatic agent. The optimized extraction process accorded with pseudo second-order kinetics, which was carried out at 78.2 °C for 1.29 h with the solid-liquid ratio of 1:34.66 g/mL with the yield up to 0.8210 g/g. After comprehensive characterizations of pectin product, a simple casting method was used to prepare the PMTP-DES based composite film. It showed that the composite film has promising compatibility, smooth surface, good breathability and ideal homogeneity. After 30 power on/power off cycles at 10 V, it exhibited satisfied conductivity stability. Moreover, the PMTP-DES film could be simply assembled as the flexible visual temperature sensor, with sensitive response at breathing or finger touch; it exhibited the highest sensitivity of 134 %/°C when the external temperature changed from 15 to 55 °C. Besides, the composite film also has preferable antimicrobial activity. The whole results and findings were aimed to contribute for the raw material, composition, preparation, and functions of the existing flexible functional materials.

Optimization of ultrasonic-assisted extraction of flavonoids from Lactuca indica L. cv. Mengzao and their antioxidant properties

In this study, the ultrasound-assisted extraction (UAE) conditions of flavonoids from Lactuca indica L.cv. Mengzao (LIM) leaves was optimized, and the flavonoids content and their antioxidant potential in different parts were analyzed. The optimal extraction parameters to obtain the highest total flavonoids content (TFC) were a a ratio of liquid to solid of 24.76 mL/g, ultrasonic power of 411.43 W, ethanol concentration of 58.86% and an extraction time of 30 min, the average TFC of LIM leaves could reach 48.01 mg/g. For the yield of flavonoids, the UAE method had the best extraction capacity compared with solvent extraction and microwave-assisted extraction (MAE). In general, the TFC in different parts of LIM followed the order flower > leaf > stem > root, the flowering period is the most suitable harvesting period. From ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS) quantification, the flower samples showed significantly higher six flavonoids and had the highest radical scavenging capacities compared to other samples. A high positive correlation was observed between the antioxidant activity and TFC, luteolin-7-O-glucoside and rutin were significantly (p < 0.05) correlated with all antioxidant evaluations. This study provides valuable information for the development and utilization of flavonoids in Lactuca indica as ingredients in food, feed and nutritional health products.

Optimization of Extraction Process and Dynamic Changes in Triterpenoids of Lactuca indica from Different Medicinal Parts and Growth Periods

In this study, the triterpenoids in the leaves of Lactuca indica L.cv. Mengzao (LIM) were extracted via microwave-assisted ethanol extraction, and the optimum extraction conditions for triterpenoids were determined through single-factor experiments and the Box-Behnken method. The effects of three factors (solid-liquid ratio, microwave power and extraction time) on the total triterpenoids content (TTC) were evaluated. The TTC of different parts (roots, stems, leaves and flowers) of LIM in different growth stages was studied, and the scavenging effects of the highest TTC parts on DPPH, ABTS and hydroxyl free radicals were investigated. The results showed that the optimum extraction conditions for microwave-assisted extraction of total triterpenoids from LIM leaves were as follows: solid-liquid ratio of 1:20 g/mL; microwave power of 400 W; and extraction time of 60 min. Under these conditions, the TTC was 29.17 mg/g. Compared with the fresh raw materials, the TTC of the materials increased after freeze drying. The leaves of LIM had the highest TTC, and the flowering stage was the best time. The triterpenoids from the leaves had a strong ability to eliminate DPPH and ABTS free radicals, and the elimination effect of dried leaves was better than that of fresh leaves, while the elimination effect of hydroxyl free radicals was not obvious. The tested method was used to extract total triterpenoids from LIM using a simple process at low cost, which provides a reference for developing intensive processing methods for L. indica.

Influence of Ultrasound-Assisted Vacuum Drying on Physicochemical Characteristics, Antioxidant Activity, and α-Glucosidase Inhibition Activity of Flos Sophorae Immaturus

Flos Sophorae Immaturus (FSI) contains a large number of bioactive substances with antioxidant and hypoglycaemic activity. However, a feasible drying process plays an important role in the retention of its biological activity. The present work investigated the effects of ultrasound-assisted vacuum drying (UAVD) on FSI samples in terms of drying time, colour, microstructure, and total flavonoid content (TFC). Meanwhile, the antioxidant activity and α-glucosidase inhibition activity were also evaluated. The results show that the drying time of UVAD samples was decreased by 40% compared to that of the single vacuum-dried (VD) samples (600 W for 10 min). The cellular porous structures of FSI tissue were formed by UAVD, which promoted the migration of water from the inside to the outside. Furthermore, samples treated by UAVD exhibited better antioxidant activities and α-glucosidase and α-amylase inhibition capacities, with DPPH (81.86%), ABTS (88.61%), FRAP (83.05%), α-glucosidase inhibition capacity (89%), α-amylase (85%), drying time (3 h), and total aberration (ΔE) (1.63) being the highest characteristic traits. In this condition, the highest levels of total flavonoid content (TFC), rutin, quercetin, kaempferol, isorhamnetin, and genistein were obtained with 266.94, 239.46, 35.56, 8.54, 10.37, and 5.64 mg/g DW, respectively. The results confirm that UAVD is a novel method that significantly reduced the VD time and promoted the release of the bioactive substances of FSI.

Hydrothermal treatment improves xanthine oxidase inhibitory activity and affects the polyphenol profile of Flos Sophorae Immaturus

BACKGROUND

Flos Sophorae Immaturus (FSI) is rich in polyphenols and a potential uric acid-lowering food. However, the processing of FSI is greatly restricted due to the heat sensitivity and low solubility of polyphenols. In this study, hydrothermal treatment - an effective strategy - was applied to FSI processing. The variation of xanthine oxidase (XO) inhibitory effect and polyphenol composition of FSI during hydrothermal treatment were recorded.

RESULTS

The XO inhibition rate of FSI increased from 32.42% to 89.00% after hydrothermal treatment at 220 °C for 30 min, as well as total polyphenols (from 0.66 to 1.11 mg mL^-1 ) and flavonoids (from 1.21 to 1.58 mg mL^-1 ). However, high thermal temperature (>160 °C) and extended thermal time (>90 min) caused the degradation of polyphenols. Rutin, kaempferol-3-O-rutinoside and narcissoside rapidly degraded and converted to quercetin, kaempferol and isorhamnetin when the temperature exceeded 160 °C. The maximum yields of quercetin, kaempferol and isorhamnetin were at 220 °C for 30 min, 90 min and 90 min, respectively. Meanwhile, the conversion kinetics conformed to the first-order model. Interestingly, these newly formed polyphenols possessed better XO inhibitory effects than their derivatives with 3-O-rutinoside.

CONCLUSION

Polyphenol conversion during hydrothermal treatment was the main reason for enhancing XO inhibitory activity. Therefore, hydrothermal treatment is an appropriate method for improving the XO inhibitory effect of FSI. © 2022 Society of Chemical Industry.

Nutritional Attributes and Phenolic Composition of Flower and Bud of Sophora japonica L. and Robinia pseudoacacia L

Sophora japonica L. (SJL) and Robinia pseudoacacia L. (RPL) are widely cultivated in China. However, the utilization of their main by-products are limited due to a lack of comprehensive nutritional attributes. Herein, the proximate composition, mineral elements, fatty acids, amino acids, monosaccharides, and phenolics were analyzed to investigate the nutritional attributes of SJL and RPL. Dietary fiber was the main ingredient in SJL and RPL, followed by protein and lipids. The content of Fe in SJL and RPL was highest, especially in flowers of SJL, reaching about 1179.51 mg/kg. The total unsaturated fatty acids accounted for 89.67% of the bud of SJL. Meanwhile, the essential amino acids contents of the flower and bud of SJL and RPL accounted for 35.95-40.59% of total amino acids. The flower of SJL (373.75 mg/g) exhibited the most abundant monosaccharides. Meanwhile, the total phenolics and flavonoid contents in the buds of SJL and RPL were significantly higher than that of the flower, implying the buds possessed better biological activity. Moreover, the bud of SJL possessed the most abundant phenolics. The results provided a reference for the development of functional food derived from SJL and RPL.

Application of Response Surface Methodologies to Optimize High-Added Value Products Developments: Cosmetic Formulations as an Example

In recent years, green and advanced extraction technologies have gained great interest to revalue several food by-products. This by-product revaluation is currently allowing the development of high value-added products, such as functional foods, nutraceuticals, or cosmeceuticals. Among the high valued-added products, cosmeceuticals are innovative cosmetic formulations which have incorporated bioactive natural ingredients providing multiple benefits on skin health. In this context, the extraction techniques are an important step during the elaboration of cosmetic ingredients since they represent the beginning of the formulation process and have a great influence on the quality of the final product. Indeed, these technologies are claimed as efficient methods to retrieve bioactive compounds from natural sources in terms of resource utilization, environmental impact, and costs. This review offers a summary of the most-used green and advanced methodologies to obtain cosmetic ingredients with the maximum performance of these extraction techniques. Response surface methodologies may be applied to enhance the optimization processes, providing a simple way to understand the extraction process as well as to reach the optimum conditions to increase the extraction efficiency. The combination of both assumes an economic improvement to attain high value products that may be applied to develop functional ingredients for cosmetics purposes.

Purification of linarin and hesperidin from Mentha haplocalyx by aqueous two-phase flotation coupled with preparative HPLC and evaluation of the neuroprotective effect of linarin

The volatile oil of Mentha haplocalyx is widely used in medicine, food, and cosmetics. However, a large amount of its residue after steam extraction of volatile oil is abandoned, resulting in a waste of resources. The method of aqueous two-phase flotation coupled with preparative high-performance liquid chromatography was established for the separation and purification of nonvolatile active compounds from Mentha haplocalyx for the first time. The parameters of the two-phase aqueous flotation were optimized. Under the optimal conditions including flotation solvent PEG 1000 aqueous solution (1:1, w/w), pH 5, (NH₄ )₂ SO₄ concentration of 350 g/L in aqueous phase, N₂ flow rate of 20 mL/min, and flotation time of 20 min, the flotation efficiency of linarin, hesperidin, and didymin was 82.24, 76.38, and 89.33%, respectively. The linarin and hesperidin with the high purities of 95.8 and 97.2%, respectively, were obtained by using preparative high performance liquid chromatography. The neuroprotective effect of linarin against H₂ O₂ -induced oxidative stress in rat hippocampal neurons was investigated. The experimental result indicated that linarin could alleviate H₂ O₂ -induced oxidative stress. The work indicated that the combination of aqueous two-phase flotation and preparative high performance liquid chromatography is a feasible and practical method for the purification of nonvolatile active substances from Mentha haplocalyx, which would provide a reference process for the comprehensive utilization of M. haplocalyx. Especially, linarin might be used as a good source of natural neuroprotectants.

Extraction assisted by far infrared radiation and hot air circulation with deep eutectic solvent for bioactive polysaccharides from Poria cocos (Schw.) wolf

In this study, a new ternary choline chloride-deep eutectic solvent was used to efficiently extract bioactive polysaccharides from poria cocos assisted by the new tool of the far infrared radiation (FIR) together with hot air circulation (HAC).

Selectivity of Current Extraction Techniques for Flavonoids from Plant Materials

Flavonoids have a broad spectrum of established positive effects on human and animal health. They find an application in medicine for disease therapy and chemoprevention, whence the interest in flavonoids increases. In addition, they are used in food and cosmetic industries as pigments and biopreservatives. Plants are an inexhaustible source of flavonoids. The most important step of plant raw material processing is extraction and isolation of target compounds. The quality of an extract and efficiency of a procedure are influenced by several factors: Plant material and pre-extracting sample preparation, type of solvent, extraction technique, physicochemical conditions, etc. The present overview discusses the common problems and key challenges of the extraction procedures and the different mechanisms for selective extraction of flavonoids from different plant sources. In summary, there is no universal extraction method and each optimized procedure is individual for the respective plants. For an extraction technique to be selective, it must combine an optimal solvent or mixture of solvents with an appropriate technique. Last but not least, its optimization is important for a variety of applications. Moreover, when the selected method needs to be standardized, it must achieve acceptable degree of repeatability and reproducibility.

Ultrasound-Assisted Extraction of Total Acetogenins from the Soursop Fruit by Response Surface Methodology

The soursop fruit or Annona muricata (A. muricata) fruit is recognized by its bioactive compounds and acetogenins (ACG) are among the most important. The effect of ACGs, with greater importance in health, is that they present anti-tumor activity; however, the methods of extraction of ACGs are very slow and with a high expenditure of solvents. To our knowledge, there is no report of an optimal method for the extraction of acetogenins from the Annonaceae family by ultrasound-assisted extraction (UAE); therefore, the aim was to find the best UEA conditions of acetogenins from A. muricata fruit (peel, pulp, seed, and columella) by using response surface methodology. The effect of amplitude (40%, 70%, and 100%), time (5, 10, and 15 min), and pulse-cycle (0.4, 0.7, and 1 s) of ultrasound at 24 kHz was evaluated on the total acetogenin content (TAC). Optimal extraction conditions of acetogenins (ACGs) with UEA were compared with the extraction of ACGs by maceration. The optimal UEA conditions in the A. muricata pulp and by-products were dependent on each raw material. The highest TAC was found in the seed (13.01 mg/g dry weight (DW)), followed by the peel (1.69 mg/g DW), the pulp (1.67 mg/g DW), and columella (1.52 mg/g DW). The experimental TAC correlated well with the model (Adjusted R2 with values between 0.88 and 0.97). The highest effectiveness in ACG extraction was obtained in seeds and peels using UEA compared to extraction by maceration (993% and 650%, respectively). The results showed that A. muricata by-products are an important source of ACGs and that UAE could be a viable alternative, with high potential for large-scale extraction.