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In this study, for the first time, polyphenols are extracted using microwave-assisted deep eutectic solvents (MW-DES) from supercritical CO2 defatted date seeds under variable operating conditions. The best conditions consisted of choline chloride: formic acid (1:2 molar ratio), a solid to solvent ratio of 1/20 (g/mL) (0.75 g of dry biomass in 15 mL solvent), an extraction time of 50 s, and a microwave power of 400 W. The maximum polyphenols extraction yield was 128 g gallic acid equivalent/kg dry biomass (g GAE/kg) (which is the highest value ever reported in literature for date seeds extracts). The antioxidant activity of the optimum extracts was assessed with the DPPH and ABTS quenching capacities being equal to 27 and 145 mg trolox equivalent/g dry biomass, respectively. Mainly mannose and manno-oligosaccharides were solubilized during extraction. The highest yields were (obtained at 200 W, 120 s) 35.07 and 32.18 mg/g of dry biomass for mannose and manno-oligosaccharides, respectively. It was also observed that the total mannose (monomer and oligomer) release during the extraction increased linearly (r2 = 0.9951) with respect to microwave energy applied per gram of date seeds (J/g). [ABSTRACT FROM AUTHOR]

In this study, the effects of microwave, ultrasound and the combination of ultrasound-microwave on the extraction of phenolic compounds from cranberrybush (Viburnum opulus L.) fruit were investigated. The effects of ultrasound treatment time, ultrasound power, microwave power (MP) and microwave treatment time on total phenolic content were investigated. Moreover, antioxidant activities (AA), pH values, total monomeric anthocyanin contents (TMAC), polymeric colour, colour density, polymeric colour ratio, vitamin C content, and concentrations of some of the phenolic compounds of extracts were also examined. In microwave-assisted extractions, the highest TPC (71.52 ± 4.16 mg GAE/g dry matter) was obtained when the samples were extracted at 360 W MP for 15 min at a solid:solvent ratio of 5:100. For ultrasound-assisted extraction (UAE), the conditions that gave the highest TPC value (54.55 ± 4.11 mg GAE/g dry matter) were 30 min extraction time, 35 W power, and 5:100 solid:solvent ratio. The process conditions of ultrasound-microwave combination extraction (UMAE), resulted in the highest TPC (72.03 ± 0.90 mg GAE/g dry matter) and AA (21.28 ± 0.60 mg DPPH/g dry matter), were found as 10 min microwave treatment at 180 W and 30 min ultrasound treatment at 35 W. The highest vitamin C content (166.60 mg ascorbic acid/100 g dry matter) was obtained in UAE process. The UMAE extracts, which provided 94.4% time-saving compared to maceration, had comparable TPC, higher AA, and higher (−) epicatechine and rutin contents. The bands found in the FTIR spectrum were detected to be associated with chlorogenic acid. [ABSTRACT FROM AUTHOR]

The assessment of the behavior of deep eutectic solvents (DESs) have been within the focus of numerous original research papers and review articles in the last two decades due to their unique properties such as low viscosity, low melting point, low volatility, high thermal stability, high conductivity, high surface tension, non-toxicity, and biocompatibility. DES have been used for the pretreatment of biomass, within conversion processes (e.g., as catalyst, co-solvent, extracting solvent) and within downstream processing. Related to an efficient use within integrated biorefineries, an important issue for the successful application of DES is their recovery and recycling. Thus, the aim of this review is to provide detailed information and assessments on current techniques (e.g., anti-solvent addition, crystallization, membrane filtration, solid–liquid extraction, liquid–liquid extraction, short path distillation, supercritical fluid extraction, separation due to density differences) to recover and recycle DES used for a specific purpose. The selection of the respective recovery option has to be based on the properties of the DES, the nature of the conversion/extraction process, the features of the target compound/product, the amount of energy required, and the equipment cost. Future aspects of DES recovery are also elaborated. However, further investigations are required to better understand the separation options while optimizing the product yields and minimizing the overall costs. [ABSTRACT FROM AUTHOR]

In this study, the effects of different coating materials (maltodextrin and gum arabic), ultrasonication time (10–20–30 min), and core to coating ratio (1:10, 1:20, and 1:30) on microencapsulation of cranberrybush fruit were investigated. Freeze drying was applied for 48 h to obtain the microcapsules. The dependent variables of the research were encapsulation efficiency, antioxidant activity, color values (L*, a*, b*, ∆E), moisture content, solubility, bulk density, storage, and baking stability. The results obtained from the study revealed that the usage of gum arabic as the coating material resulted in an increase in encapsulation efficiency, solubility, moisture content, and bulk density of the microcapsules and a decrease in average particle size. Moreover, it was found that microencapsulation enhanced the hygroscopicity, storage, and baking stability of the phenolic compounds. As a conclusion, cranberrybush fruit microcapsules can be suggested as a promising functional food additive thanks to its high phenolic content and improved storage and process stability. [ABSTRACT FROM AUTHOR]

In this study, it was aimed to extract bioactive compounds (phenolics and anthocyanins) from cornelian cherry (Cornus mas L.) using microwave (ME) and ohmic heating assisted microwave extraction (OH-ME) as an alternative to maceration (M). Total phenolic compound (TPC), total monomeric anthocyanin content (TMAC), antioxidant activity (AA), water-soluble solid matter (WSSM), color values, and pH of the extracts were determined. The effect of extraction time, solid to solvent ratio, microwave power, electrical field strength, and holding time during ohmic heating on extraction characteristics was investigated for different methods. Ohmic heating application prior to extraction has enhanced the TPC yield by 1.1 and 5.4-folds compared to that of ME and M, respectively. Moreover, the extraction time was decreased by approximately 42 and 95% as regards ME and M, respectively. The highest TMAC value (0.65 mg cya-3-glu/g dry matter) was observed with OH-ME. The experimental data obtained by ME and OH-ME methods was fitted to the Peleg model to describe the TPC yields. These results indicate that the combined application of ohmic heating and microwave extraction is a potential alternative method for total phenolic compounds extraction from cornelian cherry due to increased yields and reduced extraction times. [ABSTRACT FROM AUTHOR]

In this study, it was aimed to investigate the efficacy of microwave assisted deep eutectic solvent (MW-DES) pretreatment on the structure of wheat straw as well as the sugar and ethanol yields. The samples were treated with choline chloride: formic acid at different mole ratios (1:2, 1:3, and 1:4), microwave power (270, 360, and 450 W) and pretreatment time (2, 5, and 8 min). MW-DES pretreatment has a significant impact on lignocellulosic structure, which was also verified by XRD and SEM analysis. It was found that xylan is the most affected constituent of biomass during MW-DES pretreatment. Severe conditions can solubilize up to 90% of the xylan into liquid phase. The removal of xylan and lignin during MW-DES pretreatment led to highly digestible and fermentable wheat straw fibers. Enzymatic hydrolysis of pretreated wheat straw fibers revealed that MW-DES pretreatment was vastly effective at achieving very high sugar yields (99% glucose, 85% xylose yield). A linear correlation between xylan removal and glucose release during enzymatic hydrolysis was observed. The maximum total sugar release (619 mg/g pretreated wheat straw fibers) being twice as much of conventional deep eutectic solvent (DES) pretreatment, was observed at 1:3 mol ratio, 360 W microwave power and 8 min retention time. The theoretical ethanol yield using Escherichia coli KO11 was 81.5%. [ABSTRACT FROM AUTHOR]