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Concentrated in the skins of red grapes are the anthocyanins, the primary colorants responsible for the fruits' reddish-purple color. These colorants are recognized for their significant antioxidant properties and potent nutraceutical and pharmaceutical ingredients. Nevertheless, their widespread use is compromised by the (i) need for more efficient yet sustainable downstream processes for their recovery and (ii) by the challenges imposed by their poor stability. In this work, these drawbacks were overcome by applying eutectic solvents and stabilizing agents. Besides, the anthocyanins were successfully loaded into a solid host material (approved in both food and pharmaceutical sectors) based on silicon dioxide (SiO2, loading capacity: 1extract:7silica m/m). Summing up, with the process developed, the extraction yield (21 mganthocyanins.gbiomass-1) and the stability (under 55, 75, and 95 °C) of the recovered anthocyanins were over three times better than with the conventional process. Finally, the raw materials and solvents were recycled, allowing an economical and environmentally friendly downstream process. published

Due to the complex characteristics and variable composition of apple pomace, sample preparation for chromatographic analysis is a great challenge. To solve this problem, we proposed using a solvent gradient using Pressurized Liquid Extraction (PLE), where the solvent gradually changes from water to ethanol during the extraction. Different dynamic gradients, static time, and temperatures were evaluated and showed relevant effects on the yields of target analytes. It was possible to improve extraction yields of compounds with different characteristics using the extraction solvent gradient. By coupling solid-phase extraction in-line, it was possible to separate compounds into fractions, where furfural, HMF, and chlorogenic acid gradually eluted from the adsorbent. At the same time, flavonoids were retained and eluted in the later fractions. On-line analysis by HPLC provided real-time information about the process and permitted the creation of a 3D chromatogram of the sample.

The objective of this work was the development of an on-line extraction/fractionation method based on the coupling of pressurized liquid extraction and solid-phase extraction for the separation of phenolic compounds from apple pomace. Several variables of the process were evaluated, including the amount of water of the first stage (0–120 mL), temperature (60–80 °C), solid-phase extraction adsorbent (Sepra, Isolute, Strata X and Oasis) and activation/elution solvent (methanol and ethanol). The best results were observed with the adsorbent Sepra. The temperature had a small effect on recovery, but significant differences were observed for phlorizin and a quercetin derivative. Results indicate that ethanol can be used to replace methanol as an activation, extraction/elution solvent. While using mostly green solvents (water, ethanol, and a small amount of methanol that could be reused), the developed method produced higher or similar yields of acids (2.85 ± 0.19 mg/g) and flavonoids (0.97 ± 0.11 mg/g) than conventional methods.

Total phenolic and flavonoid contents occurring in eight types of edible mushrooms (Agaricus bisporus, Boletus edulis, Calocybe gambosa, Cantharellus cibarius, Craterellus cornucopioides, Hygrophorus marzuolus, Lactarius deliciosus and Pleurotus ostreatus) have been respectively evaluated by the Folin-Ciocalteau assay and by the colorimetric reaction with NaNO2 and AlCl3 in a basic media. Generally, the assayed mushrooms contained between 1 and 6 mg of phenolics per gram of dried mushroom, depending on the species, while the flavonoid concentrations ranged between 0.9 and 3.0 mg per gram of dried matter. The profile and concentration of individual phenolics was determined by means of high performance liquid chromatography. Homogentisic acid was the free phenolic acid significantly present in all mushrooms although the content varied considerably among the analysed species. Flavonoids, such as myricetin and catechin were also detected in the mushrooms studied. The antioxidant properties of the methanolic extracts from mushrooms were evaluated by monitoring the linoleic acid autoxidation, and all the mushrooms species showed inhibition, with C. cibarius being the most effective against lipid oxidation (74% of inhibition) and A. bisporus the species with lowest antioxidant activity (10% of inhibition). © 2011 Elsevier Ltd. All rights reserved.

The recent development of fused-core technology in HPLC columns is enabling faster and highly efficient separations. This technology was evaluated for the development of a fast method for the analysis of main curcuminoids (curcumin, demethoxycurcumin and bisdemethoxycurcumin) present in extracts of turmeric (Curcuma longa L.). A step-by-step strategy was used to optimize temperature (40-55 °C), flow rate (1.0-2.5 mL min(-1)), mobile phase composition and equilibration time (1-5 min). A gradient method was developed using acidified water and acetonitrile combined with high column temperature (55 °C) and flow rate (2.5 mL min(-1)). Optimized conditions provided a method for the separation of these three curcuminoids in approximately 1.3 min with a total analysis time (sample-to-sample) of 7 min, including the clean-up and the re-equilibration of the column. Evaluation of chromatographic performance revealed excellent intraday and interday reproducibility (>99%), resolution (>2.23), selectivity (>1.12), peak symmetry (1.24-1.42) while presenting low limits of detection (

Short-term storage stability of soy isoflavones was determined by evaluating the effects of storage duration, temperature, UV–Vis light and vial head space on individual isoflavone concentration. Concentration of isoflavones in ethanol-water extracts and standard solutions stored with temperatures between −20 and 10 °C remains unchanged up to one week. Degradation of malonyl isoflavones is affected by storage duration, temperature, incident UV–Vis light and vial head space. Glucoside isoflavones were not sensitive to the experimental storage conditions. Daidzein and glycitein were the only aglucones sensitive to UV–Vis light. Isoflavones must be kept at temperatures lower than 10 °C and protected from light. Using these conditions, the extracts can be stored up to one week with no significant degradation of isoflavones allowing better planning of routine analysis of large number of samples.

This study evaluated the use of supercritical carbon dioxide (SC-CO2) for the extraction of soybeans isoflavones (genistin, genistein and daidzein), where different temperatures, pressures and modifier percentages were tested and compared with conventional extraction methods (soxhlet and ultra-sonification) conducted in parallel. The extraction conditions were 40–70 °C, 200–360 bar, adding 0, 5 and 10 mol% of methanol 70% in water (v/v−1) as modifier. The HPLC analysis of the obtained extracts revealed that extraction of genistin and genistein at 70 °C/200 bar using a mixture of carbon dioxide (55.2 g) and modifier (10 mol%), resulted in lower values than conventional methods. The analytical results additionally showed a predominant effect of temperature in the amount of genistin and genistein extracted by SC-CO2. Extraction of daidzein at 50 °C/360 bar resulted in higher values than conventional methods and a predominant effect of the pressure was observed. A strong interaction between temperature and pressure was observed in the extraction of the tested isoflavones. The maximum amount of total isoflavonoids extracted by each method were: ultra-sonification (311.55 μg·g−1), soxhlet (212.86 μg·g−1) and SC-CO2 (86.28 μg·g−1).