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Response surface methodology (RSM) was employed to optimize the process parameters of the supercritical carbon dioxide extraction of hop cones in terms of their antifungal properties against Fusarium culmorum and Aspergillus niger. The effects of temperature (40–50 °C), pressure (200–300 bar), and CO2 consumption (25–75 kgCO2/kg) on the extraction yield, content of α- and β-acids, as well as pathogens' growth inhibition were investigated. Both pressure and CO2 consumption had a significant effect on antifungal properties. It was observed that the best results for antifungal properties were obtained when hop cones were extracted with pure carbon dioxide at the temperature of 50 °C, under the pressure of 300 bar with CO2 consumption at the level of 75 kgCO2/kg of feed for extraction. The highest antifungal properties of hop cone supercritical carbon dioxide extracts were analyzed as 100% for Fusarium culmorum and 68% for Aspergillus niger, calculated as the growth inhibition of tested pathogens. The aim of the study was to determine the optimum values of extraction parameters to achieve the maximum response and enable us to investigate the interaction of these parameters on the antifungal properties of hop cone extracts. [ABSTRACT FROM AUTHOR]

The Box–Behnken experimental design was used to investigate the effect of subcritical water extraction parameters such as temperature, process duration, and extractor shape on the extract composition and antioxidant activity of Norway maple (Acer platanoides L.) bark extracts. Spectrophotometric (UV-Vis) techniques were employed to evaluate the total polyphenols (TPC) and flavonoids (TFC). The DPPH radical scavenging method was used to evaluate the antioxidant activity of the extracts. The yield of the process was evaluated through the utilization of response surface methodology (RSM). The total polyphenol and flavonoid contents, together with antioxidant activity, are highly dependent on water temperature. The influence of changes in the process duration and the shape of the pressure cell was not observed. A temperature increase from 110 °C to 170 °C caused a 8.9-fold increase in the polyphenol content, 7.2-fold increase in the flavonoid content, and 12.6-fold increase in the antioxidant activity. The highest values for polyphenols, flavonoids, and antioxidant activity occurred at a temperature of 170 °C, which is the upper limit of the temperature variability range for these studies. This study demonstrates the importance of the appropriate selection of extraction parameters in order to obtain the desired chemical composition of the extract. [ABSTRACT FROM AUTHOR]

In this study a multi-residue determination method for 36 pesticides in dried hops was reported. The sample preparation procedure was based on the acetate buffered QuEChERS method. A few mixtures of dispersive solid phase extraction (dSPE) sorbents consisting PSA, C18, GCB, Z-Sep and Z-Sep+ were investigated to clean-up the supernatant and minimize matrix co-extractives. The degree of clean-up was assessed by gravimetric measurements, which showed the best results for mixtures containing the Z-Sep+ sorbent. This is the first study to apply Z-Sep+ sorbent for hops material and the first to improve the method for pesticide residues determination in hops. Samples were analysed using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) and the procedure was validated according to the SANTE/11813/2017 document at four concentration levels: 0.02, 0.05, 0.1 and 1 mg/kg. The limits of quantification (LOQ) were in the range of 0.02–0.1 mg/kg. For all active substances, the trueness (recovery) ranged from 70 to 120% and the precision (RSDr) value was <20%. Specificity, linearity and matrix effect were also evaluated. The validated method was applied to the analysis of 15 real dried hop samples and the relevant data on detected residues were included. [ABSTRACT FROM AUTHOR]

This study investigated the impact of subcritical water extraction parameters on the polyphenols and flavonoids content in extracts made of the bark of walnut (Juglans regia L.), as well as antioxidant activity measured using the DPPH and FRAP methods. The total polyphenols (TPC) and flavonoid (TFC) were determined using the spectrophotometric (UV-Vis) method. The response surface methodology (RSM) was employed to optimize the yield of bioactive compounds. On the basis of developed model, the highest polyphenols (192.2 mg (GAE)/100 g (dry mass)) (GAE—gallic acid equivalent), flavonoids (88.3 mg(QE)/100 g (dry mass)) (QE—quercetin equivalent) contents and antioxidant activity (21.3 × 10−6 MTE/1 g (dry mass)) (TE-Trolox equivalent) were obtained under the following extraction conditions: temperature 131.6 °C, raw material fraction size 0.9 mm and process time 10 min. The greatest impact on the extraction yield was observed in the case of the temperature, whereas the raw material fraction size and the process time had a secondary impact. Obtained results indicate that a smaller particle size and a shorter time may improve the process; however, a reduction in particle size can be challenging for a pressure cell filtration system and consequently increase the cost of the raw material pretreatment process. With the reduction in the process time, a lower cost of extract production can be achieved. This study confirmed the importance of a proper selection of extraction parameters to obtain the demanded extract composition. [ABSTRACT FROM AUTHOR]