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Nine pomegranate cultivars grown in Spain were selected, and their physicochemical (total soluble solids, pH, titratable acidity, maturity index, monomeric anthocyanin pigment, flavonoids, hydrolyzable tannins, and vitamin C) and antioxidant properties and polyphenolic composition of the juices were compared. A total of 53 polyphenols were identified, showing cultivars different profiles. Of all nine cultivars, Katirbasi had the highest contents of flavonoids, hydrolyzable tannins and vitamin C, as well as gallic acid and ellagic acid contents, explaining its high total reducing capacity. Principal component analysis allowed Katirbasi to be differentiated clearly from the others. Other cultivars presented also interesting characteristics such as high monomeric anthocyanin pigment content (CG8 cultivar) and interesting antioxidant activity (Wonderful 2 and CG8 cultivars). CG8 was the cultivar with the highest value of cyanidin-3,5-di- O-glucoside. Thus, this study will assist pomegranate producers in choosing the most suitable cultivar according to its ultimate use. [ABSTRACT FROM AUTHOR]

BACKGROUND Aqueous two-phase extraction is recognized as an effective, versatile and important emerging green-technique for the downstream processing of biomolecules. Extraction of phenolic compounds from trimmings of Eucalyptus globulus wood veneers was studied using aqueous two-phase systems ( ATPS) (water + polymer + salt) based on PEG 2000 and ammonium sulphate. The aim was the recovery of phenolic compounds to be used as natural antioxidants. Experiments were planned to optimize the extraction process. The influence of several operational conditions (time, temperature, ATPS composition, solid-liquid ratio and settlement time) on phenolics recovery was studied. RESULTS It was found that phenolic compounds have preference for the top PEG-rich phase. Settlement time had no significant impact on phase composition. Total phenols yield increased with temperature, extraction time and amount of solvent used. However, ATPS composition did not significantly influence total phenol yield. Extract analysis by RP-HPLC-ESI-TOF confirmed the presence of phenolic compounds with potential antioxidant activity, namely, mono and digalloyl glucose, (−)-gallic acid, ellagic acid and quercetin 3-O-rhamnoside. CONCLUSION Results demonstrated that extraction with ATPS ( PEG 2000 and ammonium sulphate) is an efficient way for recovering phenolics from eucalyptus wastes without requiring previous purification (total phenols yield of up to 1.88 ± 0.04 mg GAE/100 o.d. wood). © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The aim of this work was to study the extraction of phenolic compounds from chestnut bur and shell, both waste products of chestnut processing in the food industry. Two extraction techniques were compared—maceration with solvents and microwave-assisted extraction. The influence of the solvent used (water, 50% MeOH or 50% EtOH) and temperature (25-50-75°C) on extraction yield and extract total phenols content and FRAP, DPPH, and ABTS antioxidant activities was studied. In the conventional extraction, the yield was significantly higher for the bur (8.54–19.58%) than for the shell (2.91–13.27%); however, the shell extracts showed substantially greater properties. The best extract properties were achieved at 75°C using 50% MeOH for the bur and water for the shell and phenolic compounds with demonstrated antioxidant properties, as gallic acid esters of glucose and ellagic acid, were identified in these extracts by RP-HPLC-ESI-TOF. In addition, the aqueous extracts showed ability to inhibit the growth of gram positive and negative bacteria but not fungi. The kinetic of the extraction process was well fitted by the Peleg's model. The non-conventional microwave-assisted extraction slightly improved the chestnut bur extraction by reducing the extraction time. [ABSTRACT FROM PUBLISHER]

The extraction of phenolic compounds from eucalyptus ( Eucalyptus globulus) bark was examined with the aim of analyzing the potential of the extracts as natural antioxidants. Experiments were planned according to a 2 factorial design to analyze the influence of temperature and NaSO and NaOH concentrations in aqueous solutions on extraction yield, extract total phenols content, ferric reducing antioxidant power (FRAP), and number- and weight-average molecular weights. Extract total phenols content and FRAP antioxidant activity in the ranges 0.91-2.58 g gallic acid equivalent (GAE)/100 g oven-dried bark and 4.70-11.96 mmol ascorbic acid equivalent (AAE)/100 g oven-dried bark, respectively, demonstrated the potential of eucalyptus bark as a source of antioxidant compounds. Extraction at the highest temperature (100°C), the lowest NaSO concentration (1.5% on oven-dried bark), and without NaOH provided the highest extract total phenols content and FRAP antioxidant activity. Those eucalyptus bark extracts with lower molecular weight showed higher antioxidant activity. Matrix-assisted laser desorption ionization time-of-flight and reverse-phase high-performance liquid chromatography electrospray ionization time-of-flight mass spectrometry revealed the presence of polygalloyl glucoses, catechin, epicatechin, ellagic acid, quercetin-3-o-rhamnoside, and isorhamnetin in eucalyptus bark aqueous extracts. [ABSTRACT FROM AUTHOR]

Eucalyptus ( Eucalyptus globulus ) wood veneer trimmings, a waste product from the wood board industry, were studied as source of bioactive compounds. Two extraction techniques, maceration in an orbital bath and microwave-assisted extraction (MAE), were compared. In the conventional one, the effect of solvent (water, MeOH, EtOH, 50% MeOH and 50% EtOH), temperature (50 and 75 °C) and particle size (ground or unground material) on extraction yield and extract properties (total phenols content (TPC) and FRAP, DPPH and ABTS antioxidant activities) were analyzed. Extraction yield increased with increasing temperature and with reducing particle size. However, extract properties decreased when temperature was increased. Extracts obtained with EtOH at 50 °C showed the highest antioxidant properties. MAE experiments were planned according to an incomplete 3 3 factorial design to study the influence of temperature (50–70 °C), liquid–solid ratio (5:1–10:1 mL/g) and time (5–15 min) on extraction yield and extract properties. The optimal condition selected were 65 °C, liquid–solid ratio of 8.8:1 (mL/g) and 10 min. Comparing both techniques, maceration led to the extract with the best antioxidant properties, but MAE allowed to reduce significantly the extraction time. The aqueous extracts obtained under conventional extraction were able to inhibit the growth both bacteria and fungi. Gallic acid esters of glucose, gallic acid, ellagic acid and small proportions of quercetin-3-O-rhamnoside were found in the aqueous and ethanolic extracts. [ABSTRACT FROM AUTHOR]

Abstract: Pine bark represents an interesting byproduct from the forest that can be used as a source of antioxidants. To study the phenolic fraction of this matrix, Pinus radiata bark was extracted with a 75% ethanol solution at both bench- and pilot-scales followed by an analysis of the extraction yield variation, chemical composition (total phenolics content, tannins content, and phenol composition determined by RP-HPLC–DAD–MS and GPC) and antioxidant properties (free radical scavenging capacity, DPPH; reduction capacity, FRAP; chelating activity, ICA). Extractions at bench- and pilot-scales were performed at 120°C for 120min at a solid-to-liquid ratio of 1:20. Extract yields were not affected by the scale-up process (bench: 4.67±0.14%; pilot: 4.37±0.19%). No significant differences were observed in either the total phenolics content of the extracts (bench: 0.55±0.01ggallic acid/gextract; pilot: 0.54±0.01ggallic acid/gextract) or the tannin content (bench: 340.0±7.4mgcatechin/gextract; pilot: 334.0±4.4mgcatechin/gextract). The main low molecular weight compounds identified in the extracts were phenolic acids, catechin, epicatechin, procyanidin B-2, taxifolin and quercetin; to the best of our knowledge, we have tentatively identified syringic acid and homovanillic acid in pine bark for the first time. An increase in the average molecular weight (Mw) of the extract also changed with the extraction scale (bench: Mw=1689; pilot: Mw=2299). The antioxidant properties of the extracts showed a decrease in DPPH (−6.12%) and FRAP (−6.88%) and an increase in ICA (21.63%) in the pilot-scale as compared to the bench-scale extract. Based on these results, it may be technically possible to produce a polyphenolic extract from P. radiata bark at an industrial scale without extensively altering its antioxidant properties. [Copyright &y& Elsevier]