Encapsulation of Phenolic Compounds from a Grape Cane Pilot-Plant Extract in Hydroxypropyl Beta-Cyclodextrin and Maltodextrin by Spray Drying.

Grape canes, the main byproducts of the viticulture industry, contain high-value bioactive phenolic compounds, whose application is limited by their instability and poorly solubility in water. Encapsulation in cyclodextrins allows these drawbacks to be overcome. In this work, a grape cane pilot-plant extract (GCPPE) was encapsulated in hydroxypropyl beta-cyclodextrin (HP-ß-CD) by a spray-drying technique and the formation of an inclusion complex was confirmed by microscopy and infrared spectroscopy. The phenolic profile of the complex was analyzed by LC-ESI-LTQ-Orbitrap-MS and the encapsulation efficiency of the phenolic compounds was determined. A total of 42 compounds were identified, including stilbenes, flavonoids, and phenolic acids, and a complex of (epi)catechin with ß-CD was detected, confirming the interaction between polyphenols and cyclodextrin. The encapsulation efficiency for the total extract was 80.5 ± 1.1%, with restrytisol showing the highest value (97.0 ± 0.6%) and (E)-resveratrol (32.7 ± 2.8%) the lowest value. The antioxidant capacity of the inclusion complex, determined by ORAC-FL, was 5300 ± 472 µmol TE/g DW, which was similar to the value obtained for the unencapsulated extract. This formulation might be used to improve the stability, solubility, and bioavailability of phenolic compounds of the GCPPE for water-soluble food and pharmaceutical applications.

Pilot-plant scale extraction of phenolic compounds from grape canes: Comprehensive characterization by LC-ESI-LTQ-Orbitrap-MS.

Grape canes, also named vine shoots, are well-known viticultural byproducts containing high levels of phenolic compounds, which are associated with a broad range of health benefits. In this work, grape canes (Vitis vinifera cv. Pinot noir) were extracted in a 750 L pilot-plant reactor under the following conditions: temperature 80 °C, time 100 min, solid/liquid ratio 1:10. The comprehensive characterization of grape cane phenolic compounds was performed by liquid chromatography coupled to high-resolution/accurate mass measurement LTQ-Orbitrap mass spectrometry. A total of 44 compounds were identified and, 26 of them also quantified, consisting of phenolic acids and aldehydes (17), flavonoids (12), and stilbenoids (15). The most abundant class of phenolics were stilbenoids, among which (E)-ε-viniferin predominated. The phenolic profile of grape canes obtained using pilot plant extraction differed significantly from the results of laboratory-scale studies obtained previously. Additionally, we observed a high antioxidant capacity of grape cane pilot-plant extract measured by the radical antioxidant scavenging potential (ABTS+) (2209 ± 125 µmol TE/g DW) and oxygen radical absorbance capacity using fluorescein (ORAC-FL) (4612 ± 155 µmol TE/g DW). Grape cane pilot-plant extract for their phenolic profile may be used as a by-product for the development of novel nutraceutical and pharmaceutical products, improving the value and the sustainability of these residues.

Physical-Chemical Evaluation of Active Food Packaging Material Based on Thermoplastic Starch Loaded with Grape cane Extract.

The aim of this paper is to evaluate the physicochemical and microbiological properties of active thermoplastic starch-based materials. The extract obtained from grape cane waste was used as a source of stilbene bioactive components to enhance the functional properties of thermoplastic starch (TPS). The biomaterials were prepared by the compression molding technique and subjected to mechanical, thermal, antioxidant, and microbiological tests. The results showed that the addition of grape cane extract up to 15 wt% (TPS/WE15) did not significantly influence the thermal stability of obtained biomaterials, whereas mechanical resistance decreased. On the other side, among all tested pathogens, thermoplastic starch based materials showed antifungal activity toward Botrytis cinerea and antimicrobial activity toward Staphylococcus aureus, suggesting potential application in food packaging as an active biomaterial layer.

Pharmacokinetics of low molecular weight phenolic compounds in gerbil plasma after the consumption of calafate berry (Berberis microphylla) extract.

Calafate is a berry with high concentration of anthocyanins and hydroxycinnamic acids that grows in South Patagonia. To date, no metabolism studies of phenolic compounds using calafate have been carried out. A calafate extract was characterized by HPLC-DAD-ESI-MS/MS. After extract administration (300 mg/kg), a pharmacokinetic study of phenolic compounds in gerbil plasma was performed by GC-MS/MS. Sixteen phenolic acids increased after intake. Phenylacetic acid derivatives exhibit the highest concentration, while main increase of phenolic catabolites was observed 2 h post-intake. 3-hydroxyphenylacetic and phenylacetic acids increased at 4-8 h post-intake. All catabolites found in gerbil plasma exhibit concentration peaks between 0.1 and 1 µM, however no parental anthocyanins were detected. Establish in vivo plasmatic concentration ranges of phenolic compounds derived from polyphenol consumption following WHO recommendations, plays a key role to carry out future in vitro assays in order to correctly assign biological benefits of calafate berry consumption.

Oligostilbenoids in Vitis vinifera L. Pinot Noir grape cane extract: Isolation, characterization, in vitro antioxidant capacity and anti-proliferative effect on cancer cells.

The following oligostilbenoids were isolated from extracts of Vitis vinifera L. Pinot Noir grape canes produced at a pilot-plant scale: (E)-ε-viniferin, (E)-resveratrol, (E)-piceatannol, ampelopsin A, vitisin B, pallidol, (E)-δ-viniferin, (E)-ω-viniferin, (E)-trans-cis-miyabenol C, isorhapontigenin, scirpusin A, and a new isomer named isoscirpusin A. The antioxidant capacity of the isolated stilbenoids was studied by three different assays, and their 50% inhibition concentration (IC50) against cancer cells was determined by MTT reduction assay. Besides (E)-resveratrol, stilbenoids have outstanding antioxidant capacity in the ORAC-FL assay. The strongest antiproliferative effect was observed for (E)-piceatannol and ampelopsin A against the bladder cancer cell line J82. (E)-Piceatannol has inhibitory effect on human lung cancer SK-MES-1 cells. Moreover, the whole extract has antiproliferative effect on all tested cell lines. In conclusion, beside (E)-resveratrol, grape cane extract contains oligostilbenoids with potential health benefits. This underexploited viticultural residue has the potential to produce valuable phytochemicals or ingredients in functional foods.

C18 core-shell column with in-series absorbance and fluorescence detection for simultaneous monitoring of changes in stilbenoid and proanthocyanidin concentrations during grape cane storage.

Grape canes, the residues from the annual pruning of vines, contain high levels of inducible (E)-resveratrol and also oligomeric stilbenoids and proanthocyanidins. These two families of phenolic compounds are bioactive, but to quantify them in a single chromatographic run using only ultraviolet detection is a difficult task. To overcome this limitation, a chromatographic method was developed using a core shell column for separation, an ultraviolet-visible diode array detector (DAD) and a fluorescence (FL) detector connected in series for quantification, with an electrospray ionization interface (ESI) and a triple quadrupole mass spectrometric detector (MS/MS) added for identification of the analytes. The proanthocyanidins (+)-catechin, (-)-epicatechin, procyanidins B1, B2, and C1, an unknown dimer and trimer, two prodelphinidin dimers, and monogallate procyanidin dimers were detected in the tested grape cane samples. The stilbenoids detected were (E)-resveratrol, (E)-piceatannol, (E)-piceid, (E)-ε-viniferin, vitisin B, a glycosylated monomer, three oxidized dimers, an unknown dimer and a tetramer, pallidol, hopeaphenol, (E)-δ-viniferin, and (E)-ω-viniferin. However, this method required 60min for each analysis. A faster and more efficient method for quantitative analysis was developed based on HPLC-DAD-FL, reducing the time required to 24min for the simultaneous quantification of proanthocyanidins and stilbenoids in Cabernet Sauvignon, Pinot Noir, and Tintorera grape canes stored at controlled temperatures and relativity humidities for 134days after pruning. To the best of our knowledge, this is the first time a prodelphinidin dimer has been quantified in grape canes. The incorporation of fluorescence detection in series with DAD not only allowed the quantification of proanthocyanidins, it also improved the detectability of some minor stilbenoids present in the canes, such as (E)-piceid. The (E)-resveratrol and (E)-piceatannol levels increased significantly during cane storage, while those of (E)-ε-viniferin and ampelopsin A did not show significant increases. The relative humidity had a determining effect on the levels of (E)-resveratrol and (E)-piceatannol in the canes of all varieties studied; their concentrations were higher at a relative humidity of 60% than at 70%. This is the first time that the proanthocyanidin profiles of canes stored after pruning were monitored under controlled conditions of temperature, time and relative humidity. The concentration of (-)-epicatechin decreased during storage under both relative humidities. Furthermore, the levels of proanthocyanidin B1 and the prodelphinidin dimer also decreased to a certain extent.

Profiling of Vitis vinifera L. canes (poly)phenolic compounds using comprehensive two-dimensional liquid chromatography.

Grapevine canes, a pruning-derived by-product, possess a great amount of bioactive (poly)phenolic compounds belonging to different chemical classes, thus, having a good potential for further valorization. However, in order to properly design valorization strategies, the precise chemical composition of this material has to be known. Up to now, this chemical characterization has been based on analysis of different groups of components individually, due to difficulties related to their huge chemical variability. In this work, a comprehensive two-dimensional liquid chromatography-based method (LC×LC) is developed to obtain the profiles of (poly)phenolic compounds present in grapevine canes from several varieties. Three different set-ups have been tested and compared; the combination of diol and C18 columns produced the best results, allowing the characterization of the (poly)phenolic profile in around 80min. This way, 81 different components were detected in the samples; most of them could be tentatively assigned using the information provided by the DAD and MS detectors employed. Indeed, it has been possible to detect in a single run components belonging to stilbenoids, procyanidins and prodelphinidins of varying degrees of polymerization, some of them not formerly described in this natural source. The method has shown extremely good separation capabilities, and is characterized by high effective peak capacity (842) and orthogonality (A0=78%). The obtained results demonstrate that Vitis vinifera L. canes may retain a great potential to be used as an underexploited natural source of bioactive compounds, with potential applications in different fields.

Evaluation of microextraction by packed sorbent, liquid-liquid microextraction and derivatization pretreatment of diet-derived phenolic acids in plasma by gas chromatography with triple quadrupole mass spectrometry.

Miniaturized sample pretreatments for the analysis of phenolic metabolites in plasma, involving protein precipitation, enzymatic deconjugation, extraction procedures, and different derivatization reactions were systematically evaluated. The analyses were conducted by gas chromatography with mass spectrometry for the evaluation of 40 diet-derived phenolic compounds. Enzyme purification was necessary for the phenolic deconjugation before extraction. Trimethylsilanization reagent and two different tetrabutylammonium salts for derivatization reactions were compared. The optimum reaction conditions were 50 µL of trimethylsilanization reagent at 90°C for 30 min, while tetrabutylammonium salts were associated with loss of sensitivity due to rapid activation of the inert gas chromatograph liner. Phenolic acids extractions from plasma were optimized. Optimal microextraction by packed sorbent performance was achieved using an octadecylsilyl packed bed and better recoveries for less polar compounds, such as methoxylated derivatives, were observed. Despite the low recovery for many analytes, repeatability using an automated extraction procedure in the gas chromatograph inlet was 2.5%. Instead, using liquid-liquid microextraction, better recoveries (80-110%) for all analytes were observed at the expense of repeatability (3.8-18.4%). The phenolic compounds in gerbil plasma samples, collected before and 4 h after the administration of a calafate extract, were analyzed with the optimized methodology.

Differences in Vvufgt and VvmybA1 Gene Expression Levels and Phenolic Composition in Table Grape (Vitis vinifera L.) 'Red Globe' and Its Somaclonal Variant 'Pink Globe'.

A novel 'Red Globe' (RG)-derived grape variety, 'Pink Globe' (PG), was described and registered as a new genotype, with earlier ripening and sweeter taste than those of RG. Microsatellite analysis revealed that PG and RG are undifferentiable; however, the PG VvmybA1c contains six single-nucleotide polymorphisms within the coding and noncoding region, possibly related to the reduced VvmybA1 expression levels. Conversely, HPLC-DAD-ESI-MS/MS analysis showed significantly lower anthocyanin content in PG skin than in RG skin, and PG had no detectable trihydroxylated anthocyanins. Total flavonols did not differ between the variants, although some quercetin derivate concentrations were lower in PG. HPLC-FLD analysis revealed slightly higher concentrations of epicatechin and a procyanidin dimer in PG seeds, although the antioxidant capacity of crude extracts from either variety did not differ significantly. These differences, particularly in monomeric anthocyanin content, can be attributed to altered activity of a MYB-type transcription factor, reducing Vvufgt expression.

The Chilean wild raspberry (Rubus geoides Sm.) increases intracellular GSH content and protects against H2O2 and methylglyoxal-induced damage in AGS cells.

The Chilean raspberry Rubus geoides Sm. (Rosaceae) is a native species occurring in the Patagonia. Five R. geoides samples were assessed for phenolic content and composition, antioxidant activity, effect on total reduced glutathione (GSH) synthesis and protective effect against H2O2 and methylglyoxal (MGO)-induced stress in epithelial gastric AGS cells. The HPLC-DAD/ESI-MS profiles allowed the tentative identification of 39 phenolics including flavonol glycosides and tannins. R. geoides presented higher total phenolic and flavonoid content than Rubus idaeus. Two out of the five phenolic enriched R. geoides extracts (PEEs) exhibited better antioxidant activity than R. idaeus in the DPPH, FRAP and TEAC assays. A significant cytoprotective activity was observed when AGS cells were pre-incubated with extracts and subsequently challenged with H2O2 or MGO. Treatment with the PEEs increased the intracellular GSH content. R. geoides fruit extracts may induce the activation of intracellular protection mechanisms against oxidative and dicarbonyl-induced stress.

Hydroxycinnamic acids and flavonols in native edible berries of South Patagonia.

Diverse edible berries are native to the Patagonian region of Southern Chile. These berries are underused because their nutritional properties are relatively unknown. In this work, the profiles and concentrations of hydroxycinnamic acid derivatives and flavonols, and the antioxidant capacity of the berry extracts, were studied using HPLC-DAD-ESI-MS/MS and CUPRAC assays, respectively. In total, 46 compounds were identified, including 17 hydroxycinnamic acid derivatives and 26 flavonols. Caffeoylquinic acid isomers were the most abundant compounds, and quercetin and myricetin derivatives were the main flavonols found. The berries from Ribes genera showed a high diversity and concentration of these 2 families of compounds and contained 3-caffeoylquinic acid and quercetin-3-rutinoside at the highest concentrations. The Patagonian berries, especially the berries of Rubus and Ribes genera, had high cupric reducing antioxidant capacity, comparable with that described for berries from the Northern hemisphere. These results contribute to promote the nutritional study of these fruits.

Flavonols, alkaloids, and antioxidant capacity of edible wild berberis species from patagonia.

There are 20 species of the Berberidaceae family described in Chile, whose fruits are edible and show high anthocyanin and hydroxycinnamic acid levels. Berberis microphylla G. Forst, commonly known as calafate, is the most extensively distributed. Flavonols and alkaloids in seed, pulp, skin, and whole calafate berry extracts and other Berberis were studied using HPLC-DAD-ESI-MS/MS and HPLC with fluorescence detector. Berry samples from different locations in Chilean Patagonia, including different phenological stages, were systematically addressed. Results were compared with other organs of the plant and with other Berberis species. Total flavonol concentration in calafate (n = 65) was 1.33 ± 0.54 µmol/g. Glycosyl metabolites of quercetin and isorhamnetin were the most abundant. Similar profiles were observed in calafate from distinct locations, but important differences were observed for the other edible Berberis species. Calafate pulp and skin have higher flavonol concentrations than seeds, and the maturation process reduced its levels. TEACCUPRAC and TEACABTS of whole calafate extracts and fractions are also explored. Finally, only berberine was detected in the fruit (0.001%), mainly in seeds. Results contribute to the promotion of this berry as a superfruit from Patagonia.

Isolation and structural elucidation of anthocyanidin 3,7-ß-O-diglucosides and caffeoyl-glucaric acids from calafate berries.

Calafate (Berberis microphylla G. Forst) is an edible wild berry growing in South Patagonia that is very rich in anthocyanins and hydroxycinnamic acid derivatives. Calafate contains unusual phenolic compounds compared to other berries, such as anthocyanidin dihexosides, different from the common 3,5-diglucosides, and isomeric esters of caffeic acid with hexaric acids. After isolation, their structures have been elucidated by UV-vis, MS/MS, and NMR spectroscopies. The anthocyanidin dihexosides constitute the complete series of 3,7-ß-O-diglucosides of the five anthocyanidins usually found in calafate, the structures of which were completely elucidated in the cases of delphinidin, petunidin, and malvidin derivatives and tentatively suggested in the cases of cyanidin and peonidin, and their occurrence seems to be characteristic of calafate among other wild berries from South Patagonia. With regard to caffeoyl-hexaric acids, two of four isomers have been assigned as 3- and 4-trans-caffeoyl-glucaric acids, but the determination of the linkage position for each isomer was not possible. A third isomer was also isolated, but it easily degraded and was suggested to be the 2- or 5-trans-caffeoyl-glucaric acid. The caffeoyl-glucaric acids account for around half of the pool of hydroxycinnamic acid derivatives in calafate.

Determination of cocaine and its major metabolite benzoylecgonine in several matrices obtained from deceased individuals with presumed drug consumption prior to death.

In the field of forensic toxicology, femoral blood is the most useful sample for the determination and quantification of drugs; however, cases in which blood is unavailable are common. In such cases, validated methodologies for drug determination in alternative matrices can be decisive in the investigation of a case. In particular, when femoral blood is unavailable for analysis for the presence of systemic exposure to cocaine and its principal metabolite, benzoylecgonine, validated methodologies from matrices other than blood that can be obtained in the autopsy room would be useful to the forensic toxicologist in the evaluation of a specific forensic case. To address this issue, we implemented and compared in our study the systematic evaluation of extraction, chromatographic separation, and quantification of cocaine and benzoylecgonine in different biological matrices (right and left cardiac blood, femoral arterial and venous blood, urine, vitreous humor, cerebrospinal fluid, brain accumbens nucleus, brain ventral tegmental area, and liver). The studied matrices were those most likely to be obtained from different autopsy rooms at the time of forensic testing in deceased individuals who are presumed of antemortem drug consumption. Solid phase extraction of analytes from the different matrices was performed using C-8/SCX mixed-phase columns, and gas chromatographic mass spectrometry separation was performed using detection in single-ion monitoring mode. The methodological validation was performed for all the studied matrices, and the results showed similar sensitivity and recoveries without statistical differences between the studied matrices. The methods were applied to evaluate a thanatological case using all the study matrices, showing unequal postmortem distribution of cocaine and benzoylecgonine throughout the different matrices tested. The present work opens the option of applying appropriate methodologies in the analysis of matrices, other than the usual blood, to obtain reliable results that may help clarify a forensic case. In addition, we present findings from different studies. This work affirms not only the potentiality of obtaining reliable data but also reaffirms the challenge of applying these data and taking into account the complexity of interpreting results in matrices other than blood.

Influence of post-pruning storage on stilbenoid levels in Vitis vinifera L. canes.

Increasing evidence for the health benefits of E-resveratrol has triggered interest in stilbenoids in grapes, wine and by-products. Less attention has been paid to stilbenoid levels in viticulture residues. However, grape canes are a promising source of stilbenoids and have economic potential because they are a source of high-value phytochemicals. The objective of this research was to determine the effect of post-pruning storage on stilbenoid levels in grape canes. In most samples, the predominant stilbenoid was (E)-resveratrol, followed by (E)-ε-viniferin. In Pinot Noir canes stored after pruning at room temperature, the stilbenoid levels increased significantly after 8 months. The concentration was increased by up to fivefold, reaching 4,777 mg kg(-1)dw (dry weight). This effect did not occur in frozen, lyophilised or milled material. Branches collected directly from the plants after grape vintage and those remaining on the plant after pruning showed only a small increase in stilbenoid levels.

Analysis of hydroxycinnamic acids derivatives in calafate (Berberis microphylla G. Forst) berries by liquid chromatography with photodiode array and mass spectrometry detection.

Calafate (Berberis microphylla G. Forst) is a Patagonian barberry very rich in anthocyanins and one of the fruits with the highest levels of these polyphenols. Other phenolic compounds have also been described in calafate berries. However, to the best of our knowledge there is no available information on hydroxycinnamic acid derivatives. The complexity of hydroxycinnamic acids determination in calafate berries, due to their structure similarities and the interference of high anthocyanin concentration is addressed by means of solid liquid extraction, followed by solid phase extraction clean-up on MCX columns and HPLC-DAD-ESI-MS/MS. The optimized extraction, clean-up and HPLC separation method allowed the assignation of identity and quantification of 20 hydroxycinnamic acids from calafate fruits. 5-Caffeoylquinic acid was the main compound found in all the studied samples. Other 13 hydroxycinnamoyl quinic acids and 6 caffeic acid esters with aldaric acid derivatives assigned as glucaric acid were also identified. Moreover, the glucaric-based hydroxycinnamic acid derivatives accounted for almost the half of total content of this kind of phenolic compounds. The total concentration of hydroxycinnamic acids derivatives ranged between 0.32±0.00 µmol/g and 8.28±0.01 µmol/g. Effect of ripening and geographical location on hydroxycinnamic acid profiles and concentrations are also evaluated. The methodology allows the determination of hydroxycinnamic acids from calafate despite of the high anthocyanin concentrations, showing a much higher concentration of these acids than other widely consumed berries. Thus suggesting that calafate could be considered a very interesting fruit from the point of view of their nutraceutical composition. However, geographical location and ripening have incidence in levels of studied compounds.

Identification and characterization of microsatellites from calafate (Berberis microphylla, Berberidaceae).

PREMISE OF THE STUDY: Southern barberry or calafate (Berberis microphylla) is a shrub species endemic to the Patagonian region of South America that is used for human consumption. The fruit is very rich in vitamin C and anthocyanins and has a very high antioxidant capacity. There have been only a few genetic studies of this and other closely related species. • METHODS AND RESULTS: Here we present the first 18 microsatellite markers of B. microphylla that were characterized using 66 accessions of calafate from Patagonia. On average, they had 7.6 alleles per marker, with an expected heterozygosity of 0.688. The informativeness of these markers was also evaluated in another 15 Berberis species, including most of the native and endemic Chilean species. • CONCLUSIONS: The results confirm that these new simple sequence repeat markers are very polymorphic and potentially useful in genetic studies in any species of the genus Berberis.

In vitro activity on human gut bacteria of murta leaf extracts (Ugni molinae turcz.), a native plant from Southern Chile.

Despite the fact that murta infusions have been used to treat gut/urinary infections by native Chileans for centuries, the mechanisms promoting such effects still remain unclear. As a first attempt to unravel these mechanisms, human fecal samples were incubated in a medium containing water extract of murta leaves (ML) and the growth of different bacterial groups was evaluated. Control incubations were made in media containing fructooligosaccharides (FOS) and glucose as a carbon source. Phenolic compounds in the ML extract, likely promoters of bioactivity, were identified by HPLC-DAD-MS(n) . Concentrations (log10 CFU/mL) of bifidobacteria and lactobacilli in media containing the extract and FOS were 7.33 ± 0.05/4.95 ± 0.20 and 6.44 ± 0.22/6.05 ± 0.06, respectively. Clostridia, anaerobes and Enterobacteriaceae grew to a similar extent in media containing murta extract and FOS. In vitro tests (disk diffusion) showed that Gram-positive (Bacillus and Paenibacillaceae) and Gram-negative (Enterobacteriaceae) bacteria isolated from fecal samples were sensitive to both water and 50/50 ethanol/water extracts of ML (28.4 µg gallic acid equivalents). At this concentration, the antimicrobial activity of ML extracts was significantly (P < 0.05) lower than that of penicillin (10 U), whereas the difference between activity of ML extracts and gentamicine (10 µg) was no significant (P > 0.05). No evidence of dependency between the antimicrobial activity of ML extracts and the enzymatic capability of the sensitive strains was found.

Stilbene levels in grape cane of different cultivars in southern Chile: determination by HPLC-DAD-MS/MS method.

Health benefits of trans-resveratrol and other stilbenes in grapes, must, and wine have been pointed out by numerous authors. Less attention has been paid to the presence of stilbene derivatives in viticultural residues, such as grape canes. The present work reports the first results of a systematic study of stilbene levels in different grape varieties and cultivation areas in Chile, to evaluate their potential as an alternative source of bioactive stilbenes. In all cane samples, the predominant stilbene is trans-resveratrol, followed by ε-viniferin and piceatannol. In canes of Pinot noir up to 5590 ± 172 mg kg(-1) of trans-resveratrol and up to 6915 ± 175 mg kg(-1) of total stilbenes were detected. The observed concentrations of stilbenes in canes of Pinot noir from southern Chile until now are higher than those reported previously for this red variety. However, the highest concentration of total stilbenes observed in the analyzed samples was in the canes of white variety Gewürztraminer with 7857 ± 498 mg kg(-1). Preliminary results indicate that these levels can evolve if canes are left for some months on the vineyard after pruning, observing an increase during the first 2 months and a decrease after this period.

Chromatographic approaches for determination of low-molecular mass aldehydes in bio-oil.

HPLC-UV and GC/MS determination of aldehydes in bio-oil were evaluated. HPLC-UV preceded by derivatization with 2,4-dinitrophenylhydrazine allows separation and detection of bio-oil aldehydes, but the derivatization affected the bio-oil stability reducing their quantitative applicability. GC/MS determination of aldehydes was reached by derivatization with o-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine hydrochloride. Two approaches for this reaction were evaluated. The first: "in solution derivatization and head space extraction" and the second: "on fiber derivatization SPME", the latter through an automatic procedure. Both sample treatments allows the quantification of most important aliphatic aldehydes in bio-oil, being the SPME approach more efficient. The aldehyde concentrations in bio-oil were ~2% formaldehyde, ~!0.1% acetaldehyde and ~0.05% propionaldehyde.