Evolution of some phenolic components,carotenoids and chlorophylls during ripening of three Italian grape varieties

A typical Italian white grape cultivar (Erbaluce) and two red ones (Barbera and Nebbiolo), all grown in the same vineyard, were picked at various ripening stages, from differentiation of the berry to the harvest, and analysed by HPLC to determine carotenoids, chlorophylls and polyphenols, i.e. the major antioxidant components. With regard to carotenoids, mostly represented by β-carotene and lutein, similar initial concentrations were found in the three cultivars. After an initial increase, carotenoids content decreased in the three cultivars, followed in the red grapes by a new peak, mainly due to lutein. Chlorophylls decreased in all cultivars and they almost disappeared in the white grapes, while 14–20% of the initial concentration was found in the red ripe grapes. Total phenolics showed a progressive increase up to veraison, then a decrease occurred, which was counteracted in red grapes by the formation of anthocyanins. The evolution of catechins (as the sum of (+)catechin and (−)epicatechin) and flavonols (as the sum of rutin, quercetin and quercetin-3-glucoside) was similar in all grapes: initial concentration was low (about 1 mg/100 g dw), a peak corresponding to veraison was observed, then a rapid decline occurred to final concentrations between 10 and 20 mg/100 g dw. Climatic conditions and sun exposure seem to play an important role in the evolution of the components under investigation, since very similar profiles were observed in the three cultivars.     

Major flavan-3-ol composition and antioxidant activity of seeds from different grape cultivars grown in Turkey

The major flavan-3-ols composition and antioxidant activity of the seeds of 12 different common grape varieties that grow in Turkey were investigated. The quantities of gallic acid, catechin, epicatechin and total flavan-3-ol were determined with high performance liquid chromatography (HPLC) and spectrophotometric method in grape seeds extracts. Gallic acid, catechin, epicatechin and total flavan-3-ol varied from 18 to 101, 121–845, 85–893 and 4 507–13 360 mg/100 g in grape seeds, respectively. The seeds of Papaz Karası, Alicante Boushet and Kalecik Karası cultivars were good sources for these compounds among the cultivars examined. In most cultivars, the amount of epicatechin was greater than that of catechin. The cultivars that have high total flavan-3-ol content had the strongest free radical scavenging activities and results were shown that there is a highly significant correlation between the total flavan-3-ol content and antiradical efficiency (AE) (r=0.9168, P<0001).     

Identification of phenolics in Chinese toon and analysis of their content changes during storage

The tender leaves and sprouts of Chinese toon are considered to be a popular vegetable with a unique flavour. The phenolics of Chinese toon were separated and identified by HPLC–MS/MS. Gallic acid, its derivatives and quercetin-3-O-rhamnoside, were found to be the main phenolics in Chinese toon. The changes of the phenolics in Chinese toon during storage at 0, 5, 10 and 20 °C were also studied by HPLC. Results showed that, during storage, the contents of phenolics in Chinese toon first increased and then decreased as storage was prolonged.     

Classification of South African red and white wines according to grape variety based on the non-coloured phenolic content

The phenolic content of South African wines was investigated for the purpose of their classification according to variety or cultivar. Twenty-two phenolic compounds were quantified by liquid chromatography in 55 red wines of five varieties and in 38 white wines of three varieties. Data were compared to literature values reported for wines from across the globe. ANOVA was used to determine significant concentration differences between the different varieties. Further grouping of the data was investigated by principal component analysis and cluster analysis. Finally, linear discriminant analysis was used to derive classification functions for the effective recognition of red and white wine varieties which allowed 100.0% and 97.4% correct recognition of red and white wines, respectively.     

Conjugated linoleic acid content and isomer distribution during ripening in three varieties of cheeses protected with designation of origin

Cheeses have been identified as important sources of conjugated linoleic acid (CLA), a mixture of positional and geometric isomers with potential anticarcinogenic activity and other beneficial properties. The objectives of this study were to examine the effects of ripening on the overall CLA content as well as on the isomers profile using GC and Ag⁺-HPLC. Three Spanish cheeses Protected with Designation of Origin (Mahón, Manchego and Cabrales) were manufactured in different cheesemaking plants and monitored at different times during the ripening period. Total CLA content varied from 3 to 9 mg/g of total fatty acids and rumenic acid (9-cis, 11-trans C18:2, RA) represented more than 75% of total CLA. After RA, 7–9 (cis/trans plus trans/cis), 11-trans, 13-trans and 11-trans, 13-cis C18:2 were the main CLA isomers. The results achieved confirm that the effect of ripening on the total CLA concentration and isomer distribution was negligible.     

Pattern recognition of three Vitis vinifera L. red grapes varieties based on anthocyanin and flavonol profiles,with correlations between their biosynthesis pathways

The presence of anthocyanins and flavonols in three selected red grape varieties was investigated, in order to use their polyphenolic characterisation as a fingerprint. Berry skins of Gran Negro grapes were characterised by the presence of high content of malvidin- and peonidin-3-O-glucoside; Mouratón grapes, by the presence of high content of petunidin- and delphinidin-3-O-glucoside; and Brancellao grapes, by the presence of high content of cyanidin-3-O-glucoside. The main flavonols found included the 3-O-glucosides of quercetin, myricetin, kaempferol, laricitrin, isorhamnetin and syringetin. Using cluster analysis and principal components analysis, Gran Negro could be characterised by their content of isorhamnetin-3-O-glucoside and syringetin-3-O-glucoside and, along with Mouratón, by their myricetin conjugates. Flavonol profile could not provide a fingerprint of Brancellao variety. Stepwise discriminant analysis was performed in order to find the polyphenolic compounds, which characterised the selected grape varieties. Finally, anthocyanin and flavonol profiles in red grapes were compared and results confirmed that biosynthesis of flavonols is closely related to that of anthocyanins.     

Phenolic compounds in strawberry (Fragaria x ananassa Duch.) fruits: Composition in 27 cultivars and changes during ripening

Phenolic compounds in fruits of 27 cultivars of strawberry (Fragaria x ananassa Duch.) grown in Norway were characterised and quantified by HPLC-DAD-MSⁿ. Total phenolic content, calculated as the sum of the individual compounds, varied 2.3-fold among cultivars, i.e., from 57 to 133 mg/100 g of fw. There were significant differences among cultivars in concentration of all phenolic compounds. The highest variation between cultivars was found for cinnamoyl glucose (0.6-24.9 mg/100 g of fw). Concentration of anthocyanins, the most abundant class of phenolic compounds in the majority of the cultivars, varied from 8.5 to 65.9 mg/100 g of fw. Flavan-3-ols (11-45 mg/100 g of fw) and ellagitannins (7.7-18.2 mg/100 g of fw) contributed on average 28% and 14% to total phenolic contents in the strawberry cultivars, respectively. In three cultivars harvested at three stages of ripeness, anthocyanins and cinnamic acid conjugates were the compounds most affected by ripening. The anthocyanin profile for the individual cultivars was only slightly affected by ripening and growing conditions.     

Bound aroma compounds of Gual and Listán blanco grape varieties and their influence in the elaborated wines

Listán blanco and Gual are two white grape varieties grown in Spain (Canary Islands) and Gual is also grown in Portugal (Madeira Island). Wine quality could be improved by exploiting the varietal characteristics present in grapes as aroma precursors. At the present time, the enologic potential of these varieties has not yet been studied. Aroma precursors in musts and skins, and free volatiles in wines were determined in samples of both varieties. Aroma precursors of must and skins were isolated by absorption on XAD-2 resin and the aglycone liberated by means of acid hydrolysis. Free volatiles from wines and from aroma precursors were extracted with dichloromethane and then analysed by gas chromatography-mass spectrometry (GC–MS). Among the aroma precursors analysed, only α-terpineol, linalool and linalool oxides, 4-allyl-2,6-dimethoxyphenol, 2-methoxy-4-vinylphenol, 4-hydroxybenzaldehyde, vanillin and benzyl alcohol showed contents in grapes comparable to the levels observed in wine volatile compounds.     

Gut microbial catabolism of grape seed flavan-3-ols by human faecal microbiota. Targetted analysis of precursor compounds, intermediate metabolites and end-products

In vitro batch culture fermentations were conducted with grape seed polyphenols and human faecal microbiota, in order to monitor both changes in precursor flavan-3-ols and the formation of microbial-derived metabolites. By the application of UPLC-DAD-ESI-TQ MS, monomers, and dimeric and trimeric procyanidins were shown to be degraded during the first 10 h of fermentation, with notable inter-individual differences being observed between fermentations. This period (10 h) also coincided with the maximum formation of intermediate metabolites, such as 5-(3′,4′-dihydroxyphenyl)-γ-valerolactone and 4-hydroxy-5-(3′,4′-dihydroxyphenyl)-valeric acid, and of several phenolic acids, including 3-(3,4-dihydroxyphenyl)-propionic acid, 3,4-dihydroxyphenylacetic acid, 4-hydroxymandelic acid, and gallic acid (5-10 h maximum formation). Later phases of the incubations (10-48 h) were characterised by the appearance of mono- and non-hydroxylated forms of previous metabolites by dehydroxylation reactions. Of particular interest was the detection of γ-valerolactone, which was seen for the first time as a metabolite from the microbial catabolism of flavan-3-ols. Changes registered during fermentation were finally summarised by a principal component analysis (PCA). Results revealed that 5-(3′,4′-dihydroxyphenyl)-γ-valerolactone was a key metabolite in explaining inter-individual differences and delineating the rate and extent of the microbial catabolism of flavan-3-ols, which could finally affect absorption and bioactivity of these compounds.     

Anthocyanin content and antioxidant capacity in bran extracts of some Thai black rice varieties

This study investigated both the anthocyanin content and the antioxidant capacity of a set of genetically related glutinous and nonglutinous Thai black rice varieties. The ethanol/water extracts of the brans of these black rice varieties showed relatively potent antioxidant activities compared with those of tocopherol. These antioxidant activities were determined by thiocyanate, H₂O₂‐scavenging chemiluminescence (XYZ), Cu⁺⁺/bathocuproine colorimetry (PAO) and 1,1‐diphenyl‐2‐picrylhydrazyl radical‐scavenging assay. The structural identification and quantification of the black rice anthocyanins performed by high‐performance liquid chromatography coupled with electrospray ionisation and tandem mass spectrometry found cyanidin‐3‐O‐glucoside and peonidin‐3‐O‐glucoside as the major anthocyanins in the ranges of 16.01–34.40 and 2.43–7.36 μg mL^?1, respectively. The comparative study in terms of quantity of these phytochemicals and antioxidant capacity of the black rice bran extracts suggested the contribution of overall phenolic components rather than that of the particular anthocyanin pigments.     

Study of polyphenol content in the seeds of red grape (Vitis vinifera L.) varieties cultivated in Turkey and their antiradical activity

The polyphenolic content and antioxidant capacity in the seeds of 11 red grape varieties (five international and six native) widely cultivated in Turkey were investigated. Total phenolic, total flavanol and total polymeric procyanidin content ranged from 79.2 to 154.6, 89.2 to 179.4, and 27.0 to 43.3 mg/g seed, respectively. While (+)-catechin (4.71–23.8 mg/g seed) was found as main flavanol, galloylated catechin monomer and dimeric procyanidin amounts varied between 2.89–17.2 and 0.97–2.97 mg/g seed, respectively. All seed extracts showed remarkable DPPH radical scavenging activity (EC₅₀) and oxygen radical scavenging capacity (ORAC) ranging from 2.71 to 4.62 μg/mL and 1425.9 to 3009.2 μmol Trolox equivalent/g seed, respectively. With high amount of total phenolic content and antioxidant activity, seeds of Okuzgozu, Papaz Karasi, Ada Karasi and Kalecik Karasi varieties could be evaluated as dietary supplement.     

Carotenoid content and composition in rose hips (Rosa spp.) during ripening,determination of suitable maturity marker and implications for health promoting food products

Carotenoids are important antioxidants and valuable bioactive compounds contributing to the health benefits of different foods, and rose hips are known for high bioactive content. This study investigated the content of carotenoids and chlorophylls in hips from four rose species during the ripening period. Carotenoid content varied greatly between harvesting times, although species and year, and interactions between factors, also played an important role. Some carotenoids were identified only in hips of specific rose species. Some of the investigated compounds decreased (chlorophyll a) or increased (lycopene) consistently over the ripening period and could therefore be useful as maturity markers. An optimal content of total or specific carotenoids, e.g. for food products containing rose hips, might be obtained by proper choice of harvesting time and rose species.     

The interactive effects of irrigation,nitrogen fertilisation rate,delayed harvest and storage on the polyphenol content in red grape (Vitis vinifera) berries: A factorial experimental design

Polyphenol concentrations, including anthocyanidins, flavonols, flavan-3-ols and stilbenes, were quantified by liquid chromatography/mass spectrometry in two cultivars of red grapes for daily consumption, which were subjected to different kinds of water supply and nitrogen fertilisation rates. Samples from the same vineyards were also analysed after a 6 week storage in a refrigerator and 6 week delayed harvesting. Berry skins and seeds were analysed separately.     

Monitoring by LC-MS/MS of 48 compounds of sildenafil,tadalafil, vardenafil and their analogues in illicit health food products in the Korean market advertised as enhancing male sexual performance

More than 46 phosphodiesterase type 5 (PDE5) inhibitor analogues have been found to be present as illegal adulterants in various forms of health food products (powder, tablet, capsule, etc.), thereby placing the health of consumers at risk through product intake. In this study, 164 samples advertised to be effective at enhancing male sexual performance were collected over a 4-year period (2009–2012) from the Korean on-line or off-line market and screened. An LC-MS/MS method was employed to screen for the presence of 48 compounds including sildenafil, tadalafil, vardenafil and their analogues. Method validation established LOQs (0.30–10.00 ng ml^?1 or ng g^?1) and recoveries (spiked in liquid sample, 84–112%; spiked in solid sample, 83–110%). Most of the illicit products screened were adulterated with 14 of the PDE5 derivatives under examination, including considerable amounts of sildenafil and tadalafil; of the 48 compounds, tadalafil was the most frequent adulterant (42.6%), followed by sildenafil (27.9%). Specifically, tadalafil concentration ranges (mg g^?1) in the samples collected over the 4-year period were determined as follows: 2.91–52.20 (2009), 4.50–108.10 (2010), 0.37–101.40 (2011), and 0.08–138.69 mg g^?1 (2012). The concentration ranges (mg g^?1) of sildenafil were also at high levels: 4.90–117.96 (2009), 1.30–369.93 (2010), 0.03–241.77 (2011), and 18.34–297.91 mg g^?1 (2012). The results of screening for PDE5 inhibitor pharmaceuticals as adulterants in illicit health food products are of great significance with respect to the protection of public health and consumer safety.     

Thymus lotocephalus wild plants and in vitro cultures produce different profiles of phenolic compounds with antioxidant activity

We compared the phenolic metabolites and antioxidant activities of Thymus lotocephalus G. López & R. Morales wild plants and in vitro cultures using different extraction solvents. HPLC-DAD analysis allowed the identification and quantification of phenolic (caffeic and rosmarinic) acids and flavones (luteolin and apigenin) in extracts from both sources. The in vitro cultures accumulated large amounts of rosmarinic acid. However, extracts from both sources were able to neutralise free radicals in different test systems (TEAC and ORAC assays), to form complexes with Fe(2+) and to protect mouse brains against Fe(2+)-induced lipid peroxidation. The solvent significantly influenced the phenolic content and antioxidant activity of the extracts, water/ethanol being the most efficient for the extraction of antioxidant phytochemicals. We conclude that in vitro cultures of T. lotocephalus represent a promising alternative for the production of valuable natural antioxidants and an efficient tool for the in vitro biosynthesis of rosmarinic acid, therefore avoiding the need to exploit populations of wild plants.