Article

A method for anthocyanin extraction from fresh grape skin

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Tartaric and citric acid solutions were used to extract anthocyanins from fresh grape skins, in a non continuous process. The type of solvent and concentration were significant factors in the extraction operation, and tartaric acid was more efficient than citric acid in the extraction yield. Comparative trials were conducted using sulphur dioxide and acidified ethanol as solvents. The extraction yields using the optimal tar taric acid solution differed slightly from those obtained with acidified ethanol but were higher than those obtained with sulphur dioxide. Total amounts of polyphenols, proanthocyanidins and flavans were determined in the extracts obtained from the tartaric acid solutions. Solvent concentration was not a significant factor for flavan extraction yield but was highly significant for the extraction of the other compounds. The stability of the anthocyanins was evaluated at four different storage temperatures and atmospheric conditions. The combined effects of low pH of the extract (2.4), low temperature (2.0degreesC) and modified atmosphere (N-2) provided a long shelf-life. Based on the results, a 0.75% tartaric acid solution is recommended for anthocyanin extraction from fresh grape skin, and could substitute the widely used sulphur dioxide.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... Of these, methanol is not privileged by the food industry in order to prevent the toxicity of the final product. Similarly, SO 2 in water can present health risks even at low concentrations (Spagna et al., 2003). Compared to all solvents, anthocyanin extraction by ethanol is the most acceptable solvents for the food industry (Li et al., 2006). ...
Article
Full-text available
Aim: Anthocyanins are water soluble pigments mainly located in grape skin; however, these phenolic compounds are also located in vine leaves. The aim of this work was to identify, quantify and determine for the first time the anthocyanin composition in Grenache noir (Vitis vinifera) leaves. Methods and results: Five anthocyanins were identified and quantified in Grenache noir leaves by HPLC-UV-MS. Of these, cyanidin-3-O-glucoside and peonidin-3-O-glucoside were the main anthocyanins and represented 44 and 37%, respectively, while delphinidin-3-O-glucoside, petunidin-3-O-glucoside and malvidin-3-O-glucoside accounted for only 6, 5 and 8%, respectively. A multi-factorial design experiment was used to build a mathematical model to estimate the best extraction condition (highest anthocyanin extraction yield from leaf extract) for both SO 2 and ethanol in the aqueous extraction solvent. For SO 2 , the optimal extraction parameters were an extraction time ranging between 5.77 and 6 h, a temperature ranging between 20 and 23.7°C and a concentration of 500 ppm of SO 2 in the aqueous extraction solvent. Using the hydro-alcoholic extraction solvent, the optimal extraction parameters were an extraction time ranging between 3 and 4.37 h, a temperature set at 20°C and an ethanol concentration in the extraction solvent ranging between 32 and 40%. Conclusion: Only the five mono-glucoside anthocyanins usually detected in grapes have been detected, indentified and quantified in Grenache noir leaves by HPLC-UV-MS. Using a multi-factorial design experiment the optimum conditions for the extraction of these anthocyanins were obtained in hydro-alcoholic solution (i.e., extraction time ranging between 3 and 4.37 h, a temperature set at 20°C and an ethanol concentration ranging between 32 and 40%) and in water with SO 2 (i.e., extraction time ranging between 5.77 and 6 h, a temperature ranging between 20 and 23.7°C and a concentration of 500 ppm of SO 2 in water). Significance and impact of the study: Five anthocyanins were detected, identified and quantified in Grenache noir leaves by HPLC-UV-MS and the main anthocyanin were with cyanidin-3-O-glucoside and peonidin-3-O-glucoside. The optimum conditions for the extraction of these anthocyanins were estimated in hydro-alcoholic solution and in water solvent with SO 2 which will allow further investigation on these anthocyanins to be used as natural pigment for the food as well as for the pharmaceutical and cosmetic industry. Objectif : Les anthocyanes sont des pigments solubles dans l'eau qui sont principalement localisées dans la pellicule des raisins de Grenache noir, cependant ces composés phénoliques sont également présents dans les feuilles. Le but de ce travail a été d'identifier, quantifier et déterminer pour la première fois la composition des anthocyanes présentes dans les feuilles de Grenache noir (Vitis vinifera). Méthodes et résultats : Cinq anthocyanes ont été identifiées et quantifiées dans des feuilles de Grenache noir par HPLC-UV-MS. Parmi ces anthocyanes, la cyanidine-3-O-glucoside et la péonidine-3-O-glucoside étaient les anthocyanes majoritaires représentant respectivement 44 et 37%, alors que la delphinidine-3-O-glucoside, la pétunidine-3-O-glucoside et la malvidine-3-O-glucoside ne représentaient que 6, 5 et 8% respectivement. Le plan d'expérience multifactoriel a été utilisé pour construire un modèle mathématique permettant d'estimer le meilleur rendement d'extraction d'anthocyanes qui sera obtenu pour un temps d'extraction entre 5.77 et 6 h, une température comprise entre 20 et 23.7°C et une concentration de SO 2 dans l'eau de 500 ppm. En outre, une étude similaire en utilisant un solvant d'extraction hydro-alcoolique a révélé que les paramètres optimaux d'extraction des anthocyanes sont obtenus pour un temps d'extraction compris entre 3 et 4.37 h, une température fixée à 20°C et une concentration en éthanol dans le solvant d'extraction comprise entre 32 et 40%. Conclusion: Uniquement les 5 anthocyanes mono-glucoside généralement identifées dans le raisins ont été détectées, identifiées et quantifiées par HPLC-UV-MS dans des feuilles de Grenache noir. L'utilisation d'un plan d'expérience multifactoriel a permis de déterminer les conditions d'extraction optimum de ces anthocyanes en solution hydro-alcoolique (temps d'extration entre 3 et 4.37 h, une température de 20°C et concentration en éthanol entre 32 et 40%) une ainsi qu'en solution aqueuse contenant du SO 2 (temps d'extration entre 5.77 et 6 h, une température entre 20 et 23.7°C et concentration de SO 2 de 500 ppm dans l'eau). Signification et impact de l'étude: Les cinq anthocyanes détectées, identifiées et quantifiées dans des feuilles de Grenache noir sont les anthocyanes mono-glucosides généralement également présentes dans le raisin. Les conditions d'extraction optimum de ces anthocyanes ont été estimées en solution hydro-alcoolique ainsi qu'en solution aqueuse contenant du SO 2 ce qui va permettre d'étudier l'utilisation potentiel de ces anthocyanes comme colorant naturels alimentaires ou pour l'industrie pharmaceutique et cosmétique. Abstract Résumé manuscript received 16th
... Of these, methanol is not privileged by the food industry in order to prevent the toxicity of the final product. Similarly, SO 2 in water can present health risks even at low concentrations (Spagna et al., 2003). Compared to all solvents, anthocyanin extraction by ethanol is the most acceptable solvents for the food industry (Li et al., 2006). ...
Article
Full-text available
p style="text-align: justify;"> Aim : Anthocyanins are water soluble pigments mainly located in grape skin; however, these phenolic compounds are also located in vine leaves. The aim of this work was to identify, quantify and determine for the first time the anthocyanin composition in Grenache noir ( Vitis vinifera ) leaves. Methods and results : Five anthocyanins were identified and quantified in Grenache noir leaves by HPLC-UV-MS. Of these, cyanidin-3- O -glucoside and peonidin-3- O -glucoside were the main anthocyanins and represented 44 and 37%, respectively, while delphinidin-3- O -glucoside, petunidin-3- O -glucoside and malvidin-3- O -glucoside accounted for only 6, 5 and 8%, respectively. A multi-factorial design experiment was used to build a mathematical model to estimate the best extraction condition (highest anthocyanin extraction yield from leaf extract) for both SO<sub>2</sub> and ethanol in the aqueous extraction solvent. For SO<sub>2</sub>, the optimal extraction parameters were an extraction time ranging between 5.77 and 6 h, a temperature ranging between 20 and 23.7°C and a concentration of 500 ppm of SO<sub>2</sub> in the aqueous extraction solvent. Using the hydro-alcoholic extraction solvent, the optimal extraction parameters were an extraction time ranging between 3 and 4.37 h, a temperature set at 20°C and an ethanol concentration in the extraction solvent ranging between 32 and 40%. Conclusion : Only the five mono-glucoside anthocyanins usually detected in grapes have been detected, indentified and quantified in Grenache noir leaves by HPLC-UV-MS. Using a multi-factorial design experiment the optimum conditions for the extraction of these anthocyanins were obtained in hydro-alcoholic solution (i.e., extraction time ranging between 3 and 4.37 h, a temperature set at 20°C and an ethanol concentration ranging between 32 and 40%) and in water with SO<sub>2</sub> (i.e., extraction time ranging between 5.77 and 6 h, a temperature ranging between 20 and 23.7°C and a concentration of 500 ppm of SO<sub>2</sub> in water). Significance and impact of the study : Five anthocyanins were detected, identified and quantified in Grenache noir leaves by HPLC-UV-MS and the main anthocyanin were with cyanidin-3- O -glucoside and peonidin-3- O -glucoside. The</p
... Whole bunch fermentation (carbonic maceration) can also be used, but fruitier aroma compounds are extracted with this method than anthocyanins (Sacchi et al., 2005). Other methods that can be used are the addition of enzymes (Arnous & Meyer, 2009) and sulphur (Spagna et al., 2003) which will also promote the extraction of colour and tannins. ...
Article
Full-text available
ENGLISH ABSTRACT: Grape and wine phenols consist of flavanols which is the building blocks for tannins. These building blocks are called monomers which consist of catechins, epicatechins, epigallocatechins and epicatechin-gallate. Tannin is important in wine as it contributes to bitterness, mouth feel (astringency) and maturation potential of the wine. Futhermore it has a health benefit as an antioxidant. Anthocyanins are responsible for the colour of red wine. The anthocyanins combine with tannins to form stable polymeric pigments. Due to the importance of tannins and anthocyanins in wine, it is imperitative that different winemaking techniques are used to extract as much of these components as possible and that the analysis is done quickly and accurately. The aim of this study was to evaluate different winemaking techniques and their extraction of tannins and anthocyanins into the wine. Too much tannin extraction can have a negative effect on the sensory quality of the wine. Therefore a second aim was to evaluate the mouth feel properties of a Shiraz wine. A third aim was to compare the two tannin precipitation methods in terms of time efficiency, repeatability and the ease of practice. To investigate the amount of tannin concentration extracted by different winemaking techniques, two cultivars (Cabernet Sauvignon and Shiraz) were used. These treatments included the addition of an enzyme during fermentation [E], cold maceration [CM], post maceration [PM] and the combination of cold and post maceration [CM+PM]. The grapes were harvested in two different climatic areas during the 2008 and 2009 vintages. The two climatic areas were classified according to the Winkler scale as a III (Morgenster) and a IV (Plaisir de Merle). The grapes were harvested at two different ripeness levels in order to evaluate the effect of the different winemaking processes on the extraction of tannins and anthocyanins. One harvest was before (LB) and the other after (HB) the commercial harvest. The results of this study showed significant differences in the phenolic composition of the wines. It was found that the warmer area showed higher tannin concentrations than the cooler area for both cultivars. In the 2008 Cabernet Sauvignon the CM extracted higher concentrations of tannin from the cooler area at both ripeness levels. In the warmer area, CM extracted the highest tannin concentration HB, but the CM+PM extracted the highest tannin concentration from Cabernet Sauvignon at the LB and CM at the HB of the warmer area. In 2009 the PM extracted the highest concentration of tannin at the lower ripeness level, while the E treatment extracted the highest concentration from the warmer area. In the cooler area the CM+PM extracted the highest concentration of tannin at a lower ripeness level, while there were no siginicant differences between the different treatments at the higher ripeness level. The highest anthocyanin concentration was found in the cooler area. The CM treatment was found to have no effect on anthocyanin extraction. Different methods are available to quantify the tannin concentration in wine. Two of the most popular tannin analytical methods are the bovine serum albumin (BSA) and the methyl cellulose precipitable tannin (MCP) methods. The BSA method is a very complex method which uses at least 3 times more reagents than the MCP method. The MCP method only analyzes tannins, while the BSA method analyzes tannins, monomeric pigments (MP), small polymeric pigments (SPP) and large polymeric pigments (LPP). In this study a good correlation was found between the two tannin precipitation methods (R2 – 0.88). There is controversy regarding the variability of these methods. Some scientists found that the two methods show a good correlation with HPLC, while others found that there was no such correlation between the precipitation methods and the HPLC. The MCP method had a practical advantage as it could be performed in half the time required for the BSA method. This has a significant impact in scenarios where a high sample throughput is required although it only measures total tannin. The phenolic composition and mouth feel of the wine was strongly influenced by the climatic area. In the warmer area the effect of tannin concentration on mouth feel was much less than in the cooler area. The wine made of riper grapes, was more grippy, bitter and numbing than the wines made from greener grapes. The E treatment was especially associated with a dry, grippy sensation. AFRIKAANSE OPSOMMING: Druif en wyn fenole bestaan uit flavanole wat weer die boublokke is van tanniene. Hierdie boublokke, wat bekend staan as monomere, betsaan uit katesjiene, epikatesjiene, epigallokatesjiene an epikatesjien-gallaat. Tanniene is belangrik in wyn aangesien dit bydra tot bitterheid, mondgevoel (vrankheid) asook die verouderingspotensiaal van wyn. As antioksidante hou dit ook gesondheidsvoordele in. Antosianiene dra by tot die kleur van rooiwyn. Antosianiene kombineer met tanniene om meer stabiele polimeriese pigmente te vorm. As gevolg van die belangrikheid van tanniene en antosianiene is dit van uiterse belang dat verskillende wynmaak tegnieke gebruik word om ekstraksie in die wyn te bevoordeel en dat die analitiese metode so vinnig en akkuraat as moontlik gedoen word. Die eerste doel van hierdie studie was om die ekstraksie van tanniene en antosianiene deur middel van verskillende wynmaak tegnieke te evalueer. Te veel tanniene in die wyn kan negatiewe sensoriese kwaliteit tot gevolg het. Daarom is die tweede doel om die sensoriese kwaliteit van Shiraz wyn te evalueer. Die derde doel van hierdie studie was die twee tannien presipitasie metodes met mekaar te vergelyk in terme van die moeilikheidsgraad van die metode, tyd doeltreffendheid en herhaalbaarheid. Verskillende wynmaak tegnieke (ensiem byvoegings [E], koue maserasie [CM], verlengde dopkontak [PM] en ‘n kombinasie van koue maserasie en verlengde dopkontak [CM+PM]) is vergelyk ten opsigte van tannien en antiosianien ekstraksie. In 2008 en 2009 is twee kultivars (Cabernet Sauvignon en Shiraz) in twee verskillende klimatologiese areas gepars. Hierdie areas is geklassifiseer in die Winklerskaal as ‘n IV (Plaisir de Merle) en ‘n III (Morgenster). Om die effek van die verskillende wynmaak tegnieke op die ekstraksie van antosianiene en tanniene te vergelyk, is hierdie twee kultivars by twee verskillende rypheidsgrade geoes. Die eerste oes was net voor kommersiële oes (LB) en die tweede oes het net na kommersiële oes (HB) plaasgevind. Die 2009 Shiraz wyn is organolepties beoordeel om die effek van die verskillende wynmaak tegnieke op die wyn se mondgevoel te vergelyk. Die resultate van hierdie studie toon beduidende verskille in die fenoliese samestelling van die wyne. Dit is gevind dat die warmer area hoër tannien konsentrasies het as die koeler area. In 2008 het die CM+PM die meeste tanniene uit die Cabernet Sauvignon geëkstraheer by LB en die CM by HB in die warmer area. Die CM het in die koeler area meer tanniene geëkstraheer by beide die LB en HB rypheidsgrade. In 2009 het PM die meeste tanniene geëkstraheer by LB terwyl E die meeste tanniene geëkstraheer in die warmer area. In die koeler area het CM+PM die meeste tanniene geëkstraheer, terwyl geen van die behandelings ‘n effek gehad het by HB. Die meeste antosianien konsentrasie was in die koeler area gevind as in die warmer area. In beide 2008 (LB en HB) en 2009 (LB) het CM die meeste antosianiene geëkstraheer, terwyl geen behandeling ‘n effek gehad het by HB. Twee van die mees populêre tannien analitiese metodes is die BSA (bovine serum albumien) en die MCP (metielsellulose presipitasie) metodes. Die BSA metode is ‘n baie meer ingewikkelde metode waarvoor drie keer meer reagense gebruik word as vir die MCP metode. Maar waar die MCP net tanniene ontleed, ontleed die BSA metode tanniene, monomere (MP), klein polimeriese pigmente (SPP) en groot polimeriese pigmente (LPP). Dit help indien daar gekyk wil word na die evolusie van polimeriese pigmente. In hierdie studie is bevind dat daar ‘n redelike korrelasie (R2 – 0.88) tussen die BSA en MCP metode bestaan. Die herhaalbaarheid van die metodes het redelike kontroversie veroorsaak, waar sommige navorsers bevind het dat die BSA metode nie so herhaalbaar is soos eers bevind is nie. Die MCP metode het ’n praktiese voordeel aangesien dit in die helfde van die tyd van die BSA metode uitgevoer kan word. Dit het ‘n groot impak indien ‘n groot hoeveelheid monsters ontleed moet word. Die fenoliese samestelling en mondgevoel word sterk beïnvloed deur die klimatologiese area. In die warmer area was die effek van tannien konsentrasie op mondgevoel kleiner as in die koeler area. Die wyn van ryper druiwe het meer harder, verdowingseffek en bitter nasmaak gehad as by die wyn van groener druiwe. Die ensiem behandeling was meer geassossieerd met droë mond gevoel. Thesis (MScAgric (Viticulture and Oenology))--University of Stellenbosch, 2011. Includes bibliography.
... Even higher polyphenols yields have been reported for grape seed, up to 5.2-6.6 g/100 g of solid (Hong et al., 2001), but we must note here that seeds are the richest part in polyphenols and the extraction was aided by microwaves. There is abundant literature supporting the observation that the TP extracted can vary largely as function of the material, polarity of the solvent, extraction conditions or particle size (Shi et al., 2003;Spagna et al., 2003). Otherwise, the polyphenols extracted from grape pomace var. ...
Article
Both ethanolic and aqueous extraction were carried out in a laboratory-scale vertical extractor to obtain polyphenols from distilled grape pomace of Vitis vinifera var. "Albariño". An experimental design was performed to analyse the effects of flow (2 ml/min and 4 ml/min) and temperature (40 degrees C and 50 degrees C). Yields of polyphenolics from aqueous extraction were much higher (up to 30-fold) than those of ethanolic extraction, in contrast with previous results obtained by us from batch extraction of different grape varieties. Polyphenols extraction was modelled by application of second Fick's law to spherical particles of 0.5 mm diameter, so obtaining the effective diffusion coefficient as parameter. The mass transfer coefficients were also estimated, giving as result that the external mass transfer resistance was negligible. Correlation coefficients ranged 0.989-0.9999. Effective diffusivity values in water extraction assays were between 0.6x10(-11) m(2)/s and 2.1x10(-11) m(2)/s. Using ethanol as solvent, the effective diffusivity was lower, between 0.1x10(-11) m(2)/s and 0.76x10(-11) m(2)/s.
... From the results discussed so far it can be observed that the degree of extraction was the highest in case of acetone followed by 1% (v/v) HCl in methanol and then by acidified ethanol (50%, v/v ethanol). As already mentioned, use of acetone and methanol for food applications was not preferable (Spagna et al., 2003;Patil et al., 2009). Among all these extraction media, ethanol is the most acceptable one for use in food industry. ...
Article
There is an increasing interest in anthocyanins, as natural food colorants, in food products and also in pharmaceutical products due to their antioxidative potential. The present study deals with extraction and purification of anthocyanins from red cabbage. Conventional extraction methods of anthocyanin from plant material are non-selective and yield pigment solutions with large amounts of byproducts such as sugars, organic acids and proteins. Some of these impurities may accelerate anthocyanin degradation. Different extracting media were used and the mixture of 50% (v/v) ethanol and acidified water resulted in maximum anthocyanin content (390.6 mg/L). In order to obtain anthocyanins in a purified form, adsorption was carried out with six different adsorbents. Among these, non-ionic acrylic ester adsorbent, namely Amberlite XAD-7HP, showed the highest adsorption capacity (0.84 mg/mL of resin) and desorption ratio (92.85%). Adsorption results were found to be correlated best using the Langmuir isotherm equation especially at low temperature. The resulting anthocyanin solution after purification was free from sugars, which are the major cause for degradation of anthocyanin. No browning was observed and chroma increased by 27% compared to crude anthocyanin.
... Of these, methanol is not privileged by the food industry in order to prevent the toxicity of the final product. Similarly, SO 2 in water can present health risks even at low concentrations (Spagna et al., 2003). Compared to all solvents, anthocyanin extraction by ethanol is the most acceptable solvents for the food industry (Li et al., 2006). ...
Article
Aim: Anthocyanins are water soluble pigments mainly located in grape skin; however, these phenolic compounds are also located in vine leaves. The aim of this work was to identify, quantify and determine for the first time the anthocyanin composition in Grenache noir (Vitis vinifera) leaves. Methods and results: Five anthocyanins were identified and quantified in Grenache noir leaves by HPLC-UV-MS. Of these, cyanidin-3-O-glucoside and peonidin-3-O-glucoside were the main anthocyanins and represented 44 and 37%, respectively, while delphinidin-3-O-glucoside, petunidin-3-O-glucoside and malvidin-3-O-glucoside accounted for only 6, 5 and 8%, respectively. A multi-factorial design experiment was used to build a mathematical model to estimate the best extraction condition (highest anthocyanin extraction yield from leaf extract) for both SO 2 and ethanol in the aqueous extraction solvent. For SO 2 , the optimal extraction parameters were an extraction time ranging between 5.77 and 6 h, a temperature ranging between 20 and 23.7°C and a concentration of 500 ppm of SO 2 in the aqueous extraction solvent. Using the hydro-alcoholic extraction solvent, the optimal extraction parameters were an extraction time ranging between 3 and 4.37 h, a temperature set at 20°C and an ethanol concentration in the extraction solvent ranging between 32 and 40%. Conclusion: Only the five mono-glucoside anthocyanins usually detected in grapes have been detected, indentified and quantified in Grenache noir leaves by HPLC-UV-MS. Using a multi-factorial design experiment the optimum conditions for the extraction of these anthocyanins were obtained in hydro-alcoholic solution (i.e., extraction time ranging between 3 and 4.37 h, a temperature set at 20°C and an ethanol concentration ranging between 32 and 40%) and in water with SO 2 (i.e., extraction time ranging between 5.77 and 6 h, a temperature ranging between 20 and 23.7°C and a concentration of 500 ppm of SO 2 in water). Significance and impact of the study: Five anthocyanins were detected, identified and quantified in Grenache noir leaves by HPLC-UV-MS and the main anthocyanin were with cyanidin-3-O-glucoside and peonidin-3-O-glucoside. The optimum conditions for the extraction of these anthocyanins were estimated in hydro-alcoholic solution and in water solvent with SO 2 which will allow further investigation on these anthocyanins to be used as natural pigment for the food as well as for the pharmaceutical and cosmetic industry. Objectif : Les anthocyanes sont des pigments solubles dans l'eau qui sont principalement localisées dans la pellicule des raisins de Grenache noir, cependant ces composés phénoliques sont également présents dans les feuilles. Le but de ce travail a été d'identifier, quantifier et déterminer pour la première fois la composition des anthocyanes présentes dans les feuilles de Grenache noir (Vitis vinifera). Méthodes et résultats : Cinq anthocyanes ont été identifiées et quantifiées dans des feuilles de Grenache noir par HPLC-UV-MS. Parmi ces anthocyanes, la cyanidine-3-O-glucoside et la péonidine-3-O-glucoside étaient les anthocyanes majoritaires représentant respectivement 44 et 37%, alors que la delphinidine-3-O-glucoside, la pétunidine-3-O-glucoside et la malvidine-3-O-glucoside ne représentaient que 6, 5 et 8% respectivement. Le plan d'expérience multifactoriel a été utilisé pour construire un modèle mathématique permettant d'estimer le meilleur rendement d'extraction d'anthocyanes qui sera obtenu pour un temps d'extraction entre 5.77 et 6 h, une température comprise entre 20 et 23.7°C et une concentration de SO 2 dans l'eau de 500 ppm. En outre, une étude similaire en utilisant un solvant d'extraction hydro-alcoolique a révélé que les paramètres optimaux d'extraction des anthocyanes sont obtenus pour un temps d'extraction compris entre 3 et 4.37 h, une température fixée à 20°C et une concentration en éthanol dans le solvant d'extraction comprise entre 32 et 40%. Conclusion: Uniquement les 5 anthocyanes mono-glucoside généralement identifées dans le raisins ont été détectées, identifiées et quantifiées par HPLC-UV-MS dans des feuilles de Grenache noir. L'utilisation d'un plan d'expérience multifactoriel a permis de déterminer les conditions d'extraction optimum de ces anthocyanes en solution hydro-alcoolique (temps d'extration entre 3 et 4.37 h, une température de 20°C et concentration en éthanol entre 32 et 40%) une ainsi qu'en solution aqueuse contenant du SO 2 (temps d'extration entre 5.77 et 6 h, une température entre 20 et 23.7°C et concentration de SO 2 de 500 ppm dans l'eau). Signification et impact de l'étude: Les cinq anthocyanes détectées, identifiées et quantifiées dans des feuilles de Grenache noir sont les anthocyanes mono-glucosides généralement également présentes dans le raisin. Les conditions d'extraction optimum de ces anthocyanes ont été estimées en solution hydro-alcoolique ainsi qu'en solution aqueuse contenant du SO 2 ce qui va permettre d'étudier l'utilisation potentiel de ces anthocyanes comme colorant naturels alimentaires ou pour l'industrie pharmaceutique et cosmétique. Abstract Résumé manuscript received 16th
... The total soluble solids value of anthocyanin extracted by this method was 15°B at low pH the stability of the anthocyanin was high. The high amount of anthocyanin recovery could be due to the low pH of the solution, which enhanced anthocyanin extraction (Spagna et al.,2003). Effect of inlet air temperature, wall material and the anthocyanin concentration of spray dried extract on the moisture content of the microencapsulated grape skin anthocyanin powder obtained is presented in Table 3. 1. ...
Conference Paper
Full-text available
Coconut (Cocos nucifera L.) is one of the major commercial crops in south India, which is giving many useful products to the mankind. Among them, Virgin Coconut Oil (VCO) is produced from ball copra and fresh coconuts. VCO differs from commercial coconut oil in the way it was processed. In wet processing, natural fermentation was well known for its traditional and industrial outlook which was carried out by the microbes present in the natural environment, produced VCO. It leads to the production of poor quality coconut oil (usually yellow in color, rancid smell). To overcome this problem, VCO was produced by induced fermentation method where certain species of probiotic microorganisms were used. Induced fermentation process was conducted systematically in computer controlled bioreactor and succeeded to produce VCO without any contamination. Quality control parameters for both VCO produced in natural fermentation and induced fermentations were studied and compared with the standards given by APCC (Asian pacific Coconut Community). All parameters were in agreement with APCC standards except Moisture content and microbial number.
... The use of acetone and methanol is not preferred in the food industry because of their potential toxicity (Spagna et al. 2003;Patil et al. 2009); rather, ethanol is the preferred solvent. It has been suggested that pure ethanol should not be used for the extraction of pigments as some amount of water is needed to extract the hydrophilic pigment (Patil et al. 2009). ...
Article
Full-text available
Natural colorants are important alternatives to synthetic colorants. They are considered harmless and positively affect biological activities owing to their antioxidant potential. The present study deals with the assessment of the extraction processes and the effects of pH (1.0, 3.0, and 5.0), extraction media (water and 50% ethanol) and storage condition (ambient and refrigeration) on betacyanin content, color values, as well as degradation kinetics of total betacyanins in red amaranth. Betacyanin content was more stable at higher than at lower pH. The degradation rate constant (K) was higher and the half-life (t1/2) was lower at ambient temperature compared to refrigeration temperature. Betacyanin degradation was higher at ambient temperature (30 ± 2 °C) than at refrigeration temperature (4 °C). The pH, storage time, and temperature affected the stability of the color attributes. Therefore, this work suggests that water and lower temperature (4 °C) could be applied to extract more betacyanins from red amaranth and betacyanins might be used as an alternative to synthetic color.
... The winemaking industry generates a substantial volume of by-products, which can be recovered as organic fertilizers (Ferrer et al., 2001), substrates for fermentation for biomass production (Fiori, Valbusa, & Castello, 2012) and sources of value-added compounds that can be used as functional food ingredients (Spagna, Barbagallo, Todaro, Durante, & Pifferi, 2003;Teixeira et al., 2014). So-called ''nutraceuticals" are used as additives or ingredients in foods due to their ability to provide advanced technological properties and health claims, respectively, to the final product (Galanakis, 2015). ...
Article
Highly soluble maltodextrin-encapsulated grape skin phenolics comprising anthocyanins and less hydrophilic flavonoids were added as an ingredient to apple puree. Upon formulation, heat treatments were applied to achieve 3-14 decimal reductions (D) of the target microorganism (Alicyclobacillus acidoterrestris). A storage study was performed at 15-35°C for 1 month. Monomeric anthocyanins were retained at 100% after the 3 D treatment, while anthocyanin retention decreased to 72% with increasing heating intensity until 14 D. During storage, the concentration of monomeric anthocyanins decreased following first-order kinetics (k25°C = 34.4 d-1, activation energy = 51.0 kJ/mol). The flavanols were more stable than the monomeric anthocyanins. The hydroxycinnamic acid, dihydrochalcone and flavonol contents did not change. The fortified puree had a two-fold higher reducing capacity with respect to apple puree. Overall, this ingredient could meet the industrial demand for sustainable colouring agents and health promoting compounds.
... Whole bunches may also be fermented (carbonic maceration) thus producing fruity wines, with less tannins (Sacchi et al., 2005). Other methods are also available such as the addition of enzymes (Arnous & Meyer, 2009) and sulphur (Spagna et al., 2003). ...
... Researchers found that the degree of extraction of anthocyanin was the highest in the case of acetone followed by acidified methanol and acidified ethanol (Chandrasekhar et al., 2012). However, scientists also found that the use of acetone and methanol in the food industry is not preferable because of their possible toxicity (Spagna et al., 2003;Patil et al., 2009). Ethanol is the most acceptable one for use in food industry (Patil et al., 2009;Bridgers et al., 2010;Truong et al., 2010;Lu et al., 2011;Chandrasekhar et al., 2012;Truong et al., 2012;Burgos et al., 2013;Kang et al., 2013). ...
Article
Full-text available
Banana (Musa balbisiana) bracts were investigated as a potential source of natural colorant. In this study, the total anthocyanin from selected banana bracts was extracted with ethanol solutions and characterized by UV-visible spectrophotometry and their content was found 224.41 ± 1.91 mg/kg, which was highest at 40% solvent concentration with pH 4. Moreover, the color characteristics were varied with the variation of solvent concentration and pH. Similarly, the values of chroma and hue angle were also investigated and the value of chroma was higher at pH 4 in all different concentrations. The results revealed that the color of anthocyanin was decreased due to increase of pH. The value of hue angle was in the range of (73.69±0.33) to (-71.14±1.39), which indicated the color from yellow to magenta, and this is the natural color of anthocyanin. Therefore, banana bracts can be used as a potential source of extracting natural colorant instead of synthetic dyes in different food industries.
Article
Full-text available
Further developments in artichoke cultivation in south Italy could be achieved by extending the use of new genotypes which might broaden and better organize the harvest period of heads and differentiate the quality of the product. During the harvest period weather conditions change and could influence the quality characteristics of heads. This research aimed at studying the effects of location, harvest period and genotype on some quality characteristics of heads. A field experiment was carried out including two typical locations for globe artichoke cultivation in Sicily, three harvest periods (December, February and April) and three genotypes ('Violetto di Sicilia', 'Violet de Provence' and 'Tema 2000'). Head quality characteristics were affected by location, harvest period and genotype. Heads from Caltagirone compared to heads from Ramacca showed higher fresh weight (+8%), incidence of receptacle on whole head (+4%) and bracts anthocyanin content (+24%) but lower L/D ratio (-9%) (shorter shape), dry matter content of head (-8%) and of receptacle (-7%). Heads harvested in December showed the highest fresh weight and incidence of receptacle on whole head, whereas heads harvested in February showed the highest head thickness, lightness and colour intensity, bracts anthocyanin content, dry matter content of head and of receptacle. Heads of 'Violet de Provence' and 'Tema 2000' showed in comparison to 'Violetto di Sicilia' lower L/D ratio (on average -6%), lightness (L*) (on average -19%), chroma (C*) (on average -28%), and dry matter content of head (on average -11%.) and of receptacle (on average -16%), but higher fresh weight (on average +16%) and bracts anthocyanin content (on average +108%).
Article
Herein, the phenolic composition and colour attributes of red grapes extracts (obtained with a fast methodology) were correlated with those of their corresponding wines to predict the final quality properties of wines. The phenolic parameters were evaluated as total phenolic compounds (TPC), total anthocyanins (TA) and total condensed tannins (TCT), whereas the chromatic parameters were evaluated as colour intensity (CI), tonality (To), and the percentages of yellow, red and blue tones. All of them were determined by usual UV–Vis spectrophotometric methods. To get robust models, grapes of five red varieties were collected at three different ripening stages throughout the 2009 vintage. Good correlations between the results from grapes and wines were obtained, showing high regression coefficients and low prediction errors for TPC (R 2 = 0.929, RMSE = 5.99%), TA (R 2 = 0.953, RMSE = 7.23%) and CI (R 2 = 0.954, RMSE = 7.58), concluding that these wine phenolic properties can be predicted reliably from the extracts obtained with an optimised fast extraction method from grapes on the ripening controls along the maturity process.
Data
Full-text available
a b s t r a c t Eggplant is one of most common vegetables consumed all around the world. This study has assayed antioxidants from the byproduct (peel) of eggplant (Solanum melongena), using three extraction solvents: 70% methanol, 70% ethanol and 70% acetone. For each solvent, content of total phenolics, flavonoids, tan-nins, and total anthocyanins were quantified. Antioxidant activity of different extracts were screened using the ferric reducing power, 1,1-diphenyl-2-picryl hydrazyl (DPPH •) radical scavenging, hydrogen peroxide (H 2 O 2) scavenging and metal chelating activities. The results showed that 70% methanol is the best solvent for the extraction of anthocyanins (82.83 ± 1.07 mg DGE/100 g DP), whereas, 70% ace-tone is the best solvent for the extraction of total phenolics, flavonoids and tannins (29.3 ± 1.23 mg GAE/100 g DE; 18.5 ± 0.07 mg QE/100 g DE and 5.37 ± 0.22 mg TAE/100 g DE, respectively). Anthocyanic extracts have exhibited the higher reducing power (39 ± 2.5 mg QE/100 g DE) and scavenging activity (IC 50 = 2.88 ± 0.02 mg/mL), whereas the phenolic extracts have shown the highest metal chelating activity (18.53 ± 0.4%).
Article
The extraction procedure is of great importance for the extraction of natural colorants. In the present study, an alternate process is reported for anthocyanin from the peels of red radish (Raphanus sativus L.). Different extracting mediums are used and the mixture of 50% ethanol and acidified water resulted in maximum anthocyanin content (37.26 mg/100 ml) with better chroma (69.03) and hue angle (44.54). Membrane pertraction is used for the first time to dealcoholize and concentrate the anthocyanin extract (from 37.26 mg/100 ml to 62.58 mg/100 ml). The extract is further concentrated using osmotic membrane distillation (485 mg/100 ml) at ambient temperature and atmospheric pressure.
Article
Full-text available
Tartaric and malic acid solutions were tested to extract anthocyanins from eggplant peel by a discontinuous process to obtain a natural red colorant. Extraction optimization was carried out, using different solvents, acid concentration, temperature, time of extraction and solvent-to-solid ratio as independent variables. Tartaric acid was more efficient than malic acid in both extraction yield and rate. Comparative tests were carried out using acidified ethanol as solvent. Delphinidin-3-rutinoside was extracted and identified as the major anthocyanin in eggplant peel. Concentration of different extracts from eggplant peel was carried out using EXA-31, a methacrylic food grade resin, the best performing resin to obtain highly concentrated extracts.
Article
Pomace from different grape varieties was studied with regard to the content of extractable anthocyanins. Total anthocyanin concentrations of 24.5-126 mg dm(-3) were found in the extracts. The amount of extractable pigment was dependent on the variety of grape. The extracts were applied in textile dyeing operations using cotton fabric pre-mordanted with tannin as textile substrate. Red/violet shades were obtained that showed good water-fastness; however, limited light-fastness indicated need for improvement to fulfil requirements for textile application. Colour measurement by means of CIE-Lab coordinates and Kubelka-Munk value showed a direct correlation between extractable anthocyanin concentration and colour depth of the dyed material. Thus the analytically determined concentration of anthocyanins in the aqueous extract can serve as a measure of quality of grape pomace as raw material for textile dyeing application. Copyright © 2007 Society of Chemical Industry.
Article
Because there is not a single method for carrying out phenolic ripening analysis, it is very difficult to compare the results obtained by different researchers. In this study, the three most widely used extraction methods of polyphenols (Glories, AWRI, and ITV) have been analytically compared by evaluating two of the most important parameters for the wine industry: total polyphenols and total anthocyanins. Samples from different grape varieties (Tempranillo, Garnacha, Carinena, Syrah, Merlot, and Cabernet Sauvignon), from three different vintages (2006, 2007, and 2008), and at different ripening states (from the beginning of ripeness until harvest) were analyzed to obtain a wide range of representative phenolic contents. To avoid external interferences on the comparisons, the same grape puree was used to make the maceration assays using the different solvents according to each extraction method. Although every extraction method exhibits a different extraction efficiency, the correlation between the results obtained with each one was very good both for total anthocyanins and for total polyphenols. Thus, after having determined a parameter value of the phenolic ripeness using a specific method, the relationship found can be used to predict the parameter value of the phenolic ripeness provided by the other two methods.
Article
Eggplant (Solanum melongena L.) fruit of six Japanese cultivars and eight cultivars/lines from Bangladesh were covered with a dark, cloth, 3-5 or 10-20 days after anthesis, depending on the cultivar and kept covered until harvest. The purpose of the experiment was to study the effect of darkening on the production of anthocyanins in the skin. The composition of the anthocyanin was determined for the 14 cultivars. The fruit color of all Japanese cultivars and 'Shinghnath' is purplish black, whereas those of 'KL purple' and 'Bork' is dark reddish purple; that of 'Uttara' is moderately reddish purple. The fruits of 'SL 28', 'SL 32', and 'SL 50' have a yellowish green stripe on green and partly red purple, whereas that of 'SL 65' is yellowish green and partly red purple. The major anthocyanin in fruit skin of all the cultivars/lines, except 'Wase-Beikokuoomaru', was identified as delphinidin 3-pcoumarylrhamnosylglucoside -5-glucoside(Nasunin); the ratio of this anthocyanin to the total ranged from 69.1 to 87.7% in these cultivars/line. The major anthocyanin of 'Wase-Beikokuoomaru', delphinidin 3-glucosylrhamnoside, made up 79.5% of the total. The fruit color of 'Wase-Beikokuoomaru' changed into dark purplish red in the dark, however, the anthocyanin component was the same as that of control treatment. The fruit color of 'Senryou-2gou', 'Syoyaoonaga', 'Borka' changed into yellowish white and partly moderate reddish purple, and that of 'SL 50' changed into yellowish white and partly pale yellowish pink in the dark but the percentage of major anthocyanin in fruit skin of these four cultivars/line remained unchanged. In the other seven cultivars/lines; 'Kurumenaga', 'Toochi', 'Miyukisennari', 'KL purple', 'SL 28', 'SL 32', and 'SL 65', the epidermal cells failed to produce anthocyanin in the dark.
Article
Freezing point depression and some physical characteristics of Vitis vinifera grapes var. Ancellotta were investigated after two different post-harvest treatments of samples (slow air-freezing at −18°C and storage at 2°C in N2 atmosphere). The measured acinus mean weight and diameter, relative weight composition of a cluster and total soluble solids content differed slightly from those of fresh grapes. The observed freezing point depression values for treated grapes and grape juice were smaller than the respective calculated data. The differences were characterized by alteration in soluble solids composition due to the treatments, which decreased solute-solvent interactions.
Article
The phenolic antioxidant phytochemicals in wines have been implicated for the lower rates of cardiac disease mortality among people drinking wine regularly in certain European populations. The activities of 20 selected California wines in inhibiting the copper-catalyzed oxidation of human low-density lipoproteins (LDL) were determined. This antioxidant activity was related to the major phenolic compounds and not to resveratrol analyzed in wines by HPLC and GC-MS. The relative inhibition of LDL oxidation varied from 46 to 100% with the red wines and from 3 to 6% with the white wines. When compared at the same total phenol concentration, the inhibition of LDL oxidation varied from 37 to 65% with the red wines and from 27 to 46% with the white wines. The relative antioxidant activity correlated with total phenol contents of wines (r = 0.94) and with the concentrations of gallic acid (r = 0.92), catechin (r = 0.76), myricetin (r = 0.70), quercetin (r = 0.68), caffeic acid (r = 0.63), rutin (r = 0.50), epicatechin (r = 0.45), cyanidin (r = 0.43), and malvidin 3-glucoside (r = 0.38). Therefore, the activity of wines to protect LDL from oxidation appeared to be distributed widely among the principal phenolic compounds.
Article
In 15 young Beaujolais red wines from the 1974 and 1975 vintages statistically significant linear correlations were found between overall quality and the contents of total pigments, total anthocyanins, coloured anthocyanins and tasters' mean colour scores; and also between flavour and the contents of total pigments and total anthocyanins. In 1974 additional significant correlations were found between (a) overall quality and wine colour density; non-coloured anthocyanins and pH, (b) flavour and colour scores and coloured anthocyanins, (c) aroma and total pigments, total anthocyanins, coloured and non-coloured anthocyanins and pH and (d) the chemical parameters of pH and total pigments and total anthocyanins. In 1975 flavour was correlated also with non-coloured anthocyanins and pH. The results demonstrate the desirable effects of anthocyanins on wine flavour and quality, whereas the polymeric pigments formed on ageing of Beaujolais appear to be indifferent features of quality. Thus, the negative correlations found between quality factors and wine ‚chemical age’ tend to support the opinion that most Beaujolais should be drunk young. Comparison of the results with data on Australian and Swiss red wines suggests that sulphur dioxide affects not only quality itself but also the nature of the quality correlation found. Simple colour measurement of acidified wine provides a useful indication of quality in young red wines of the same grape cultivar and age, having minimal sulphur dioxide content.
Article
This paper reviews the literature on the occurrence of anthocyanins in foods and their transformation during processing, including the formation of adducts and derived tannins. Data describing the safety of anthocyanins and possible dietary effects are examined. Attention is drawn to some misquotations in the literature and to some serious gaps in our knowledge, in particular, the lack of pharmacokinetic data in humans essential to an understanding of associated biological effects.© 2000 Society of Chemical Industry
Article
Extraction of anthocyanins from black currants using aqueous ethanol was optimized for yield and antioxidant activity. The process variable having the most effect on the extraction was the solvent to solid ratio, which increased phenolic extraction in the whole range from 0 to 19 L/kg. Total phenolics increased with ethanol concentration up to a maximum at about 60% and then decreased with further increase in solvent concentration irrespective of the solvent to solid ratio. Temperature only affected the extraction of anthocyanins. Increasing the temperature beyond 30 to 35 °C resulted in degradation of anthocyanins and reduction of yields. Variation in extract composition was not sufficiently large to affect antioxidant activity.
Article
The present study was aimed at evaluating the in vitro antioxidant activity and in vivo photoprotective activity of an extract of wine obtained from Jacquez (Vitis aestivalis-cinerea × V vinifera) grapes (JW-E). The chemical profile of the JW-E was characterised by a significant level of proanthocyanidins, together with lower amounts of anthocyanins and hydroxycinnamic acids. The antioxidant activity of the JW-E was assessed by means of various in vitro tests (bleaching of the stable 1,1-diphenyl-2-picrylhydrazyl radical; peroxidation, induced by the water-soluble radical initiator 2,2′-azobis(2-amidinopropane) hydrochloride, on mixed dipalmitoylphosphatidylcholine/linoleic acid unilamellar vesicles; UV radiation-induced peroxidation in phosphatidylcholine multilamellar vesicles). In all in vitro tests employed, the JW-E proved to possess strong antioxidant/free radical-scavenging effectiveness. Furthermore, when topically applied, a gel formulation containing the JW-E afforded significant in vivo protection against UVB light-induced skin erythema (monitored by reflectance spectrophotometry) in healthy human volunteers.© 2002 Society of Chemical Industry
Article
An anthocyanin extract was prepared by treating Concord grape filter trim with methanol acidified with 0.01% citric acid. The extract was concentrated to provide an aqueous extract for testing as a colorant for beverages. The concentrate was freeze-dried on a dextran carrier for use with a dry beverage mix. The stability of the anthocyanins in beverages with added glucose or sucrose was not pH dependent over the range from pH 2.8—3.6. Presence of ascorbic acid increased the pigment degradation rate. 5-hydroxymethyl-Zfurfural (HMF) did not accumulate on storage in sufficient amounts to affect appreciably the degradation rate. D2 1 2 and z values were determined under aerobic conditions for several systems. The calorimetric “a/” L' function correlated well with anthocyanin content at higher storage temperatures. The pigment was very stable in carbonated beverages, jelly and dry beverage base mix.
Article
Optimization of the extraction of phenolic compounds from milled berries has been studied and the effective diffusivity and mass transfer coefficient have been measured during solid–liquid extraction in an agitated vessel. Optimization was carried out by a surface response methodology, using ethanol or sulfured water concentration, temperature, and solvent-to-solid ratio as independent variables. Maximum yields of total phenolics and anthocyanins were obtained at 19 l of solvent per kg of milled frozen berries with 1000–1200 ppm SO2, or 60% ethanol concentration. The increase of the extraction temperature increased the rate of extraction and reduced the extraction time by increasing the diffusivity. The higher the SO2 concentration in the solvent mixture, the higher the diffusivity, however ethanol concentration increased diffusivity up to a maximum and decreased it with further increase of ethanol concentration. Diffusivities of 24.3×10−11 and 12.3×10−11 m2 s−1 and mass transfer coefficients of 3.85×10−5 and 2.36×10−5 ms−1 were obtained for extraction of anthocyanins at 40 °C using 700 ppm SO2 and 67% ethanol, respectively.
Article
The anthocyanins (Acy) of 14 black Vitis rotundifolia hybrid grapes were separated and quantified by reversed phase high performance liquid chromatography (HPLC) on a C18 column. Twenty-five pigments were separated and 20 anthocyanins were identified. All the cultivars investigated contained mono and diglucosides of acylated and non-acylated anthocyanidins in varying quantities. Total Acy concentration in grapes ranged from 55 to 357 mg/berry. Most of the cultivars had no delphinidin 3,5-diglucoside and the relative amounts of the other non-acylated Acy, which are the pigments found on V. rotundifolia grapes, were very low. The relative malvidin content ranged from 0·0% of total grape Acy content in M4-83, to 25·5% in Conquistador. No correlation was found between the relative content of any type of Acy and either the lightness (L) or hue (θ) values of the grapes and their juices. The cultivars were ranked for their possible wine color characteristics and selection in breeding programs, based on their total delphinidin and malvidin content. CD12-72 was rated the best cultivar while AD2-75 was the least desirable cultivar used in the study.
Article
In this review of the scientific literature on the relationship between vegetable and fruit consumption and risk of cancer, results from 206 human epidemiologic studies and 22 animal studies are summarized. The evidence for a protective effect of greater vegetable and fruit consumption is consistent for cancers of the stomach, esophagus, lung, oral cavity and pharynx, endometrium, pancreas, and colon. The types of vegetables or fruit that most often appear to be protective against cancer are raw vegetables, followed by allium vegetables, carrots, green vegetables, cruciferous vegetables, and tomatoes. Substances present in vegetables and fruit that may help protect against cancer, and their mechanisms, are also briefly reviewed; these include dithiolthiones, isothiocyanates, indole-3-carbinol, allium compounds, isoflavones, protease inhibitors, saponins, phytosterols, inositol hexaphosphate, vitamin C, D-limonene, lutein, folic acid, beta carotene, lycopene, selenium, vitamin E, flavonoids, and dietary fiber. Current US vegetable and fruit intake, which averages about 3.4 servings per day, is discussed, as are possible noncancer-related effects of increased vegetable and fruit consumption, including benefits against cardiovascular disease, diabetes, stroke, obesity, diverticulosis, and cataracts. Suggestions for dietitians to use in counseling persons toward increasing vegetable and fruit intake are presented.
Article
The antioxidant and prooxidant behavior of flavonoids and the related activity-structure relationships were investigated in this study using the oxygen radical absorbance capacity assay. Three different reactive species were used in the assay: 2,2'-azobis(2-amidino-propane) dihydrochloride, a peroxyl radical generator; Cu(2+)-H2O2, mainly a hydroxyl radical generator; and Cu2+, a transition metal. Flavonoids including flavones, isoflavones, and flavanones acted as antioxidants against peroxyl and hydroxyl radicals and served as prooxidants in the presence of Cu2+. Both the antioxidant and the copper-initiated prooxidant activities of a flavonoid depend upon the number of hydroxyl substitutions in its backbone structure, which has neither antioxidant nor prooxidant action. In general, the more hydroxyl substitutions, the stronger the antioxidant and prooxidant activities. The flavonoids that contain multiple hydroxyl substitutions showed antiperoxyl radical activities several times stronger than Trolox, an alpha-to copherol analogue. The single hydroxyl substitution at position 5 provides no activity, whereas the di-OH substitution at 3' and 4' is particularly important to the peroxyl radical absorbing activity of a flavonoid. The conjugation between rings A and B does not affect the antioxidant activity but is very important for the copper-initiated prooxidant action of a flavonoid. The O-methylation of the hydroxyl substitutions inactivates both the antioxidant and the prooxidant activities of the flavonoids.
Article
The effects of glycosylation and acylation on the spectral characteristics, molar absorptivity, and color attributes of purified acylated and non-acylated pelargonidin derivatives were compared. Pigments were obtained from strawberries, radishes, red-fleshed potatoes, and partially hydrolyzed radish pigments. Individual pigments were isolated by using semipreparative HPLC. Spectral and color (CIELch) attributes of purified pigments were measured. Molar absorptivity ranged from 15 600 to 39 590 for pelargonidin-3-glucoside (pg-3-glu) and pg-3-rutinoside-5-glucoside acylated with p-coumaric acid, respectively. The presence of cinnamic acid acylation had a considerable impact on spectral and color characteristics, causing a bathochromic shift of lambda(max). Sugar substitution also played an important role, with a hypsochromic shift caused by the presence of glycosylation. Pg-3, 5-diglu and pg-3,5-triglu possessed a higher hue angle (>40 degrees ) than the other pg derivatives at pH 1.0, corresponding to the yellow-orange region of the color solid. Acylation with malonic acid did not affect lambda(max) and showed little effect on color characteristics. The solvent system had an effect not only on the molar absorptivity, but also on the visual color characteristic of the pigments.
Article
Changes in phenolics (anthocyanins, flavonols, tartaric esters, and total phenolics) during ripening of grapes and in phenolics and color during vinification and aging of Cabernet Franc, Merlot, and Pinot Noir wines were studied. Anthocyanins in grape skins showed variations in accumulation pattern, concentration, and distribution depending on variety and to a lesser extent on season. During vinification, colorless phenolics increased during alcoholic fermentation, reached maximum values at pressing, and remained stable during malolactic fermentation and subsequent storage. Anthocyanins and color density, on the other hand, increased during the early stages of alcoholic fermentation, reached maximum values 2-3 days after the start of fermentation, decreased during malolactic fermentation, and slowly declined during subsequent storage. Viticultural practices that increased cluster sun exposure generally led to higher phenolics and color density of wines, whereas changing yeasts used for fermentation had minimal effects.
Article
Fruits and leaves from different cultivars of thornless blackberry (Rubus sp.), red raspberry (Rubus idaeus L.), black raspberry (Rubus occidentalis L.), and strawberry (Fragaria x ananassa D.) plants were analyzed for total antioxidant capacity (oxygen radical absorbance capacity, ORAC) and total phenolic content. In addition, fruits were analyzed for total anthocyanin content. Blackberries and strawberries had the highest ORAC values during the green stages, whereas red raspberries had the highest ORAC activity at the ripe stage. Total anthocyanin content increased with maturity for all three species of fruits. Compared with fruits, leaves were found to have higher ORAC values. In fruits, ORAC values ranged from 7.8 to 33.7 micromol of Trolox equivalents (TE)/g of fresh berries (35. 0-162.1 micromol of TE/g of dry matter), whereas in leaves, ORAC values ranged from 69.7 to 182.2 micromol of TE/g of fresh leaves (205.0-728.8 micromol of TE/g of dry matter). As the leaves become older, the ORAC values and total phenolic contents decreased. The results showed a linear correlation between total phenolic content and ORAC activity for fruits and leaves. For ripe berries, a linear relationship existed between ORAC values and anthocyanin content. Of the ripe fruits tested, on the basis of wet weight of fruit, cv. Jewel black raspberry and blackberries may be the richest source for antioxidants. On the basis of the dry weight of fruit, strawberries had the highest ORAC activity followed by black raspberries (cv. Jewel), blackberries, and red raspberries.
Article
The free radical scavenging activities and inhibitory effect of lipid peroxidation of a delphinidin derivative in eggplant were investigated. Delphinidin-3-(p-coumaroylrutinoside)-5-glucoside (nasunin), an anthocyanin, was isolated as purple colored crystals from eggplant peels. Using electron spin resonance spectrometry and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), hydroxyl radicals (OH) or superoxide anion radicals (O(2)(-)) generated by the Fenton reaction or the hypoxanthine-xanthine oxidase system were measured as DMPO-OH or DMPO-OOH spin adducts. L-Ascorbic acid 2-[3, 4-dihydro-2,5,7,8-tetramethyl-2-(4,8, 12-trimethyltridecyl)-2H-1-benzopyran-6yl-hydrogen phosphate] potassium salt (EPC-K1) and bovine erythrocyte superoxide dismutase (SOD) were used as standards for OH and O(2)(-) scavengers, respectively. Nasunin showed potent O(2)(-) scavenging (143+/-8 SOD-equivalent U/mg) and OH scavenging (0. 65+/-0.07 EPC-K1-equivalent micromol/mg) activities. Then, by changing the concentration of DMPO to vary the trapping rate of OH, the presence of a competitive reaction between nasunin and OH was studied. The 50% inhibition dose (ID(50)) obtained from the inhibition curve did not change, indicating OH scavenging of nasunin is not due to direct scavenging but inhibition of OH generating system by chelating ferrous ion. Nasunin protection against H(2)O(2)-induced lipid peroxidation in rat brain homogenate was measured at 586 nm using the indicator of malonaldehyde and 4-hydroxyalkenals. Nasunin (<50 microM) protected against lipid peroxidation of brain homogenates. The findings suggest that nasunin is a potent O(2)(-) scavenger and has protective activity against lipid peroxidation.
Article
Plants consumed by humans contain thousands of phenolic compounds. The effects of dietary polyphenols are of great current interest due to their antioxidative and possible anticarcinogenic activities. A popular belief is that dietary polyphenols are anticarcinogens because they are antioxidants, but direct evidence for this supposition is lacking. This chapter reviews the inhibition of tumorigenesis by phenolic acids and derivatives, tea and catechins, isoflavones and soy preparations, quercetin and other flavonoids, resveratrol, and lignans as well as the mechanisms involved based on studies in vivo and in vitro. Polyphenols may inhibit carcinogenesis by affecting the molecular events in the initiation, promotion, and progression stages. Isoflavones and lignans may influence tumor formation by affecting estrogen-related activities. The bioavailability of the dietary polyphenols is discussed extensively, because the tissue levels of the effective compounds determine the biological activity. Understanding the bioavailability and blood and tissue levels of polyphenols is also important in extrapolating results from studies in cell lines to animal models and humans. Epidemiological studies concerning polyphenol consumption and human cancer risk suggest the protective effects of certain food items and polyphenols, but more studies are needed for clear-cut conclusions. Perspectives on the application of dietary polyphenols for the prevention of human cancer and possible concerns on the consumption of excessive amounts of polyphenols are discussed.
Article
Health benefits of fruits, vegetables, and red wine are attributed to anthocyanins and other phytochemicals. In this research, the extraction of phenolics from black currants was optimized using different SO(2) concentrations (28, 300, 700, 1100, and 1372 ppm), temperatures (6, 20, 40, 60, and 74 degrees C), and solvent to solid ratios (S/S) (6, 20, 40, 60, and 74 mL/g). Surface response methodology was used to optimize yields of anthocyanins and total phenolics, as well as their antiradical and antioxidant activities. The extraction of phenolics varied with the SO(2) concentration, S/S, and temperature. Maximum yields of total phenolics and anthocyanins were obtained at an SO(2) concentration of 1000-1200 ppm and 19 L of solvent/kg of milled frozen berries. The increase of extraction temperature increased the rate of extraction and, thus, times to reach equilibrium for the extraction of total phenolics and anthocyanins were reduced. However, for the extraction of anthocyanins it is recommended that temperatures of 30-35 degrees C be used, as higher temperatures will degrade these compounds. Antioxidant activity was affected by all three experimental variables evaluated; however, the main variable affecting it was S/S. The higher the S/S, the lower the antioxidant index.
Article
Anthocyanins in common foods in the United States, other than fruits and berries, were identified and characterized by high-performance liquid chromatography (HPLC)-electrospray ionization-tandem mass spectrometry coupled with diode array detection. Of all of the 40+ vegetables, nuts, and grains screened, seven vegetables, one nut, and one grain were found to contain anthocyanins; the number of anthocyanins detected varied from two in pistachio nuts to 34 in red radishes. The individual anthocyanins were identified by comparing their mass spectrometric data and retention times with those of standards, published data, and reference food samples. In all of the samples analyzed, except for sorghum, only six common anthocyanidins (delphinidin, cyanidin, pelargonidin, petunidin, peonidin, and malvidin) were found as their glycosides. Anthocyanins in certain vegetables such as red cabbage and red radish were highly conjugated with sugars and acylated groups, and thus, their structures were very complicated. Eight different either aliphatic or aromatic acylated groups (acetoyl, coumaroyl, malonoyl, p-hydroxybenzoyl, feruoyl, caffeoyl, sinapoyl, and oxaloyl) were identified in the anthocyanins. In addition to glucose, six other sugar moieties (galactose, xylose, rhamnose, rutinose, sambubiose, and laminaribiose) were observed. Three varieties of sorghum were found to contain 3-deoxyanthocyanidins and their derivatives as major anthocyanins. A number of new anthocyanins were identified in the foods studied. This paper presents complete HPLC profiles and MS spectrometric data, obtained under the same experimental conditions, for common vegetables, pistachio nuts, and sorghum that contain anthocyanins.
Article
Consumption of plant foods, particularly fruits, vegetables and cereal grains is encouraged because they render beneficial health effects. Phenolics and polyphenolics are among the most desirable food bioactives because of their antioxidant activity, brought about by a number of pathways, or due to other mechanisms. The analysis of phenolics and polyphenolics requires their extraction possible purification and structure elucidation. This overview provides a cursory account of the source, extraction and analysis of phenolics in fruits, vegetables and cereals.