LC–MS analysis of anthocyanins from purple corn cob

Liquid chromatography coupled with diode array spectrophotometry and mass spectrometry detection (LC–DAS–MS) has been applied to the study of the anthocyanin composition of a commercial extract from purple corn cob used as a colourant additive in the food industry. Nine different anthocyanins were isolated using semipreparative HPLC and identified by LC–MS and hydrolytic techniques. Useful information for the identification of compounds was also obtained from their fragmentation patterns (MS–MS spectra). Six of these anthocyanins seem to be present in the original cob, namely cyanidin‐3‐glucoside, pelargonidin‐3‐glucoside, peonidin‐3‐glucoside and their respective malonyl derivatives. The other three are produced during the industrial extraction process and have been identified as the corresponding ethylmalonyl derivatives. © 2002 Society of Chemical Industry     

First confirmation in red wine of products resulting from direct anthocyanin–tannin reactions

Analysis of wine fractions before and after thiolysis confirmed the occurrence in red wine of direct reactions between anthocyanins and tannins established earlier in model solutions. Results showed the presence of two types of structures differing in the linkage position of the anthocyanin moiety. On one hand, detection of malvidin‐3‐glucoside (Mv3g) among thiolysis products revealed the presence of anthocyanin‐derived pigments in which Mv3g is linked by its C‐6 or C‐8 top. On the other hand, LC/MS analysis allowed the detection of two derivatives tentatively identified as flavenes or a bicyclic condensation products yielded by the reaction of a flavanol monomer (C‐6 or C‐8 top) with malvidin‐3‐glucoside (C‐4 position). The presence of the corresponding benzylthioethers after thiolysis of the polymeric fractions confirmed that procyanidins are similarly involved in the latter reaction. Besides, MS also allowed the detection of new benzylthioethers of catechin derivatives released after thiolysis of the wine fractions, indicating that in addition to the postulated processes other types of reactions take place in wines. © 2000 Society of Chemical Industry     

Effect of the modifier (Graciano vs. Cabernet Sauvignon) on blends of Tempranillo wine during ageing in the bottle. I. Anthocyanins, pyranoanthocyanins and non-anthocyanin phenolics

The effect of Graciano (GRA) (Spanish valuable variety of limited production) vs. Cabernet Sauvignon (CS) (world wide known French variety) wines on the anthocyanin, pyranoanthocyanin and non-anthocyanin phenolic composition of wines from Tempranillo (TEM-base wine) (largely cultivated Spanish variety) was studied in wine blends prepared with 25% and 10% (v/v) of each modifier after 4, 6, 9, 16.5 and 23 months of ageing in the bottle. Blending mainly resulted in a higher concentration of peonidin anthocyanins for the TEM-GRA blends, of acetyl-glucoside anthocyanins and anthocyanin-pyruvic acid adducts for the TEM-CS blends, and of flavanols for the blends with both GRA and CS varieties, giving rise to wines with a more balanced anthocyanin/flavanol ratio. Blending also enhanced the changes expected to occur in the phenolic compounds during ageing in the bottle. Particularly, anthocyanins and flavanols in the blends disappeared faster than in the base wine, and this was more pronounced for the 75:25 than for the 90:10 blends. These effects were similar for both modifier wines, independent of the specific changes produced in the anthocyanin profile of the base wine, but coincided with the similar optimization of the anthocyanin/flavanol ratio provided by both Graciano and Cabernet Sauvignon wines.     

Application of a Novel Small-Scale Sample Cleanup Procedure Prior to MALDI-TOF-MS for Rapid Pigment Fingerprinting of Red Wines

This study evaluates the anthocyanin and derived pigment composition of Vitis vinifera red wines of Vranec, Merlot, and Cabernet Sauvignon produced in 2006, 2007, and 2008 vintages from the Tikve? wine region in the Republic of Macedonia. Their profile was established using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) technique. A total of 22 anthocyanins and derived pigments have been identified in the samples including 10 anthocyanins, 1 ethyl-bridged flavanol–anthocyanin adduct, and 11 pyranoanthocyanins. MALDI-TOF-MS analysis was performed after solid-phase extraction of the wines by using, for the first time, the Zip-Tip® C18 stationary phase, introducing a novel small-scale sample cleanup procedure prior to the rapid MALDI-TOF-MS fingerprinting of wine samples. 2′,4′,6′-Trihydroxyacetophenone (dissolved in acetonitrile/water 1:1, v/v) was used as a matrix. The qualitative screening of anthocyanins and derived pigments with MALDI-TOF-MS confirmed the presence of glucoside, acetylglucoside, and p-coumaroylglucoside derivatives of anthocyanins in the wine samples. Furthermore, pyranoanthocyanins formed by reactions of anthocyanins with pyruvic acid and acetaldehyde, as well as flavanol–pyranoanthocyanins and ethyl-bridged flavan-3-ol-anthocyanin adduct pigments have been detected in the samples.     

Effect of ellagitannins,ellagic acid and volatile compounds from oak wood on the (+)‐catechin,procyanidin B1 and malvidin‐3‐glucoside content of model wines

Background and Aims: During ageing in oak barrels, wine undergoes changes because of the release of polyphenols and other molecules from wood. The aim of this study was to evaluate the influence of some oak wood‐derived volatile compounds, ellagic acid and oak wood extracts on the levels of (+)‐catechin, procyanidin B1 and malvidin‐3‐glucoside. Methods and Results: Phenolics and the oak wood derived volatile compounds studied were quantified by HPLC and by GC, respectively. Additionally, the new compounds formed in the solutions were characterised by their spectral properties. Ellagic acid and/or oak wood extracts slowed the decline in the levels of (+)‐catechin and procyanidin B1. In contrast, the decrease in malvidin‐3‐glucoside was more pronounced in the presence of ellagic acid and oak wood chip extracts. Furfural slowed (+)‐catechin degradation, while breakdown of malvidin‐3‐glucoside was slightly more pronounced in the presence of guaiacol, furfural, vanillin and eugenol. (+)‐Catechin, procyanidin B1 and malvidin‐3‐glucoside did not significantly affect the rate of the degradation of ellagitannins during the storage time studied. Finally, new HPLC peaks were detected in the solutions containing (+)‐catechin and ellagic acid, as well as with malvidin‐3‐glucoside with ellagic acid and oak wood extract. Conclusions: Malvidin 3‐glucoside and (+)‐catechin and procyanidin B1 presented distinct behaviours during time in the presence of volatile and non‐volatile compounds from oak wood. Significance of the Study: This work points out the importance of oak wood components in the degradation of anthocyanins and tannins, as well as the reactions that occur during the ageing of red wine.     

Evolution of red wine anthocyanins during malolactic fermentation,postfermentative treatments and ageing with lees

A comparative study was conducted on nine batches of wine, from the same initial wine, subjected to malolactic fermentation and ageing in barrels, under different technological conditions: Malolactic fermentation in barrel or in tank, with or without wine clarification, ageing with or without lees and stirring or no stirring of the lees. Samples were taken of the initial wine, of the wine at the end of malolactic fermentation, of the wines after clarifying treatments, and after 3, 6, 9, 12 and 14 months of ageing in the barrel, making a total of 48 wines. As a result of the anthocyanin analysis of all the wines studied, a total of 21 different anthocyanin compounds were detected, which can be classified into four groups: simple glucosides, acetyl glucosides, cinnamoyl glucosides and pyroanthocyanins. During MLF, it was shown that the effect of the container used seems to be more important than the metabolic activity of the bacteria responsible for the process. From application of the LSD test, significant differences were found in the concentrations of all the anthocyanin compounds identified due to ageing time and significant differences were also revealed for most anthocyanin compounds in relation to the manufacturing method, especially the presence or absence of lees.     

Tissue distribution of anthocyanins in rats fed a blackberry anthocyanin‐enriched diet

Anthocyanins are natural dietary pigments that could be involved in various health effects. The aim of this study was to investigate the distribution of anthocyanins to various organs (bladder, prostate, testes, heart and adipose tissue) in rats fed with a blackberry anthocyanin‐enriched diet for 12 days. Identification and quantification of anthocyanins were carried out by HPLC‐DAD. The urinary excretion of total anthocyanins (native anthocyanins and their metabolites) was low (0.20 ± 0.03%, n = 8). Proportions of anthocyanin derivatives (methylated anthocyanins and glucurono‐conjugated derivatives) differed according to the organ considered. The bladder contained the highest levels of anthocyanins followed by the prostate. Prostate, testes and heart contained native cyanidin 3‐glucoside and a small proportion of cyanidin monoglucuronide. Cyanidin 3‐glucoside and methylated derivatives were present in adipose tissue. Thus, anthocyanin feeding in rats resulted in a wide distribution of anthocyanin derivatives to several organs. Identification of target tissues of anthocyanins may then help to understand the mechanisms of action of anthocyanins in vivo.     

Comparative study of phenolic compounds in Cabernet Sauvignon wines made in traditional and Ganimede fermenters

Chemical profiles of anthocyanin and non-anthocyanin phenolics of Cabernet Sauvignon wine made by two different winemaking techniques (traditional vinification and Ganimede method) were determined by high performance liquid chromatography–mass spectrometry (HPLC–MS). Particularly, effect of extraction on and subsequent stability of the phenolic compounds from the end of fermentation to bottling were investigated. The results showed that the total anthocyanin content was higher in the young wines produced in the Ganimede fermenter. The anthocyanin contents in these wines subsequently decreased significantly after two years of ageing. By contrast, the traditional vinification was slightly better than the Ganimede to yield the non-anthocyanin phenolics. This indicates that the Ganimede fermenter might be suitable for the production of brightly coloured red wines for early consumption, which could save time and labour cost for industrial production of highquality wines.     

Identification of New Coloured Anthocyanin–Flavanol Adducts in Pressure-Extracted Pomegranate (<Emphasis Type="BoldItalic">Punica granatum</Emphasis> L.) Juice by High-Performance Liquid Chromatography/Electrospray Ionization Mass Spectrometry

Pomegranate (Punica granatum L.) juice, obtained by pressure extraction of the whole fruit, contains coloured flavanol–anthocyanin adducts (the flavanol occupies the upper part of the dimmer) from the direct condensation between anthocyanidins delphinidin, cyanidin and pelargonidin and flavan-3-ols (epi)gallocatechin, (epi)catechin and (epi)afzelechin. The presence of adducts between these same flavanols and anthocyanidins, but belonging to the coloured anthocyanin–flavanol adduct type (anthocyanin occupies the upper part of the dimmer) has been revealed by reversed-phase liquid chromatography coupled to tandem mass spectrometry (ion trap), with positive electrospray ionization (LC–ESI/MS ⁿ ). These new adducts are isotopic with their corresponding counterparts (flavanol–anthocyanin adducts) and indistinguishable from them by comparison of the mass spectra from the MS² of the isotopic parent ions. However, they can be distinguished by comparison of the mass spectra from the MS³ of their corresponding isotopic aglycons. Hence, the MS³ of the aglycon from a given flavanol–anthocyanin adduct always yields a mass spectrum containing five characteristic ions, the three with smaller m/z being only dependent on the anthocyanidin and the other two on both the anthocyanidin and the flavanol. In contrast, the mass spectrum from the MS³ of the aglycon of its counterpart anthocyanin–flavanol adduct gives only two of the above five characteristic ions, where the ion with smaller m/z only depends on the anthocyanidin and the other on both the anthocyanidin and the flavanol. Ten 3-hexoside derivatives of coloured anthocyanin–flavanol adducts were detected in pomegranate juice being reported for the first time this type of adducts from a natural source.     

Flavanol–anthocyanin condensed pigments in plant extracts

Pigments resulting from the direct condensation of anthocyanins and flavanols are usually associated with reactions taking place during processing and storage of plant-derived foods and beverages and have been particularly studied in aged red wines. In this paper, small amounts of flavanol–anthocyanin condensed pigments are found in different plant extracts. Structures are suggested for 10 such condensed pigments detected in extracts of strawberry, runner beans, purple corn and grape skins, based on their MSⁿ fragmentation patterns, following analyses by electrospray tandem mass spectrometry. All of them correspond to dimers containing a flavan-3-ol [either (epi)afzelechin, (epi)catechin or (epi)gallocatechin] as the upper unit carbon–carbon linked to a lower anthocyanin unit consisting of different delphinidin, cyanidin, pelargonidin, peonidin or malvidin derivatives. The detection of these pigments in plant extracts may suggest that they are natural pigments and not products exclusively formed during storage and ageing of processed foods and beverages, as was previously assumed.     

Effects of Vinification Techniques Combined with UV‐C Irradiation on Phenolic Contents of Red Wines

Red wines are typically high in phenolic and antioxidant capacity and both of which can be increased by vinification techniques. This study employed 3 vinification techniques to assess the increase in phenolic compounds and antioxidant capacity. Wines were obtained from Bo?azkere grape cultivar by techniques of classical maceration, cold maceration combined with ultraviolet light (UV) irradiation, and thermovinification combined with UV irradiation and changes in phenolic contents were examined. Total phenolic and anthocyanin contents and trolox equivalent antioxidant capacity of wines were measured spectrophotometrically and phenolic contents (+)‐catechin, (–)‐epicatechin, rutin, quercetin, trans‐resveratrol, and cis‐resveratrol were measured by High Pressure Liquid Chromatography with Diode Array Detection (HPLC‐DAD). As a result of the study, the highest phenolic content except for quercetin was measured in the wines obtained by thermovinification combined with UV irradiation. We demonstrated that the highest phenolic compounds with health effect, total phenolic compounds, total anthocyanin, and antioxidant activity were obtained from thermovinification with UV‐C treatment than classical wine making.     

Headspace solid‐phase micro extraction coupled to comprehensive two‐dimensional with time‐of‐flight mass spectrometry applied to the evaluation of Nebbiolo‐based wine volatile aroma during ageing

This study presents the application of a headspace solid‐phase microextraction (HS‐SPME) method on the analysis of Nebbiolo‐based wine volatiles by comprehensive two‐dimensional gas chromatography (GC×GC) and time‐of‐flight mass spectrometry (TOF‐MS). The aroma patterns were established for different samples of Nebbiolo‐based wines, aged in oak wood barrels for 18 months at constant temperature. The methodology allowed for the simultaneous analysis of over 130 different volatile compounds detected in the headspace. The odour activity values (OAVs) were assessed to identify potentially important odorants of Nebbiolo‐based wine during ageing. The highest OAVs were obtained for several compounds such as ethyl octanoate, ethyl hexanoate, isoamyl acetate, β‐damascenone, ethyl cinnamate, ethyl 3‐methylbutanate and acetaldehyde. Ethyl butanoate, octanoic acid, ethyl dihydrocinnamate and γ‐nonalactone were also at concentrations higher than their corresponding threshold. Also vanillin, (E)‐whisky lactone, (Z)‐whisky lactone, guaiacol and 4‐ethyl guaiacol seem to be important odorants after oak wood ageing period.     

Anthocyanin pattern of Tempranillo wines during ageing in oak barrels and storage in stainless-steel tanks

The anthocyanin fingerprint of Tempranillo wines made with grapes from two different vineyards of Rioja Alta has been studied by high-performance liquid chroatography during their ageing in oak barrels and their storage in stainless-steel tanks. The data were submitted to multifactorial analysis of variance, taking into account several factors: vineyard, age of wines, type of wine (free run wine and a coupage of free run wine and press wine), and type of container (oak barrels or stainless-steel tanks). The results indicate that both the length of ageing or storage and the vineyard where the grapes were grown affect the anthocyanin fingerprint of wines. The effect of the other two factors (type of wine and type of container) on the anthocyanin fingerprint of wines was quite low, despite the differences observed in several spectrophotometric parameters related to colour and phenolics.     

Guaiacol and 4‐methylguaiacol accumulate in wines made from smoke‐affected fruit because of hydrolysis of their conjugates

Background and Aims: Taint in smoke‐exposed grapes have been associated with elevated levels of guaiacol and 4‐methylguaiacol. Previous research has reported guaiacol and 4‐methylguaiacol in both fruits and wines. In some cases, these compounds were not detected, or were detected at low levels in the fruit while high levels were subsequently identified during or after winemaking. Later research indicated that this was due to the presence of glycosidic conjugates. Here we report a method for the routine analysis of guaiacol and 4‐methylguaiacol released after acid hydrolysis of glycoside precursors. Methods and Results: Chardonnay, Merlot, Shiraz, Sangiovese and Cabernet Sauvignon fruits were collected following bushfire events in 2006–2007 in the King Valley wine region of NE Victoria, Australia. Gas chromatography‐mass spectrometry (GC‐MS) was used to detect free guaiacol and 4‐methylguaiacol in both fruits and wines. Low levels of free and bound forms were present in fruit not exposed to smoke. Substantial levels of free guaiacol and 4‐methylguaiacol were detected in the wines made from the smoke‐affected fruits. These compounds increased during bottle storage. Acid hydrolysis of wines and berries resulted in a several‐fold increase in free guaiacol and 4‐methylguaiacol. Conclusions: The validated GC‐MS method is suitable for monitoring free and glycosidically bound guaiacol and 4‐methylguaiacol after acid hydrolysis in both fruits and wines. Acid hydrolysis of wines provided evidence that bound volatiles, most probably glycosidically, act as reserve for guaiacol and 4‐methylguaiacol, which are released during ageing of wines. Significance of the Study: This is the first study published in a refereed journal to demonstrate that smoke taint‐associated volatiles increase during ageing of wine and bound forms of guaiacol and 4‐methylguaiacol represent an aroma reserve for smoke taint in ageing/bottled wines.     

Nutritional composition of commercial pickled garlic

The effect of pulp treatment on the qualitative and quantitative changes to polyphenol compounds, such as anthocyanins and flavanols, in musts and wines from blackcurrant and cherries was investigated. The following variants of pulp treatment were used: hot maceration, hot maceration and pulp pectinolysis with Rohapect MA Plus and Pectopol PM preparations, and also pulp pectinolysis with Rohapect and Pectopol preparations. The method of treatment affected the content of anthocyanins and flavan-3-ols in the musts. Different types of phenolic compounds reacted differently under must-making conditions. Wines made with different treatments presented statistical differences with the control wine and between them for the parameters studied.As a result of the analysis of cherry musts and wines by HPLC, the following flavan-3-ols were identified: catechin, epicatechin, dimer B₂ and trimer C₁. In the cherry wines studied, in the variants subjected to pectinolysis and fermentation in the pulp, epicatechin occurred in a smaller amount than catechin, while in the wines subjected to thermal treatment it was predominant. In the blackcurrant musts and wines the following flavanols were identified: gallocatechin, catechin, epigallocatechin, dimer B₂, epicatechin and trimer C₁. In the cherry musts and wines the following anthocyanin pigments have been identified: cyanidin 3-glucoside, cyanidin 3-rutinoside and cyanidin 3-glucosylrutinoside, the amount of which was the greatest. Anthocyanins identified in the blackcurrant musts and wines were delphinidine and cyanidine glycosides: delphinidin 3-glucoside, delphinidin 3-rutinoside, cyanidin 3-glucoside and cyanidin 3-rutinoside; their aglycones were also found.     

Oak barrel maturation vs. micro-oxygenation: Effect on the formation of anthocyanin-derived pigments and wine colour

The objective of this study was to check whether micro-oxygenation (MO) could mimic oak barrel ageing as regard the effect on wine colour. A red wine was submitted to micro-oxygenation for three months while another lot from the same wine was matured in oak barrels for three or six months. After these times, oak-matured and micro-oxygenated wines were bottled and analyzed six months later. The chromatic characteristics of these wines were also compared with those of a control wine that remained in a stainless steel tank all the time. Anthocyanins and anthocyanin-derived compounds were studied by LC–ESI-MS. Monomeric anthocyanins and other compounds including direct anthocyanin–flavanol adducts, ethyl-linked anthocyanin–flavanol compounds, and pyranoanthocyanins were detected. The application of MO for three months produced wines with a lower concentration of monomeric anthocyanins and a higher concentration of vitisin-related pigments than the control wine, the oak mature wines showing similar results than MO wines when aged for the same period of time. Differences were also observed in the chromatic characteristics, the micro-oxygenated and the oak matured wines showing a higher colour intensity than control wine. However, after six months in bottle differences were found between the micro-oxygenated wines and oak matured wines, the latter showing a more stable colour, probably due to the beneficial effects of compounds extracted from the wood (e.g. ellagitannins or wood aldehydes).     

Anthocyanin and colour evolution during maturation of four port wines: effect of pyruvic acid addition

The formation of vitisin A‐type compounds has been studied in four maturing fortified red port wines stored for 29 weeks at 15 °C. The anthocyanin concentrations were determined by high‐pressure liquid chromatography (HPLC), and colour changes were monitored by spectrometric measurements. The losses of anthocyanins followed first‐order reactions, and the concurrent formation of polymeric pigments was demonstrated. Vitisin A‐type compounds were found to be in low concentration in these four naturally maturing fortified wines. The addition of pyruvic acid to the wines led to the formation of large concentrations of vitisin A derivatives. Up to 23 mg litre⁻¹ vitisin A derivatives (vitisin A and its acylated forms acetylvitisin A and p‐coumarylvitisin A) could be determined. Owing to their greater colour expression and greater stability than malvidin 3‐glucoside, these new anthocyanins were shown to play an important role in the colour quality of the wines. An analytical survey of 32 port wines matured for between 2 and 6 years showed that vitisin A‐type compounds were the main, and sometimes the only, anthocyanins present. © 2000 Society of Chemical Industry     

Practical interventions that influence the sensory attributes of red wines related to the phenolic composition of grapes: a review

The phenolic composition of red wines is complex and intimately involved in colour, taste, mouth‐feel and aroma. There have been significant advances in knowledge of compounds with relatively simple structures, but understanding of those with more complex and probably diverse structures is challenging. A number of phenolic compounds may form temporary complexes with anthocyanins and/or be involved in reactions that lead to relatively stable coloured compounds. A wide range of phenolic compounds is implicated in the oral sensory attributes of red wines. Of particular importance are flavan‐3‐ols, including proanthocyanidins (PAs). The generally observed decline in the extractability of PAs during berry ripening is due to binding with cell wall material, which may occur within the developing berry and also from tissues brought into contact during processing. Studies have shown that exposure/reduced vigour results in an increasing proportion of skin PAs being extractable during wine making. Temperature and light influence anthocyanin with temperature probably being more important and the most sensitive stage being 1–3 weeks after véraison. Skin PAs are extracted earlier than those from seeds during wine‐making. Recent results suggest some rearrangement of skin and/or seed PAs occurs during vinification which involves the cleavage of large polymers or the aggregation of small ones. The polymeric material is particularly influential in wine astringency and is transformed by incorporation of anthocyanins into tannin‐like compounds during wine‐making and storage. Although some grape‐derived phenolic compounds contribute to the aroma of red wines, likely of greater importance are the effects of nonvolatile phenolics on the volatility of a diverse range of aroma compounds. Advances in analytical techniques are likely to provide greater insights into the structures and conformations of phenolic polymers and the role of cell wall material in relation to phenolic extraction and reaction during vinification. In relation to aroma, much more research is required to reveal the details of the interactions involving phenolics with volatile compounds. It seems likely that the ability to influence the relative extraction and subsequent reaction of skin and seed phenolics is important in the production of full colour, aromatic and long‐lived wines.     

Original article: Anthocyanin profile in Monastrell grapes in six different areas from Denomination of Origen Jumilla during ripening stage

The aim of our research has been to investigate the pattern of accumulation of anthocyanins in the skin of Monastrell variety and to establish if the fingerprint of this cultivar changed in six different areas from Denomination of Origen Jumilla during ripening stage in two consecutive seasons (2007 and 2008). The results show that the anthocyanin profile for Monastrell variety is maintained: it could be observed a higher proportion of non‐acylated anthocyanins, a higher proportion of coumarylated than acetyl derivatives and a higher proportion of trihydroxylated than dihydroxylated anthocyanins. During ripening period, in all zones studied, we observed the same trends: increasing of cyanidin, peonidin and malvidin‐3‐glucoside and decreasing of the other two monoglucosides (delphinidin and petunidin). Slightly quantitative differences were observed for the different zones in the 2 years studied, leading to the conclusion that edaphoclimatic factors also influence the accumulation of anthocyanin compounds.     

Spectral evaluation of young red wines: Anthocyanin equilibria,total phenolics,free and molecular SO2, “chemical age”

Red wine colour is an integration of contributions from monomeric anthocyanins and polymeric pigment forms. Because of gross differences between the two fractions in their responses to pH change and to SO₂ addition, approximate measures of the states of anthocyanin equilibria in young red wines can be routinely made. Recent correlations of such measures with independent assessments of relative wine quality have prompted further examination and development of the original analytical concepts. The equilibria may be described in terms of two percentage parameters α and α ', the values of which are related to wine pH and to SO₂ added after fermentation. Measures of free SO₂ and also molecular SO₂, anthocyanin content and total phenolics are obtained from the same set of spectral data. The interpretations are based upon a number of analytical premises for which certain approximations have been necessary. These appear to be well justified in comparative evaluations because of the wide range of parameter values observed in surveys of current vintage wines. Observations of ageing changes in the composition of wine colour, with proposed spectral indices of “chemical age”, are also presented.