Major flavonoids in grape seeds and skins: antioxidant capacity of catechin, epicatechin, and gallic acid

Grape seeds and skins are good sources of phytochemicals such as gallic acid, catechin, and epicatechin and are suitable raw materials for the production of antioxidative dietary supplements. The differences in levels of the major monomeric flavanols and phenolic acids in seeds and skins from grapes of Vitis vinifera varieties Merlot and Chardonnay and in seeds from grapes of Vitis rotundifolia variety Muscadine were determined, and the antioxidant activities of these components were assessed. The contribution of the major monomeric flavonols and phenolic acid to the total antioxidant capacity of grape seeds and skins was also determined. Gallic acid, monomeric catechin, and epicatechin concentrations were 99, 12, and 96 mg/100 g of dry matter (dm) in Muscadine seeds, 15, 358, and 421 mg/100 g of dm in Chardonnay seeds, and 10, 127, and 115 mg/100 g of dm in Merlot seeds, respectively. Concentrations of these three compounds were lower in winery byproduct grape skins than in seeds. These three major phenolic constituents of grape seeds contributed <26% to the antioxidant capacity measured as ORAC on the basis of the corrected concentrations of gallic acid, catechin, and epicatechin in grape byproducts. Peroxyl radical scavenging activities of phenolics present in grape seeds or skins in decreasing order were resveratrol > catechin > epicatechin = gallocatechin > gallic acid = ellagic acid. The results indicated that dimeric, trimeric, oligomeric, or polymeric procyanidins account for most of the superior antioxidant capacity of grape seeds.     

Phytochemicals and antioxidant activity of milled fractions of different wheat varieties

The health-promoting effects of whole-grain consumption have been attributed in part to their unique phytochemical contents and profiles that complement those found in fruits and vegetables. Wheat is an important component of the human diet; however, little is known about the phytochemical profiles and total antioxidant activities of milled fractions of different wheat varieties. The objectives of this study were to investigate the distribution of phytochemicals (total phenolics, flavonoids, ferulic acid, and carotenoids) and to determine hydrophilic and lipophilic antioxidant activity in milled fractions (endosperm and bran/germ) of three different wheat varieties, two of which were grown in two environments. Grain samples of each of the wheat varieties were milled into endosperm and bran/germ fractions. Each fraction was extracted and analyzed for total phenolics, ferulic acid, flavonoids, carotenoid contents, and hydrophilic and lipophilic antioxidant activities. Total phenolic content of bran/germ fractions (2867-3120 micromol of gallic acid equiv/100 g) was 15-18-fold higher (p < 0.01) than that of respective endosperm fractions. Ferulic acid content ranged from 1005 to 1130 micromol/100 g in bran/germ fractions and from 15 to 21 micromol/100 g in the endosperm fractions. The bran/germ fraction flavonoid content was 740-940 micromol of catechin equiv/100 g. On average, bran/germ fractions of wheat had 4-fold more lutein, 12-fold more zeaxanthin, and 2-fold more beta-cryptoxanthin than the endosperm fractions. Hydrophilic antioxidant activity of bran/germ samples (7.1-16.4 micromol of vitamin C equiv/g) was 13-27-fold higher than that of the respective endosperm samples. Similarly, lipophilic antioxidant activity was 28-89-fold higher in the bran/germ fractions (1785-4669 nmol of vitamin E equiv/g). Hydrophilic antioxidant activity contribution to the total antioxidant activity (hydrophilic + lipophilic) was >80%. In whole-wheat flour, the bran/germ fraction contributed 83% of the total phenolic content, 79% of the total flavonoid content, 51% of the total lutein, 78% of the total zeaxanthin, 42% of the total beta-cryptoxanthin, 85% of the total hydrophilic antioxidant activity, and 94% of the total lipophilic antioxidant activity. Our results showed that different milled fractions of wheat have different profiles of both hydrophilic and lipophilic phytochemicals. These findings provide information necessary for evaluating contributions to good health and disease prevention from whole-wheat consumption.     

Changes of ochratoxin A in grapes inoculated with Aspergillus carbonarius and subjected to chamber-drying under controlled conditions

The production pattern for ochratoxin A in grapes inoculated with Aspergillus carbonarius and changes in its concentration during raisining of Merlot, Syrah, Tempranillo, and Cabernet Sauvignon red grapes and Pedro Ximenez white grape were studied. Grapes were chamber-dried under controlled temperature and humidity conditions, with and without dipping pretreatments in alkaline emulsions of olive oil or ethyl oleate. Based on the results for the grapes that developed the fungus (Merlot and Pedro Ximenez), a temperature of 50 °C in the absence of dipping stopped ochratoxin A production and even degraded part of the toxin already formed. Both dipping pretreatments facilitated removal of the toxin and led to its virtually complete disappearance. However, dipping in the ethyl oleate emulsion caused substantial changes in the sensory characters of the musts obtained from the raisins, so it should be avoided to ensure the expected quality in the sweet wines elaborated from them.     

Influence of ethanol concentration on the extraction of color and phenolic compounds from the skin and seeds of Tempranillo grapes at different stages of ripening

The aim of this paper is to study how grape ripeness and ethanol concentration affect the extraction of color and phenolic compounds from skins and seeds during the maceration/fermentation process. Simulated maceration assays were carried out with the grapes at three stages of berry development (vitis vinifera cv. Tempranillo) and different percentages of ethanol in the maceration media. Both ripeness and ethanol content have a considerable effect on the extraction of color and phenolic compounds. Of these two factors, ripeness increases the extractability most. The presence of ethanol in the medium facilitates anthocyanin and especially proanthocyanidin extraction, but it also decreases copigmentation phenomena, which can decrease the color intensity. The higher the ethanol concentration is in the maceration media, the higher the astringency of proanthocyanidins.     

Effect of drying of figs (Ficus carica L.) on the contents of sugars, organic acids, and phenolic compounds

Fresh figs were subjected to two different drying processes: sun-drying and oven-drying. To assess their effect on the nutritional and health-related properties of figs, sugars, organic acids, single phenolics, total phenolics, and antioxidant activity were determined before and after processing. Samples were analyzed three times in a year, and phenolic compounds were determined using high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS). In figs, monomer sugars predominate, which is important nutritional information, and the content of sugars as well as organic acids in fresh figs was lower than in dried fruits. However, the best sugar/organic acid ratio was measured after the sun-drying process. Analysis of individual phenolic compounds revealed a higher content of all phenolic groups determined after the oven-drying process, with the exception of cyanidin-3-O-rutinoside. Similarly, higher total phenolic content and antioxidant activity were detected after the drying process. With these results it can be concluded that the differences in analyzed compounds in fresh and dried figs are significant. The differences between the sun-dried and oven-dried fruits were determined in organic acids, sugars, chlorogenic acid, catechin, epicatechin, kaempferol-3-O-glucoside, luteolin-8-C-glucoside, and total phenolic contents. The results indicate that properly dried figs can be used as a good source of phenolic compounds.     

Investigation of the antioxidant behavior of air- and freeze-dried aromatic plant materials in relation to their phenolic content and vegetative cycle

The total phenolic and flavonoid content of the aerial parts of five aromatic plants harvested at different periods was estimated, and their antioxidant capacity was evaluated. Major phenolic compounds present in their extracts were determined by RP-HPLC. The results demonstrated different amounts of total phenolic compounds and various degrees of antioxidant activity depending on the plant species, the time of harvest, and the drying method employed. Extracts from air-dried Mentha viridis L., Origanum majorana L., and Rosmarinus officinalis L. demonstrated the greatest efficacy during the flowering stage, in which the identified flavonoids were found in significantly higher amounts, whereas phenolic acids were found in their lowest concentration. Extracts from air-dried Laurus nobilis L. and Foeniculum vulgare Mill were less efficient in terms of antioxidant activity, with the highest values being observed during the early fruiting stage. This stage was characterized by the lowest flavonoid content and high phenolic acid content, except for L. nobilis L. extracts. Overall, the amount of identified phenolic acids did not vary considerably within the investigated year. The total phenolic concentration in all plant extracts decreased significantly when freeze-dried rather than air-dried samples were used. The HPLC analysis further supported the above for most of the phenolic compounds present in the extracts, except for hydroxybenzoic acids, which were better retained during the freeze-drying process.     

Drying of Pedro Ximenez grapes in chamber at controlled temperature and with dipping pretreatments. Changes in the color fraction

The drying of Pedro Ximenez grapes in chamber at a controlled temperature of 40 or 50 degrees C is studied. Compared to traditional sun-drying, the chamber-drying shortened the drying time by about 40% at 50 degrees C. In color terms, the musts obtained from grapes dried at 50 degrees C were closer in CIELab coordinates to those obtained by sun-dried grapes, with similar h(ab) values and slightly lower L* and C(ab)*. To shorten further the drying times at 50 degrees C, the grapes were dipped in olive oil or ethyl oleate emulsions containing potassium carbonate. The ethyl oleate pretreatment shortened additionally the drying time by about 25%, providing musts with chroma, lightness, and hue similar to those without grape pretreatment. In general, except for the phenolic compounds corresponding to the drying with ethyl oleate pretreatment, most of these compounds in the remainding conditions studied increased to a lesser extent than expected because of water losses of the grapes during drying, revealing degradation reactions.     

Antioxidant activity of Sicilian pistachio (Pistacia vera L. var. Bronte) nut extract and its bioactive components

Pistacia vera L. is the only species of Pistacia genus producing edible nuts. This paper investigates the antioxidant potential of a Sicilian variety of pistachio nut by chemical as well as biological assays and measured antioxidant vitamins and a number of antioxidant polyphenols in either the hydrophilic and/or the lipophilic nut extract. In accordance with the majority of foods, the total antioxidant activity, measured as a TAA test, was much higher (50-fold) in the hydrophilic than in the lipophilic extract. Substantial amounts of total phenols were measured. The hydrophilic extract inhibited dose-dependently both the metal-dependent and -independent lipid oxidation of bovine liver microsomes, and the Cu+2-induced oxidation of human low-density lipoprotein (LDL). Peroxyl radical-scavenging as well as chelating activity of nut components may be suggested to explain the observed inhibition patterns. Among tocopherols, gamma-tocopherol was the only vitamin E isomer found in the lipophilic extract that did not contain any carotenoid. Vitamin C was found only in a modest amount. The hydrophilic extract was a source of polyphenol compounds among which trans-resveratrol, proanthocyanidins, and a remarkable amount of the isoflavones daidzein and genistein, 3.68 and 3.40 mg per 100 g of edible nut, respectively, were evaluated. With the exception of isoflavones that appeared unmodified, the amounts of other bioactive molecules were remarkably reduced in the pistachio nut after roasting, and the total antioxidant activity decreased by about 60%. Collectively, our findings provide evidence that the Sicilian pistachio nut may be considered for its bioactive components and can effectively contribute to a healthy status.     

Quantification of phenolic compounds during red winemaking using FT-MIR spectroscopy and PLS-regression

We present a rapid method to quantify phenolic compounds all during the red winemaking process using Fourier transform mid-infrared (FT-MIR) spectroscopy and chemometrics. To get the reference values, we used the usual UV–vis spectroscopy methods, and the compounds studied were evaluated as total phenolic compounds (TPC), total anthocyanins (TA), and condensed tannins (CT). Sampling from five different grape varieties (Merlot, Tempranillo, Syrah, Cari?ena, and Cabernet sauvignon), harvested at different ripening states, and monitored over 10 days of vinification produced a total of 600 spectra. These were used to build and validate four different predictive models by partial least-squares (PLS) regression. The spectral regions selected for each model were between 979 and 2989 cm(–1), and when selecting the most suitable one in each case, good values of performance parameters were obtained (R2(val) > 0.95 and RPD > 4.0 for TPC; R2(val) > 0.90 and RPD > 3.0 for TA; R2(val) < 0.8 and RPD < 3.0 for CT). Furthermore, also more specific PLS regression models for each phenolic parameter and each grape variety were developed using different regions with results similar to those obtained when dealing with all of the grape varieties. It is concluded that FT-MIR spectroscopy together with multivariate calibration could be a rapid and valuable tool for wineries to carry out the monitoring of phenolic compound extraction during winemaking.     

快速脱水抑制葡萄干制过程中膜脂过氧化及褐变

为探索脱水速度对无核白葡萄干制过程中膜脂过氧化作用及褐变的影响,以新疆无核白葡萄为试验材料,经过葡萄促干剂处理后,采用快速脱水和缓慢脱水2种处理,质量每减轻10%进行取样,测定脱水过程中果实干基含水率、干燥速率、褐变度、细胞膜透性、丙二醛(malonaldehyde,MDA)含量、脂氧合酶(lipoxygenase,LOX)、超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)、过氧化物酶(peroxidase,POD)、多酚氧化酶(polyphenol oxidase,PPO)活性以及总酚含量的变化。结果表明:与缓慢脱水相比,快速脱水处理显著(P0.05)降低了无核白葡萄褐变度的上升,减少MDA生成量以及膜透性的增加,抑制LOX活性的升高,保持较高的活性氧清除酶SOD、CAT及POD活性及较高的总酚含量,且使PPO活性保持在一个较低的水平。因此认为,快速脱水可以有效地抑制无核白葡萄的膜脂过氧化作用对细胞膜的破坏,保持细胞的完整性,且PPO活性较低,从而减少无核白葡萄脱水褐变的发生。研究结果为快速脱水在无核白葡萄干制中的应用提供参考。     

Rapid peroxyl radical scavenging capacity (PSC) assay for assessing both hydrophilic and lipophilic antioxidants

This paper reports a simple, rapid, and sensitive assay for assessing peroxyl radical scavenging capacity (PSC) of both hydrophilic and lipophilic antioxidant compounds and food extracts. The assay is based on the degree of inhibition of dichlorofluorescin oxidation by antioxidants that scavenge peroxyl radicals, generated from thermal degradation of 2,2'-azobis(amidinopropane). For hydrophilic antioxidant activity, the dose required to cause a 50% inhibition of the reaction (EC(50)) ranged from 2.41 +/- 0.02 (EGCG) to 21.26 +/- 0.38 microM (ferulic acid). EC(50) values for the hydrophilic antioxidant activity of food extracts ranged from 309.2 +/- 3.63 (apple) to 3345.1 +/- 151.5 micromol of vitamin C equiv/100 g for wheat bran. The EC(50) values for lipophilic antioxidant activity were 1.58 +/- 0.11 (Trolox), 4.35 +/- 0.43 (alpha-tocopherol), 18.94 +/- 0.38 (BHA), and 182.69 +/- 13.7 microM (BHT). Whole grain lipophilic antioxidant activity ranged from 3.49 +/- 0.57 (wheat) to 8.79 +/- 1.98 micromol of alpha-tocopherol equiv/100 g of rice. Hydrophilic antioxidant activity contributed >98% of the total antioxidant activity (hydrophilic plus lipophilic) of whole grains tested. The PSC assay was accurate (86-108% recovery), precise (0.12-11% CV), and reproducible (12% RSD) and produced results comparable to those of similar published assays. The PSC assay can be routinely used to analyze or screen both hydrophilic and lipophilic antioxidants or food extracts and will be a valuable alternative biomarker for future epidemiological studies of chronic diseases.     

Antioxidant composition in cherry and high-pigment tomato cultivars

Fourteen cultivars of cherry tomatoes and four cultivars of high-pigment tomato hybrids were cultivated in southern Italy, and the red-ripe fruits were analyzed for their content in different classes of antioxidants and for their antioxidant activity. Among the different cultivars, significant differences were found between lycopene, beta-carotene, alpha-tocopherol, vitamin C (ascorbic acid and dehydroascorbic acid), and total phenolic and flavonoid contents. LS203 and Corbus appear to be the cultivars with the highest content of lipophilic and hydrophilic antioxidants among cherry tomatoes, respectively. All cultivars of high-pigment tomato hybrids showed an expected exceptionally high lycopene content. Among them, the highest content of lipophilic and hydrophilic antioxidants was found in cv. HLY 13. Hydrophilic and lipophilic antioxidant activities were both significantly influenced by genotype. Such results highlight an existing unexploited variability in tomato germplasm and stress the need to evaluate the biodiversity and to support conventional breeding programs to improve tomato nutritional value.     

Influence of grape maturity and maceration length on color, polyphenolic composition, and polysaccharide content of cabernet sauvignon and tempranillo wines

The aim of this paper was to study how maturity and maceration length affect color, phenolic compounds, polysaccharides, and sensorial quality of Cabernet Sauvignon and Tempranillo wines at three stages of grape ripening. Ripeness increased color extractability, phenolic compounds, and polysaccharide concentrations. Moreover, the proanthocyanidin mean degree of polymerization (mDP) and the percentage of prodelphinidins also increased with maturity, whereas the percentage of galloylation decreased. In general, wines from riper grapes contain higher proportions of skin proanthocyanidins. Color and anthocyanin concentration decreased when the maceration was longer, whereas polysaccharide and proanthocyanidin concentrations did the opposite. It was also detected that the mDP and the percentage of prodelphinidins decreased when the maceration was extended, whereas the percentage of galloylation increased. These data seem to indicate that proanthocyanidin extraction from seeds is clearly increased throughout the maceration time.     

Stability of the phenolic and carotenoid profile of gazpachos during storage

Gazpacho is a ready-to-use vegetable soup containing tomato, cucumber, pepper, olive oil, and other minor constituents such as onion, garlic, wine vinegar, sea salt, and water. In this work, changes in individual phenolic and carotenoid compounds of commercial gazpachos, as well as in their hydrophilic and lipophilic antioxidant capacities (measured through ABTS+ and DPPH radicals), were assessed for 3 months at 4 °C. The storage of gazpachos at 4 °C for 3 months results in a slight decrease in their polyphenol and carotenoid content and also in the hydrophilic and lipophilic antioxidant capacities, but the levels achieved could not be construed as a nutritional drawback. The main degradation was quercetin oxidation because the hydroxy function at the C-ring of the flavonoid is not blocked by a sugar moiety as it is in the case of rutin and kaempferol-3-O-rutinoside and glycosylated caffeic and ferulic acids. Lycopene underwent significant losses throughout storage as 11 conjugated double bonds are present in its structure and should be more reactive than trans-lutein and trans-β-carotene. cis-Lycopene isomers slightly decreased. However, 5-cis-lycopene underwent a slight increase. This phenomenon could be explained by cis-isomerization increasing the proportion of cis-isomers.     

Varietal differences among the phenolic profiles and antioxidant activities of seven table grape cultivars grown in the south of Italy based on chemometrics

Seven table grape cultivars grown in Apulia region were considered: Italia, Baresana, Pizzutello, Red Globe, Michele Palieri, Crimson Seedless, and Thompson Seedless. Seeds, skins and pulps were extracted and analyzed for their phenolic profiles and antioxidant activities. The hierarchy in the phenolic contents was seeds, skins, and pulps. These results indicate that the intake of the whole berries (seeds included) must be strongly recommended. The highest phenolic contents were detected on Italia and Michele Palieri cv., respectively within the white and the red/black table grapes. Seeds gave a high contribution to the berry antioxidant activity, as they had higher phenolic content than skins and contained high quantities of proanthocyanidines, but the strongest antioxidant activity was shown by the pulp juices due to their content in hydroxycinnamyl acids. The principal component analysis applied to the phenolic composition and antioxidant activity of skins, pulps, and seeds allowed a good separation of Italia and Michele Palieri cultivars. According to the cluster analysis, cultivars were grouped into two clusters, one including Michele Palieri and the other one including Italia, Baresana, Pizzutello, and Thompson Seedless.     

Application of FT-MIR spectroscopy for fast control of red grape phenolic ripening

The content of phenolic compounds determines the state of phenolic ripening of red grapes and is a key criterion in setting the harvest date to produce quality red wines. In this study, the feasibility of Fourier transform mid-infrared (FT-MIR) spectroscopy combined with partial least-squares (PLS) regression to quantify phenolic compounds is reported. The reference methods used for quantifying these compounds (which were evaluated as total phenolic compounds, total anthocyanins, and condensed tannins) were the usual ones used in cellars that employed UV-vis spectroscopy. To take into account the high natural variability of grapes when building the calibration models, fresh grapes from six varieties, at different phenolic ripening states were harvested during three vintages. Destemmed and crushed grapes were subjected to an accelerated extraction process and used as calibration standards. A total of 192 extracts (objects) were obtained, and these were divided into a training set (106 objects) and a test set (86 objects) to evaluate the predictive ability of the models. Among the different MIR regions of the extract raw spectra, those that provided the highest variability on the absorption were selected. The results showed that the best PLS regression model was the one obtained when working in the region of 1168-1457 cm(-1) because it gave the most accurate and robust prediction for total phenolic compounds (RMSEP%=4.3 and RPD=4.5), total anthocyanins (RMSEP%=5.9 and RPD=3.5), and condensed tannins (RMSEP%=5.8 and RPD=3.8). Therefore, it can be concluded that FT-MIR spectroscopy can be a fast and reliable technique for monitoring the phenolic ripening in red grapes during the harvest period.     

Phenolic composition of the Brazilian seedless table grape varieties BRS Clara and BRS Morena

The detailed phenolic composition (anthocyanins, flavonols, hydroxycinnamic acid derivatives, stilbenes, and flavan-3-ols) in the skin and flesh of the new BRS Clara and BRS Morena seedless table grapes has been studied using HPLC-DAD-ESI-MS/MS. The two grapes, especially BRS Morena, contained high amounts of phenolic compounds, mainly located in their skins and qualitatively not different from those found in Vitis vinifera grapes. In addition, BRS Morena (a teinturier variety) showed qualitatively different phenolic compositions in its skin and flesh, mainly affecting the anthocyanin and flavonol profiles. Consistent with high phenolic contents, high antioxidant capacity values were registered for both grape varieties, especially for BRS Morena. Proanthocyanidins and hydroxycinnamoyl-tartaric acids were the major phenolic compounds found in BRS Clara and were also important in BRS Morena, although anthocyanins were the main phenolic compounds in the latter case. These results suggest that the entire grapes, including the skin, may potentially possess properties that are beneficial to human health. In this context, the BRS Morena grape can be considered as a high resveratrol producer.     

From plums to prunes: influence of drying parameters on polyphenols and antioxidant activity

Prunes, which are industrially obtained by dehydrating fresh plums at 85-90 degrees C for 18 h, contain higher levels of phenolic compounds than most other fruits. Prune phenolics have shown beneficial effects on human health. Reports are available in the literature on ascorbic acid, phenol composition, and antioxidant activity of fresh plums and prunes, but there is a lack of publications on the influence of drying parameters on the phenolic compounds and antioxidant activity. A study was carried out on two plum cultivars using two sets of air-drying temperatures: (i) air temperature at 85 degrees C until 50% of prune moisture level and then the temperature was lowered to 70 degrees C; (ii) air temperature at 60 degrees C. Whole fresh and dried fruits were assessed for phenolics (catechins, hydroxycinnamic acids, anthocyanins, and flavonols), ascorbic acid, and antioxidant activity (all parameters were calculated on a dry matter basis). Analysis of data shows that chlorogenic and neochlorogenic acid changes were affected by both process parameters and cultivar. Drying destroyed anthocyanins, and there was a significant decrease in flavonols. Ascorbic acid was drastically reduced in relation to process temperature. The most striking result was that drying at 85 degrees C doubled antioxidant activity in both cultivars, while contradictory results were found for 60 degrees C processed plums.     

Evolution of antioxidant capacity during storage of selected fruits and vegetables

Interest in the consumption of fresh fruits and vegetables is, to a large extent, due to its content of bioactive nutrients and their importance as dietary antioxidants. Among all of the selected fruits and vegetables, strawberries and black grapes have relatively high antioxidant capacities associated with high contents of total phenolic compounds, ascorbic acid, and flavonols. More interesting, the results of this study indicated that in most fruits and vegetables storage did not affect negatively the antioxidant capacity. Better, in some cases, an increase of the antioxidant capacity was observed in the days following their purchase, accompanied by an increase in phenolic compounds. In general, fruits and vegetables visually spoil before any significant antioxidant capacity loss occurs except in banana and broccoli. When ascorbic acid or flavonoids (aglycons of flavonols and anthocyanins) were concerned, the conclusions were similar. Their content was generally stable during storage.     

Phytochemical composition and antioxidant stability of fortified yellow passion fruit (Passiflora edulis)

Yellow passion fruit juice (PFJ, Passiflora edulis f. flavicarpa) is an important component of many tropical fruit beverages, but limited data exist on its antioxidant chemical composition and stability during processing and storage. PFJ fortified with ascorbic acid (450 mg/L) and sucrose (10%) was compared to a nonfortified control, and each was evaluated with and without vacuum deaeration to remove dissolved oxygen. Following pasteurization, juices were stored for 28 days at 37 degrees C to accentuate physicochemical changes. Pasteurization (85 degrees C for 30 min) resulted in minor changes to physicochemical attributes, but appreciable changes occurred during storage that resulted in termination of the study after 28 days. Oxygen control strategies proved to be ineffective for quality retention and indicated oxygen-independent reactions affecting juice color, phytochemical content, and antioxidant activity. Ascorbic acid and sucrose fortification had an overall preservation effect on total carotenoids, the former resulting in hyperchromic shifts in absorbance, indicating their chemoprotection. Pasteurization resulted in a 25% loss in l-ascorbic acid, which was completely destroyed after 14 days of storage; losses coincided with increased juice browning and formation of 5-hydroxymethylfurfural. Numerous polyphenolics were present in PFJ, and 16 of them were tentatively characterized on the basis of spectral similarities to known standards. Individually, polyphenolics increased during pasteurization, only to decline during storage at elevated temperatures. Antioxidant activity was measured in PFJ and in two subfractions (hydrophilic and lipophilic) after processing and storage, but antioxidant values were nonadditive. A significant chemical interaction affecting antioxidant capacity was found for hydrophilic juice components, but none was observed in the presence of lipophilic phytochemicals. Physicochemical attributes and overall quality of PFJ were retained following pasteurization but were significantly impacted by degradative reactions during accelerated storage.