Metabolic constituents of grapevine and grape-derived products

The numerous uses of the grapevine fruit, especially for wine and beverages, have made it one of the most important plants worldwide. The phytochemistry of grapevine is rich in a wide range of compounds. Many of them are renowned for their numerous medicinal uses. The production of grapevine metabolites is highly conditioned by many factors like environment or pathogen attack. Some grapevine phytoalexins have gained a great deal of attention due to their antimicrobial activities, being also involved in the induction of resistance in grapevine against those pathogens. Meanwhile grapevine biotechnology is still evolving, thanks to the technological advance of modern science, and biotechnologists are making huge efforts to produce grapevine cultivars of desired characteristics. In this paper, important metabolites from grapevine and grape derived products like wine will be reviewed with their health promoting effects and their role against certain stress factors in grapevine physiology

Anthocyanidins and anthocyanins: colored pigments as food, pharmaceutical ingredients, and the potential health benefits

Anthocyanins are colored water-soluble pigments belonging to the phenolic group. The pigments are in glycosylated forms. Anthocyanins responsible for the colors, red, purple, and blue, are in fruits and vegetables. Berries, currants, grapes, and some tropical fruits have high anthocyanins content. Red to purplish blue-colored leafy vegetables, grains, roots, and tubers are the edible vegetables that contain a high level of anthocyanins. Among the anthocyanin pigments, cyanidin-3-glucoside is the major anthocyanin found in most of the plants. The colored anthocyanin pigments have been traditionally used as a natural food colorant. The color and stability of these pigments are influenced by pH, light, temperature, and structure. In acidic condition, anthocyanins appear as red but turn blue when the pH increases. Chromatography has been largely applied in extraction, separation, and quantification of anthocyanins. Besides the use of anthocyanidins and anthocyanins as natural dyes, these colored pigments are potential pharmaceutical ingredients that give various beneficial health effects. Scientific studies, such as cell culture studies, animal models, and human clinical trials, show that anthocyanidins and anthocyanins possess antioxidative and antimicrobial activities, improve visual and neurological health, and protect against various non-communicable diseases. These studies confer the health effects of anthocyanidins and anthocyanins, which are due to their potent antioxidant properties. Different mechanisms and pathways are involved in the protective effects, including free-radical scavenging pathway, cyclooxygenase pathway, mitogen-activated protein kinase pathway, and inflammatory cytokines signaling. Therefore, this review focuses on the role of anthocyanidins and anthocyanins as natural food colorants and their nutraceutical properties for health. Abbreviations: CVD: Cardiovascular disease VEGF: Vascular endothelial growth factor

Factors affecting the formation of red wine pigments

The development of pigments during red wine fermentation has been shown to proceed by the conversion of the relatively unstable grape-derived anthocyanins to more complex and color stable pigments through the formation of both ethyl-linked and vitisin-like pigments. These ethyl-linked pigments are more resistant to hydration and bisulfite bleaching than the parent anthocyanins, a phenomena explained by steric hindrance to nucleophilic attack and by alteration of the electronic properties of the anthocyanin entity. Furthermore, they have been shown to be formed rapidly during fermentation and likely to consume much of the anthocyanins extracted from the grapes. Because they are purple in color it is suggested that the purple hues of young red wines, particularly immediately after the completion of fermention, are a result of the high concentrations of these pigments. The ethyl-linked pigments are degraded quickly with time, however, and may provide a pool of reactive intermediates in the formation of more stable red wine pigments. The vitisin-like compounds, on the other hand, are long lived and have been shown to persist in red wine over many decades. Whilst the reaction to produce the ethyl-linked pigments requires the loss of a proton in the reaction sequence, the production of the vitisin-type compounds depends on an oxidation step. The presence of atmospheric oxygen has been shown to be necessary for the formation of vitisin A in model systems but in red wine ferments the rate of vitisin A synthesis may be correlated with active oxidants rather than just oxygen concentration. © 2004 American Chemical Society.David F. Lee, Ewald E. Swinny, Robert E. Asenstorfer, Graham P. Joneshttp://www.lavoisier.fr/notice/gb281521.htm

Toward an understanding of mechanisms involved in non-polyphenol oxidase (non-ppo) darkening in yellow alkaline noodles (YAN)

Asian noodles prepared from bread wheat flour darken over time due to a combination of polyphenol oxidase (PPO) activity and non-PPO effects. Although the enzymatic mechanism associated with the PPO reaction is well established, the non-PPO component consists of both physical (e.g., changes in surface properties) and chemical reactions. Variations in pH and solvents were used to gain a quantitative estimate of the contribution of physical and chemical components to non-PPO darkening in yellow alkaline noodles (YAN). In a set of five common high-PPO Australian wheat cultivars it was estimated that on average non-PPO darkening accounted for 69% of total darkening, with approximately two-thirds of this due to physical darkening and one-third had a chemical origin. Data from the chemical portion of non-PPO darkening is consistent with the presence of a PPO-like enzyme that oxidizes tyrosine, has a pH maximum of 8.1, and is inhibited by 50% methanol or ethanol but in the noodle is insensitive to PPO inhibitors such as tropolone. Therefore, with low-PPO and PPO-free wheat varieties becoming available, it may be possible to further reduce darkening in YAN by breeding for wheat varieties with low or zero levels of this PPO-like enzyme.Robert E. Asenstorfer, Marie J. Appelbee, Christine A. Kusznir, and Daryl J. Mare

Oxovitisins: A new class of neutral pyranone-anthocyanin derivatives in red wines

Jingren He, Joana Oliveira, Artur M. S. Silva, Nuno Mateus, and Victor De Freita