Grape phenolics are structurally diverse, from simple molecules to oligomers and polymers that are usually designated “tannins,” referring to their ability to interact with proteins. Anthocyanin pigments and tannins are particularly important for red wine quality. Their extraction depends on their location in the berry and their solubility. All phenolic compounds are unstable and undergo numerous enzymatic and chemical reactions. Color and taste changes during red wine aging have been ascribed to anthocyanin-tannin reactions. The structures and properties of tannins and pigmented tannins from these reactions are often misunderstood. Current research on wine phenolic composition is reviewed, with emphasis on the following issues: (1) reactions of tannins yield both larger polymers and smaller species; (2) anthocyanin reactions can generate colorless species as well as polymeric and small various pigments; (3) some polymeric pigments undergo sulfite bleaching while some low molecular weight pigments do not; (4) polymers are both soluble and astringent, so the astringency loss during aging may involve cleavage rather than polymerization; and (5) sensory properties of anthocyanins and tannins are modulated by interactions with other wine components.

Structure and properties of wine pigments and tannins

Phenolic compounds are partly responsible for the color, astringency, and bitterness of wine, as well as for numerous physiological properties associated with wine consumption. Mass spectrometry has allowed for great progress in the identification and characterization of wine polyphenols. The aim of the present article is to summarize the numerous advances recently achieved in this field. The main type of phenolic compounds found in wine, including hydroxybenzoic and hydroxycinnamic acids, stilbenes, flavones, flavonols, flavanonols, flavanols, and anthocyanins, are firstly described. Chemical reactions and mechanisms involving phenolic compounds during winemaking are also extensively discussed, including enzymatic and chemical oxidation reactions, direct and acetaldehyde-mediated anthocyanin-tannin condensation reactions, acetaldehydemediated and glyoxylic acid-mediated tannin-tannin condensation reactions and, C-4/C-5 anthocyanin cycloaddition reactions with 4-vinylphenols, vinylflavanols and pyruvic acid, among others, leading to the formation of pyranoanthocyanins. Useful mass spectral data of well-known and novel phenolic compounds recently identified in wine, and details related to their fragmentation pathway according to different ionization techniques, are given.

Updated Knowledge About the Presence of Phenolic Compounds in Wine

Effect of oxygenation on polyphenol changes occurring in the course of wine-making

Extraction of phenolic compounds from elder berry and different grape marc varieties using organic solvents and/or supercritical carbon dioxide

Originating in the grapes, anthocyanins and their derivatives are the crucial pigments responsible for the red wine color. During wine maturation and aging, the concentration of monomeric anthocyanins declines constantly, while numerous more complex and stable anthocyanin derived pigments are formed, mainly including pyranoanthocyanins, polymeric anthocyanins produced from condensation between anthocyanin and/or flavan-3-ols directly or mediated by aldehydes. Correspondingly, their structural modifications result in a characteristic variation of color, from purple-red color in young red wines to brick-red hue of the aged. Because of the extreme complexity of chemical compounds involved, many investigations have been made using model solutions of know composition rather than wine. Thus, there is a large amount of research still required to obtain an overall perspective of the anthocyanin composition and its change with time in red wines. Future findings may well greatly revise our current interpretation of the color in red wines. This paper summarizes the most recent advances in the studies of the anthocyanins derived pigments in red wines, as well as their color evolution.

https://www.mdpi.com/1420-3049/17/2/1483/pdf

Anthocyanins and their variation in red wines. II. Anthocyanin derived pigments and their color evolution.

A pigment derived from the acetaldehyde-mediated condensation between (+)-catechin and malvidin 3-O-glucoside has been prepared and isolated by semipreparative HPLC, and its characteristics of color and stability have been studied and compared with that of malvidin glucoside in aqueous solutions. When the pH was increased from 2.2 to 5.5, the solution of the pigment became progressively more violet (lambda(max) = 560 nm at pH 5.5), whereas similar solutions of the anthocyanin were almost colorless at pH 4.0. This behavior indicated that the anthocyanin moiety of the pigment was more protected against water attack, and thus the formation of its quinonoidal forms was favored. The color of the pigment also showed more stability with regard to bleaching by SO(2) than that of malvidin glucoside. Nevertheless, the pigment was more sensitive to degradation in aqueous solution than the anthocyanin. The cleavage of the ethyl bridge that links the anthocyanin and the catechin constituted the first step in its degradation, as demonstrated by the formation of malvidin glucoside as a major product.

Color and stability of pigments derived from the acetaldehyde-mediated condensation between malvidin 3-O-glucoside and (+)-catechin.

Cullen´s sign and Grey Turner sign are, respectively, the cutaneous ecchymoses located in periumbilical region and tissues flanks along the lower portion of the abdomen. Both have been observed in <1% of individuals with acute pancreatitis, suggesting poor prognosis in terms of gravity and mortality. However, these signs are not exclusive for acute pancreatitis, as they can appear in other identities such as: ruptured ectopic pregnancy, aortic aneurysm, rectus abdominis muscle hematoma, perforated duodenal ulcer, common bile duct rupture and biliary peritonitis, idiopathic perirenal hemorrhage, infectious mononucleosis with splenic rupture, metastatic esophageal and thyroid cancer, non-Hodgkin lymphoma, amoebic liver abscess, portal hypertension, and liver tumor disease. Based on the review of the literature, it is patent that Cullen´s sign and Grey Turner sign are neither sensitive nor specific for acute pancreatitis, therefore it may be best to relate these findings in the physical examination to conditions associated with abdominal pathology and retroperitoneal hemorrhage. We report the case of a 60-year-old Spanish female, with previous history of squamous small cell neuroendocrine lung carcinoma with hepatic extension in follow-up by palliative care services. Due to disease progression after two palliative chemotherapy sessions, the patient came to the emergency room with jaundice and abdominal pain in superior regions. On physical examination, notable findings included ecchymoses in the right flank and periumbilical region. Laboratory findings showed elevated bilirubin and transaminase levels, as well as a small increase in the serum amylase and lipase levels. Cholangioresonance was performed to discard acute biliary pancreatitis. The imaging revealed no enlargement of the pancreas, dilatation of the common bile duct without visible stone, and a liver full of new cancerous liver implants. These findings were consistent with diffuse distribution metastases lesions, concluding the progression of liver disease.

/pdf/uncommon-etiology-of-cullens-sign-and-grey-turner-sign-3cbkiv4z.pdf

Marta Álvarez-García

Papers

Color and stability of pigments derived from the acetaldehyde-mediated condensation between malvidin 3-O-glucoside and (+)-catechin.

Uncommon etiology of Cullen´s sign and Grey Turner sign.