tannins and tartaric-acid

Atmospheric aerosol particles can exhibit liquid solution concentrations supersaturated with respect to the dissolved organic and inorganic species and supercooled with respect to ice. In this study, thermodynamic and optical properties of sub- and supersaturated aqueous solutions of atmospheric interest are presented. The density, refractive index, water activity, ice melting temperatures, and homogeneous ice freezing temperatures of binary aqueous solutions containing L(+)-tartaric acid, tannic acid, and levoglucosan and ternary aqueous solutions containing levoglucosan and one of the salts NH(4)HSO(4), (NH(4))(2)SO(4), and NH(4)NO(3) have been measured in the supersaturated concentration range for the first time. In addition, the density and refractive index of binary aqueous citric acid and raffinose solutions and the glass transition temperatures of binary aqueous L(+)-tartaric acid and levoglucosan solutions have been measured. The data presented here are derived from experiments on single levitated microdroplets and bulk solutions and should find application in thermodynamic and atmospheric aerosol models as well as in food science applications.

Topics: Aerosols; Ammonium Sulfate; Atmosphere; Glucose; Nitrates; Optical Phenomena; Particulate Matter; Tannins; Tartrates; Thermodynamics; Water

Red muscadine (Vitis rotundifolia Michx.) juices with natural organic, phenolic acids and polyphenol compounds were tested against Cronobacter sakazakii. The concentration of total phenolic compounds of commercial baby juices ranged from 176.7 to 347.7 mg/mL. Commercial baby juices showed poor antimicrobial activity, reducing less than 1-log of C. sakazakii in juice samples for 2 h at 37 degrees C. Red muscadine juices, regardless of processing methods (filtration, pasteurization, and sterilization), achieved a 6-log reduction of C. sakazakii in the same time period (2 h). The mixture of synthetic organic acids (malic and tartaric acids) and polyphenolic acid (tannic acid) showed strong antimicrobial activity against C. sakazakii. Among synthetic organic acids, tannic acid was undetected in commercial baby juices. Tannic acid showed the highest antimicrobial activity (1.4- to 3.8-log reduction) against C. sakazakii, while malic and tartaric acids showed less than 0.5-log reduction. These results suggest that red muscadine juice could be utilized as a natural antimicrobial in baby food formulations to inhibit C. sakazakii.

Topics: Anti-Infective Agents; Beverages; Cronobacter sakazakii; Ellagic Acid; Flavonoids; Food Handling; Food Microbiology; Food Preservatives; Fruit; Humans; Hydrogen-Ion Concentration; Infant; Infant Food; Malates; Phenols; Polyphenols; Resveratrol; Stilbenes; Tannins; Tartrates; Vitis

The objectives of this research were to show the anti-Escherichia coli O157:H7 effect of fresh (FRMJ) and processed red muscadine (Vitis rotundifolia) juice (PRMJ) and to discern the active compounds responsible for anti-E. coli O157:H7.. Polar and phenolic compounds of FRMJ and PRMJ were analysed by high-performance liquid chromatography. Antibacterial activity of FRMJ, PRMJ, their polar and polyphenol fractions, individual synthetic acids and their mixture with or without sugars were investigated on E. coli O157:H7. FRMJ and PRMJ inactivated (P < or = 0.05) 5-log cocktail cells of E. coli O157:H7 within 4 h at 37 degrees C. Polar fractions that contained malic, tartaric and tannic acids showed strong antimicrobial activity (P < or = 0.05) against E. coli O157:H7. Tannic acid among the synthetic acids showed the highest antimicrobial activity against E. coli O157:H7.. FRMJ, PRMJ and their polar compounds showed strong anti-E. coli O157:H7 activity.. Earlier findings have failed to show any anti-E. coli O157:H7 effect of grape juice without adding preservatives. Our findings show that red muscadine juice has natural antibacterial substances and suggest that these can be used as active antimicrobial ingredients against E. coli O157:H7 in nonalcoholic beverages.

Topics: Anti-Bacterial Agents; Beverages; Chromatography, High Pressure Liquid; Colony Count, Microbial; Dicarboxylic Acids; Escherichia coli O157; Food Microbiology; Food Preservation; Malates; Tannins; Tartrates; Vitis

Water-soluble extracts were prepared from purple (cultivar Ison) and bronze (cultivar Carlos) muscadine seeds with or without heating. The Ison extracts had strong antimicrobial activity against a cocktail of three strains of Escherichia coli O157: H7. This extract had higher acidity (pH 3.39 to 3.43), total phenolics (2.21 to 3.49 mg/ml), tartaric acid (5.6 to 10.7 mg/ml), tannic acid (5.7 to 8.1 mg/ml), and gallic acid (0.33 to 0.59 mg/ml) than did the Carlos extracts. Heat treatment on both extracts increased antimicrobial activity, possibly because of increased acidity, tartaric acid, total phenolics, and individual phenolics. Heating of Ison extracts increased ellagic acid up to 83%. Up to 10.7 mg/ml tartaric acid alone was not as effective against E. coli O157:H7 as were water-soluble seed extracts. This finding suggests the involvement of other factors, such as tannic and gallic acids, in inactivation of this pathogen. Water-soluble muscadine seed extracts may be useful for incorporation into juice and other beverage products as natural preservatives.

Topics: Anti-Bacterial Agents; Colony Count, Microbial; Dose-Response Relationship, Drug; Ellagic Acid; Escherichia coli O157; Food Preservation; Hot Temperature; Humans; Hydrogen-Ion Concentration; Microbial Sensitivity Tests; Phenols; Plant Extracts; Seeds; Solubility; Tannins; Tartrates; Vitis