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Bioactive, structural, and mechanical properties were measured of a cellulose biopolymer produced by Gluconacetobacter xylinus using hydrolyzed collagen and phenolic compounds from teas and grape pomace (GP) in an optimized culture medium. Biopolymers were impregnated with an antibiotic to investigate possible antibacterial activities. Hybrid bacterial cellulose (BC)-collagen membranes obtained from cultures with green tea and a ternary mixture (TM) of teas with GP presented a high concentration of phenolic compounds (879.7 and 1312.8 mg gallic acid equivalent per liter) and antioxidant activity (973.3 and 575.9 mmol/g), respectively. BC membranes included a nanodimensional network of microfibrils, and the addition of hydrolyzed collagen in the TM of teas in situ resulted in thicker structures with improved mechanical properties. BC-collagen membranes pretreated with cephalexin exhibited significant inhibition against Escherichia coli and Staphylococcus aureus. The enrichment of the culture media with plant phenolic compounds and collagen resulted in the formation of hybrid BC membranes in a shorter time when compared to those produced without these components. Membranes modified with bioactive compounds in situ and antibiotics ex situ can be turned into potential products for application in biomaterials with antioxidant activity. KEYWORDS antimicrobial activity, antioxidant activity, bacterial cellulose, grape pomace, teas, 1 | INTRODUCTION Bacterial cellulose (BC) is a polysaccharide that forms as a pellicle at the interface air/culture media. This polysaccharide is secreted by bacterial cells, such as those of [...]

Byline: Gerard Gremaud (1), Sylvie Quaile (2), Umberto Piantini (3), Elmar Pfammatter (4), Claude Corvi (5) Keywords: Swiss wine; Geographical origin; Isotopes; IRMS; Elemental analysis; FT-IR Abstract: The objective of this work was to study methods to check the geographical origin of Swiss wines. Authentic grape samples from the vintages 2000 and 2001 were collected in representative locations, and the wines produced from these samples were subjected to isotopic [(.sup.2]H/ [.sup.1]H.sub.ethanol 18.sup.O/ [.sup.16]O.sub.wine water), elemental (Mn, Al, B, Ba, Ca, Fe, Mg, Na, Rb, Sr, Zn) and FT-IR (ethanol, pH, total acidity, volatile acidity, malic acid, fructose, tartaric acid, lactic acid, succinate, citric acid, glycerol, 2,3-butandiol, dry matter and relative density (d .sub.20)) analyses. The results showed that the variables 18.sup.O/ [.sup.16]O.sub.wine water, strontium, rubidium, and ethanol%, when considered in a monovariate approach, allowed the best discrimination of the geographical origins of Swiss wines. By using a combination of all variables (multivariate approach), Switzerland was divided in four main production zones with a separation power that has never before been achieved. These zones were defined as Tessin, Valais, Romandie and Alemanique. A fifth zone (Graubunden) could be evidenced in vintage 2001. Author Affiliation: (1) Swiss Federal Office of Public Health, 3003, Bern, Switzerland (2) Nestle Research Center, 1000, Lausanne 26, Switzerland (3) University of Applied Sciences (HEVs), 1950, Sion, Switzerland (4) Official Laboratory of the Canton of Valais, 1950, Sion, Switzerland (5) Service de protection de la consommation, 1211, Geneve 4, Switzerland Article History: Registration Date: 16/03/2004 Received Date: 05/12/2003 Online Date: 03/04/2004

Byline: Emma Cantos (1), Francisco A. Tomas-Barberan (1), Adrian Martinez (2), Juan Carlos Espin (1) Keywords: HPLC-MS-MS; Post-harvest; Piceatannol; Piceid; Resveratrol; Stilbenes; UV-C irradiation; Viniferins; Vitis vinifera; Wine; Wine grapes Abstract: The stilbene induction capacity of the red wine grape varieties 'Tempranillo' (TEM), 'Cabernet Sauvignon' (CAS), 'Merlot' (MER), 'Syrah' (SYR), 'Monastrell' (MON), 'Garnacha' (GAR) and 'Carinena' (CAR) exposed to post-harvest UV-C irradiation is reported for the first time. The induction of trans-piceatannol, trans-resveratrol and viniferins, among other stilbenes, was characterized using high-performance liquid chromatograph with diode-array and mass spectrometric detection (HPLC-DAD-MS-MS). All the wine grape varieties increased their resveratrol, piceatannol and viniferin content after UV-C treatment with the exception of the variety MON in which only piceatannol was induced. Other stilbenes such as astringin (piceatannol glucoside) or piceid (resveratrol glucoside) were induced to a lesser extent and only in some varieties. The stilbene induction capacity of grapes submitted to UV-C irradiation did not necessarily match the final corresponding maximum stilbene content reached in each variety. The total stilbene induction capacity of the grapes ranged from 2.4-fold (in MER) to 10.9-fold (in both CAS and CAR) with respect to untreated grapes (control). The total stilbene content (mg stilbene/100 g fresh weight, fw) after UV-C irradiation ranged from 1.16 in MON to 3.5 in MER. In general, the maximum induction of specific stilbenes in all the varieties followed the sequence: resveratrol &gt piceatannol &gt [epsilon].sub.1-viniferin &gt piceid. This maximum induction was 22.7-fold for resveratrol in CAS, 6.4-fold for piceatannol in CAR, 3.8-fold for piceid in TEM and 8.4-fold for [epsilon].sub.1-viniferin in both CAS and CAR with respect to the control. The maximum concentration of the specific stilbenes reached after UV-C irradiation was 2.5 (mg stilbene/100 g fresh grape weight) for resveratrol in MER, 0.42 for piceatannol in MER, 0.16 for piceid in MON and 0.39 for [epsilon].sub.1-viniferin in CAR. The screening of stilbene induction capacity in red wine grapes treated with UV-C irradiation could be useful for selecting the most suitable variety to produce stilbene-enriched red wines with potentially increased health-promoting properties. Author Affiliation: (1) Research Group on Quality, Safety and Bioactivity of Plant Foods, Department of Food Science and Technology, CEBAS-CSIC, P.O. Box 164, 30100, Espinardo, Murcia, Spain (2) Department of Viticulture and Enology, CIDA Consejeria de Agricultura Ganaderia y Pesca, 30150 , La Alberca (Murcia), Spain Article History: Received Date: 11/02/2003 Online Date: 02/08/2003

Byline: Xinxin Guo (1), Dane Bicanic (2,4), Koos Keijser (3), Robert Imhof (1) Keywords: Optothermal transient emission radiometry; Infrared radiation; Non-destructive evaluation; Hydration; Grape Abstract: The concept of optothermal transient emission radiometry at a wavelength of 2.94 um was applied to non-destructively determine the level of hydration and the profile of hydration in the skin of intact fresh grapes taken from top and bottom sections of the same bunch. Author Affiliation: (1) School of EEIE, South Bank University, 103 Borough Road, London, SE1 0AA, United Kingdom (2) Laser Laboratory for Photoacoustic and Photothermal Research, Division of Biophysics, Department of Agrotechnology and Food Sciences, Wageningen University and Research Centre, Dreijenlaan 3, 6703 HA, Wageningen, The Netherlands (3) Plant Morphology, Wageningen University and Research Centre, Arboretumlaan 1, 6704 HE, Wageningen, The Netherlands (4) Laboratory for Food Chemistry and Nutrition, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierotijeva 6, 10000 , Zagreb, Croatia Article History: Received Date: 10/01/2003 Online Date: 22/05/2003

Byline: M. Luz Silva (1), F. X. Malcata (1) Keywords: Key wordsaBagaceira; Grape pomace; Distillation; Volatiles Abstract: aThe effects of fermentation time and distillation cuts on the composition of distillates in terms of ethanal, 1,1-diethoxyethane, methanol, 1-butanol, 2-butanol, 1-propanol, 2-methyl-1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol, ethyl acetate, ethyl 2-hydroxypropanoate, 3-methylbutyl acetate, hexyl acetate, 2-phenylethyl acetate, hexanol, trans-2-hexenol, trans-3-hexenol, cis-3-hexenol, 2-phenylethanol, ethyl butyrate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, ethyl dodecanoate, 2-methylpropanoic acid, 3-methylbutanoic acid, hexanoic acid, octanoic acid, decanoic acid, and dodecanoic acid were assessed through data generated according to a factorial design using analysis of variance and principal component analysis. Four times of storage of pomace obtained following winemaking of two grape varieties of white Verde wine (Alvarinho and Loureiro) and three distillation cuts were considered volatile compounds in the 24 samples generated were analyzed directly, and indirectly after extraction and concentration, by capillary gas chromatography. The results generated have suggested clear differences (P&lt 0.05) between distillate cuts obtained throughout fermentation times for each grape variety. The major differences between the different distillate fractions analyzed were accounted for by the contents of diethyl butanoate, ethyl 2-hydroxypropanoate, and the sum of 3-methylbutanoic and 2-methylpropanoic acids for Loureiro, whereas the main differences were accounted for by the contents of diethyl butanoate and the sum of the carboxylic acids for Alvarinho. Author Affiliation: (1) Escola Superior de Biotecnologia, Universidade Catolica Portuguesa, Rua Dr. Antonio Bernardino de Almeida, P-4200 Porto, Portugal, PT Article note: Received: 23 January 1998 / Revised version: 5 June 1998

The partial purification through XAD-7 column chromatography followed by C-18 HPLC/diode array detector (DAD), HPLC/ MS, and HPLC/MS/MS analysis to determine the characterize and quantify anthocyanins in grape cultivars of OII-Meoru (Vitis coignetiae x Vitis labrusca), Neut-Meoru (Vitis coignetiae x Vitis labrusca), Muscal Bailey A. (Vitis labruscana), and Campbell Early (Vitis labrusca x V. vinifera) grown in Korea is described. The outcomes are the first report on the correct characterization and quantification of anthocyanins in the grape juices cultivated in Korea.

The different impacts of four different commercial pressing methods on the juice stilbene content in muscadine and bunch grapes are determined. The greatest juice stilbene concentration is shown to be achieved by the HP (hot press of fresh berries) method.

The gas chromatography-mass spectrometry technique is employed for the characterization of the free flavor compounds found in Traminette grape . The impact of the vineyard training system and location on their properties is also discussed.

The confidence intervals for the parameters of nutraceuticals and the predicted concentrations are determined using a nonisothermal method. Anthocyanin concentration in the grape pomace is measured and the prediction bands for anthocyanin retention are plotted.