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Ochratoxin A contamination of red wines might be quite severe in certain high-risk regions and vintages, thus requiring corrective measures to fulfill acceptable standards for human consumption. This work proposes an innovative and environmentally friendly corrective measure to reduce ochratoxin A levels by repassage of contaminated musts or wines over grape pomaces having no or little ochratoxin A contamination. Grape pomaces have a high affinity for ochratoxin A and have been shown to remove ochratoxin A from must and wine during vinification. Time course experiments showed that ochratoxin A adsorption by pomaces is a rapid process, reaching equilibrium in less than 10 h, and is not affected by the tested toxin concentrations. Repassage of wine from Primitivo grapes spiked with 2-10 microg/kg ochratoxin A over pomaces obtained from the same grapes removed up to 65% ochratoxin A within 24 h. Similar results (50-65% ochratoxin A reduction) were obtained with Primitivo or Negroamaro wines repassed over pomaces from different grape varieties including white grapes (Malvasia, Greco di Tufo) and red grapes (Sangiovese, Aglianico). Grape pomaces maintained a good efficacy in removing ochratoxin A after being reused four times. Unlike other enological fining agents, the use of grape pomaces to adsorb ochratoxin A from red wines of the same grape variety (Primitivo) did not affect relevant wine quality parameters, including color intensity and health-promoting phenolic content (trans-resveratrol, quercetin, total polyphenols). These quality parameters were instead positively or negatively affected when contaminated wines were repassed over grape pomaces from other grape varieties, the effect being related to the intrinsic characteristics of the pomace variety. The proposed decontamination procedure can be applied in a modern winery provided that contaminated grapes are identified early and processed separately from uncontaminated grapes.

Los orujos de uva son los principales subproductos generados en la vinificación. Existen diversas vías de valorización de estos residuos, destacando la extracción de polifenoles. Sin embargo, no se ha estudiado su composición aromática y las posibilidades de su recuperación. Con el fin de determinar el potencial aromático en orujos de uva de variedades tintas, se ha llevado a cabo un procedimiento experimental basado en una extracción verde empleando disoluciones acuosas y un análisis por cromatografía de gases, previo aislamiento de los aromas por extracción en fase sólida. Asimismo, se ha determinado que los factores de mayor influencia en la extracción de aromas en orujos secados a vacío y liofilizados son pH y temperatura, y se han fijado sus valores óptimos, correspondientes a un pH de 2,4 en el medio y una temperatura de 56 ºC. Los compuestos volátiles más abundantes en los orujos estudiados son alcohol bencílico, 3-metil-butanol, 1-hexanol, ácido hexanoico, decanoato de metilo y hexadecanoato de metilo. Grape pomaces are the most important by-products generated in wine production. There are several options to valorise these wastes, highlighting the extraction of polyphenolic compounds. Nevertheless, its aromatic composition and the possibility to recover its volatile compounds, hasn´t been studied yet. In order to determine the aromatic potential of red grape pomaces, an experimental procedure based on a green extraction by using aqueous solutions and an analysis by gas chromatography, previous isolation of the volatile compounds by solid phase extraction, has been carried out. In addition, it has been determined that the factors that affect significantly in the extraction of volatile compounds in vacuum dried and lyophilized grape pomaces are pH and temperature, established its optimum values as pH 2,4 in the medium and a temperature of 56 ºC. The most abundant volatile compounds determined in the grape pomaces studied are benzyl alcohol, 3-methyl-butanol, 1-hexanol, hexanoic acid, methyl decanoate and methyl hexadecanoate. Máster Universitario en Tecnología y Calidad en las Industrias Agroalimentarias por la Universidad Pública de Navarra Nekazaritzako Elikagaien Industrietako Teknologiako eta Kalitateko Unibertsitate Masterra Nafarroako Unibertsitate Publikoan

Grape pomaces are increasingly being used as starting material in the industrial production of plant food supplements (PFS), food coloring, and tartrates, but they are at risk of ochratoxin A (OTA) contamination, a mycotoxin with nephrotoxic and carcinogenic effects. We analyzed 24 commercial PFS and 13 food coloring samples derived from Vitis vinifera, mainly pomaces, using a HPLC-FLD method for OTA determination. OTA was found in 75% of PFS samples and 69% of food coloring samples at levels of

Ochratoxin A (OTA) is an extremely harmful mycotoxin, having nephrotoxic, immunosuppressive, teratogenic and carcinogenic properties. Aspergillus carbonarius was identified as the main species responsible for OTA accumulation in grape and derived products. During winemaking, 95% of OTA originally present in grapes remains adherent onto pomaces, the main by-product. Grape pomaces are increasingly being used as starting material in the industrial production of plant food supplements (PFS), food colouring and tartrates. The occurrence of OTA in commercially available PFS (24 samples), food colouring (13 samples) and leavening agents containing tartrates (4 samples), all derived from Vitis vinifera was investigated in this study by using an improved HPLC-FLD method. The occurrence of OTA in 32 samples of grape pomaces collected from vineries of Apulia and Basilicata during 2013 and 2014 was also investigated. OTA was found in 75% of commercial PFS samples and 69% of food colouring samples at levels of 0.50-20.23 ?g/Kg and 0.50-32.00 µg/kg, respectively. The four commercial leavening agents containing tartrates were negative for OTA. Ninety-six percent of grape pomaces samples collected in 2013 contained OTA at levels of 3.60-140.90 µg/kg. All samples collected in 2014 contained OTA at level of 2.80-47.30 µg/kg. Higher levels of OTA (up to 849.10 µg/kg) were measured in samples of grape pomaces collected in Apulia in the past. The high incidence of positive samples as well as the high variability of OTA levels in grape pomaces makes it imperative to check the OTA level in this starting material if used for production of PFS and food colouring agents. Maximum permitted level(s) of OTA should be established in commercial PFS and food colouring agents derived from V. vinifera due to the high incidence of OTA contamination in these products.

J. Inst. Brew. 114(3), 262–269, 2008 The enzymatic transformations during storage of pomaces greatly affect the composition of Italian Grappa. This study examines the impact of pectin methylesterase (PME), βglucosidase (βG) and esterases (ESTs) on the composition of Moscato and Prosecco Grappa. Grape pomaces were fermented for differing periods of time. After protein extraction, the enzymatic activities were detected by spectrophotometric and electrophoretic methods. To determine by gas chromatography the evolution of methanol, terpenes, ethyl acetate and lactate in pomaces and Grappa samples, distillations by Cazenave equipment and a traditional copper alambic were performed. Sensorial evaluation was carried out. There is a close relationship between the PME activity of grape pomaces, the degree of pectin methylation, and the concentration of methanol before distillation. The results obtained suggest that inhibition of grape pomaces PME may be adopted to control methanol concentration. The glycosidases of grape and/or yeast seem to have a limited effect on the release of volatile compounds from glycosides located in grape skins. As regards the contribution of grape and microorganism esterase, several hypotheses are discussed.