ABSTRACT
We evaluated the effect of addition of commercially available pectolytic enzyme preparations in the must from Sharad variety, cultivated in India and its influence on some oenological parameters of red wine. The small scale fermentations demonstrated marked difference of organoleptic (colour) and rheologic characteristics (filterability, settling rates) and aroma between enzyme treated samples and control samples. We observed 29% enhancement in free-run juice yield and a remarkable 43% reduction in the fermentation time compared to the control. This biotechnological approach has demonstrated the economic feasibility and the benefits of adding 0.05 g. Kg-1 grapes pectolytic enzyme in terms of yield, aroma, colour, clarity and fermentation period.
Subject(s)
Beverages/analysis , Beverages/standards , Color , Enzymes/metabolism , Feasibility Studies , Fermentation , Food Technology/methods , Odorants , Pectins/metabolism , Quality Control , Saccharomyces cerevisiae/metabolism , Time Factors , Vitis/metabolism , Vitis/microbiology , Wine/analysis , Wine/standardsABSTRACT
The aim of this work was to evaluate the fate of ochratoxin A (OTA) content from must to wine during the red wine making process in a pilot scale vinification. The study was done using musts obtained from two red grape varieties (Bonarda and Tempranillo) artificially contaminated with two OTA levels. A duplicate set of tanks of 100 l each was established for each must (Bonarda and Tempranillo). The fermentations were initiated by inoculation of two Saccharomyces spp. strains having different fermentation performance. The must from the Tempranillo variety was spiked with 6 μg/l of OTA while that from the Bonarda variety with 0.3 μg/l of the toxin. Samples were collected at different stages of the process. Performance of the alcoholic and malolactic fermentations was monitored. Titratable and volatile acidity, pH, ethanol, sugar and SO2 concentrations were determined following standard methods proposed by the Office International de la Vigne et du Vin (OIV). OTA analysis was done by HPLC. Detection and quantification limits were 0.01 and 0.1 ng/ml, respectively. The OTA levels during the vinification trials dropped to an average of about 86.5%. The type of Saccharomyces strains used showed no effect on toxin reduction.
El objetivo del presente trabajo fue evaluar la evolución del contenido de ocratoxina A (OTA) en mostos durante un proceso de vinificación a escala piloto. Se utilizaron mostos de dos variedades de uvas tintas (Bonarda y Tempranillo) contaminados artificialmente con dos niveles distintos de OTA. El ensayo fue llevado a cabo por duplicado en tanques de fermentación de 100 l cada uno. La fermentación se inició mediante la inoculación de dos cepas de Saccharomyces spp. con diferentes características fermentativas. El mosto de la variedad Tempranillo fue contaminado con 6 μg/l de OTA y el mosto de la variedad Bonarda con 0,3 μg/l de la toxina. Se colectaron muestras durante los diferentes estadios del proceso de vinificación. Se estableció el avance de dicho proceso sobre la base de la evolución de las fermentaciones alcohólica y maloláctica. Se determinó la acidez total y volátil, el pH y el contenido de etanol, de azúcar y de SO2 siguiendo los protocolos estándares propuestos por la Oficina Internacional de la Vid y el Vino (OIV). El contenido de OTA se evaluó por HPLC. Los límites de detección y cuantificación fueron 0,01 y 0,1 ng/ml, respectivamente. Los niveles de OTA disminuyeron alrededor del 86,5% al final del proceso de vinificación. El tipo de cepa de Saccharomyces spp. utilizada no tuvo efecto sobre la reducción de OTA.
Subject(s)
Food Contamination , Industrial Microbiology/methods , Ochratoxins/analysis , Wine/analysis , Argentina , Ethanol/analysis , Fermentation , Hydrogen-Ion Concentration , Industrial Microbiology/standards , Pilot Projects , Species Specificity , Saccharomyces cerevisiae/classification , Saccharomyces cerevisiae/metabolism , Vitis/chemistry , Vitis/classification , Wine/standardsABSTRACT
A avaliaçäo sensorial realizada por um grupo de degustadores utilizando critérios objetivos é uma das maneiras mais eficazes de apreciar a qualidade de um vinho. Este trabalho descreve metodologia para testar a homogeneidade e a eficiência de degustadores, levando em consideraçäo um conjunto de 23 variáveis simultaneamente, utilizando-se o potencial das análises multivariadas