THERMODYNAMIC PARAMETERS OF POTASSIUM BITARTRATE DURING THE YOUNG WINES COLD STABILIZATION

The present work was undertaken to study the effect of the treatment temperature on the potassium bitartrate stability and composition of young wines. The thermodynamic parameters, namely ∆G°, ∆H°, ∆S° were calculated to predict the nature of potassium hydrogen tartrate (KHT) precipitation. According to the achieved results, the exothermal nature and thermodynamical feasibility of KHT precipitation in young wines were established. Based on thermodynamics, negative ∆G°, ∆H° values and positive ∆S° value give a spontaneous KHT process at lower temperatures

THE INFLUENCE OF THERMAL REGIME ON STABILIZATION PROCESS OF YOUNG WINES INFLUENCE DU RÉGIME THERMIQUE SUR LE PROCESSUS DE STABILISATION TARTRIQUE DES VINS JEUNES

The excess of tartaric salts determines in certain conditions the formation of characteristic crystals that fall in the form of sediment. The aim of the study is to search the optimal process of tartaric stabilization conditions of young wines. We examined the tartaric stabilization of young wines by decreasing their content in tartaric salts by conventional cold stabilization and contact seeding with three thermal regimes (-5 °C, 0 °C and 5 °C). The study results showed a reduction with 23÷40 % of chromatic intensity, with 16.45÷24 % of the content of potassium and a titratable acidity between 0.73 and 1.04 g∙L-1. The recommendations of optimum regime of the stabilization of young wines, based on experimental results, included: cooling of wine at -5 °C or 0 °C, followed by the administration of cream of tartar in a doses 4÷8 g∙L-1, maintaining in these conditions until the stabilization and isothermal filtration before bottling. The described process generates a healthy and balanced product, good nutritional value and organoleptic quality

EQUILIBRIUM AND KINETIC PARAMETERS FOR THE SEDIMENTATION OF TARTARIC SALTS IN YOUNG WINES

In young wines potassium hydrogen tartrate is always present in supersaturating concentration and crystallizes spontaneously. The aim of this study is to obtain kinetic parameters, which explain the stability of young wines during the stabilization treatments. The kinetic and equilibrium parameters were evaluated and discussed. The heating factor has a decisive influence on the reaction rate of potassium hydrogen tartrate precipitation in young wines. An increase of temperature leads to a decrease in efficiency of stabilization process and to an enhancement of the activation energy of the system. According to the obtained experimental results, the optimal regime for production and stabilization of young wines has been established

THE INFLUENCE OF APPLIED STABILIZATION METHOD ON THE CRYSTALLINE STABILITY OF YOUNG WHITE WINES

Crystalline precipitate which occurs due to the presence of tartaric salts is frequently encountered in young wines in form of white-dirty lamellar crystals at the bottom of tank. The aim of the study is to prevent the tartaric salts from crystallization in young wine blend Biance/Sauvignon by implementing various schemes and procedures

EFFECT OF BIOACTIVE ADDITIVES ON BIOMASS FERMENTATION FROM AGROINDUSTRIAL SECTOR

Wastes from the agro-industrial sector, due to their toxic effects with regard to plants and living organisms, cannot be dumped in the soil. However, they can serve as renewable source of value-added products, following the specific digestive treatment. This research was focused on studies of vinasse fermentation processes in the presence of bioactive substances introduced directly into the digested biomass. The results obtained testify that the substances of natural origin used as additives, demonstrate the pronounced effects on alcoholic fermentation of vinasse under the mesophilic conditions. The comparative assessment of different additives action in the studied processes have demonstrated that the dihydroxyfumaric acid caused the emission of 266 cm3 CO2 in 76 hours, aescinum – 251 cm3 in 55 hours, tomatin – 233 cm3 during 78 hours, sclareol – 232 cm3 during 55 hours, vanillin – 229 cm3 during 69 hours, whereas catechin – 180 cm3 during 61 hours of fermentation, until the fermentation process was completed. Thus, the study of the effects of bioactive substances with possible antioxidant properties on biomass from winemaking sector with identification of these processes mechanisms can be a perspective direction, suggesting the new ways of wastes valorisation

POSSIBILITY AND NECESSITY OF TARTARIC ACID PRODUCTION IN THE REPUBLIC OF MOLDOVA

The wine industry has been and remains a source of natural- tartaric acid. The tartaric acid can be obtained from such wastes as grape marcs, yeast, vinasse and wine stone. But the use of these wastes was limited in the Republic of Moldova by the production of tartaric acid lime (calcium tartrate) and wine stone, which were shipped to Ukraine and Armenia where the finished product is obtained. Currently, tartaric acid is used in considerable quantities in the winemaking and food industry, being a quite expensive imported product. The Department of Oenology and Chemistry has developed a complete technological scheme for the use of wine wastes to obtain the finished product – tartaric acid. The realization of the proposed tartaric acid production in the Republic of Moldova is important for the country's economy and it does not require large investments. Wineries can also help to organize tartaric acid production by providing calcium tartrate, wine stone, pressed or dried yeast, and other ingredients

Research and Science Today No. 1(7)/2014

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