Wine Technology Research Articles

Transgenic wine yeast technology comes of age: is it time for transgenic wine?

Saccharomyces cerevisiae is the main yeast responsible for alcoholic fermentation of grape juice during wine making. This makes wine strains of this species perfect targets for the improvement of wine technology and quality. Progress in winemaking has been achieved through the use of selected yeast strains, as well as genetic improvement of wine yeast strains through the sexual and pararexual cycles, random mutagenesis and genetic engineering. Development of genetically engineered wine yeasts, their potential application, and factors affecting their commercial viability will be discussed in this review.

Scaling-up in industrial winemaking using low electric current as an alternative to sulfur dioxide addition

To better understand the outcome of employing low electric current (LEC) technology as a new preservation and alternative in wine technology, and to contribute to its development. It is used in industrial-scale winemaking with commercial yeast (Saccharomyces cerevisiae) during the grape must fermentation. LEC (200 mA, time 16 days) was applied to fresh grape must as an alternative method to the usual sulfur dioxide addition used in the industrial process; two tanks, each 30,000 l, were employed for parallel fermentations. The results show that LEC decreased the survival time and increased the death rate of apiculate yeasts, whereas it did not affect the growth and survival of S. cerevisiae. A comparison was made of the main chemical and sensory parameters of the wines obtained. The results have demonstrated that the low-voltage treatment had a positive effect on the grape juice fermentation (yeast microflora) during the early stages of winemaking. SIGINIFICANCE AND IMPACT OF THE STUDY: These results could be of significant importance in developing, for 'biological wine', new winemaking technologies for an innovative control process of yeast fermentation.

Formulation of low-cost fermentative media for lactic acid production with Lactobacillus rhamnosus using vinification lees as nutrients.

Lees coming from different steps in white wine and red wine vinification were characterized under physicochemical analyses to determine the content in carbon, nitrogen, ashes, solids in suspension, organic compounds, and minerals. Due to the hydrolytic activity of Lactobacillus strains, lees without autolysis treatments were used directly as the unique nutrient or in combination with corn steep liquor to carry out the glucose to lactic acid fermentation with Lactobacillus rhamnosus CECT-288. Time courses of glucose and lactic acid were modeled according to reported models. Using 20 g/L of lees coming from the white wine technology and re-collected after the second decanting step before distillation, as the only nutrient, the values achieved (P = 105.5 g/L, Q(P) = 2.470 g/L.h) were even higher than those obtained with the costly MRS broth (P = 104.3 g/L, Q(P) = 2.251 g/L.h).

Comparison of some commercial pectic enzyme preparations applicable in wine technology

The preparations of pectic enzymes are used for a more efficient extraction of desirable red grape pigments and other phenol compounds which are bound in plant cells and can be faster released by the action of pectic enzymes. Moreover, they shorten the time of maceration, settling, and filtration. The results of our experiments gives a comparison of the efficiency of preparations applicable in wine technology. The best preparation was Trenolin Rot followed by Vinozym G that could shorten the time of prefermentation to about 3 days thanks to a more intensive extraction of red grape pigments. By using the enzyme preparations Gammapect AWP and Ovopres, the time of filtration was ten times shorter. Compared to the control sample, the speed of desliming was threefold and twofold faster, respectively, for Gammapect AWP and Gammapect W2L.  

The aroma of grapes. Localisation and evolution of free and bound fractions of some grape aroma components c.v. Muscat during first development and maturation

AbstractThe localisation of some aroma components in the different parts of the berry of Muscat grape varieties was studied. The evolution of these compounds was also monitored during the development and maturation of the fruit. The aromatic substances were certain terpenols in free and glycosidically bound forms and certain aromatic alcohols, benzyl and 2‐phenyl ethyl alcohols. The skin was the richest in free and bound terpenols in the berry. The ratio of bound free terpenols in skin, pulp and juice was similar. Free terpenols (in particular geraniol and nerol) were much more abundant in skin than in juice. It was possible to distinguish between the two Muscat varieties studied here using their levels of bound terpenols. These were abundant from the green stage of the grape berry onwards; their levels increased during development of the fruit to reach very high levels at the end of maturation. The bound terpenols have a considerable aroma potential, mainly located in grape skins, which it would be interesting to make use of in new wine technology.

Význam selektovaných vínnych kvasiniek vo vinárskej technológii. IV. Časť: Aplikácia aktívnych suchých vínnych kvasiniek v československom vinárstve.

Význam selektovaných vínnych kvasiniek vo vinárskej technológii. IV. Časť: Aplikácia aktívnych suchých vínnych kvasiniek v československom vinárstve.

Význam selektovaných vínnych kvasiniek vo vinárskej technológii. II. časť: Príprava a charakteristika aktívnych suchých vínnych kvasiniek.

Význam selektovaných vínnych kvasiniek vo vinárskej technológii. II. časť: Príprava a charakteristika aktívnych suchých vínnych kvasiniek.

Význam selektovaných kvasiniek vo vinárskej technológii. I. Časť: Úloha a postavenie čistých kultúr vinných kvasiniek v československom vinárstve.

Význam selektovaných kvasiniek vo vinárskej technológii. I. Časť: Úloha a postavenie čistých kultúr vinných kvasiniek v československom vinárstve.

Induction de la fermentation malolactique des vins par inoculation d'une biomasse industrielle congelée de <em>L. oenos</em> après réactivation

<p style="text-align: justify;">Stimulation of malolactic fermentation can be obtained by adding to wine an industrial biomass of <em>L. oenos</em>. Before use, deepfreeze bacteria need to be reactivated according to some special conditions which have been studied. Yeasts concerned in alcoholic fermentation have an influence on malolactic fermentation capacity of wines ; this fact is in connection with some differences observed in wine technology. Among the strains of commercial dry yeasts, the influence of <em>S. cerevisiae</em> is lower than that of <em>S. bayanus</em>.</p>

Immobilization ofLeuconostoc Oenosml 34 in Calcium Alginate Gels and its Application to Wine Technology

<i>Leuconostoc oenos</i> ML 34 cells were immobilized in 1.67% calcium alginate gels to test their ability to convert L-malic acid into L-lactic acid in wine. Activity of the immobilized cells, assayed in standard buffers, was highest at pH 4.0 and 15% ethanol (v/v), and it stayed constant for 540 min. The sequential replacement of the spent incubation medium with fresh medium gave rise to an increase in activity during the first two days and to a decrease in activity thereafter. After 36 days, the activity was 60% of the maximum. About 45% to 60% of the L-malic acid was transformed into L-lactic acid by the immobilized cells in wine, and the decrease in titratable acidity was equivalent to 50% of the L-malic acid originally present, in accordance with the mechanism of malolactic fermentation in winemaking. After stirring the gels in wine several times, the activity of the immobilized cells gradually decreased until no activity was detectable. The living cells inside the gel were 2 x 10⁸/mL, and only 0.1% leakage occurred during use.

Grapes and Wine Technology: Grapes to Wine

Wine making is an art which is developing more into a science. This paper concerns wine technology particularly as it relates to growing the grape to fermentation of grape juice, subsequent storage and aging of wine, and finally to its evaluation as a quality wine. Factors which affect growing of grapes, such as geographical location requirements, time of physiological maturity and subsequent harvest, are discussed. Classification of different vineyards according to the heat summation technique is described. During grape juice fermentation, the important role of sulfur dioxide, acidity, incubation temperature, and oxygen content are discussed as well as the relationship between sugar concentration and alcohol production. Type of storage and manner of aging the wine further play a very critical role in development of a quality wine. Finally, grading of wine is discussed with respect to the relative importance of individual characteristic qualities such as appearance, color, aroma and bouquet, vinegary taste, total acidity, sweetness, body, flavor, bitterness, and general quality. Ultimately, each bottle of wine must be judged on its own merits based on each consumer's attitude and experiences with wine drinking.

The Technology of Passion Fruit and Mango Wines

The two fruits studied (passion fruit, "Maracuya" variety, and mango, "Hilacha" variety) can be recommended as raw materials for the production of good-quality fruit wines; passion fruit for dessert wine, and mango for white semisweet table wine. Technological schemes for the production of these wines are presented. Tables describing the taste and chemical composition of these wines are given which show necessary specifications for production.

Úloha kyseliny mléčné ve vinařské technologii.

Úloha kyseliny mléčné ve vinařské technologii.

Použití tepla ve vinařské technologii.

Použití tepla ve vinařské technologii.

Chemistry and Technology of Wines and Liquors

Chemistry and Technology of Wines and Liquors