beta-Glucanases as a tool for the control of wine spoilage yeasts

The production and application of enzymes related to the quality of fruit wine

Grape wine is the most widely consumed fruit wine in the world. With the increasing diversification of consumers' needs, the variety of fruit wines in the market is becoming more and more abundant. Whether it is the production of grape wine or other fruit wines these processes are inseparable from the participation of enzymes. The quality of these wines is closely related to the application of enzymes in the winemaking process. Enzymes are involved in pretreatment, fermentation, filtration, flavoring, aging and storage of fruit wines. This review systematically illustrated the role of pectinase, β-glucanase, β-glucosidase, glucose oxidase, lysozyme, protease, tannase and urease in the production of wines and their current production status and also provided a theoretical basis for better application of various enzymes in the production of various fruit wines. This knowledge could be great significance to improve the quality of fruit wines and reduce the production costs in the fruit wine industry.

Biotechnological Approach Based on Selected Saccharomyces cerevisiae Starters for Reducing the Use of Sulfur Dioxide in Wine

Sulfites are considered the main additives in winemaking for their antimicrobial, antioxidant and anti-oxidasic activities. The current concern about the potential negative effects of sulfur dioxide (SO2) on consumer health has focused the interest on replacing or reducing SO2 use. Our work aims to develop a strategy based on the use of selected starter culture, able to perform wine fermentation without SO2 addition. Four selected Saccharomyces cerevisiae indigenous strains were tested as mixed starter cultures in laboratory scale fermentations. The starter culture, characterized by a similar percentage of dominance of both strains composing the mixed starter and able to produce a wine characterized by the best combination of chemical and aromatic characteristics, was chosen. This mixed culture was tested as a starter at pilot scale with and without SO2 addition, by using a higher inoculum level in the vinification without SO2. The selected starter confirmed higher dominance ability in vinification without SO2 addition than in SO2-added fermentation, demonstrating that sulfite addition is not a guarantee to reach an absolute dominance of starter culture on indigenous microflora. The proposed biotechnological tool allowed to produce good quality wines possessing also "functional properties", as NO-SO2 added wines were characterized by high polyphenol content and antioxidant activity.

Alternative Methods to SO2 for Microbiological Stabilization of Wine

The use of sulfur dioxide (SO₂ ) as wine additive is able to ensure both antioxidant protection and microbiological stability. In spite of these undeniable advantages, in the last two decades the presence of SO₂ in wine has raised concerns about potential adverse clinical effects in sensitive individuals. The winemaking industry has followed the general trend towards the reduction of SO₂ concentrations in food, by expressing at the same time the need for alternative control methods allowing reduction or even elimination of SO_2. In the light of this, research has been strongly oriented toward the study of alternatives to the use of SO₂ in wine. Most of the studies have focused on methods able to replace the antimicrobial activity of SO₂ . This review article gives a comprehensive overview of the current state-of-the-art about the chemical additives and the innovative physical techniques that have been proposed for this purpose. After a focus on the chemistry and properties of SO₂ in wine_, as well as on wine spoilage and on the conventional methods used for the microbiological stabilization of wine, recent advances on alternative methods proposed to replace the antimicrobial activity of SO₂ in winemaking are presented and discussed. Even though many of the alternatives to SO₂ showed good efficacy, nowadays no other physical technique or additive can deliver the efficacy and broad spectrum of action as SO₂ (both antioxidant and antimicrobial), therefore the alternative methods should be considered a complement to SO₂ in low-sulfite winemaking, rather than being seen as its substitutes.

Zygosaccharomyces rouxii: Control Strategies and Applications in Food and Winemaking

The genus Zygosaccharomyces is generally associated to wine spoilage in the winemaking industry, since a contamination with strains of this species may produce re-fermentation and CO2 production in sweet wines. At the same time, this capacity might be useful for sparkling wines production, since this species may grow under restrictive conditions, such as high ethanol, low oxygen, and harsh osmotic conditions. The spoilage activity of this genus is also found in fruit juices, soft drinks, salad dressings, and other food products, producing besides package expansion due to gas production, non-desired compounds such as ethanol and esters. Despite these drawbacks, Zygosaccharomyces spp. produces high ethanol and acetoin content in wines and may play an important role as non-Saccharomyces yeasts in differentiated wine products. Control strategies, such as the use of antimicrobial peptides like Lactoferricin B (Lfcin B), the use of dimethyl dicarbonate (DMDC) or non-thermal sterilization techniques may control this spoilage genus in the food industry.

Beta-1,3-glucanase from Delftia tsuruhatensis strain MV01 and its potential application in vinification

During vinification microbial activities can spoil wine quality. As the wine-related lactic acid bacterium Pediococcus parvulus is able to produce slimes consisting of a β-1,3-glucan, must and wine filtration can be difficult or impossible. In addition, the metabolic activities of several wild-type yeasts can also negatively affect wine quality. Therefore, there is a need for measures to degrade the exopolysaccharide from Pediococcus parvulus and to inhibit the growth of certain yeasts. We examined an extracellular β-1,3-glucanase from Delftia tsuruhatensis strain MV01 with regard to its ability to hydrolyze both polymers, the β-1,3-glucan from Pediococcus and that from yeast cell walls. The 29-kDa glycolytic enzyme was purified to homogeneity. It exhibited an optimal activity at 50°C and pH 4.0. The sequencing of the N terminus revealed significant similarities to β-1,3-glucanases from different bacteria. In addition, the investigations indicated that this hydrolytic enzyme is still active under wine-relevant parameters such as elevated ethanol, sulfite, and phenol concentrations as well as at low pH values. Therefore, the characterized enzyme seems to be a useful tool to prevent slime production and undesirable yeast growth during vinification.