Use in wine production

If the grapes are destined for use in wine production, no thermal processing steps are involved. The grapes are ground, and the entire mass is fermented. The fermented juice is then decanted from the pulp, or lees, and moved into other tanks for aging. 

The most significant ketone produced by yeast is diacetyl (2,3-butanedione), a vicinal diketone, although malolactic fermentation is a more important source, when it is used in wine production. Having a sensory threshold of 0.2-2.9 mg/L, according to the type of wine, it is characterised by a nutty , toasty or buttery aroma depending on concentration (Martineau et al. 1995). Dry white wines tend to contain lower concentrations (0.1-2.3 mg/L) than red wines (0-7.5 mg/L) (Bartowsky et al. 2002 Martineau et al. 1995). Acetoin, which produces a buttery flavour, is formed by partial reduction of diacetyl, and is itself reduced to 2,3-butanediol. Acetoin is usually present at concentrations (<80 mg/L) much lower than its sensory threshold of 150 mg/L (Romano and Suzzi 1996). 

Enzymes are used also in fruit juice manufacturing. Addition of pectinase, xylanase, and ceUulase improve the liberation of the juice from the pulp. Pectinases and amylases are used in juice clarification. Similarly enzymes are widely used in wine production to obtain a better extraction of the necessary components, and thus improving the yield. Enzymes hydrolyze the high molecular weight substances like pectin. 

Spontaneous fermentations are used for wine production in Erance, some other European countries and in South America. In recent years, smaller California wineries have begun experimentation with spontaneous fermentations as well. They generally start more slowly than fermentations inoculated with commercial dried yeast, are more difficult to control, and may suffer from growth of undesirable contaminants. However, it is claimed that the resulting wines possess better organoleptic properties, particularly more complex flavor and aroma. 

UF is used to clarify various fruit juices (apple, grape, pear, pineapple, cranberry, orange, lemon) which are recovered as the permeate [Blanch et al., AlChE Symp. Ser. 82, 59 (1986)]. UF has also been used to remove pigments and reducing browning in wine production [Kosikowski in Membrane Separations in Biotechnology, McGregor (ed.), Marcel Dekker, New York, 1986]. 

Residues on crops may either be on the surface of the crops if applied as surface sprays, or they may be throughout the crop matrix if applied as systemic treatments. If the product is applied as a spray, the residue may be removed or significantly diminished as a result of washing. If the crop is not washed, e.g., grapes used in wine, juices, or raisins, the residue may remain with the fruit. 

Mat r industries use phenolic materials in their manufacturing processes. Phenol is also used in the production of dmgs, weed killers, and synthetic resins. Phenol and its derivatives are present in the wastewaters of industries such as cooking, pulp mills, paint and dyes, wine distilleries, oil and gasoline, synthetic rabber, textiles, pharmaceuticals, solvent, manufacture of pesticides, paper, and wood etc. [1]. 

A large spectrum of berries and fruits are used in the production of fruit juice products. The range of products is substantially extended by an additional (fermentation) process to produce alcohol, and transform the fruit into wine. Enzymes, some of them proteolytic, are used to increase the yield of fruit juice during extraction, and to produce the required degree of clarity for the final product. 

The removal of macromolecules by ultrafiltration has often been used in the production of clear fruit juices and wine (Girard and Fukumoto, 2000). This treatment removes both proteins and polysaccharides. Ultrafiltration through a 10,000 Da cut-off membrane has been shown to stabilize wines against haze formation (Flores, 1990). 

The main commercial use for gelatin is in the preparation of food, approximately 70% of all production used for this purpose, with an additional 15% going to the pharmaceutical industry, and 10% used for photographic film. The remaining 5% is used in wine making, printing, abrasive manufacturing, and paper production. 

The heads fraction may be highly acidic and corrosive if sulfur dioxide or bisulfite is used in the production or preservation of the wine. The reversible reactions involved are ... 

Preservatives. Sulfur compounds, such as sulfur dioxide and sodium bisulfite, are used commercially to preserve the color of various food products, such as orange juice, dehydiated fruits and vegetables, such as apricots, carrots, peaches, pears, potatoes, and many odiers. Concentrated sulfur dioxide is used in wine-making to destroy certain bacteria. The color preservation of canned green beans and peas is enhanced by dipping the produce in a sulfite solution prior to canning. In 1986, some of these compounds and uses were put under closer regulation in the United States. 

The yeasts used in the production of mead are usually strains of Saccharo-myces cerevisiae, similar to that used in wine, beer, and champagne productions. These yeasts metabolize sugars, such as glucose and fructose, resulting in the formation of ethanol and carbon dioxide. Nevertheless, the yeast Hansenula anomala had also given good results (Qureshi and Tamhane, 1987). 

Cessation of fermentation is one of the technical problems in botrytized wine production that needs further research and development. Dimethyldicarbonate (DMDC) is now considered a reliable inhibitor which could replace some of the S02. Although DMDC has proven suited for treating wines especially just before bottling, its use in Sautemes production has been investigated (Divol et al., 2005). The results showed that DMDC at a rate of 100-200 mg/1 stopped fermentation but did not replace the antioxidant functions of SO2. Sulfite addition was necessary to limit wine oxidation and yeast reactivation. 

FIGURE 7.3 Major varietal constituents found in Vitis vinifera L varieties used in the production of Madeira wines. 

Tamarind (Tamarindus indica L.) is an important tropical tree widely grown in India. Although its fruit can be used for wine production, its wine is not preferred due to its high acidity. An attempt has been made to convert its wine into vermouth of acceptable quality (Lingappa et ah, 1993). In this process, the base wine was made from tamarind fruit (50 g/L), at 0.9% acidity, followed by raising the TSS to 23 °Brix and adding 150 ppm sulfur dioxide. Fermentation was conducted by S. cere-visiae var. ellipsoideus at 27 1 °C. Both dry and sweet vermouths, with 17% alcohol content, were found acceptable. 

A number of botanicals, flavoring substances, and natural substances long used in wines have been regulated. It is mandatory that product should be free from thujone (In Europe, maximum admissible thujone concentrations are 0.5 mg/kg in food and beverages, 5-35 mg/kg in alcoholic drinks, and 25 mg/kg in food products containing sage Schmandke, 2005.)... 

The authors conceive of the text as being useful to a wide audience chemists, enologists, viticulturalists, and those interested in wine production and wines. For this wide audience we have used the most familiar measures acres and gallons, but °C and mg and mL when appropriate. In some cases two systems are given. 

Cold Duck is a blend of white and red sparkling wines. It probably originated in the Middle States, and the flavor of Concord grapes is predominate, or at least recognizable. For this reason, some California producers import Concord grape juice or concentrate from other states for use in this product. 

Wine spirits used in shermat production should be low (150 mg/L or less in higher-molecular-weight alcohols), but may contain 100 mg/L or more of aldehydes (or heads) without adversely affecting the quality of the wines. A muscat aroma should be avoided in shermat production. Muscat aroma is characteristically sweet like and flowery and is not compatible with sherry aromas, which tend to be dry and oxidized. 

The post-1960 developments for various types of wine and different regions of the country are the substance of the remaining chapters. White table wines are now the most important wines produced in California s north coastal region, and consumption is increasing. The new technological procedures being used in their production are particularly emphasized. Some indication of future trends is also included. 

The oxidising properties of ozone have led to the application of this gas to the bleaching of such substances as starch, flour, oils, and wax, delicate fabrics, etc. It has been used in the production of artificial silk and synthetic camphor. It has also been used to aid the ageing or maturing of wines, spirits, and tobacco. The action of ozone on unsaturated organic compounds provides a very convenient general method for the preparation of aldehydes and ketones, which has already been applied to the manufacture of vanillin for flavouring purposes and heliotropin for perfumery. 

Industrial catalysis is an old practice. Catalysts have always been used in the production of wine and beer. Among the first industrial catalytic processes are a few inorganic oxidation processes, viz. the Deacon process (oxidation of HC1 into CI2) and the production of sulphuric acid. These processes were developed before a scientific basis of chemical reactivity was established. Only after the formulation of the theory of chemical equilibria by van t Hoff did a framework for catalyst development become available. This had a major impact on the development of a process for the synthesis of ammonia at the beginning of the twentieth century, allowing a systematic, scientifically based search for a good catalyst to be performed. It also initiated the development of chemical process engineering as we know it today. 

---