USA: +1-585-535-1023

UK: +44-208-133-5697

AUS: +61-280-07-5697

ALCOHOLIC BEVERAGES

They are found in different forms in different regions, e.g., in cooler regions of Europe, Poland and Russia production and consumption of beer from barley is more common; whereas, in warmer countries, like Spain, Greece, Italy and France, wines derived from grapes are more common.

The starting material normally contains either:

a.      sugary materials, like apple juice (to get cider), grape, pear, palmyra (to get toddy in India and South East Asia) juices, molasses (to get distilled rum, and gin is obtained from distillation of rum in the presence of juniper berries), honey, sweet potato, etc., or

b.      starchy materials like barley, rice, rye, sorghum, beet root, potato, etc., and the starchy materials need to be hydrolyzed to simple sugars by some saccharifying agent, like, grain malt, Aspergillus oryzae, Rhizopus, Mucor, Bacillus, etc., (the process is known as saccharification) before the fermentation process.

When the surgary substrates are incubated with suitable microorganism (generally yeast) after fermentation an acidic, nutrient-poor liquid containing a few per cent to about 16% (or more) ethanol is formed which does not allow growth of most of the contaminating microorganisms. These beverages require a period of storage (aging) that leads to improved flavour and taste. Distillation process increases the concentration of ethanol to about 40-50%, e.g., whisky, brandy, vodka, gin, rum.

Most regularly used fermenting organism is the yeast species, Saccharomyces cerevisiae, S. carisbergensis or Zygosaccharomyces sp., which can utilize simple sugars, like glucose and
fructose to metabolize them to ethanol. The selected species is tolerant to high concentration of
etanol:

C6H12O6    →     2C2H3OH + CO2

i.            Wine: Wine means fermented grape juice and historically, it is a Middle Eastern and European drink. France, Italy and Germany are its major producers. It is obtained from fruit juices, mainly from the wine grape, Vilis vinifera, which contains 15-25% sugar. Some of the important types of wines are:

a.      Red Wine is formed from the fermentation of crushed whole black grapes (with skin).

b.      White Wine is produced from the black grapes without skin or green grapes.

c.       Rose Wine is produced from black grapes with some skin.

d.      Dry Wine is obtained from the complete fermentation of the sugar.

e.       Sweet Wine retains some sugar.

f.      Sparkling Wine (champagne) is obtained from secondary fermentation of wine containing 1 % fermentable sugars and yeast in sealed bottles. The CO2 produced, due to fermentation of added sugars by yeast, gets dissolved under pressure in the bottle. After the fermentation, the water in the neck of bottle is frozen to form an ice-plug. The cork plug with attached yeast is removed and replaced by a new cork plug. Thus, the CO2 is not allowed to escape from the bottle.

g.      Fortified Wines (distilled) in which additional alcohol is added after the fermentation, thus, raising the alcohol content to about 20%, e.g., brandy.

For the formation of wine, first grapes are crushed and the juice, thus, obtained, called must (containing glucose and fructose), is sterilized by SO2 to control the natural fermentation by the contaminating yeasts. Then, it is inoculated with the desired strain of yeast, Saccharomyces cerevisiae vem ellipsoideus, and is subjected to fermentation (of the simple sugars, glucose and fructose), in tanks or bioreactors for a few days to 14 days (no saccharification is required). After fermentation, it is stored for months or years (aging) for chemical changes to improve the flavour, aroma and for clarification by settling of impurities. The alcoholic contents of wines ranges from 7-15%.

Moderate wine consumption is beneficial for coronary heart diseases. Champagne and brandy are obtained from distillation of wine.

 ii.            Beer: It is produced from starchy substrates, e.g., barley com, potato, etc. Additional carbohydrate sources, called adjuncts, may also be added. There are five major steps in the manufacture of beer:

(a)     Malting: Dried barley seeds are soaked in water and spread on the floor for germination. This results in the formation of amylases (starch-degrading enzymes) and proteases (protein-degrading enzymes) and other enzymes by the embryo. The germinated seeds are subjected to slow heating upto a temperature of 80°C for the embryo [which otherwise would utilize the reserve starch (a polymer of glucose) and proteins in the seeds for its own growth] whereas, the enzymes are not spoiled and remain active even at high temperature. The seeds are dried and powdered. This product is called malt, which contains maltose, glucose, dextrins (short chain of glucose), hydrolyzed proteins, unhydrolyzed starch and proteins, etc.

(b)     Mashing: The dried powdered malt is added with warm water (55-70oC) to initiate further hydrolysis of unhydrolyzed starch (process known as saccharification) and protein by amylases and proteases, respectively, in the malt. The content is called mash, which mostly contains the fermentable sugars like glucose and galactose, dextrins, proton breakdown products, growth factors, minerals, etc.

(c)     Formation of Beer Wort: The content is filtered and the filtrate is given some more time for the saccharification process. Sometimes extra amylase (from the fungus Aspergillus oryzae or some bacteria) is also added to the filterate to enhance the hydrolysis of starch The product is known as beer wort and mostly contains fermentable sugars like, glucose, galactose, etc.

(d)     Fermentation: The beer wort is boiled with hops (papery scales of female flowers of Humulus lupulus) to stop saccharification, for development of t1avour, aroma and colour and to impart mild antibacterial activity. After cooling, the content is added with commercially available culture of the yeast, Saccharomyces carisbergensis (modern yeast, settles at the bottom after fermentation) or Saccharomyces cerevisiae (traditional yeast, floats at the surface after fermentation). The yeast may contain dextrin-utilizing gene from Saccharomyces diasticus by recombinant DNA technology (normally the yeast cannot utilize dextrins) to increase the amount of fermentable sugars. Thus, greater amount of alcohol after the fermentation for 5-10 days is produced. Finally, the growth of yeast is limited by anaerobic condition, ethanol (yeast action ceases after 18% alcohol) and drop of pH. The product is known as fermented wort, which predominantly contains ethanol.

(e)     Conditioning: The fermented wort is chilled to 0°C for a period of two weeks to many months that leads to the clarification and removal of harsh flavour and undesirable characters. Now, the contents are stored at normal temperature for 8-10 months to further improve the quality and eliminate the off flavours. Sometimes papain (a protease, obtained from papaya latex) is added to hydrolyze the proteins and to remove the haziness. The yeast is finally removed (that either settles at the bottom -or floats at the surface, depending upon the species) and the beer is either pasteurized at 60°C (20 min) to kill any leftover yeast cells and other microbes, or it is filtered to remove them. The final product is known as beer, which contains 3-6% alcohol. Vodca and whisky are obtained from the distillation of beer.