The upcoming discussion will update you about the difference between acetic vinegar and vinegar.
The word ‘vinegar’ is derived from the French term ‘vinaigre’ (vin = Wine+ aigre = sour), meaning “sour wine”. It contains about 40% acetic acid by weight and small quantities of alcohol, glycerol, esters, sugars, and salts. Vinegar is the product obtained as a result of impartial oxidation of alcohol in a fermenting sugar containing fruit or cane juice, molasses, fermented mash of malted grain, honey, maple skimming, syrups, etc. Since, the vinegar contains considerably large amount of acetic acid it is generally used in the place of acetic acid. But, for the pure acetic acid the vinegar is subjected to purification.
The fermentation of vinegar involves two types of biochemical reactions:
(i) Alcoholic fermentation of carbohydrate. It is the first step in the production of vinegar and takes place under anaerobic condition. This step in which sugar is fermented to alcohol is completed by the action of yeast species.
(ii) Oxidation of alcohol to acid. This is the second step in the production of vinegar and is aerobic process. This step in which alcohol is oxidized to acetic acid is completed by the action of acetic acid bacteria i.e., Acetobacter Orleanais and A. schulzenbachi.
After the fermentation is over, calcium citrate is precipitated from the fermented broth by adding calcium hydroxide/ Ca (OH)2. It is then filtered, washed, and treated with sulphuric acid (H2SO4) to precipitate calcium sulphate and retain the citric acid. The citric acid is purified and finally crystallized. In recent years, citric acid fermentation by yeast is significantly growing because a variety of yeasts, e.g., Candida, Hansenula, etc. have been found to ferment citric acid from carbohydrates and hydrocarbons.
The yeast, Candida lipolytica, appears promising and result in good yield of citric acid from various raw materials. Citric acid is an important chemical used in food and candies, beverages, medicines, flavouring extracts, manufacture ot ink, effervescent slats, dyeing, mirror silvering, and detergent industries. It is also increasingly used in the removal of toxic and corrosive gases in air.