Vinegar is a filtered, clarified, distilled liquid which contains around 5–20% acetic acid. Rest is water along with some trace chemicals and flavourings. Acetic acid bacteria are utilized in the process of fermentation of ethanol. Vinegar is widely used as a cooking ingredient, pickling and preservative. As it inhibits pathogenic microbial growth and contributes to good aroma it is used in a number of foods. Commonly the products containing vinegar are sauces, ketchup and mayonnaise.
It was in 1958 when scientist Cruess defined vinegar as a condiment made from various sugary and starchy materials by alcohol and subsequent acetic fermentation. It can be produced by many different methods utilizing many raw materials. One can obtain vinegar by using wine, cider, fruit musts, malted barley, or pure alcohol. Traditionally, wood casks and surface culture are used. Submerged fermentation is another method by using acetators. Acetic acid is formed in a four-step reaction starting from conversion of starch tosugar by utilizing enzymes amylases. In the absence of oxygen anaerobic conversion of sugars to ethanol takes place by the fermentation of yeast. Then, aerobically with the help of acetic acid forming bacteria (Acetobacter) acetic acid is formed. Common types of vinegar include white distilled vinegar, cider vinegar, winevinegar, rice vinegar, and malt vinegar. Afterwards, acetic acid can be bottled.
As per the regulation act in the US, a minimum of 4% acetic acid is required.Vinegar plays an important role in salad dressings, ketchup, hot sauce and other sauces. As the demand is huge industrial fermentation systems must maintain reliable controls. The colour and aroma depends on the starting material used. Balsamic vinegar from white grapes is brown in colour and has a sweet-sour flavour. Cane vinegar utilizes fermented sugarcane and has a mild sweet flavour. Champagne vinegar made from Chardonnay or Pinot Noir grapes contains no bubbles. United States commonly usesvinegar made from apples .Thai foods use coconut vinegar which has a musty flavor. Distilled vinegar is harsh and used for pickling. Chinese use rice wine vinegar which may be red (used as a dip for foods and as acondiment in soups), white (used mostly in sweet and sour dishes), and black.
– Dr Renu Agrawal