Salting or Curing
Salting is being done in case of meat and fish preservation since ancient times. Curing draws moisture from the meat through osmosis and makes it unavailable for microbial growth and enzyme action and hence, food is preserved. Meat is generally cured with salt or sugar, or both. Nitrates and nitrites are also often used to cure meat and contribute towards the characteristic pink colour, as well as inhibit Clostridium botulinum. Dry salting is used in India for the preparation of preserved tamarind, raw mango, aonla, fish and meat.
The preservation of food in common salt or in vinegar is known as pickling. It is one of the most ancient methods of preserving fruits and vegetables. Pickles are the relishing accompaniments in the Indian as well as continental meals. They are known to be good appetizers and add to the palatability of a meal. They stimulate the flow of gastric juice and thus help in digestion.
The preservation by picking is achieved by conversion of fermentable carbohydrates into organic acids mainly lactic acid, preservative action of salt, vinegar and other ingredients and antimicrobial activity of organic acids, oil and spices. Pickling occurs due to fermentation by lactic acid bacteria, which are generally present on surfaces of fresh fruits and vegetables. These bacteria can grow well in acidic medium and can tolerate 8-10 per cent salt concentration. Whereas, undesirable microorganisms do not grow well in acidic solutions and this is the basis of preserving fruits and vegetables by pickling. Some of the fruits and vegetables, which are generally pickled as they undergo lactic acid fermentation, are raw mangoes, limes, Indian gooseberry (aonla), ginger, turmeric, cabbage, cauliflower, broccoli, carrot, turnips, radish, cucumber, olive, garlic, apples, pear, green plums, lemons, banana and green chillies.