Fermentation in food processing

Introduction

Fermentation in food processing is a metabolic process that consumes sugar in the absence of oxygen. The products are organic acids, gases, or alcohol. It occurs in yeast and bacteria, and also in oxygen-starved muscle cells, as in the case of lactic acid fermentation. The science of fermentation is known as zymology.

History

Fermentation is one of the oldest forms of food preservation technologies in the world. Many cultures have been practicing food fermentations for thousands of years, in some cases without knowing the science behind the process. The discovery of yeast's role in fermentation in 1857 by Pasteur gave birth to zymology.

A close-up view of a fermentation process in a glass jar, showing bubbles produced by the reaction.

Types of Fermentation

There are several types of fermentation that are used in food processing:

Lactic Acid Fermentation

Lactic acid fermentation is a metabolic process by which glucose and other six-carbon sugars are converted into cellular energy and the metabolite lactate, which is lactic acid in solution. It is an anaerobic fermentation reaction that occurs in some bacteria and animal cells, such as muscle cells.

Ethanol Fermentation

Ethanol fermentation, also called alcoholic fermentation, is a biological process which converts sugars such as glucose, fructose, and sucrose into cellular energy, producing ethanol and carbon dioxide as by-products.

Acetic Acid Fermentation

Acetic acid fermentation is the process by which ethanol produced by sugar and starch fermentation is converted to acetic acid with the help of acetobacter. It is used in the production of vinegar.

Butyric Acid Fermentation

Butyric acid fermentation is a process that produces butyric acid, a short-chain fatty acid. It is carried out by obligate anaerobic bacteria.

Fermented Foods

Fermentation is used in the development of many different types of food and beverages worldwide. Here are some examples:

Bread

The production of bread using yeast and fermentation is one of the most common forms of food fermentation. The yeast ferments the sugars present in the dough, producing carbon dioxide and ethanol.

Wine

The fermentation of grapes and other fruits to produce wine is a form of ethanol fermentation. The sugars in the fruit are fermented by yeast to produce ethanol and carbon dioxide.

Cheese

The fermentation of milk to produce cheese is a form of lactic acid fermentation. The lactose in the milk is fermented by bacteria to produce lactic acid, which curdles the milk proteins to form cheese.

Yogurt

Yogurt is produced by bacterial fermentation of milk. The bacteria used to make yogurt are known as yogurt cultures. The fermentation of lactose by these bacteria produces lactic acid, which acts on milk protein to give yogurt its texture and characteristic tart flavor.

Sauerkraut

Sauerkraut is finely cut raw cabbage that has been fermented by various lactic acid bacteria. It has a long shelf life and a distinctive sour flavor, both of which result from the lactic acid that forms when the bacteria ferment the sugars in the cabbage leaves.

Kimchi

Kimchi is a traditional Korean dish made of salted and fermented vegetables, most commonly napa cabbage and Korean radishes, with a variety of seasonings including chili powder, scallions, garlic, ginger, and jeotgal (salted seafood).

Benefits of Fermentation

Fermentation in food processing can have many benefits:

Preservation

Fermentation can help to preserve food and extend its shelf life. The acids or alcohol produced by the fermentation can help to prevent the growth of harmful bacteria.

Nutrient Enhancement

Fermentation can also enhance the nutritional value of food. It can increase the availability of vitamins and minerals for our bodies to absorb. Additionally, fermentation can break down nutrients that are difficult to digest into forms that are easily digestible.

Flavor

Fermentation can also enhance the flavor of food. It can create unique flavors that are not present in the original food.

Risks and Safety

While fermentation can have many benefits, it can also carry some risks. If not properly managed, the fermentation process can lead to the growth of harmful bacteria. The use of proper sanitation practices is essential to prevent the growth of these bacteria.