Fermented foods have a long history in many cultures, having existed for millennia, dating back to the Neolithic period. Civilizations have historically fermented food to preserve perishable food and extend its shelf life. Yet the popularity of fermented foods has not waned, even with the invention of refrigerators and other preservation methods. From kefir to soy sauce to kimchi to yogurt, fermented foods are everywhere nowadays, appreciated for their health benefits. However, what exactly goes on during the fermentation process?
Fermentation is a metabolic process that involves the breakdown of sugars into simpler compounds by enzymes of microorganisms in the absence of oxygen. The types and numbers of microorganisms involved in the process can cause the taste of the fermented food to change dramatically.
There are three main types of fermentation.
Lactic acid fermentation is a process that breaks down starches or sugars to produce lactic acid. Lactic acid bacteria help to protect the body from microbial disease. This method of fermentation produces foods such as pickles and yogurt.
Ethanol (or alcohol) fermentation involves breaking down sugar molecules into alcohol and carbon dioxide with yeast. This process can produce wine and beer, as well as bread.
Acetic acid fermentation is an oxidation process. It converts sugars from grains or fruits into vinegar or condiments, like apple cider vinegar.
Though fermentation as a food processing process was initially developed for food preservation, as mentioned above, it has evolved beyond that now. The focus of fermentation now is to create more nutritional foods.