You surely know that different types of fermentation are used to make great foods like beer and cheese, but did you know that it's also used to make soy sauce, pepperoni, sauerkraut, yogurt, bread, and even chocolate? Food has been fermented by humans since the Neolithic era, long before anybody understood the science underlying fermentation. We now understand why fermentation not only improves the flavor of foods like sourdough bread, cheese, and wine, but also serves to keep us alive, thanks to the scientific findings of French scientist Louis Pasteur, who demonstrated that living organisms begin fermentation. So, what are the 3 types of fermentation? Today we are bringing you some great information about the three types of fermentation and fermented foods, lactic acid fermentation, ethanol or alcohol fermentation and acetic acid fermentation. Learn a little about the science behind each ferment and how they lend themselves to some yummy fermented recipes!
WHAT IS FERMENTATION?Fermentation is the chemical breakdown of a substance by bacteria, yeasts, or other microorganisms, typically involving effervescence and the giving off of heat. Fermentation is any metabolic process in which the action of microbes causes a desired change in food or drinks, whether it's to improve flavor, preserve goods, or provide health benefits. Ferment is derived from the Latin verb "fervere," which means "to boil." Fermentation is, ironically, achievable without the use of heat.
WHAT DOES FERMENTATION DO TO OUR FOOD?Fermentation takes place in the absence of oxygen (anaerobic conditions) and in the presence of beneficial microorganisms that get their energy from fermentation (yeasts, molds, and bacteria). Even when oxygen is plentiful, some yeast cells, such as Saccharomyces cerevisiae, prefer fermentation to aerobic respiration if there is enough sugar available. These beneficial microorganisms break down sugars and starches into alcohols and acids during the fermentation process, making food more nutritious and preserving it so it may be stored for extended periods of time without rotting. The enzymes required for digestion are found in fermentation products. This is significant because individuals are born with a certain amount of enzymes, which decreases as they become older. Fermented foods have the enzymes needed to digest them. Pre-digestion is also aided by fermentation. Microbes feed on sugars and starches during the fermentation process, breaking down food before it is digested. We love this TedED talk by Erez Garty. It really breaks down the process and gives some great insight into fermentation. Take a look at this video by TedED.
THE 3 TYPES OF FERMENTATION
1. Lactic Acid Fermentation (Or Lacto- Fermentation)
Lacto-Fermentation is arguably one of the most common types found in food. Lactic acid fermentation is responsible for the production of foods like yogurt, sauerkraut, and pickles. Thanks to lactic acid bacteria, a sequence of chemical processes change your components into something quite different (and delicious).
No heat is required in the conversion of starches or sugars to lactic acid by yeast strains and bacteria. Pyruvic acid employs nicotinamide adenine dinucleotide + hydrogen (NADH) to create lactic acid and NAD+ in these anaerobic chemical processes. (Fun Fact: Lactic acid fermentation takes place in human muscle cells as well.) Many of the tasty ferments that you may already be acquainted with may be made using this approach. Lactic acid bacteria aid in the preservation of foods. Look at it this way: yogurt and sour cream are both preserved forms of milk, while sauerkraut is a preserved cabbage. They also induce desirable changes in flavor and texture in addition to preservation! Want to read more about lacto-fermentation? We go into detail in another blog post: What is Laco-Fermentation?
2. Ethanol Fermentation And Alcohol FermentationBrewing beer and manufacturing wine have become hugely profitable agricultural enterprises. These industries sprang from ancient and empirical knowledge gathered from a variety of cultures throughout the world. This historical expertise has now been coupled with fundamental scientific understanding and applied to current manufacturing techniques.
- In the first step, glucose is converted to pyruvate by glycolysis
- In the second step, pyruvate is converted to ethanol and carbon dioxide by using a molecule of NADH
3. Acetic Acid FermentationGrain and fruit starches and sugars ferment to produce sour vinegar and sauces. Apple cider vinegar, wine vinegar, and kombucha are examples of products that utilize this form of
TYPES OF FERMENTED FOODS
Kefir is a consumable yogurt-like fermented milk product prepared from cow, goat, or sheep's milk. Vitamin B12, calcium, magnesium, vitamin K2, biotin, folate, enzymes, and probiotics are all found in significant amounts in kefir.
Kefir has been ingested in some form or another for over 3,000 years. The name "kefir" was coined in Russia and Turkey to describe a drink that makes you feel wonderful. Best of all, Cultures For Health has starter grains that make it easy to get started at home!