Fermentation vs Decomposition
When considering the difference between decomposition and fermentation, it depends on the bacteria for decomposing. If putrefactive bacteria are in large quantities, then deterioration usually occurs, and if there are many fermentative bacteria, fermentation is the likely outcome.
Fermentation is a process involving microorganisms, particularly yeast types. Enzymes required to facilitate this process may vary from those involved in decomposition. It is a metabolic process that converts sugar to 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. Decomposition is a term that relates to ecology. It is the microbial digestion and destruction of dead material that is consumed by the bacterial process. This putrefaction, also known as decomposition, is very different from lactic acid fermentation. Both methods can produce some unique smells from the toxic compounds produced during the breakdown. During decomposition, small organisms decompose to get their required energy for growth and development.
Fermentation happens through autolysis and starts from a lactic acid enzyme in the spine of the fish. Together with bacteria, pungent-smelling acids are formed, such as propionic acid, butyric acid and acetic acid. The salt raises the brine’s osmotic pressure above the zone where bacteria responsible for rotting can thrive and prevents decomposition of proteins into oligopeptides and amino acids.
Instead, the osmotic conditions enable Haloanaerobium bacteria to thrive and decompose the fish glycogen into organic acids, making it sour. It plays a vital role in many parts of the world for the production of traditional fish products. The fermentation chemical process begins with the standard post mortem processes in the fish. Forming lactic acid, this is due to an anaerobic situation in the muscle tissue, continued by autolysis of proteins and lipids. Followed by the establishment of a fermentative microbial flora; there are many autolytic enzymes in the muscle tissue; another essential source of autocatalytic enzymes is the pyloric ceca in the gut; together with bacteria, pungent-smelling acids form in the fish such as propionic acid, butyric acid, and acetic acid. The salt increases the brine’s osmotic pressure above the zone where bacteria responsible for rotting can thrive and prevents decomposition of fish proteins into oligopeptides and amino acids.
Fermented fish is an old staple food in European cuisines; for instance, the ancient Greeks and Romans made a famous sauce from fermented fish called garum. Fermentation and drying food have been a necessary way of preserving food for hundreds of years. In northern Europe, only a few traditional fermented fish products are active. This production relies both on naturally occurring enzymes as well as bacteria. In Southeast Asia, fermented fish products have a long history, and they are of great nutritional importance. Surströmming typically contains 11.8% protein, 8.8% salt, and 3.8% fat.
There are signs of surströmming origin as early as 1300. The method seems to have familiar about a couple of hundred years later due to a salt shortage. Salt is used to create surströmming but is far lesser than those used to prepare regular salted herring. The occurrence of rancid and putrid aroma was a much more natural part of the daily food, explaining the event of several dried and fermented fish products in the Nordic countries. There is also an excellent reason to believe that the general sensory acceptance of aroma and taste was quite different in former times; many people found it hard to accept salt during the Middle Ages.