The Origin
Fermented foods have been known to mankind since the dawn of times. Historical evidence has revealed the fact that the fermentation of different foods and their consumption existed across many civilizations. Excavations from the Natufian burial sites have uncovered the historical data about beer brewing. The Natufian culture which is believed to have existed between 12500BC-9500BC in Palestine and Southern Syria during the Mesolithic age, consisted of sedentary or semi-sedentary population (meaning people living in one place for a lengthy period). Similar evidence gathered from the stone tools in the region of Mozambique dating back to the Mesolithic age, has revealed the existence of the practice of grain processing especially wild sorghum thus giving a clue to the possibility of beer brewing.
As man discovered and adopted to new ways of living in the Neolithic or New stone age, evidence provided more clarity about the fermentation practices. In China, unearthing of the pottery vessels and their chemical analysis has brought into light that the concept of fermentation existed around 7000 BC. The fermentation was purposely done on foods such as rice, honey and fruits. Evidence also indicates that alcoholic beverages were made from fermented cereals.
Looking into the other clues, the Mesopotamian civilization needs a special mention. The region of Mesopotamia holds a distinct place in history due to its rich cultural heritage. It is referred as the ‘cradle of ancient civilization’, as this region was the point of origin to a myriad of world’s oldest civilizations. The Mesopotamian civilization that was centered in the region of Iraq saw the convention of making fermented foods and beverages as early as 7500BC. Foods such as milk, meat, fruits and vegetables were used for fermentation. The presence of tartaric acid and grape juice residue from old jars reveal that the tradition of wine making prevailed in this region roughly around 5000BC.It is said that the fermentation of the malt of cereals and brewing happened in the later part of the Neolithic period. According to the available data, it is presumed to have coincided with the discovery of pottery though there are possible hints that this could have emerged much earlier.
The advancement to Chalcolithic and Bronze ages saw improvements in the fermentation skills. Archeological evidence from various sites in Egypt have pointed to the existence of beer brewing and bread making dating back to 2000BC. The Bronze age was also marked by the cultivation of grapes. In addition to these, the tradition of fermentation was seen across many ancient cultures including Babylonian (beer brewing), East Asian (soy sauce), Middle East and Europe (yogurt) and Greece (fruit fermentation). Interestingly in Greek mythology, Dionysus is the ancient Greek God related to grape-harvest, wine making, orchards, fruit and vegetation and hence considered as the God of fruit fermentation. With the practice of fermentation passed down to several generations, many of these ancient foods have successfully made their voyage across centuries into the current world.
The ancient objective
In accordance with the historical time line, fermentation is said to have co-existed during the Neolithic or New Stone Age period. This prehistoric period which was marked by significant cultural and technological advancements, saw the evolution of agriculture, domestication of animals and establishment of permanent settlements. The seasonal changes encountered during the cultivation of crops witnessed variation in the availability of food from ample amounts to times of acute shortage. On the other hand, rearing of animals such as sheep, goat and cattle became an important source for meat and milk. In order to overcome food shortage during unfavorable seasons and enhance the storage life of perishable foods like meat and milk, the practice of fermentation came into existence. The tradition of cheese making also prevailed during this period. In addition to the extended shelf life, fermented foods were an important source of nourishment during the periods of food scarcity. Also, the process of fermentation was applied conventionally to improve the taste of foods and they also formed an integral part of traditional medicine and ceremonies. However, the importance of microorganisms and the health benefits of fermented foods were unknown.
Emerging microbes
The link between man, microbes and food has been established since the times man began to explore the ways to modify the foods for the better. The evidence to the use of microbes for fermentation across ages comes from the molecular and chemical examination of the remnants obtained from the vessels excavated from the Neolithic sites of China, Mesopotamia and Egypt. It is said that the driving force behind the fermentation process was the use of yeast. It is most likely that the process of fermentation could have been initiated by yeast present in nature as in fermented fruits and through insects like bees and drosophila (this insect feeds on the yeast contained in overripe fruits). But there is no clarity as to when specific types of yeasts were used for making bread, wine and beer. The yeast Saccharomyces cerevisiae that is naturally present in fruits such as grapes and dates, cereals such as wheat and barley and the guts of bees and wasps, has expanded genetically into many strains in continuum with human activity across centuries. There is also some affirmation to the domestication of earliest strains related to the production of rice wine and grapes. Despite being known as the microbe of antiquity, the knowledge about its existence and role in fermentation was unknown.
In the several centuries that followed the pre historic period, the breakthrough discovery of Antoni Van Leeuwenhoek in the year 1670s gave new insights into the world of microbes. He was the first scientist to bring into light the existence of microorganisms including bacteria and yeasts. Even though the bacteria were seen as pathogens in the initial phases of discovery, their potential benefits to human health were recognized later. However, their role in fermentation was unknown till mid 1850s when Louis Pasteur discovered fermentation. Interestingly his groundbreaking work on fermentation was done on the request of a beetroot-based alcohol manufacturer from Lille-agricultural industrial region who was facing problems with the production. The discovery of the fungus Aspergillus oryzae by the German scientist Korschelt in 1878 was followed by recognition of numerous microbes and starter cultures.
The 1800s also saw the recognition of the bacteria Lactobacillus acidophilus which marked the beginning of a new era to the world of probiotics. Initially called as Bacillus acidophilus (which means fond of acids), they were first isolated in the year 1890 by Dr. Ernst Moro. They were found in the intestinal tract of humans and animals and were also found in the feces of infants fed on milk as well as adults who were consuming a diet containing excessive milk and lactose. In the year 1899, bifidobacteria were discovered by Henry Tissier which were isolated from the stools of breast-fed infants. Both these bacteria gained recognition for their health benefits.
The development of starter cultures provided new insights into not only improving the quality of fermented foods, but also expanded their scope for commercialization. These are basically microbial preparations consisting of single or mixed microbes which when added to foods aid fermentation in a controlled manner. The microbes in question are bacteria, yeast and fungus. The discovery of fermentation by Pasteur provided a novel beginning for starter cultures. The very first pure culture of lactic acid bacteria (LAB) was isolated by Joseph Lister in 1873. Later the Russian scientist Elie Metchnikoff proposed the beneficial effects of LAB on human health. In the year 1919, Orla Jensen identified seven groups of lactic acid bacteria. Among these only Streptococcus remains in the picture today. Currently Lactic acid bacteria comprises of 16 groups among which 12 are linked with food. The attempt to genetically modify some of these bacteria in 1982 proved to be an important milestone in improving their characteristics to enhance the quality of fermented foods. With continuing genetic research, a new method involving gene editing was developed in 2013. Since this falls under the category of genetically modified organisms (GMO), scientists are still working towards its approval in food industry. Some of the classes of microbes that are used as starter cultures are listed below
Lactic acid bacteria (LAB): Lactobacillus, Leuconostoc, Enterococcus, Streptococcus, Oenococcus, Pediococcus.
Non-LAB bacteria: Micrococcaceae, Bifidobacterium, Propionibacterium, Brachybacterium.
Yeast and molds: Debaryomyces, Kluyveromyces, Saccharomyces, Aspergillus, Mucor, Penicillium, Rhizopus.
Science explained
Zymology or the science behind the concept of fermentation was not known until Pasteur’s discovery in 1857. His proposed theory of microbial role and his innovative work on alcoholic and lactic acid fermentation brought into light about the chemical reactions involved in the process. The interpretation of fermentation depends on the perspective it is looked upon. The simple definition of fermentation is ‘a series of chemical changes brought about in the food or beverage as a result of microbial action'. From the chemical standpoint it is ‘a process in which substrates are transformed into alcohols, carbon dioxide and organic acids anaerobically (absence of oxygen)’. The substrate or the raw material in question can be either solids or liquids. Some examples of the liquid substrates are fruit juices or byproducts like molasses which contain natural sugars. On the other hand, the use of solid substrates containing low moisture like cereal grains, legume seeds, rice and wheat bran etc. is called solid-substrate fermentation. Finally, the meaning of fermentation in food production generally refers to the beneficial changes brought about in the food or drink as a result of microbial action. The four fundamental types of fermentation based on the biochemical pathways are
Alcoholic or ethanol fermentation: This is a chemical process mostly involving yeast (Saccharomyces cerevisiae) and to a lesser extent bacteria (Zymomonas mobilis). Here sugar is converted into ethyl alcohol and carbon dioxide. The first step in this fermentation is the breakdown of glucose by yeast to give rise to pyruvate molecules. These are converted into acetaldehyde during which more carbon dioxide is released. In the final step, acetaldehyde gets converted to ethanol. As the name indicates, this fermentation is used to produce bread, beer and wine.
Lactic acid fermentation: In this fermentation, the chemical process involves Lactic acid bacteria (LAB) wherein the sugars are converted into lactic acid or lactate. The lactic acid bacteria can be grouped into homo, hetero and facultative fermenters depending on the end product. In homofermentaion only lactate is produced whereas in heterofermentation ethanol and carbon dioxide are produced along with lactate. Facultative fermenters follow either homo or heterofermentation based on the availability of substrate and environmental conditions. This fermentation is mainly used to produce yogurt, kimchi and fermented cereals.
Acetic acid fermentation: The chemical process involves bacteria that belong to Acetobacter group. Here the alcohol and sugars present in the substrate are converted into acetic acid. This type of fermentation is used in the production of vinegar, acidic beer, cocoa, water kefir and kombucha. In the above mentioned types of fermentation, the organic acids that are produced prevent the growth of harmful bacteria in addition to enhancing the quality of fermented foods.
Alkali fermentation: The chemical process involves the bacteria that come under Bacillus and coagulase-negative Staphylococcus group. Here the proteins that are present in the substrate are converted into amino acids, peptides and ammonia. The ammonia released during fermentation rises the PH value of food thus making it alkaline. This prevents the spoilage of food. Also, ammonia is responsible for imparting umami flavor to the food (along with sweet, sour, bitter, salty tastes, umami is considered to be a fifth taste and is regarded as a pleasant savory taste). Foods such as Japanese natto and African fermented legumes and eggs are produced by this method.
Alkali fermentation: The chemical process involves the bacteria that come under Bacillus and coagulase-negative Staphylococcus group. Here the proteins that are present in the substrate are converted into amino acids, peptides and ammonia. The ammonia released during fermentation rises the PH value of food thus making it alkaline. This prevents the spoilage of food. Also, ammonia is responsible for imparting umami flavor to the food (along with sweet, sour, bitter, salty tastes, umami is considered to be a fifth taste and is regarded as a pleasant savory taste). Foods such as Japanese natto and African fermented legumes and eggs are produced by this method.
Alcoholic fermentation: Saccharomyces cerevisiae (yeast), Zymomonas mobilis (bacteria).
Lactic acid fermentation: Lactic acid bacteria (LAB).
Homofermentive LAB: Lactococcus lactis, Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus helviticus, Lactobacillus delbrueckii, Pediococcus and Enterococcus genera.
Heterofermentative LAB: Leuconostoc species, Fructilactobacillus sanfranciscensis, Levilactobacillus brevis, Limosilactobacillus fermentum, Limosilactobacillus reuteri.
Facultative LAB: Lactiplantibacillus plantarum, Lacticaseibacillus casei, Latilactobacillus curvatum.
Acetic acid fermentation: Acetobacter species.
Alkali fermentation: Bacteria belonging to Bacillus and coagulase-negative staphylococcus group.
Techniques uncovered
From the ancient past: Traveling back to the Paleolithic times, it is speculated that our predecessors consumed foods that underwent natural fermentation. Despite having no scientific knowledge, with passage of time man acknowledged the unique qualities of fermented food in terms of preservation, taste and also the effects the fermented foods had on the body and mind. According to the historical evidence, intentional fermentation seems to have commenced in the Neolithic times and coincided with the evolution of agriculture. The probable use of the naturally occurring yeast evolved into domestication of the same in the centuries that followed. These techniques were used for brewing of alcoholic beverages involving cereals.
With the development of grape cultivation, the fermentation of grape juice was initiated by mixing it with figs. Also, the pulp of other fruits such as jujubes and carobs were collected and after the addition of figs and water, they were kept in special vessels for controlled fermentation. Probably the figs aided the initiation of fermentation process due to the presence of yeast in the deposited pollen, transmitted by insects, such as wasps. The spontaneous fermentation took place as a result of the contact of yeast with the fruit pulp. However, fermentation depended on the presence of ample amounts of sugar in the fruit pulp.
In quest for a more controlled method of fermentation, honey gained recognition as it contained yeast in addition to adequate sugar. This method of fermentation gained popularity in the Neolithic period. Recent archeological evidence points to the fact that rearing of bees was associated with beer and wine making. Hence honey was considered as an agent for fermentation rather than a mere sweetener.
To the modern times: The discovery of microbes and the science behind fermentation in the 18th and 19th centuries paved way to the modernization of the fermentation techniques. Fermentation can be achieved by the following methods depending on the source of microbes as
Spontaneous or Wild ferments: In this method, fermentation of the food is brought about by the microbes that are either naturally present in the food or the environment in which they are processed. Since the ancient times this type of fermentation has been in practice and still continues to be the practiced on a small-scale basis in many households. Here the prerequisites for the fermentation process are modified which includes the environmental conditions as well as the ingredients. The success rate of the spontaneous fermentation depends upon the ability of the friendly microbes in achieving an upper hand over the harmful ones in the given environment. In addition to this the presence of precise microbes as well as favorable conditions are also important. However, the production of fermented food with required qualities cannot be fully assured.
Spontaneous fermentation can be made more efficient by following a process called back-slopping. In this method a small quantity of food that has been satisfactorily fermented previously is added to a new batch of food that needs to be fermented. This method reduces the failure rate, fermentation time and also enhances the microbial type and quality. But the drawback with back-slopping is the challenges faced with regard to the correct microbial load needed for fermentation.
Spontaneous ferments examples: Sauerkraut, kimchi, some fermented soy products.
Back-slopping examples: Sourdough bread, Sauerkraut, kefir, beer, cheese, dry sausages.
Starter cultures: These are live preparations containing single or mixed microbes that are used in the fermentation of foods. Depending on the temperature that is needed for the growth of the culture, starters can be either mesophilic or thermophilic. Mesophilic grow at moderate temperatures (around 30 degrees C) whereas thermophilic grow at higher temperatures (around 42 degrees C). Starter cultures can also be classified on the basis of the microbial strain content and its potential for fermentation as
·
*Natural starters: In general, these form the main source of microbes for the starter cultures. There is no limit to the number and types of microbial strains contained in natural starters. Despite being economical, inconsistencies exhibited in their microbial composition and fermentation process, together with possible risk for contamination and the presence of harmful microbes are some of the drawbacks.
*Mixed-strain starters (MSS):These starter cultures are sourced from finest natural starters and are regulated under controlled conditions to suit specific types of food products. Apart from the limitations they pose to their use, their inconsistencies with microbial composition and variability exhibited with fermentation results prove to be their drawbacks. The natural and mixed strain starters are together called as traditional starters.
*Defined-strain starters (DSS): As the name suggests, these starters contain definitive number of selected microbes that are meticulously regulated thus enhancing the quality and outcome of fermentation process. Hence these starters are preferred for industrial use as opposed to the traditional starters.
The careful selection of the starter cultures for fermentation is essential to ensure a fermented product of high standard. Since the distinctive features imparted to a fermented product is dependent on the ongoing metabolic process in a microbe, it becomes critical to ensure the safety of the microbe. In accordance with the Food and Drug Administration (FDA) and European Food Safety Authority (EFSA), the microbes selected for fermentation should fit into a group labeled as ‘generally recognized as safe (GRAS). Also, starter cultures should show competency with a wide range of substrates, be able to multiply fast and also withstand the chemical stress encountered during fermentation such as changes in temperature and PH. As fermented foods are vulnerable for fungal contamination, using microbes exhibiting anti-fungal activities can ensure the safety of fermented food. In addition to this, starter cultures should not have a negative influence on the sensory qualities of the food like aroma and taste and also should be able to enhance the nutritive and health benefits of fermented foods.
Examples for starter culture application in various food industries
Dairy: Cheese, yogurt, sour cream, cultured buttermilk.
Meat: Sausages.
Alcoholic beverages: Beer, wine.
Manufacture of vinegar
Rice and soy based oriental products: Miso, Shoyu, natto, tempeh.
Bakery: Sourdough bread.
Fermented cereals: Boza (malt drink made of cereals like maize, rice, wheat), Chicha (beverage made of rice from the region of Peru).
Fermented fruits and vegetables: Kimchi, sauerkraut, fermented cucumbers.
Fermented foods decoded
On a global note, it is estimated that there are more than 5000 varieties of fermented foods that are produced and consumed. But given the fact that fermented foods exhibit regional differences with regard to the raw materials and fermentation methods, the number of varieties is expected to notably diversify. Though there are many ways by which the fermented foods can be classified, most often the classification is based on the non-fermented food substrate as follows
Cereal based
The use of cereals is known to mankind since ancient times. In addition to being a staple food worldwide, they are the main source of energy and nutrients such as carbohydrates, proteins, fiber, vitamins and minerals. However, processing them affects their nutritional value and as such they also lack in key nutrients such as essential amino acids. Fermentation is one of the ways by which their nutritive value can be improved. The fermented cereals will have reduced carbohydrate content as the microbes present in the culture convert the sugar and starch present in the cereals to lactic acid and carbon-dioxide. Also, there is enhanced amino acid production and the bio availability of the B group of vitamins. Apart from these changes, the compounds such as phytates, tannins and polyphenols which have no nutritive value are reduced. There is improved action of compounds such as amylase, phytase, hemi-cellulose and protease which have a positive effect on shelf life and digestibility. Finally fermented cereals as known to exhibit anti-oxidant activity. Some examples of cereal based fermented foods are
Rice based:
The humble idli
This is a traditional fermented food indigenous to India and Sri Lanka. The main ingredients of idli are rice and black gram. For the preparation of the batter, rice and de-skinned black gram are soaked ground separately by adding required water. Then both the batters are mixed together with the addition of salt and this is allowed to ferment at room temperature overnight. The fermented batter is transferred to special idli pans and steamed.
The fermentation is caused by microbes that are naturally present in the ingredients and the environment. The naturally occurring bacteria Leuconostoc mesenteroides and Streptococcus thermophilus start growing during soaking and further continue to grow during grinding. The lactic acid and carbon dioxide produced cause the batter to leaven (rise). Nutritionally the changes that take place are increased vitamin B and C and essential amino acid methionine and choline(B vitamin like nutrient essential for bodily functions). Also, the phytates that are present in the rice and black gram are broken down during fermentation, thus enhancing the efficient absorption of minerals like iron and zinc.
Studies conducted on the role of starter cultures in the fermentation of idli batter have shown better outcomes in terms of texture, nutrition and shelf life.
Fermented rice (Indian)
Fermented rice has been a part of Indian gastronomic culture since time immemorial. This conventional, yet simple food is increasingly gaining scientific recognition since the last two decades. Farmers in rural part of India kick start their day with fermented rice.
This rice is prepared by soaking cooked rice in water. Generally, the rice which is prepared in the afternoon is cooled down to room temperature followed by its soaking in water which is also at room temperature. This mixture of cooked rice and water is stored in a clay pot and left to ferment overnight at room temperature which will be ready for consumption the next morning. It is eaten with raw onion and green chilli as accomplishments. Also, it can be eaten with yogurt and a sprinkle of salt after draining extra water.
Fermented rice is healthier compared to the regular cooked rice as fermentation brings about many favorable changes with respect to the nutritional values. The fat content of the rice is reduced and there is an increase in the protein and fiber content. The anti-nutritional factors such as phytates are decreased and this improves the digestibility and absorption of important minerals like calcium and iron in the body. The probiotic potential of this rice improves the digestive health and consumption of this food on a regular basis alleviates the symptoms of lactose intolerance. There is enhanced availability of B group vitamins as well as vitamins A, C and E. It also has protective effect on cancer of the esophagus, stomach, colon, liver and bladder.
Wheat based:
Sourdough bread
This is a type of leavened bread that has a history dating back to 2000 BC and was used by ancient Egyptians. The ingredients that are required for the preparation of sourdough bread are flour, water and starter. The starter culture is prepared by mixing flour and water and allowing it to ferment. The process of fermentation is brought about by lactic acid bacteria and yeasts that are naturally present in the flour and the surrounding environment. The starter needs to be fed everyday with flour and water and takes about seven days for the starter to be fully ready for usage.
The flour that is preferred is whole wheat flour or strong white bread flour. But this can be combined with flour from rye, corn, rice, quinoa, sorghum or chickpea. The use of other flours gives a more diverse microbial picture. For the preparation of the sourdough bread, a small amount of the starter is added to the flour and water to initiate the fermentation process (backslopping). The interaction between the microbes and the substrate leads to the fermentation of sugars and raising of the dough.In addition, the acetic acid producing microbes are at times naturally present in the dough.The final flavor of the bread depends on the end products formed during fermentation. The production of lactic acid gives a more yogurt like flavor whereas a tangier flavor is due to the formation of acetic acid.
The difference between the sourdough bread and regular bread is that the later uses ‘bakers yeast’ while sourdough uses naturally occurring ‘wild yeast’ and lactic acid bacteria present in the flour. The advantages of using the sourdough are better protein digestibility, increased fiber content, reduced glycemic index, reduced phytate levels and other anti-nuclear factors and increased levels of vitamins, minerals and anti-oxidants. The fermentation process also reduces the amount of oligosaccharides fructans and raffinose which are hard to digest. Hence sourdough bread is better tolerated in individuals with irritable bowel syndrome.
The fact that the microbes contained in the sourdough bread, breakdown the proteins such as gluten, thus reducing its adverse effects has been studied in individuals with coeliac disease. Though the results were encouraging, they were short duration studies. However, it is worth noting that there is incomplete breakdown of gluten by the microbes and hence sourdough bread is not considered gluten free.
Soy sauce: A dark brown liquid made of soybeans and wheat popular in China, Japan and Far East.
Kishk:Fermented milk is added to par-boiled wheat which is free from bran. The final product is rolled into balls and stored. This is popular in the Middle East and has a high nutritive value being rich in B vitamins. The use of whole-meal wheat is said to add more nourishment in terms of micro-nutrients such as calcium, iron, magnesium and zinc.
Tarhana:This is a preparation of wheat flour, sheep milk yogurt, yeast mixed with vegetables such as onions and tomatoes and spices which include paprika, salt and mint. The final product is dried and flattened into biscuits. The main nutritive significance is increased protein content of the cereal.
Corn based:
Ogi:This is a gruel prepared from maize. Sometimes sorghum or millet is also used. It is regarded as a weaning food for infants in West Africa. Though fermentation brings about an increase in the levels of niacin (vit B3) and riboflavin (vit B2), some of the nutrients especially amino acids are lost during processing of the grain. Hence utilizing the Lactobacteria species that produce amino acids is important.
Kenkey: This is a fermented maize dough that is popular in Ghana.
Pozol: A fermented maize dough that is shaped into balls of various sizes from the region of Mexico.
Sorghum-based:
Injera:This is prepared from the milled tef grain and is popular in Ethiopia. It is rich in calcium and iron.
Kisra: This is prepared from the fermented dough of sorghum or pearl millet flour. The dough is rolled into thin sheets and baked. It is popular in Arabian Gulf, Sudan and Iraq.
Fermented beverages:
Beer
This is one of the oldest and widely consumed fermented beverage since ancient times. Being an alcoholic beverage, too much consumption has harmful effects on health. However, moderate consumption has been shown to confer beneficial effects with regard to prevention of cardiovascular disease, reducing the risk of gastro-intestinal infections (H. Pylori), diabetes risk, obesity incidence, depression and improved cognitive function.
Beer brewing has a long history dating back to several millennia. The scientific and technological advancements over centuries have resulted in the improved quality and diversity of the product. Conventionally, for the preparation of beer, four ingredients are used. They are malted cereals (barley or wheat, sorghum, rye, oats), water, hops and yeast.
Nutritionally, beer contains mostly water. In addition to this, it is a source of carbohydrates, vitamins, minerals, amino acids and phenolic compounds. The presence of these nutrients can be attributed to the brewing and fermentation. The Hop flowers that serve as bittering and flavoring agents, contain many phenols which have health benefits. One compound of particular interest is called Xanthohumol which prevents platelet aggregation without increasing the risk of bleeding. Hence the brewing is modified so as to obtain beer with high Xanthohumol content.
Sake:This is a traditional alcoholic beverage of Japan made from fermented sake rice. The ingredients present in sake are rice, water, yeast and a mold known as koji. The microbes Aspergillus oryzae and Saccharomyces cerevisiae bring about fermentation and the final ethanol concentration is roughly 20%. Though light to moderate consumption of sake has been claimed to confer health benefits in terms of reduced risk for diabetes, heart disease, stroke and cancers, more extensive studies are needed to ascertain the same as these studies were conducted on the sake yeast.
Boza:A wheat based alcoholic beverage popular in Egypt and Turkey. It is said to have known since the pharaoh times. This is produced by fermenting cereals such as rice, barley, corn, oats and millet and is consumed during winter and autumn. The fermentation process includes lactic acid and alcoholic fermentation. Here the lactic acid that is produced imparts acidity and carbon dioxide provides volume to the drink. In addition to being a source of essential nutrients such as carbohydrates, proteins, fiber and minerals, reports from a study suggest that this drink is a source of ACE- inhibitory peptides (these helps lower the blood pressure by relaxing the blood vessels). Hence, boza is regarded as a functional beverage (non-alcoholic drinks having health benefits).
Vegetable and fruit Based
Fruits and vegetables are an important source of vitamins, minerals, dietary fiber and phytochemicals (natural chemicals present in plants. They are non-nutritive but offer numerous health benefits. Ex. Carotenoids, flavonoids, curcumin). Since vegetables naturally have reduced sugar content and have a neutral PH, they provide an ideal ground for lactic acid fermentation. The fruits and vegetables that are fermented offer many benefits in terms of nutritive quality and human health. Fermentation conserves the key nutrients and colored pigments. Hence fermented fruits and vegetables not only form a source of balanced nourishment, but also have enhanced anti-oxidant properties that shield against many diseases such as liver cirrhosis, diarrhoea, cancer, arthritis and ageing. It has been reported that vegetables like Chinese cabbage, cabbage, tomato, carrot and spinach have an edge towards better fermentation. Some of the fruits that are mostly used in fermentation are apples, pears, immature mangoes, immature palms, lemons and banana pulp. Some examples are
Kimchi
This is a conventional food of Korea. Here the main ingredient is Chinese cabbage. Along with this radish, green onion, red pepper powder, ginger, garlic and fermented sea food are added. The fermentation of kimchi is dependent on the temperature i.e., higher the temperature, quicker it ferments. In order to avoid the excess production of acid it is preferably fermented at low temperatures. The microbial composition of kimchi is predominated by Leuconostoc and Lactobacillus species. It is said that preceding fermentation, kimchi contains many types and species of microbes. However, three days following fermentation, the above-mentioned species dominate the picture. Also, the type of microbes present in kimchi depends upon the variety and quantity of the ingredients used. For example, addition of large amounts of garlic leads to increased Lactobacillus content whereas the inclusion of red pepper powder results in lower Lactobacillus and Leuconostoc and higher concentration of Weissella species.
The typical taste of kimchi is a mixture of sweet, sour and carbonated taste. Kimchi is loaded with phytochemicals, vitamin C, dietary fiber, amino acids and organic acids. This food has an array of health benefits such as anti-cancer, anti-aging and anti-inflammatory effects, reduced risk for atherosclerosis, cholesterol lowering effects, reduced obesity risk and immune system boosting properties. Studies have shown that kimchi might reduce insulin resistance in individuals with pre-diabetes. Kimchi is also regarded as a pro-biotic food. This food also has the potential to relieve the symptoms of inflammatory bowel disease by modifying the intestinal microbial flora.Due to its health benefits, kimchi has been crowned as one of the top five healthiest foods in the world. Even though concerns have been raised about its high salt content, studies have not shown any association between kimchi consumption and hypertension.
Sauerkraut
Sauerkraut is one of the popular traditional fermented food whose history dates back to 4th century BC. Literally meaning ‘sour cabbage’, it has been consumed in China since the times of antiquity for its health benefits. The fermentation process involves the shredding of cabbage and its subsequent mixing with 2.3-3% salt. This mixture is let to undergo spontaneous fermentation. The microbial and biochemical changes encountered during the fermentation process brings about favorable changes with respect to the flavor, quality and safety of the product. Here the fermentation is brought about by the lactic acid bacteria that are naturally present in raw cabbage. The microbial composition of sauerkraut contains mainly species of Lactobacillus and Leuconostoc and also yeast and fungi. The PH of sauerkraut ranges between 3.6-3.8 which is ideal for its preservation.
The nutritive content of sauerkraut has been found to be rich in Vitamin C, B group vitamins, vitamin E, calcium, iron, potassium, phosphorus and phenolic compounds (plant substances that have numerous health benefits). Its range of health benefits include anti-oxidant, anti-cancer, anti-inflammatory effects and immune boosting effects. In addition to these effects, there is limited evidence to its effect in reducing the symptoms of irritable bowel syndrome (IBS) as a result of its positive effect on intestinal microbial composition.
Yan-taozih (pickled peaches)
The pickled peaches are widely consumed in the region of China and Taiwan. Here the fresh peaches are mixed with 5-10%salt. This mixture is then lightly shaken till the water is released from the peaches. Again, the peaches are washed and then combined with 5-10% sugar and 1-2% pickled plums. The mixture is allowed to ferment for a day or two. Some of the species of Lactobacillus, Leuconostoc, Weissella and Enterococcus have been isolated from yan-taozih. Despite its popularity, this fermented food lacks comprehensive studies.
Red wine
Red wine has a long association with human civilization for over 6000years. The multifaceted use of wine as a part of social and religious gatherings, as a medication, a medical solvent and as a complimentary beverage served with food has been passed down to several generations, though the modern mindset relates to its role as a complimentary beverage.
Wine is prepared by fermenting Vitis Vinifera grapes also commonly called as grapevine. After harvesting, the grapes are prepared for fermentation. The preparation of red wine involves the fermentation of the pulp of black or red grapes along with the skin. The primary fermentation occurs in the presence of natural yeast or added yeast. Here sugars present in the grapes are converted into ethanol and carbon-dioxide. This initial fermentation is followed by the separation of the wine (free run wine). Also, the skin of the grapes is pressed to extract the remainder wine (pressed wine). These two are blended and kept warm for the rest of the fermentation to complete.
The next step is the malo-lactic fermentation which occurs naturally or may be induced by bacteria. The microbe responsible for this fermentation is Oenococcus oeni that belongs to the family of Lactic acid bacteria. Here malic acid present in grapes is converted into lactic acid which contributes to the soft taste of wine. This is followed by storing the wines in oak barrels for aging which may take months to years. The final steps are blending and clarifying which gives wine fine flavor and clarity.
The constituents of the wine include water, alcohol, carbohydrates, minerals, organic acid and polyphenols. The health benefits of the red wine are attributed to the presence of phenols. Some of the polyphenols present in red wine are resveratrol, catechins, anthocyanins and tannins. Among these resveratrol plays an important role in cardiovascular protection such as improved endothelial function (important for the normal functioning of the blood vessels), metabolism of glucose, reducing inflammation as well as maintaining normal blood lipid levels including increased HDL cholesterol levels. It also has a protective effect on the brain and nerve cells and prevents the formation of clots. Studies have pointed that these protective effects are related to moderate wine consumption.
Vinegar
The term vinegar is derived from the French word ‘vin aigre’ meaning ‘sour wine’. Vinegar has a fascinating history as its practical applications can be traced back to antiquity. It was used by Hippocrates to treat wounds. The military leader Hannibal of Carthage used vinegar to dissolve the rocks that stood in their path. The Egyptian queen Cleopatra used vinegar to dissolve precious pearls and offered the ‘portion of love’ to Antony. In the later centuries, it was used to treat many ailments like dropsy (edema or swelling) and stomach aches. Vinegar tea was given to the diabetic patients to manage blood sugar before the discovery of medications.
The substrate for vinegar production is a carbohydrate that can be easily fermented such as apples, pears, grapes, berries, melons, potatoes, beats, malted grains, sorghum, dates, molasses, wine, beer, honey and coconut. Here the fermentation process involves alcoholic and acetic acid fermentation. The sugar that is present in the substrate is converted into ethanol and carbon-dioxide by yeast followed by the conversion of ethanol into acetic acid and water by Acetic acid bacteria.
Apart from its application in the food industry as a preservative and flavoring agent, vinegar has been demonstrated to have anti-bacterial properties. In addition to its application to treat wounds and ulcers, some studies have reported its potential to treat ear infections. In the coastal regions it is a practice to apply vinegar on the site of jelly fish sting. It is also used in the treatment of warts, head-lice and fungal infection of the nail, though scientific evidence behind this is lacking. Also, vinegar has been associated with health benefits such as reduced risk of obesity, cancer, diabetes and atherosclerosis.
Legume based
Legume is a type of plant bearing a pod which is nothing but an elongated part that contains seeds. When the seeds are in the dried form they are called as pulses. Some examples of legumes are beans, peas, chickpeas, lentils, soybeans etc. They are a source of carbohydrates, dietary fiber, proteins including the essential amino acids, minerals like iron, calcium, zinc, magnesium, selenium, phosphorus and B group of vitamins. Legumes also contain phytochemicals which have anti-oxidant action protecting against chronic diseases such as cardiovascular disease, diabetes, obesity, cancer and hypercholesterolemia.
Also, legumes contain certain substances called anti-nutritional factors (ANF) which have more of beneficial value on health rather than nutritional value. These include oligosaccharides, protease inhibitors, phytates and saponins. These ANF’s are responsible for some unwanted side effects such as bloating and digestive problems. It has been shown that application of methods such as soaking, steaming, boiling, germination and fermentation eliminates these substances. Fermented legumes are beneficial in terms of nutritional value and digestibility as fermentation increases the availability of important nutrients especially vitamins, minerals and amino acids as well as decreases the level of ANF’s. There has been reports about the fermented legumes demonstrating anti-diabetic properties. The legumes that are mainly used for the preparation of legume based fermented foods are soy beans, mung beans, black gram and Bengal gram. Some examples of the legume based fermented foods are
Tempeh
This is a conventional food of Indonesia that is made from fermented soybeans. After removing the husk from soybeans, they are boiled followed by the addition of a starter culture which is usually a fungus belonging to the Rhizopus species. The fermentation is done at room temperature for 35-37 hours. The final product is a cake which is white and soft having a chewy consistency and mushroom like taste. This cake is sliced and used for cooking. Tempeh has not been studied extensively. Some preliminary studies have proposed the potential of tempeh in improving the intestinal bacteria as well as protecting the cells from damage by removing the harmful substances such as free radicals and super-oxides.
Natto
Natto is a popular food in Japan and is prepared from fermented soybeans. This unsalted food is prepared from yellow soybeans which is cooked and fermented using the microbe called Bacillus subtilis natto. In the process of fermentation certain chemicals called bio-active factors are produced. These include nattokinase, bacillopeptidase F and vitamin K2 which have health benefits. Nattokinase has been shown to prevent blood clots and maintain normal blood pressure. The role of natto in diversifying the intestinal microbial flora and regulating the bowel movements needs more studies.This fermented food is viscous with a strong odour.
Miso
Miso is a fermented soy bean paste that is used to prepare miso soup and is widely consumed in Japan. This is made by mixing cooked soy beans with salt. The fermentation is brought about by adding ‘koji’ which is a starter culture made by infusing rice with a fungus called Aspergillus oryzae. There is some preliminary evidence regarding the beneficial effects of miso on gastrointestinal disorders such as dyspepsia and reflux disease.
The predominance of the soy based diet in China and Japan have been proposed to be the possible reasons behind the low incidence of colon and prostate cancers in these regions. One possible reason behind this could be due to the presence of isoflavones. These are naturally occurring compounds present in plants that imitate the action of estrogen and are mainly present in soy beans. Though some lines of research support the beneficial effects of these compounds as having anti-inflammatory, anti-microbial, anti-oxidant and anti-cancer properties, concerns have been raised to its estrogen mimicking effects and risk of breast cancer. However more extensive studies are warranted in this field. In addition to the above findings, studies have also shown that regular consumption of miso soup which is known to be high in salt, does not lead to hypertension. Though the mechanisms behind this is not fully known, it is said that certain ingredients of miso soup actually lower the blood pressure and heart rate.
Roots/tubers based
These are considered as the main source of energy, next to cereals, especially in the tropical and sub-tropical regions. Some of the roots and tubers are potatoes, cassava, sweet potatoes, yams and aroids. Their nutritive content and the wide range of health benefits offered have projected them as foods that have the potential of providing a balanced nutrition on an economic note. Roots and tubers contain many bio-active compounds that have health promoting effects. These include phenolic compounds, saponins, bio-active proteins, glycoalkaloids, carotenoids and vitamin C.
The diversity of the phenolic compounds depends upon the cultivation methods and environmental conditions. However, the phenolic compounds present in tubers such as phenolic acids and flavonoids have been found to possess anti-inflammatory, anti-bacterial, anti-mutagenic effects (meaning preventing DNA changes in the cells) and immune boosting effects. Dioscorin, a bio-active protein present in yam has been shown to have anti hypertensive properties. On the other hand, sporamin which is a bio-active protein present in sweet potatoes has been shown to have anti-cancer effects. The saponin compounds present in yam have been shown to reduce the blood cholesterol levels. The biological activity of glycoalkaloids include antitumor, antiviral, antifungal and antiestrogenic activities. Yam consumption has been shown to bring hormonal balance and protect against osteoporosis in post-menopausal women.
Carotenoids, which are present abundantly in sweet potato and yam are an important source of vitamin A and also controls gene expression in a cell (a process in which the information present in the DNA of the cell is used for the production of an end product such as protein). Finally, vitamin C or ascorbic acid is found in significant amounts in potatoes, sweet potatoes and cassava. But cooking could affect the availability of vitamin C and hence it is recommended to make use of the skin and water that was used for cooking. Some studies have reported the wound healing properties of the skin of sweet potatoes owing to the presence of vitamin C. However, the concentration of vitamin C also depends on the external factors such as environmental conditions, cultivation practices and the type of fertilizers used. Some examples of roots and tuber based fermented foods are
Fermented cassava
This is regarded as the main food crop of the tropics and Africa. Conventionally cassava is processed prior to consumption as processing tends to eliminate the cyanogenic glucosides present in the raw cassava which are potentially toxic. Also, it helps in the preservation and the final product after processing has a better quality. The different methods of processing includes cooking, drying and fermentation. For the fermentation of cassava lactic acid bacteria and yeast are used.
The fermentation of cassava involves two methods. One is solid-state fermentation wherein grated or sliced cassava is exposed to the natural atmosphere and is allowed to undergo fermentation. This method is used in the making of gari, a flour which has a fine or granular texture prepared from fermented and mashed cassava. Gari is consumed in various forms such as cooked dough, as a deep fried snack by mixing it with maize flour and sugar or as a light meal by adding honey/sugar, roasted peanuts and evaporated milk. Nutritionally gari is rich in carbohydrates, has a low-fat content and also contains B vitamins, vitamin C and iron.
The other method of fermentation is called submerged fermentation wherein the cassava roots either peeled or unpeeled are fermented in water for 4-6 days. This method is used for the production of fufu and lafun. The boiled, pounded and rounded cassava dough is called fufu where as lafun is basically a stiff porridge. Both are eaten with soups and stews. Overall, the protein content of cassava flour can be enhanced by the addition of legumes such as soybean or cow pea during fermentation.
Shochu
This is a traditional distilled liquor popular of Japan which is made by using sweet potato, barley, rice, buckwheat and brown sugar fermented using koji. It is consumed either plain, mixing with ice, diluting with room temperature or hot water and fruit juice. Studies have found that shochu is effective in raising the level of urokinase (an enzyme produced by the kidneys that activates enzymes involved in the dissolution of clots) thus preventing the formation of blood clots.
Dairy based
The consumption of milk has been known since the 7th millennium BC. Milk and dairy foods are considered to be nutritionally rich as they provide energy and high-quality proteins in addition to vitamin D, vitamin B12, vitamin A,calcium, magnesium, potassium, zinc and phosphorus. These minerals play an important role in maintaining the bone health in all age groups. The main milk proteins include casein (80%) and whey protein (20%). Several studies have demonstrated the beneficial effects of the bio-active compounds present in the milk. These are naturally present in milk and are liberated during digestion of milk proteins, processing and bacterial fermentation. They have antihypertensive, cholesterol lowering, anticancer, anti-inflammatory, antithrombotic and immune boosting effects.
The dairy based fermented foods holds a unique place in history as they were one of the earliest foods that were processed and consumed.With scientific advancements, these foods have been studied comprehensively for their health benefits. Fermented dairy products have been linked to reduced risk for obesity, cardiovascular disorders, metabolic diseases as well as cognitive deterioration. In addition to the vitamins, minerals, fatty acids and bio-active peptides, fermented dairy products are also a source of living microbes which have a probiotic effect. These probiotic microbes in addition to improving digestive health, also have been proposed to improve mental health, lower cholesterol levels and boost the immune system thus reducing the intensity of allergies.
Most of the fermented dairy products use lactic acid bacteria (LAB). One of the prime reasons to use LAB is to enhance the shelf life and maintain the nutritive value of the fermented product.The lactic acid produced during fermentation not only provides an acidic medium preventing the growth of harmful microbes, but also relieves the symptoms such as abdominal pain and diarrhoea in those with lactose intolerance. Also, recent studies have shown the anti-hypertensive potential of the lactic acid fermented dairy products and this is attributed to the action of LAB on the milk proteins releasing compounds called peptides.
The commonly used lactic acid bacteria are Lactobacillus, Streptococcus, Lactococcus and Leuconostoc. These occur either naturally in the substrate or make up the starter cultures. Apart from these microbes, probiotic bacteria belonging to the species Lactobacillus and Bifidobacteria are also added. Some of the fermented dairy products are
Kefir
The name kefir comes from the Turkish word ‘keyif’ which means ‘good feeling’. This is a traditional fermented milk beverage which is said to have originated in the Balkans, Eastern Europe and Caucasus. Here the fermentation is initiated by the addition of a starter culture called ‘kefir grains’ to milk. These grains look like small florets of cauliflower with a size range of 1-4 cm and are white to light yellow in color. They are not true grains but rather consist of a mixture of lactose fermenting yeast, non-lactose fermenting yeast along with lactic acid and acetic acid producing bacteria enclosed within a protein structure called kefiran. The microbes present in kafir grains share a symbiotic relationship.
The production of kefir involves two methods depending upon its scale of production. On a smaller-scale, kefir is produced by directly adding kefir grains to the milk which has been pasteurized and cooled to a temperature of 20-25 degrees. The grains are retrieved after fermentation to be reused again.On a bigger scale, kefir is produced by adding starter cultures directly to the milk or by following backslopping method wherein the fermentation is initiated by using natural starters which is the kefir that is obtained from the grains. Although kefir is commonly made by using cows’ milk, other types of milk obtained from goat, sheep, buffalo and camel have been used.
The process of formation of kefir grains is not fully understood.Traditionally the milk was fermented in goat skins, clay pots or wooden buckets. Due to the continuous adding and removal of milk, probably the microbes present in the residual milk in the containers together with those in the fresh milk colonized to form grains. Recent studies have proposed that the complex interaction between the microbes in the form of aggregation and biofilm formation lead to the formation of grains.
Kefir has been the center of focus in recent years due to its innumerable health benefits. The positive health benefits attributed to kefir are anti-hypertensive, anti-inflammatory, cholesterol lowering, anti-cancer, anti-bacterial, anti-fungal, anti-diabetic, anti-oxidant, anti-allergic and probiotic effects. Though studies indicate the potential of kefir in improving the intestinal health, more extensive studies are needed to ascertain the same. Recent studies have brought into light the anti-viral potential of kefir and its role in protection against Covid-19 and its complications.
Yogurt
Yogurt is a fermented, coagulated milk product wherein the bacterial strains are added to the primary ingredient milk. The most commonly used microbes are Lactobacillus bulgaricus and Streptococcus thermophilus which produce lactic acid fermentation. The nutritive content of yogurt is similar to that of milk. However, in the fermented state, the concentration of protein, vitamin B12, vitamin B2, calcium, magnesium, potassium and zinc are increased. Yogurt is a good source of probiotics and iodine. Though lactose is present in yogurt, it is well tolerated by the individuals sensitive to lactose and this is attributed to the presence of live microbes.
The fat content of yogurt needs a special mention here as now a days commercially available yogurt with differing fat contents are available. However, the fatty acids present in yogurt which include short and medium chain fatty acids and conjugated linoleic acid have been said to confer anti-inflammatory, anti-diabetic and anti-cancer properties.
Cheese
The origin of cheese dates back to 8000 years.It was conventionally called ‘milk pimples’ by the Mongolian, Kazak and nomadic people belonging to northwestern part of China.Cheese can be defined as a food that is made by separating water from milk, so that the nutrients present in the milk are in a concentrated form with an enhanced flavor and aroma. There are more than 2000 cheese varieties in the world.
Cheese is consumed either in the fresh or fermented form. The key ingredients to cheese making are milk, microbes, salt and enzymes.The milk is sourced from cow, sheep, goat or water buffalo. Here the milk, cream or partially skimmed buttermilk is curdled followed by the addition of lactic acid bacteria. Most of the cheeses are made by using raw sterilized milk which has been heated to a temperature of 63 degrees for 30 minutes or 72 degrees for 15 seconds. The sterilization of milk is likely to kill most of the lactose fermenting bacteria present in the milk. So, it becomes necessary to add starter cultures for a stable end product.
The curdling agent is either rennet, acid, heat and acid or a combination of these agents. The product that is obtained after the separation of whey, is allowed to mature for a specific time period.The characteristic features of cheese such as aroma, color, texture, flavor and solidity depend on the milk source, moisture content and the duration of maturity. Also, the presence of microbes such as yeast, molds and bacteria impart these characteristic features.
With regard to the nutritive content of cheese, much concerns have been raised about its fat, salt and cholesterol content. However,studies conducted on the relationship between cheese consumption and chronic diseases like cardiovascular disease, diabetes, cancer (prostate) and Parkinson’s disease have produced conflicting results. But looking beyond these associations, it is obvious that cheese is a nutrient dense food containing proteins, fats, vitamin A, vitamin B6, vitamin B12, vitamin K2, zinc, phosphorus. Magnesium, calcium and potassium.
Evidence from studies conducted on the nutritive content of cheese have found its positive association with health. The high calcium content of cheese has been attributed to have a neutralizing effect on blood lipid levels. The whey protein has been shown to have weight and blood pressure reducing effects. Also, the vitamin K2 produced by the bacteria contained in the cheese protects against cardiovascular diseases. Studies have also shown that the energy value is maximum in cheese containing molds.
With respect to fatty acids, it should be noted that generally the levels of saturated fats in dairy foods are not substantial. The presence of fatty acids such as branched chain fatty acids, trans-fatty acids, conjugated linoleic acids have protective effects on the heart. The attempt to produce cheese with low salt content without having a negative effect on the quality of the final product have been evaluated for certain varieties of cheese.
Meat based
Meat has a long history as being an integral part of the human diet. Though cultural differences exist in the way it is consumed, nutritionally speaking it is a good source of proteins, vitamins, minerals and essential amino acids. Sine the composition of meat is equivalent to that of human skeletal muscle, it provides all the necessary support such as building and maintaining the muscle mass. Some of the minerals present in meat are iron, zinc, selenium and phosphorus. Meat is an excellent source of natural vitamin B12. Also, with regard to zinc and iron, the availability and absorption is higher in meat-based diets.
The fat content of meat, especially the saturated fat, has been an issue behind health concerns such as cardiovascular diseases and diabetes. Though a modified fatty acid profile can be obtained through changing the animals feed, it is said that such meats do not meet the needs of the consumers. But the fact that meat contains other fatty acids such as conjugated linoleic acid, branched chain fatty acids and rumenic acids (derived from ruminants like cattle) which have health benefits are often neglected. However, studies conducted on these fatty acids have produced conflicting results.
Meat can be fermented either naturally or by adding starter cultures. In natural fermentation the microbes present in the substrate and the processing environment bring about changes in the texture and flavor of meat. Lactic acid bacteria are frequently used as starter cultures for meat fermentation as lactic acid production during fermentation leads to PH reduction, prevents the growth of harmful microbes and imparts flavor in addition to extending the shelf life of meat. Some of the starter strains that are used commercially in certain regions have been shown to have probiotic effects.
The presence of high salt and nitrites in processed meat has been a cause for concern as it has been linked to hypertension and colorectal cancers. But these compounds play a crucial role in maintaining the safety, texture, flavor and stability of the fermented product. The addition of ascorbic acid has a protective effect against the harmful effects of these compounds. Some of the fermented meat products are
Sucuk
This is a dry fermented sausage popular in Turkey. Here the meat from beef or water buffalo or mutton is chopped followed by the addition of spices, fat, preservatives, colorings, additives and starter cultures. The fat derived from the beef or sheep tail is used. Apart from salt being a major additive, nitrate or nitrite are used for their anti-bacterial, anti-oxidant and color imparting properties. The substrate for fermentation is sucrose or glucose. Some of the added spices include black pepper, red pepper, all-spice and garlic.
The combination of Lactic acid bacteria and micrococci used in fermentation produce a final product with desirable taste, texture and nutritive value. The flavor and odour of the dry fermented sausage is due to the formation of volatile compounds (aldehydes, ketones, sulfur compounds, acids, esters, alcohols, aromatic hydrocarbons, terpenes) formed during ripening. Terpenes contribute to the aroma and these are derived from the added spices. Even though this food is much appreciated owing to its sensory qualities, it has been under the radar due to the presence of high salt, fat and amines.
Pastirma
This is a dry cured meat prepared from the whole muscle of beef or water buffalo and is widely consumed in Turkey. The production of Pastirma involves drying, curing, pressing of meat, followed by the addition of cemen, which contains a mixture of ground fenugreek, red pepper, paprika and garlic which are made into a paste. The process of fermentation leads to desirable changes with color, flavor, texture and shelf-life.
The breakdown of proteins and fats are the key reactions in the processing of Pastirma. The amino acid content of the meat is increased due to protein breakdown. Cemen gives the food the characteristic traditional taste. The anti-oxidant and the ACE inhibitor effect (blood pressure lowering effect) of Pastirma have been demonstrated in one study and this has been linked to the cemen content and breakdown of proteins.
Fish based
Fish is a food commodity known for its economic and nutritional value and is predominantly cultivated in the tropical and sub-tropical regions. The popularity of fish continues to grow world wide not only due to their nutritional and economical values, but also due to their aggregable palate.
Fish is considered as a nutritionally dense food as it is a good source of proteins, lipids, vitamins and minerals. The protein present in the fish is nutritionally superior as it contains the essential amino acids which have health benefits such as anti-hypertensive effects, muscle repair and maintenance and enhancement of blood quality.Fish contains polyunsaturated fatty acids (PUFA) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) that protect against cardiovascular and coronary heart diseases. DHA is important for the normal growth and function of the brain in infants and also maintains the normal functioning of the brain cells in adults. Some of the vitamins present in fish are A and D and B12. The mineral content is species dependent and includes calcium, iron, zinc, selenium, iodine, phosphorus and potassium.
In its fresh form, fish is regarded as a highly perishable food as it is vulnerable to microbial spoilage. Fermentation is one of the ways to preserve fish as it improves the flavor, texture, aroma as well as the nutritive content. The use of fermented fish in culinary practices exists since the ancient times. The preserved fish was also a source of nourishment during food scarcity. One of the earliest known fermented fish sauce was called ‘garum’ which was popular in ancient Rome. It was made from the blood and viscera of Mackerel fish.
The method of processing of fish is more or less the same in all regions. In many regional communities around the world, fish fermentation is an integral part of their life and culture. In the region of Africa, the methods include, fermentation with salting and drying, fermentation and drying without salting, fermentation with salting and no drying. Both African and Asian methods involve spontaneous fermentation in which no starter is used. However, in Europe, North America, Australia and New Zealand, specific starter cultures are used.
Fermented fish products are classified according to their forms as follows
Fermented products wherein the fish is in its original form or chunks: Some examples are
Buro: This is a mixture of rice porridge and a sea food which is usually shrimp or fish popular in the Philippines.
Peda: This is the traditional, semi-dried and salted fermented mackerel fish of Indonesia.
Colombo cured mackerel:This is wet salt cured and pickled fish. This type of curing was practiced by fisherman of West coast of India.
Fermented products wherein fish is in the form of paste: Some examples are
Bagoong:This is a fermented salted fish or shrimp paste of Philippines.
Trassi: This is the fermented shrimp paste of Indonesia.
Ngapi:This is a fermented shrimp or fish that is salted, ground and sun dried. It has a pungent taste and is popular in Burmese cuisine.
Fermented products wherein the fish is in liquid form: Some examples are
Patis: This is a byproduct of bagoong and is basically an extract that is removed from the upper layers of bagoong that is undergoing fermentation. The sauce is consumed widely in Philippines.
Nuoc-mam: This is a Vietnamese fish sauce made from anchovies, mackerel, scabbard fish and salt.
Budu: This is a fermented anchovies sauce of Malaysia. The peptides contained in this sauce have been found to have anti-cancer potential.
The microbial content of fermented fish products is diverse. Among the many species that have been isolated, it has been found that Lactobacillus and Staphylococcus were the most prevalent ones. The proteins present in the fish are broken down into amino acids and polypeptides by the enzymes present in the microbes. In the fermented fish products, there is no contrast in the quality of amino acids compared to fresh fish. The bio active peptides that are released as a result of protein breakdown have many health benefits like anti-oxidant, anti-microbial, anti-thrombotic, anti-hypertensive and also cholesterol lowering effects.The fermented fish oil has been found to have increased levels of EPA and DHA. However, the limiting factor of fermented fish products is their high salt content. These products have condimental value and are not consumed in large quantities on an everyday basis.
Herb based
Herbal beverages often referred as ‘herbal teas’ are being increasingly recognized for their health benefits. They have carved a place for themselves among the predominant beverages such as tea, coffee and cocoa which also have a plant origin. On a general note, herbal teas are prepared from the morphological parts of plants such as leaves, stems, fruits, buds and flowers.
The herbal teas are an excellent source of bio-active compounds as they are derived from the plants. They include carotenoids, flavonoids, coumarins, phenolic acids etc. These bioactive compounds have a wide range of health benefits including antioxidant, antibacterial, antiviral, anti-inflammatory, antiallergic, antithrombotic, anticancer and antiaging effects.
Some of the herbal teas based on the regions of the world include
Asia: Centella asiatica which is a dried whole herb often mixed with garlic, coriander and ginger. The Bael fruit which is indigenous to Southeast Asian countries, is rich in vitamin C,coumarins and riboflavin. The extract of this fruit is used as a traditional medicine to treat dysentery and also exhibits anti-diabetic activity.
Africa: African rooibos, borututu are popular herbal teas. The extract of rooibos is used to treat infantile colic, allergies, asthma and dermatological diseases. In addition it keeps the heart healthy and also has anti-cancer effects,
South America:Yerba mate is a caffeine containing herbal beverage popular in this region. It has diuretic effects, protects the liver as well as stimulates the central nervous system.
Europe: Chamomile tea made from dried flower heads is popular here. Apart from its antioxidant effects, this tea has been demonstrated to have anxiolytic and antiplatelet effects. Peppermint tea has been shown to have antibacterial, antioxidant and calming effects.
The fermented herbal beverage includes
Kombucha
Comments