An overview of some ethnic fermented fish products of the Eastern Himalayan region of India lists available at ScienceDirect J Ethn Foods (2016) 1e8 Contents Journal of Ethnic Foods journal homepage h[.]
J Ethn Foods - (2016) 1e8 Contents lists available at ScienceDirect Journal of Ethnic Foods journal homepage: http://journalofethnicfoods.net Original article An overview of some ethnic fermented fish products of the Eastern Himalayan region of India Ranendra K Majumdar a, *, Deepayan Roy a, Sandeep Bejjanki b, Narayan Bhaskar b a b College of Fisheries (Central Agricultural University), Lembucherra, Tripura, India Central Food Technological Research Institute (CFTRI), Council of Scientific and Industrial Research, Mysore, Karnataka, India a r t i c l e i n f o a b s t r a c t Article history: Received November 2016 Received in revised form December 2016 Accepted December 2016 Available online xxx Background: Like southeast Asian countries fermented fish is a well known strategy of food preservation in the northeast region of India The northeastern region of India is known for its vast natural resources and a cauldron of different people and cultures, lie deep in the lap of easternmost Himalayan hills in northeastern part of India Here the fermentation technology evolved by compulsion of people Popular fermented fish products of this region of India include Shidal and lonailish Fermented fish contributes a regular menu in the diets of people of almost all categories Methods: The traditional technology was explored by thorough interrogation with the local producer in their place The origin of the technology as well as the compulsion for diversification of the traditional fish drying process to fermentation was known from the very old people in the community Results: The technology was observed while in operation and attempted to justify the science behind each step in the fermentation process The Shidal technology was found to be evolved even before the use of salt by the people Conclusion: It was revealed that as the northeastern states of India, being the highest rainfall area of the world, did not provide a congenial environment for simple sun drying of fish and fermentation was the only option to preserve fish © 2016 Korea Food Research Institute Published by Elsevier B.V This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Keywords: ethnic foods fermented fish Northeast India shidal Introduction The North-Eastern Region of India is known for its vast natural resources and a cauldron of different people and cultures lie deep in the lap of easternmost Himalayan hills in the North-Eastern part of India, connected to the rest of India by just 20 km of wide land The region comprises of states like Arunachal Pradesh, Nagaland, Manipur, Tripura, Mizoram, Meghalaya, Assam, and Sikkim NorthEast India (NEI) shares over 2,000 km of border with Bhutan, China, Myanmar, and Bangladesh Its total is 2,55,168 km2 with a population of 40 million (as per the 2010 census), of which the Brahmaputra valley in Assam alone houses almost half of its population People of all religions like Hinduism, Islam, Buddhism, and Christianity all live here NEI is home to a varied number of tribal groups (almost 166) Each tribe has their own distinct culture, which gives them a unique cultural identity Numerous art forms and festivals of * Corresponding author College of Fisheries (Central Agricultural University), Lembucherra, West Tripura District, Tripura-799210, India E-mail address: drrkmcof@gmail.com (R.K Majumdar) the region are an intrinsic part of its rich culture and tradition Although NEI is very rich in its food culture, it differs vastly from the rest of the country in its taste as well as flavors Normally, inhabitants of the region are nonvegetarian, and fond of spices NEI tribes can be largely associated with the ethnic groups of Indo Mongoloids, Tibeto-Burmese, and proto-Austrioloids who represent the AsioeAustric culture on Indian hilly regions The trends of these ethnic groups are visible in the looks as well as the traditions which are followed by these communities They provide a cultural bridge between India on one side and South-East Asia, China, and Inner Asia and Burma on the other side by ethnic and linguistic angles Their existence can be traced back to the prehistoric times NEI is not only rich in plant diversity but also has a great treasure of cultural, social, and linguistic variability, conserved by tribal people The region is a treasure of indigenous knowledge systems pertaining to agriculture, medicine, food, and natural resources management Indigenous people are habituated to live and survive with the forest and “Jhum” cultivation culture, which ensures a range of ethnic foods rich in nutrition and compatible to culture and ethnicity of tribes Since time immemorial, rural women of this http://dx.doi.org/10.1016/j.jef.2016.12.003 2352-6181/© 2016 Korea Food Research Institute Published by Elsevier B.V This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/) Please cite this article in press as: Majumdar RK, et al., An overview of some ethnic fermented fish products of the Eastern Himalayan region of India, Journal of Ethnic Foods (2016), http://dx.doi.org/10.1016/j.jef.2016.12.003 J Ethn Foods 2016; -: 1e8 region have selected many wild plants and nonvegetarian foods through trial and error Different fermented and nonfermented foods are used in various combinations with traditional vegetables to meet food and nutritional security The traditional foods consumed by tribes of NEI are intimately connected to virtually all aspects of their socio-cultural, spiritual life, and health The new generation in the same community has undergone a rapid change in their diets over the past 30 years due to the intervention of modern crop varieties, materialistic life, and current trends towards increasing the use of commercial processed foods The fish fermentation technology in NEI states evolved by the compulsion of people NEI, having the highest rainfall in the world, does not provide a congenial environment for simple sun drying of fish People used to preserve fish for use in lean periods by drying under the sun Hence, such drying used to be prolonged due to the high humid atmosphere and frequent rainfall, particularly during the peak fishing seasons (i.e., from May to September) NEI, being abundant in low lying areas where accumulation of water during rainy season, offers an ideal habitat for the breeding of weed fishes such as Puntius spp., “darkina” (Esomus danricus), and “mola” (Amblypharyngodon mola) The fishermen, therefore, were in search of a method through which they could preserve the heavy catches of such less valued weed fishes for consumption and sale in the dry seasons (from November to April) when there was scarcity of raw fresh fish in the market Moreover, due to the nonavailability of ice and good road communications, this perishable produce could not have been transported to the distant markets where they could get a higher price which they never used to earn in the village markets It is fact that the tastes and food habits of the rice-eater prefers to eat his rather tasteless rice mixed with little morsels of products bearing strong flavors In this situation, the fermented fish could become ideal to cater their needs Fermentation involves the breakdown of proteins in the raw fish to simpler substances which are stable at the normal temperature of storage Cleavage of proteins by microbial or indigenous proteases yields the bioactive peptides, leading to substantial increases in the biological properties of the food [1] Traditionally cured fish is a major source of dietary protein in many developing countries [2] In addition to preservation, fermented foods can also have the added benefits of enhancing flavor, increasing digestibility, and improving therapeutic values [3] NEI is bestowed with many fermented fish products such as shidal, lonailish, ngari, hentaak, tungtap, and numsing etc Fermented fish contributes to regular menus, especially in the diets of tribal people These products are traditionally prepared by different tribes of NEI in their household Fig Fermented fish product, “punti shidal.” It is made from Puntius spp It is a very popular fermented fish product of the Eastern Himalayan region of India Fermentation period is 3e5 months in an earthen container This can be stored at room temperature and the processes are normally handed down from generation to generation The traditional people of NEI used to consume these ethnic fermented fish products along with their daily dishes with some ethnic beliefs and these products are intimately connected to virtually all aspects of their socio-cultural, spiritual life, and health Besides fermented fish products, different dried and smoked fish products are also available in NEI which includes “gnuchi” and “suka ko maacha” (smoked and sun-dried fish products), “sidra” and “sukuti” (sun-dried/salted fish products) of eastern Nepal and Sikkim, “karati”, “bordia”, and “lashim” (sun-dried/salted fish products) of Assam, etc [4] Unlike salt fermented fish products of Southeast Asia, the saltfree fermented fish products of NEI indicates the fact that the technology of salt-free fermentation originated long before the men started using salt (sodium chloride) Later on, salt was used for fermentation as was observed with lonailish Preparation of such fermented fish products is simple but most of the critical steps are optimized by experiences for getting a yield of different qualities To date, traditional methods are in practice due to lack of adequate scientific intervention and standardization of methods Details of the traditional technology of the two most popular fermented fish products of India are discussed here Shidal Shidal is a salt-free fermented fish product indigenous to the Northeast sector of India Shidal is exclusively prepared either from Puntius sp (generally Puntius sophore) which is popularly known as Punti shidal or from estuarine fish Setipinna phasa, known as Phasa Shidal (Figs 1A and 1B) The product is very much popular due to its strong flavor It is popularly called “seedal”, “sepaa”, “hidal”, “verma”, and “shidal” in Tripura, Assam, Mizoram, Arunachal Pradesh, and Nagaland In particular, Assam and Tripura are the major producers of shidal amongst the Northeast states [5] The typical strong flavor of shidal is due to the breakdown of fish proteins and lipids, which produce some peptides, amino acids, fatty acids, indole, skatole, etc., producing the strong characteristic odor of shidal [6] The appearance of the product is solid, bilaterally compressed, and pasty and the shape of the fish remains almost unchanged except a little disintegration near the belly and caudal portion The color of the best quality product is a dull white that gradually becomes slight brownish to deep brownish on continuous exposure to air 2.1 Origin The technology is very old and originated in the former undivided India (now Bangladesh) and believed to have come into existence at least before the British era in NEI, i.e., before 1824 Revealed through Indian history, the people of this region did not know the use of salt before its introduction by the British Government Even after the British era, the salt used to be treated as a highly valued and scarce commodity and as an alternative to salt people used to use a substance known as “khar,” made from banana or papaya plant Thus, people could not afford to buy salt for fish preservation and this may be one of the reasons why they preserved fish in a unique way without using salt The plains of Bangladesh and adjoining NEI are famous for their “beel fisheries,” which is a kind of weed-infested shallow water body and gets dried up fully or partially during winter The “beel fisheries” is an excellent habitat for weed fish such as Puntius sp which propagate naturally at the beginning of the rainy season and form a good fishery when the water level starts decreasing with the onset of winter The reason for the exclusive use of the Puntius sp for shidal production possibly lies with the huge availability of this fish Please cite this article in press as: Majumdar RK, et al., An overview of some ethnic fermented fish products of the Eastern Himalayan region of India, Journal of Ethnic Foods (2016), http://dx.doi.org/10.1016/j.jef.2016.12.003 R.K Majumdar et al / Ethnic fermented fish products in India particularly in the postmonsoon period and this has probably necessitated the evolution of this cheaper technology of fish preservation for their use in off season 2.2 Process Shidal is usually produced in the months of November to February Dried salt-free Puntius species or Setipinna phasa are usually used for its production The fermentation process takes place in earthen containers (locally called “matka”) Different steps in traditional shidal technology, including its scientific explanation are as follows (Figs 2AeD and Figs 3AeD) 2.2.1 Matka and its oil processing Matka is a local name and this is an earthen pear-shaped container used for the fermentation of fish Although matkas of different sizes are in use, most common size has a neck diameter of 20 cm, diameter of the middle-expanded part is 24 inch, and the height is 36 inch The capacity ranges from kg to 40 kg Since matkas are made of earth, they are breakable and can be used for several batches of fish until they break The best quality matkas are made from very fine black soil, due to the fact that these matkas Fig Fermented fish product, “phasa shidal.” It is made from estuarine fish Setipinna phasa It is a very popular amongst poor people as substitute of punti shidal Fermentation period is 3e5 months in an earthen container This can be stored at room temperature Fig Oil processed “matka.” Earthen pear-shaped container used for fermentation of fish The most common size is having the dimension of neck diameter inch, diameter of middle expanded part 24 inch, and height 36 inch The capacity ranges from kg to 40 kg Before use, matkas are smeared with oil followed by drying under sun repeatedly for 7e10 days Usually such matkas are breakable and used for one time only absorb a small amount of oil during oil processing and they also provide very less air permeability Producers' believe that the older the matka the better the product quality and lesser the cost of production, because of the fact that older matkas absorb a small amount of oil during oil processing and they also provide very good airsealability Before use, matkas are smeared with oil in order to close the micropores present in its wall to make it almost nonpermeable to air and vapor Oil extracted from Puntius is generally preferred by fishers and commercial producers if it is available in plenty In cases of large-scale production of shidal, vegetable oildespecially mustard oildis preferably used Oil is smeared in both inner and outer walls of the matka followed by drying in the sun The oil smearing and subsequent drying process is continued for 7e10 days in case of new matkas, until they become fully saturated with oil and unable to absorb any more oil even after a fresh drying The matka is now ready for the packing of fish In cases of reusing the matka, 2e5 days of oil smearing and subsequent drying is required Micropores of earthen-made matka are blocked with edible or fish oil to allow the fermentation process in a microaerophilic condition [6] Oil saturation helps to prevent the entry of very minute foreign materials from the outside to inside the matka Moreover, when the matka is fully saturated with oil it does not absorb water from the fish which are filled in the matka with sufficient compaction 2.2.2 Water soaking and drying of dried fish The dried Puntius after procurement are cleaned and sorted and further dried in the sun for 3e5 days This is done to remove moisture from the fish to the maximum possible extent and also to drive away the maggots, if any Fish with signs of infestation are not taken for shidal production Drying is followed by water soaking of fish in porous bamboo baskets This is usually done for 10e15 minutes, preferably in running water Absorption of water becomes higher and quicker due to previous drying of fish After water soaking, fish are spread across a bamboo mattress or on a cemented floor under shade overnight for drying Evening hours is the best time for water soaking, because the subsequent drying of water-soaked fish for 8e10 hours passes without any interference from flies and birds This step is very critical for a yield of a good quality shidal and for determining the total fermentation period The duration of water soaking and subsequent drying is determined by previous experience depending on the quality, desired period of fermentation, and shelf-life of the end product required Soaking of raw materials is very important in the preparation of shidal and is crucial for obtaining the best quality [7] Generally, the duration of water soaking depends upon the total time of fermentation and the market demand However, as a rule of thumb, for short-duration fermentation, more time is needed for water soaking For a 1-month fermentation period fishes are water soaked for 20e25 minutes, for a 2e3-month fermentation period water soaking is done for 15e20 minutes, for a 6-month fermentation fishes are water soaked for 5e10 minutes After water soaking and drying the fish become soft textured with a dry surface and are ready for filling in the matka 2.2.3 Filling of matka Before filling, the oil-processed matka is placed in the ground by digging a hole in such a way that one-third of the belly remains buried in the ground The dug-out soil is gathered surrounding the underground portion of the belly and the matka is fixed to the ground very tightly ensuring that it stands exactly in a vertical position This is done to allow the matka withstand the pressure during the filling of fish with compaction Clean gunny bags are spread surrounding the matka to avoid any raw material getting contaminated with the soil underneath After fixing the matka in the ground, the partially dried fish are spread in a layer and uniform Please cite this article in press as: Majumdar RK, et al., An overview of some ethnic fermented fish products of the Eastern Himalayan region of India, Journal of Ethnic Foods (2016), http://dx.doi.org/10.1016/j.jef.2016.12.003 J Ethn Foods 2016; -: 1e8 pressure is applied with bare hands or feet (in cases of a large mouth matka) Once the layer is tightly packed, subsequent layers are put in a similar manner until the layer reaches close to the neck Sometimes a wooden stick is also used along with hands or feet for almost air-tight packing About 35e37 kg of dried punti is required to fill one 40-kg capacity matka 500 mg N/kg [12] Aerobic mesophilic counts and LAB in ngari (local name of shidal in the Manipur State) were reported to be in the range of 6.3e7.2 log cfu/g and 5.8e7.2 log cfu/g, respectively [13] Thapa et al [14] also found antagonistic activity of LAB isolated against some pathogenic bacteria The TVBN value of shidal from the markets of Manipur State was reported to be 173.33 mg% [15] 2.2.4 Sealing of filled matka Once the matka is filled up to the neck, it is primarily sealed with a cover paste The cover paste is prepared from the dust of dry fish The thickness of the cover layer is 2e2.5 inch This paste (cover paste) seems to form a good medium for the growth of microbes and probably plays a major role for initiating the fermentation process Then, either any broad leaf or newspaper is placed over the wet seal of the cover paste or finally the matka is sealed using a layer of wet mud made from clay soil This layer is checked often for about weeks for any crack and is repaired immediately with fresh wet mud The mud clay layer is given as a final layer upon the mouth of the matka in order to seal the entry of air/moisture inside the matka; moreover, it protects the cover paste from flies and maggots The matkas are left for fermentation at room temperature for 3e5 months [6] The filled matkas are lifted to the surface and left undisturbed under a shade for maturation The usual period of maturation is 4e6 months but it may be extended to year About 40e42 kg of shidal is obtained from each matka 2.4 Traditional culinary preparations Shidal is highly relished by the ethnic people of NEI and they used to prepare various recipes from shidal and eat it along with their main meal [9] Some popular traditional ready-to-eat food recipes prepared from shidal are godak, shidal-chutney, etc (Figs 4AeD) Godak is a nonoily dish prepared by boiling fermented fish shidal with vegetables and consumed with rice It is mainly consumed by the tribal community people of Tripura The product needs no spices and is good from a health point of view [16] Shidalchutney is another popular oily recipe which is mostly popular among the Bengali community, as well as the tribal community people of this state It is a very good appetizer and flavoring agent in respect to the food habits of the people It is an oily dish prepared from shidal and oil generally floats on the side when the final product is ready The smell of shidal-chutney is so strong that during its preparation the smell spreads out in the neighboring area These products are usually served as the focus at traditional festivity Lonailish 2.3 Biochemical and microbiological characteristics of shidal Fermented fish product, shidal, plays a very important role in the nutrition of people of the Northeast sector of India This ethnic fish product bears good nutritional quality in terms of crude protein, total lipids, and inorganic compounds (minerals) The crude protein, lipid, and ash contents of punti and phasa shidal are 38.35%, 27.2%, 20.31%, 24.1%, 7.19%, and 10.2%, respectively [7] Sarojnalini and Viswanath [8] reported 5.49% ash, 38.38% crude protein, and 13.36% total lipids in shidal of the Manipur State The traditional belief related to the malaria-curing ability of shidal drives people to have it as medicine despite its unpleasant smell [5] Microflora play an important role at the initial period as well as continuing the fermentation process The presence of microorganisms during fermentation contributes to the degradation of proteins and the development of flavor and aroma [9] Rich microbial diversity is observed in shidal samples collected from various sources of NEI The total bacterial load of punti and phasa shidal from Assam was reported as 5.4 log cfu/g and 5.1 log cfu/g, respectively [6], whereas Roy et al [6] reported total plate count and total fungal count values were 6.42 log cfu/g and 4.02 log cfu/g, respectively, for Telesech from Tripura Mahanta and Muzaddadi [10] also reported a similar microbial load in punti shidal of Tripura Although some authors [5,7] have reported the presence of pathogenic bacteria in shidal samples, the load is much less Among the bacterial load, Bacillus sp., Staphylococcus sp., and Micrococcus sp were reported as dominant groups of bacteria in shidal [5,6] Besides these sufficient numbers of lactic acid bacteria (LAB) are also present in shidal samples which might have an antimicrobial effect against foodborne pathogens which can reduce the number of other undesired microorganisms in the fish products as well as help in the preservation of fish [11] Volatile compounds like total volatile base nitrogen (TVBN) were reported to be 116.2 mg% and 108.24 mg% in punti and phasa shidal of Assam, respectively [7], whereas, Roy et al [6] reported 210.92 mg% and 390.73 mg% TVBN and alpha amino nitrogen content in Telesech samples from Tripura However, the fish would be rejected for human consumption when the total volatile nitrogen level exceeds approximately Lonailish is a salt fermented fish product, prepared exclusively from Indian shad (Tenualosailisha) It is a high fat fish (fat content of adult hilsa ranges from 14% to 25%) and is very popular in NEI due to its typical flavor and aroma The product is sliced hilsa, about 1.50e2.00 cm thick A typical lonailish has a uniform pink color with a glossy appearance immediately after taking the product out of the brine The texture remains firm and the flesh does not easily separate from its bone It has a characteristic strong aroma mixed with some sweet, fruity, and acidic notes along with some saltiness [17] 3.1 Origin The technology of lonailish actually originated in Bangladesh about 100 years ago on the banks of the rivers Padma and Meghna under the Noakhali district It is assumed that the technology evolved during the glut period when there were no such preservation techniques except sun drying and salting Sun drying was Fig Sorting of dried Puntius fish before fermentation This is done to remove broken pieces of fish It also helps to remove other undesirable matter from the dry fish Please cite this article in press as: Majumdar RK, et al., An overview of some ethnic fermented fish products of the Eastern Himalayan region of India, Journal of Ethnic Foods (2016), http://dx.doi.org/10.1016/j.jef.2016.12.003 R.K Majumdar et al / Ethnic fermented fish products in India not suitable for hilsa-like high fatty fishes due to the rapid development of rancidity on being exposed to the sun In addition, sun drying was difficult during the continuous spells of rain in July and August that corresponds to the main glut period This way of processing might have been started to quickly preserve large quantities of fish in an inexpensive way The technology has not changed much since the earlier days and the practice is still one of the major means of preservation of hilsa by the fishermen community of Bangladesh Although different technologies have come into being to date, no other preservation techniques except salt drying and to some extent canning are in use presently The technology got entry in to NEI through migrants The large-scale production and consumption of lonailish is limited mostly in the Chandpur subdivision in the Noakhali District of Bangladesh and NEI One of the reasons of localized consumption in India may be due to the practical difficulties of its transport However, there is a good demand for the product in the fish-eating communities in other areas [18] 3.2 Process 3.2.1 Preprocessing of fish Some photographs of traditional lonailish technology are given in Figs 5AeD and Figs 6AeD The fish (Tenualosa ilisha) after washing are descaled and the tail portion and head are removed leaving the guts inside The fish are cut diagonally in such a way that the steak/chunk has more flesh exposed than that or the skin The thickness of the steaks is generally 1.5e2.0 cm Each of the fish steaks are rolled thoroughly in salt (the fish to salt ratio is 4:1) and kept in a bamboo made basket layer after layer with the flesh side down Salt is sprinkled between each layer and above the top layer The filled basket is covered with a black polythene sheet so as to avoid entry of light The baskets are stored in a dark place The selfbrine formed is allowed to drain In the dry salted condition, the fish steaks are kept for 48 hours A considerable amount of moisture content from the fish is reduced during this process and the color of the flesh becomes dull white and the texture becomes somewhat tough The salt-cured hilsa steaks are ready to pack in a fermenting container (Figs 7e17) 3.2.2 Fermenting medium and container Saturated brine is prepared and boiled day before packing the hilsa steaks and is then cooled overnight The containers used for this fermented product are the empty tin-made containers of cooking oil Fig Filling of matka with partially dried Puntius fish The matka is kept in soil after digging a small pit to avoid breaking during compact filling The dug-out soil is gathered surrounding the underground portion of the belly and matka is fixed to the ground very tightly ensuring that it stands exactly at vertical position Clean gunny bags are spread surrounding the matka to avoid any raw material getting contaminated with the soil underneath After fixing the matka in the ground, the partially dried fish are spread in a layer and uniform pressure is applied with bare hand or feet (in case of a large mouth matka) Fig Filled matka with Puntius fish up to the neck region Once the matka is filled up to the neck, filling is stopped Then it is primarily sealed with a cover paste Cover paste is prepared from the dust of dry fish The thickness of the cover layer is 2e2.5 inch 3.2.3 Filling of fermenting containers The salted hilsa steaks are shaded well before packing to remove any adhering salt Packing of salt-cured hilsa is done layer after layer and compacted uniformly by hand after packing each layer until the fish layer reaches at least 2e3 cm below the top Then cold saturated brine is poured slowly into the container over the fish to fill the voids between the steaks and maintain a level of brine about 2e3 cm above the fish All the containers are stacked in one dark room and left undisturbed for 4e6 months for fermentation If the fish is exposed to air and light for few hours, the pink red color changes to greyish/black which is not acceptable [19] 3.3 Biochemical and microbiological characteristics of lonailish Fig Washing of dried Puntius fish in running water It also helps in removing dirt, etc attached to the fish This is usually done in clean running water, preferably in a river This process is done in the evening Lonailish has been revealed to have high nutritional significance as the product is rich in lipids, inorganic compounds (minerals), and crude protein Total lipids, ash, and crude protein content of lonailish are 9.41%, 16.73%, and 20.94%, respectively [20] The nutrient profile of lonailish showed that the product is rich in unsaturated fatty acids and essential amino acids [17] Moreover, the product also has good antioxidant activity Please cite this article in press as: Majumdar RK, et al., An overview of some ethnic fermented fish products of the Eastern Himalayan region of India, Journal of Ethnic Foods (2016), http://dx.doi.org/10.1016/j.jef.2016.12.003 J Ethn Foods 2016; -: 1e8 Fig Filled and sealed matka with clay soil The wet seal of cover paste of the filled matka is covered with either any broad leaf or newspaper Then it is finally sealed by a layer of wet mud made from clay soil This layer is checked on, often for about weeks, for any crack and is repaired immediately by fresh wet mud The mud clay layer is given as final layer upon the mouth of matka in order to seal entry of air/moisture inside the matka; moreover, it protects the cover paste from flies and maggots Fig Filled and sealed matka in a fermentation shed The filled matkas are lifted to the surface and left undisturbed under a shade for maturation The usual period of maturation is 4e6 months but it may be extended to year The fermentation should allow partial sunlight to enter and also slight rainfall There should be free air movement crossing the fermentation shed Fig 10 Traditional culinary preparation from shidal Two popular traditional preparations from shidal are shidal chutney and godhak Godhak is a completely oil-free preparation from shidal and is considered to be good for health and an appetizer too Fig 11 Lonailish It is a salt fermented fish product, prepared exclusively from Indian shad (Tenualosa ilisha) The product is sliced hilsa, about 1.50e2.00 cm in thickness A typical lonailish has a uniform pink color with a glossy appearance It has a characteristic strong aroma mixed with some sweet, fruity, and acidic notes along with some saltiness Fig 12 Tenualosa ilisha Hilsa is considered as fatty fish It is also known as Indian shad This fish is very much popular in almost all fish-eating communities due mainly to its peculiar flavor and taste Fig 13 Diagonally cut steaks of hilsa fish The fish are cut diagonally in such a way that the steak/chunk has more flesh exposed than that or the skin The thickness of the steaks is generally 1.5e2.0 cm Please cite this article in press as: Majumdar RK, et al., An overview of some ethnic fermented fish products of the Eastern Himalayan region of India, Journal of Ethnic Foods (2016), http://dx.doi.org/10.1016/j.jef.2016.12.003 R.K Majumdar et al / Ethnic fermented fish products in India Fig 14 Salt cured steaks of hilsa fish prevented from exposure to sunlight Salt cured steaks of hilsa fish Each of the fish steaks are rolled thoroughly in salt (fish to salt ratio is 4:1) and kept in a bamboo made basket layer after layer with flesh side down Salt is sprinkled between each layer and above the top layer The filled basket is covered with a black polythene sheet so as to avoid entry of light The baskets are stored in a dark place The self-brine formed is allowed to drain In dry salted condition, fish steaks are kept for 48 hours A considerable amount of moisture content of fish is reduced during this process and color of the flesh becomes dull white and texture becomes somewhat tough Fig 16 Salt cured hilsa steaks in saturated brine in tin container for fermentation Salt cured steaks of hilsa fish Each of the fish steaks are rolled thoroughly in salt (fish to salt ratio is 4:1) and kept in a bamboo made basket layer after layer with flesh side down Salt is sprinkled between each layer and above the top layer The filled basket is covered with a black polythene sheet so as to avoid entry of light The baskets are stored in a dark place The self-brine formed is allowed to drain In dry salted condition, fish steaks are kept for 48 hours A considerable amount of moisture content of fish is reduced during this process and color of the flesh becomes dull white and texture becomes somewhat tough 3.4 Traditional culinary preparations In the North-eastern states lonailish is highly preferred by the Bengali community due to its typical flavor and aroma Due to its high salt content (14%) no salt is added during its culinary preparation The product is cooked before consumption and it is mainly consumed as a main dish rather than condiment Besides these, traditional people also used to prepare some curry, chutney, or fried items from it One popular culinary style is cooking of lonailish with spices wrapped by leaves of curd Conclusion Fig 15 Salt cured steaks of hilsa fish after 48 hours of storage Salt cured steaks of hilsa fish Each of the fish steaks are rolled thoroughly in salt (fish to salt ratio is 4:1) and kept in a bamboo made basket layer after layer with flesh side down Salt is sprinkled between each layer and above the top layer The filled basket is covered with a black polythene sheet so as to avoid entry of light The baskets are stored in a dark place The self-brine formed is allowed to drain In dry salted condition, fish steaks are kept for 48 hours A considerable amount of the moisture content of the fish is reduced during this process and the color of the flesh becomes dull white and texture becomes somewhat tough Bacterial proteases play a significant role in the fermentation and flavor and aroma producing processes [21] The aroma in fermented fish product has been claimed to be derived from the activity of various halophilic bacteria [22] As the product is highly salted the surviving bacteria in lonailish belongs to the halophilic group Total bacterial load in lonailish was reported 3.38 log cfu/g; Bacillus licheniformis and Micrococcus kristinae were reported as the dominant groups of bacteria in lonailish [19,23] Moreover, sufficient numbers of LAB are also present in lonailish samples which might have antagonistic effect against some foodborne pathogens Volatile compounds like TVBN and alpha amino nitrogen were reported to be 48.0 mg% and 163.5 mg%, respectively [19] Accumulation of such low molecular weight nitrogenous components might have resulted due to degradation of tissue protein and to some extent that may possibly be responsible for the generation of typical flavor and aroma of the final product, lonailish [20] The many different fermented fish products, while noisome in their original state, have a beneficial role in human nutrition They are rich in amino acids, nitrogen, and various trace elements, including sodium chloride, phosphorous, calcium, and fluoride They have undoubtedly contributed to the survival and good health of entire generations that had only a small quantity of rice and vegetables to eat Fermented fish products are mostly consumed as condiments; however, low salt fermented fish products can be consumed in large quantities The flavor of fermented fish products is of importance Food fermentation involves mixed cultures of microorganisms that grow simultaneously or in succession One can contemplate that indigenous people are using microorganisms unknowingly for varied purposes A sincere study on the traditional fermentation process may reveal the intellectual richness of the indigenous people of our country in terms of their ability in preparing microbial products for varied purposes in addition to food and beverages Fermentation is not only a method of preservation; in addition, the fermented foods also have the added benefits of enhancing flavor, increased digestibility, improving nutritional value, and provide pharmaceuticals Fermented foods are associated with a unique group of microflora which increases the levels of proteins, vitamins, essential amino acids, and fatty acids Malnutrition associated with protein and vitamin deficiencies are major problems of the third world countries Although there is good demand for these ethnic products among the North-eastern consumers, maximum production is still limited to household levels only However, there is a lack of hygienic Please cite this article in press as: Majumdar RK, et al., An overview of some ethnic fermented fish products of the Eastern Himalayan region of India, Journal of Ethnic Foods (2016), http://dx.doi.org/10.1016/j.jef.2016.12.003 J Ethn Foods 2016; -: 1e8 Fig 17 Traditional culinary preparation from shidal Salt cured hilsa steaks in saturated brine in a tin container for fermentation The containers used for this fermented product are the empty tin made containers of cooking oil The salted hilsa steaks are shaded well before packing to remove adhering salt Packing of salt cured hilsa is done layer after layer and compacted uniformly by hand after putting each layer until the fish layer reaches at least 2e3 cm below the top Then cold saturated brine is poured slowly in the container over the fish to fill the voids between the steaks and maintain a level of brine about 2e3 cm above the fish knowledge in production for Good Manufacturing Practice and nutritional safety of these traditional fish products are the major issues The preparation of these traditional cured fish products and associated dynamics are transmitted from generation to generation and over a period of time it exchanged within and between the communities These processed fish products have some health beneficial effects and there is enough scope for research on fermented fish products of the NEI region to search bioactive compounds related to immunity against malaria and other seasonal illness, short chain fatty acids having antimicrobial properties, any microbial metabolites beneficial for health, etc Scientific investigations are ongoing to find out these healthful compounds from the fermented fish products of NEI [7] [8] [9] [10] [11] [12] [13] Conflicts of interest [14] The authors have nothing to disclose [15] Acknowledgments Authors thank the Department of Biotechnology, Government of India, New Delhi for funding the project (Grant Number BT/307/NE/ TBP/2012, Dt 06/12/2012) under which this work was undertaken [16] [17] [18] References [19] [1] Steinkraus KH Fermentations in world food processing Compr Rev Food Sci F 2002;1:23e32 [2] Poulter RG Processing and storage of traditional dried and smoked fish products In: Burt JR, editor Fish smoking and drying: the effect of smoking and drying on the nutritional properties of fish London (UK): Elsevier Applied Sciences; 1988 p 85e90 [3] Jeyaram K, Singh TH, Romi W, Devi AR, Singh WM, Dayanidhi H, Singh NR and Tamang JP Traditional fermented foods of Manipur Indian J Tradit Know 2009;8:115e21 [4] Thapa N Ethnic fermented and preserved fish products of India and Nepal J Ethnic Foods 2016;3:69e77 [5] Muzaddadi AU and Basu S Shidalda traditional fermented fishery product of North East India Indian J Tradit Know 2012;11:323e8 [6] Roy D, Majumdar RK, Maurya SK, Tripathi HH, Dhar B and Priyadarshini BM Understanding of traditional knowledge and characterization of telesechda [20] [21] [22] [23] fermented fish product of Tripura state Indian J Nat Prod Res 2014;5: 351e8 Kakati BK and Goswami UC Characterization of the traditional fermented fish product 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fish products of North-East India World J Microbiol Biotechnol 2004;20:599e607 Thapa N, Pal J and Tamang JP Phenotypic identification and technological properties of lactic acid bacteria isolated from traditionally processed fish products of the Eastern Himalayas Int J Food Microbiol 2006;107:33e8 Sarojnalini C and Suchitra T Microbial profile of starter culture fermented fish product “Ngari” of Manipur Indian J Fish 2009;56:123e7 Dhar B, Roy D, Majumder A and Ray N Indigenous knowledge on processing of “Godak”ea delicacy of the tribal population in Tripura and its nutritional quality Keanean J Sci 2012;1:83e8 Majumdar RK Technology evaluation and improvement of “Lonailish”da traditional salt fermented fish product of North East India Ph.D thesis Mumbai: Central Institute of Fisheries Education, ICAR; 2005 Majumdar RK, Basu S and Anandan R Biochemical and microbiochemical characteristics of salt fermented hilsa (Tenualosa ilisha) Fish Technol 2005;42: 67e70 Majumdar RK and Basu S Characterization of the traditional fermented fish product Lonailish of Northeast India Indian J Tradit Know 2010;9:453e8 Majumdar RK and Basu S Studies on the biochemical composition of Hilsa ilisha (Tenualosa ilisha) and its fermented product “lonailish” Biochem Cell Arch 2004;4:29e32 Thongthai C and Siriwongpairat M The sequential quantization of microorganisms in traditionally fermented fish sauce (Nam-pla) In: Reilly PJA, Parry RW and Barile LE, editors Post-Harvest Technology, Preservation and Quality of Fish in South East Asia Stockholm: International Foundation of Science; 1990 Van Veen AG Fish preservation in South East Asia Adv Food Res 1953;4: 209e31 Majumdar RK, Nayak BB and Basu S Involvement of Bacillus licheniformis and Micrococcus kristinae during ripening of salt fermented Indian Shad (Tenualosa ilisha) J Aquat Food Pro Technol 2008;17:423e40 Please cite this article in press as: Majumdar RK, et al., An overview of some ethnic fermented fish products of the Eastern Himalayan region of India, Journal of Ethnic Foods (2016), http://dx.doi.org/10.1016/j.jef.2016.12.003 ... there is a lack of hygienic Please cite this article in press as: Majumdar RK, et al., An overview of some ethnic fermented fish products of the Eastern Himalayan region of India, Journal of Ethnic. .. al., An overview of some ethnic fermented fish products of the Eastern Himalayan region of India, Journal of Ethnic Foods (2016), http://dx.doi.org/10.1016/j.jef.2016.12.003 R.K Majumdar et al / Ethnic. .. al., An overview of some ethnic fermented fish products of the Eastern Himalayan region of India, Journal of Ethnic Foods (2016), http://dx.doi.org/10.1016/j.jef.2016.12.003 R.K Majumdar et al / Ethnic