Keywords

16.1 Introduction

Mizoram is one of the eight states of Northeast India situated in the southernmost landlocked state which shares an international boundary with Myanmar in the east and south and Bangladesh to the west and to the northwest and shares an interstate boundary with Tripura to the north and Assam and Manipur to the northeast. The capital of Mizoram is Aizawl and is situated in the north-central part of the state at an altitude of approximately 4000 ft. above the sea level. Mizoram, ‘Land of the Mizos’, was known as the Lushai Hills District of Assam before it was renamed the Mizo Hills District in 1954 (The Lushai Hill District (Change of Name) Act 1954]. In 1972, it became a centrally administered union territory under the name of Mizoram, and in 1987 it achieved statehood. There are eight districts in the state, namely, Aizawl, Lunglei, Siaha, Champhai, Kolasib, Champhai, Mamit and Lawngtlai, with average square density of 52 per sq. km and literacy rate of 91.85%. The total area of the state is 21,087 sq. km with population of 1,091,014 as per 2011 census (www.mizoram.nic.in). The state has tremendous biodiversity, and climatic conditions vary from sub-tropical humid to temperate (Sati and Rinawma 2014). As per economic classification of workers 2011 census, more than 70% of the total workers are engaged in agricultural and allied sector in Mizoram (Economic Survey Mizoram 2017–2018).

Agriculture is the main source of occupation of the state, and the main crops include cereals like wheat, rice, barley, maize, rye, oats and millets. There is also considerable cultivation of orange, hatkora, passion fruit, pineapple, banana, papaya and ginger (Sati 2017). Since rice is the staple food in Mizoram, the minimum rice requirement of the state is estimated to be around 1,80,000 MT per year. Out of the yearly requirement, only about 58,994 MT of rice is produced which is a meagre 32% of the total requirement, and the remaining has to be imported from outside (Economic Survey Mizoram 2014–2015). Shifting cultivation or ‘jhumming’ is a characteristic of traditional agriculture in Mizoram that is practised mainly in the highlands till today; it is also the main source of income in the rural area and is called the ‘way of life of Mizos’ (Anup et al. 2006). However, this type of cultivation is said to lead to enormous forest degradation and soil erosion which is not environmentally and economically sustainable (Sati 2017). In order to solve various problems faced in traditional agricultural methods, crop diversification programme has been introduced which largely focused on promoting the cultivation of cash crops like sugarcane, pulses, ginger, turmeric, Mizo chilli, oil seeds, etc. that have seasonal advantage over other crops (Economic Survey Mizoram 2014–2015).

As mentioned earlier, the staple diet of Mizo people is rice, along with vegetables and meats as side dishes, which is usually boiled and with fewer spices. Earlier, the methods of food processing among the Mizo were very simple and found to be more or less similar throughout the state, even though a slight difference may be observed from place to place. With the onset of Christianity by the British missionaries in this state in the 1890s, the methods of food preparation improved tremendously (Lalthanpuii et al. 2015).

Fermented foods and beverages are a primary part of every traditional heritage and culture. Fermentation not only presents foods which have diverse taste and nutrition but also offers a preservation technique so that fermented foods may be consumed during the off-season. Indigenous fermented foods constitute the essential component of the daily diet of Mizo people. Indigenous inhabitants of Mizoram prepared fermented food such as sa-um (fermented pork fats), bekang-um (fermented soybean), tam-um (fermented mustard), ai-um (fermented crabs), etc. (Tungoe 2016). Fermented alcoholic rice-based beverages of different forms have been reported to be consumed by the tribal people of Mizoram since time immemorial. Some fermented alcoholic beverages are zupui, zufâng, tin-zû and rakzû (Dokhuma 1992) in which zû means alcohol and the prefix or suffix of zu indicates the way the beverage is prepared. These alcoholic products have some similarities with Yu of Meitei tribe in Manipur; Vatejnard of Sikkim; Zutho of Angami tribe in Nagaland; Apong of Arunachal Pradesh; Jou of Bodo tribe, Chu of Garo tribe and Chako of Rabha tribe in Assam; Chubitchi of Garo tribe, Kyiad of Khasi tribe and Sadhiar of Jaintia tribe in Meghalaya; and ChuwakBwtwk and Chuwarak of Tripura (Tamang et al. 2012, 2016).

Earlier, the practice of consuming fermented foods and alcoholic beverages has its roots in many cultural and religious practices of the people of Mizoram and practically supplements health-promoting benefits to consumers (Table 16.1). Nowadays, many of the Mizo youths are reluctant to consume fermented products and especially fermented alcoholic beverages as they are convinced that the foods and drinks may cause harm to their body and spiritual life.

16.2 Ethnic Fermented Foods of Mizoram

16.2.1 Bekang-um (Fermented Soybean)

Bekang-um (Picture 16.1) is an ethnic fermented food prepared from soybean seeds by the indigenous Mizo people.

Picture 16.1
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‘Bekang-um’, a Mizo traditional fermented soybean

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It is similar to other sticky fermented soybean foods of northeast such as kinema of Sikkim, hawaijar of Manipur, aaxone of Nagaland and tungrymbai of Meghalaya (Tamang et al. 2012). Bekang-um is a fermented sticky soybean which serves as a cheap source of high protein in local diet. It is consumed as it is or made into curry with the addition of salt, green chillies and tomatoes. It is commonly used as a side dish and often used as a seasoning food. During the preparation, the seeds of soybean are cleaned, washed and soaked in water for 10–12 h. After removing the excess water, the beans are cooked/boiled for about 1 h until they become soft. Excess water is drained off; placed on a traditional tray made of bamboo called kho lined with previously cleansed leaves of Callicarpa arborea, locally called hnahkiah; sprinkled with ashes; and again covered with hnahkiah leaves. The tray is near the earthen oven or in warm place and is allowed to ferment naturally for 3–4 days (Chettri and Tamang 2015). The method of preparation of bekang-um is highlighted in Fig. 16.1.

Fig. 16.1
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Steps involved in traditional method of preparation of bekang-um

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16.2.2 Sa-um (Fermented Pork Fat)

Sa-um is an ethnic fermented pork fat common to every Mizo family. The preparation method of sa-um is highlighted in Fig. 16.2. Pork fat is mainly collected from the inner abdominal portion (sometimes fats from other parts of the pig’s body were also used) (Lalthanpuii et al. 2015), cut into little pieces and boiled in water for an hour or 2, till most of the water evaporates out. Then, the fat is transferred into the already cleansed and sun-dried sa-um bur (Picture 16.2a) which is prepared from the dried fruit of the plant ûm (Lagenaria siceraria) bottle gourd (Sawmliana 2013). The container was closed tightly with a wooden lid and then kept over the fireplace or in the sun for 3–5 days. The anaerobic fermentation process could have eliminated the growth of aerobic spoilage bacteria and hence results in perfectly fermented sa-um (Picture 16.2b). However, no inoculation of starter culture is being done as the microbe responsible for the production of sa-um has not been identified yet. The fermented fat is then used to make bai, a typical Mizo vegetable stew, by emulsification with cooking soda. It is also used to make bâwl, typical Mizo chutney, again with cooking soda.

Fig. 16.2
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Flowchart of preparation of sa-um

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Picture 16.2
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(a) ‘Sa-um’, fermented pork fat in traditional container ‘sa-um bur’. (b) Final product of ‘sa-um’ to be stored in refrigerator for longer shelf life (Photo credit: Zawna Pachuau)

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Sa-um is considered to be one of the food courses in typical Mizo’s kitchen, but the risk of stomach cancer caused by sa-um was reported by Malakar et al. (2014). It is also suggested that H. pylori infection interacted with consumption of sa-um plays a role in promoting stomach cancer in Mizoram (Phukan et al. 2006).

16.2.3 Chhi-um (Fermented Sesame Seeds)

Sesamum indicum, locally known as chhibung, is used to prepare this fermented food item.

Traditional method of chhi-um preparation is depicted in Fig. 16.3. Sesame seed is lightly roasted and crushed with wooden mortar and wooden pestle, which is then tightly wrapped with hnahthial leaves. The tightly wrapped crushed ‘chhibung’ is placed over the fireplace for fermentation. After 3 days, chhi-um (Picture 16.3) is ready to be used as taste enhancer for other food items or consumed as chutney.

Fig. 16.3
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Steps involved in traditional method of preparation of chhi-um

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Picture 16.3
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‘Chhi-um’, a Mizo traditional fermented sesame seeds (Photo credit: Zothansanga)

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16.2.4 Ai-um (Fermented Crabs with Sesame Seeds)

Ai-um is a traditional fermented Mizo food which is usually consumed as side dish or used as taste enhancer. Sesame seeds (chhibung) are lightly roasted in medium heat and pounded with sum and suk, a traditional mortar and pestle made from wood. Juvenile fresh water crabs mainly about the size of a thumb, and sometimes matured crabs, captured from the rivers and streams are killed with hot water and pounded with the ground sesame seeds to make coarse paste. Bigger crabs with thick shells may also be used to prepare ai-um. The steps involved in the preparation of ai-um are given in Fig. 16.4.

Fig. 16.4
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Steps involved in traditional method of preparation of ai-um

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The coarse paste is wrapped with hnahthial leaves (Phrynium capitatum Wild.) and placed above the fireplace (Lalthanpuii et al. 2015) (Picture 16.4a). After about 3 days, the coarse paste has been fermented to ai-um. This fermented product is usually served as side dish or may be consumed as it is, after frying with oil. Ai-um (Picture 16.4b) is sometimes mixed with roasted chilli and tomatoes to make tasty chutney. It may also be added to bai, a Mizo traditional vegetable stew, to enhance the flavour and the aroma.

Picture 16.4
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(a) Incubation of ‘ai-um’ over ‘thuk’, a Mizo traditional fireplace. (b) ‘Ai-um’, fermented crab with sesame seeds (Photo credit: Zosangliana)

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16.2.5 Aite-um (Fermented Small Crabs)

This fermented food is prepared only with whole juvenile fresh water crabs which are small with soft carapace, and steps involved are highlighted in Fig. 16.5. The crabs are first killed with hot boiling water and washed properly. The crabs are then placed in a bamboo cavity with the opening plugged with banana leaves or wrapped with hnahthial leaves.

Fig. 16.5
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Steps involved in traditional method of preparation of aite-um

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The bamboo or the wrapped leaves containing the small crabs are kept near the fireplace for 3–4 days. The crabs are fermented in the process which may be mixed with chilli and salt to make chutney or added to vegetable stew called bai for flavour enhancement (Picture 16.5).

Picture 16.5
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‘Aite-um’, fermented freshwater crab (Photo credit: Zosangliana)

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16.2.6 Ṭam-um (Fermented Mustard Leaves)

Ṭam-um—fermented mustard leaves—is one of the most popular foods of the Mizo. For this, a variety of mustard locally known as Ṭampui (Brassica rapa/B. juncea) is used. Ṭampui is washed meticulously and is pounded with a wooden mortar and pestle called sum and suk and is wrapped with the leaf of P. capitatum locally known as hnahthial and kept over the fireplace for 2–3 days. After this the water is squeezed, which is locally known as ṭam-er, which can also be taken with food as side dish. Fresh fermented ṭam-um is either sun-dried or dried over the fire so that it can be stored for a longer period of time. The dried ṭam-um (Picture 16.6) may be lightly roasted and grinded with salt, chilli, and small amount of hot water, which is then ready to be served as side dish (Lalthanpuii et al. 2015). The method of preparation of tam-um is given in Fig. 16.6.

Picture 16.6
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‘Tam-um’, fermented mustard leaves

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Fig. 16.6
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Steps involved in traditional method of preparation of tam-um

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16.2.7 Tuai-um (Fermented Bamboo Shoot)

Fermented bamboo shoot or tuai-um is not as popular as the other traditional fermented foods of Mizo but is mainly prepared and eaten in the northern parts of Mizoram. Mautuai or bamboo shoot is washed, cut into smaller pieces, and pounded with a wooden mortar and pestle called sum and suk. The pounded mautuai is then wrapped with the leaf of P. capitatum locally known as hnahthial and kept over the fireplace for about 3 days. The steps involved in the traditional preparation of tuai-um are given in Fig. 16.7.

Fig. 16.7
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Steps involved in traditional method of preparation of tuai-um

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The pounded and fermented bamboo shoot is either sun-dried or dried over the fire so that it can be stored for a longer period of time. The dried tuai-um may be soaked with hot water, mixed with salt and chilli, and is then ready to be served as a very tasty side dish.

16.3 Ethnic Fermented Beverages of Mizoram

All the fermented beverages of Mizoram are alcoholic drinks and are prepared from different varieties of rice, and the processes discussed are based on the traditional methods of Mizo tribes. Most surprisingly, without any scientific knowledge, the forefathers knew that starter culture is required to make alcoholic drinks, and they even developed yeast starter culture from scratch. This yeast starter culture is called chawl or dawdim which is used to make all the different kinds of traditional alcoholic beverages of Mizo tribe.

16.3.1 Dawdim/Chawl (Dried Starter Culture)

Dawdim or chawl is a traditionally prepared dried starter to produce various alcoholic beverages in Mizoram (Anupma et al. 2018). The starter culture used in all Mizo traditional alcoholic drinks is made from a bark of climber called zangzu, nilengthlum or hawhmathlum. Rice is first soaked in water overnight and dried for about 15 min to remove excess water. The soaked rice is made into powder by pounding it and made into homogenous paste by adding small amount of water. The paste mass is made into a small elliptical cake-like mass, about 2 in. diameter. The powdered zangzu is sprinkled evenly on the surface of the rice cake which is kept in a container with paddy husk. The container is incubated in a hearth for 4–5 days after which the rice ball has swollen a bit which is now called chawl (Picture 16.8a). Then, chawl is taken out and air-dried for storage. The preparation of dawdim/chawl is similar to other starters of Northeast India such as marcha of Sikkim, hamei of Manipur, humao of Assam, thiat of Meghalaya, etc. (Singh and Singh 2006; Jeyaram et al. 2009; Tamang 2010; Anupma et al. 2018).

The flowchart in Fig. 16.8 shows the steps involved in the making of chawl/dawidim.

Fig. 16.8
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Steps involved in preparation of chawl

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16.4 Alcoholic Beverages and Drinks of Mizoram

16.4.1 Zupui

Zupui is one of the most popular fermented rice-based beverages of Mizo (Dokhuma 1992). During preparation of ‘Zupui’, rice is milled manually into fine powder, removing its husk using the traditional wooden mortar and pestle (sum and suk). The rice is processed specially to be made into Zupui from the beginning and hence is sometimes called Hranden Zû. Bellâm is a vessel dedicated specially to cook/steam the milled rice and consists of two pots. The lower pot is a bigger one where water is kept, and the smaller upper pot has some holes punched in its bottom. A sieve made from bamboo called ngânsap is kept to cover the holes so that the milled rice stays on the upper pot without falling through the holes. The upper pot is covered as tight as possible, and the space between the upper and lower pot is also sealed using clay. Then, the rice is steamed till it is cooked properly. After the rice is cooked, it is transferred to another vessel, and a starter yeast culture called chawl is sprinkled over the cooked rice to start fermentation.

A special earthen pot called ngânbel (Picture 16.7a) is used for fermentation of the beverage. After fermentation, a small pipe made of iron called dawnkâwn (Picture 16.7b) is immersed into the fermenting mixture, and the rice beer is sucked through the pipe. The steps involved in traditional method of preparation of Zupui are given in Fig. 16.9. Zupui is the main beverage usually served during festive occasions and has a special place in the Mizo religion and culture.

Picture 16.7
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(a) ‘Nganbel’, a vessel dedicated to ferment ‘Zu-pui’, a Mizo traditional rice beer. (b) A picture showing ‘Nganbel’ and ‘Ngansap’

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Fig. 16.9
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Steps involved in traditional method of preparation of Zupui

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16.4.2 Zufâng

Zufâng is the alcoholic beverage prepared from sticky rice. As the name suggests, zufâng is not a concentrated alcohol beverage as zû means ‘alcoholic drink’ and fâng means ‘not real’ and is considered to be a lesser alcoholic drink (Dokhuma 1992).

The steps involved in traditional method of preparation of zufâng are given in Fig. 16.10. Mizo sticky rice called buhban, usually kâwnglâwng variety, is used to prepare zufâng. Sticky rice is cooked and fermented in zufângbêl, a special vessel dedicated only to make zufâng after a starter yeast culture called chawl is sprinkled over the cooked rice to start fermentation. Zufâng (Picture 16.8b) is a mild-alcoholic beverage with sweet taste and is consumed anytime along with the undissolved rice.

Fig. 16.10
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Steps involved in traditional method of preparation of zufâng

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Picture 16.8
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(a) ‘Chawl’, Mizo traditional yeast starter culture and (b) ‘zufâng’, a mild Mizo traditional rice beer (Photo credit: Zawna Pachuau)

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16.4.3 Tin-zû

Tin-zu also called as faisazû is one of the alcoholic beverages made from rice grain after the husk is removed. It does not have a vessel dedicated only for its fermentation; hence any type of vessel is used (Dokhuma 1992). It is prepared exactly similar to zufâng except that sticky rice is not used. Moreover, the undissolved rice is filtered out, and only the liquid part is consumed. Most of the time, a big tin can is used as a fermenting vessel and hence the name tin-zû. This alcoholic drink may be consumed anytime with no occasion. The method of preparation of tin-zû is given in Fig. 16.11.

Fig. 16.11
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Steps involved in traditional method of preparation of faisazû/tin-zû

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Tin-zû was introduced by the non-Mizo soldiers during the 1890s, and many do not consider it as a Mizo traditional beverage (Lalthangliana 2005).

16.4.4 Rakzû

This is an alcoholic drink developed after non-Mizos entered from outside the Mizo Hills, and steam distillation principle is utilised for its preparation. The fermentation procedure is similar to tin-zû, but the liquefied fermentation product is again distilled using traditional steam distillation unit to obtain a clear and strong rakzû. The distillation unit of rakzû has three main components and has three different sizes of vessels which are kept over one another. The lowest vessel is the biggest one where the fermented mash of rice mixed with water is kept. The middle vessel has a big hole bored at the bottom, and a small vessel may be kept in the middle to collect the condensed alcohol. The uppermost and the smallest vessel contains cold water, the bottom of which acts as a condenser. All the vessels, after arranging them properly, are sealed with clay of wood ash so that steam cannot escape from the sides (Pictures 16.9a, b). The vessel containing the fermented rice is heated up where the steam rises up to be condensed by the topmost vessel containing cold water. The condensed alcohol is then collected by the small vessel below it, which may be sampled out using the small pipe connected to the collector. The water at the topmost vessel needs to be replaced with cold water after it becomes warm.

Picture 16.9
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Two ways of distillation to make ‘rak-zu’. (a) The lowermost container holds the fermenting mixture which is being heated; the middle container has collector for condensed alcohol fitted with pipe and is collected outside; the uppermost vessel holds cold water and acts as condenser. (b) The lowermost container holds the fermenting mixture which is being heated; the middle container has collector fitted inside (probably by hanging a small vessel) to collect condensed alcohol; the uppermost vessel holds cold water and acts as condenser Photo credit: (a) Zosangliana and (b) Zawna Pachuau

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The flowchart in Fig. 16.12 depicts the method of preparation of rakzu. Rakzû is as clear as water, but since the alcohol content is very high, one needs to be careful when consuming it. And since its concentration is high, it fetches a good price in the market and is still popular in the present days (Lalthangliana 2005). This type of alcoholic drink is also made by Chakma tribe of Mizoram, but double distilled, and goes by the name Duichuani.

Fig. 16.12
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Steps involved in method of preparation of rakzû

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Table 16.1 Ethnic fermented foods and beverages of Mizoram
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16.5 Socio-economic and Ethnical Value

Mizoram holds lots of indigenous knowledge when it comes to medicine, food, agriculture and natural resources management. The people of Mizoram have been utilising both produces of the forest and of shifting cultivation that provides vast arrays of ethnic nutritious foods. Many wild plants and animals had been selectively consumed, and their conservation had been done for food and nutritional security (Singh et al. 2007). Fermentation plays very important role in food conservation as fermented foods and beverages are significant components of the daily dietary culture of the Mizos. Mostly, women are engaged and play very important role in the production of the fermented products as well as in preserving the ethnic knowledge (Advani 2005). Among all the traditional fermented products, alcoholic beverages had a strong importance among ethnic people of Mizoram, where most of the olden traditional festivals and many important rituals were involved with the consumption of appreciable quantities of alcohol. Traditional alcoholic beverages were offered to perform ethnic religious practices to please god, or sometimes the devil. Zupui was usually consumed during Chapchar Kut, the biggest Mizo festival which usually lasted for 6 whole days. The alcoholic beverage was served from the third day, called as Zupui Ni, the day which all the youths in the village come out in the open field to perform a dance called Chai. The fourth and the fifth days of Chapchar Kut were called as Zuthing Ni and Thing Leh Ni, respectively, in which the remains of alcoholic beverage Zupui were consumed and Chai dance was performed again by the youths in the open field. One can say that the last 2 days were simply repetition of Zupui Ni. Zufâng, as mentioned earlier, was not considered a real alcoholic drink and was usually consumed after doing any heavy work or offered to guests visiting their home, as how any other non-alcoholic drink is offered nowadays (Dokhuma 1992). However, with the onset of Christianity, the Mizos have been taught that consumption of alcohol is an offence and a vessel of the devil by the early Christians, and hence, consumption of alcoholic beverages was prohibited. This mentality still remains large in the minds of Mizos, and hence, much of the traditional knowledge of alcoholic beverage preparation methods is lost with time.

16.6 Microbiology and Nutritional Composition

Very few scientific studies are available on the microbiology and nutritional components of the fermented foods and beverages of Mizoram. Even the processes of preparation of those fermented products are not usually well-documented and were passed on verbally from generation to generation. It is a well-known fact that microorganisms change the nutritional constituents of substrates, be it of plant or animal origins, during fermentation. The fermentation process is usually brought about by microorganisms, mainly lactic acid bacteria, yeast and filamentous moulds. It may be believed that the same microbial reactions are involved in the production of various traditionally fermented foods and beverages of Mizoram.

Among the fermented products of Mizoram, only bekang-um (fermented soybean food) has been studied, and its microbiology and functionality have been reported (Omizu et al. 2011; Chettri and Tamang 2014, 2015; Tungoe 2016). It has been observed that the nutritional value of bekang-um (carbohydrate 267.5 mg/100 g, fat 9.952 mg/100 g, protein 5.09 mg/100 g, moisture content 54.99%, ash value 7.744%, 1.375 calories per g) slightly varies when compared with the cooked non-fermented soybean (carbohydrate 339 mg/100 g, fat 12.688 mg/100 g, protein 4.4125 mg/100 g, moisture content 55.04%, ash value 9.52%, 1.64 calories per g) (Vanlalruati and Das 2012). The pH of bekang-um is usually 7.2–8.0 signifying its alkaline character with ammonical flavour (Chhetri and Tamang 2014). It has also been found that bekang-um, after the pH crosses 8.5, is considered to be non-palatable as its ammonic smell and taste become too strong. Moreover, with prolonged fermentation time, the microbial load has increased which resulted in the high alkalinity of the fermented product (Tungoe 2016). The microorganisms involved in bekang-um are Bacillus subtilis, B. pumilus, B. licheniformis, B. sphaericus, B. brevis, B. coagulans, B. circulans, Enterococcus faecium, E. hirae, E. raffinosus, E. durans and E. cecorum and yeasts Saccharomyces cerevisiae, Debaryomyces hansenii and Pichia burtonii (Chettri and Tamang 2015), and Bacillus species are the predominant organisms reported in similar non-salted sticky fermented soybean foods of Asia (Tamang 2015). Bekang-um prepared in the laboratory of Department of Pharmacy, Regional Institute of Paramedical and Nursing Sciences (RIPANS), Aizawl, Mizoram, using Mizo traditional method showed the presence of Bacillus sphaericus, B. macernas and B. brevis (Tungoe 2016). With increase in fermentation time, the amount of reducing sugar present decreases, while the amount of free amino acids, protease and amylase activity increases in bekang-um which is also observed with other traditionally fermented soybean (Omafuvbe et al. 2000). Other studies on bekang-um had revealed that Bacillus sp. isolated shows high proteolytic activities which explains the increase in free amino acids as fermentation proceeds and improves the digestibility of proteins (Chettri and Tamang 2014). The strains of lactic acid bacteria (LAB) from bekang-um do not show amylolytic and proteolytic activity, but many were found to have probiotic properties (Chettri and Tamang 2014). 49% of LAB strains isolated from bekang-um could cause coagulation of milk at 30 °C with significant drop in pH that shows their potential as starters or adjunct cultures in the production of fermented products (Chettri and Tamang 2014). LAB isolated could not produce antimicrobial bacteriocin and biogenic amines under the applied study condition, while 45% of LAB strains degraded phytic acid, 35% degraded raffinose and 20% degraded both phytic acid and raffinose that are antinutritive factors, hence making soybean fit for consumption (Chettri and Tamang 2014). Bekang-um is also found to contain phenolic compounds, considered to be one of the most important antioxidant compounds, ranging from 2.6 to 4.2 mg GAE/g fresh weight depending upon the place of sampling (Chettri and Tamang 2014). Moreover, bekang-um has been shown to exhibit certain amount of DPPH scavenging (IC50 values ranging from 456.7 to 493.3 μg/mL) and ABTS scavenging (IC50 values ranging from 145 to 170 μg/mL) activities (Chhetri and Tamang 2014).

Biochemical analysis of sa-um showed that the moisture content is 6.21% by weight and fat content accounted for 91%; protein, 0.7%; and carbohydrates, 2% with a total ash value of 0.1 (Mandal et al. 2018). The high fat content is reflected in its calorific value, i.e. 830 kcal/100 g, and the pH of sa-um is found to be slightly acidic (6.60). It is also seen that sa-um contains traces of iron, zinc and magnesium, while sodium, potassium and calcium were present in higher quantity. Microbial analysis of sa-um showed that the dominant microbes present are from the phyla Firmicutes, Proteobacteria, Bacteroides, Actinobacteria, Chloroflexi, Planctomycetes, Synergistetes and Acidobacteria and at the genus level dominated by Clostridium, Bacteroides, Oscillospira, Corynebacterium, Megamonas, Faecalibacterium, Proteus, Ruminococcus and Prevotella (Mandal et al. 2018).

Nutritional value determination and biochemical and microbiological analysis studies on chhi-um, ai-um, aite-um, tam-um and tuai-um are not yet available but are discussed in the light of similar fermentation products of other regions.

Chhi-um or fermented sesame could be compared with ogiri-saro of Nigeria even though the preparation is slightly different; the substrate for both the fermentation products is the same. Studies have shown that fermentation of such sesame seeds resulted in significant increase in mineral concentrations which could be due to conversion of insoluble reserve foods during fermentation (Makinde and Akinoso 2014).

Crabs are excellent source of proteins while they are fair source of minerals like calcium, potassium, magnesium, sodium and iron (Varadharajan and Soundarapandian 2014). The Indian freshwater crabs have high contents of monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA), exhibiting a higher percentage of essential fatty acids out of total fatty acids (Das et al. 2015). However, consumption of fermented crabs is mainly localised in Northeast India, mainly in Mizoram and other areas where Mizo tribes reside. Fermentation of crabs is also practised by Nigerians in which juvenile crabs are fermented wholly with carapace, or for mature crabs, carapaces are crushed and wrapped in layers of banana leaves after carefully washing the crabs. The crabs are allowed to ferment by keeping them in warm place for 3–4 days to produce ogiri-nsiko (Achi et al. 2007). The method of preparation of ogiri-nsiko is quite similar to the Mizos’ preparation of aite-um and hence may have similarities in many aspects. Fermentation of crabs with sesame seeds appears to be practised by Naga communities whose method of preparation is similar with that of ai-um (Mao and Odyuo 2007). However, a scientific study for the fermented crabs of both Mizo and Naga tribes is not available.

Wickerhamomyces anomalus, Candida glabrata, Pichia anomala and Saccharomycopsis fibuligera were reported from dawidim, traditionally prepared dried starter for alcohol production in Mizoram (Sha et al. 2018). Zufâng, an alcoholic beverage that utilise dawidim for its production, has an average alcohol content of 6.3% and pH of 4.32 with total acidity of 0.59 g per 100 mL and total antioxidant capacity of about 11% (Zonunmawii et al. 2017). It should be kept in mind that zufâng is the mildest drink among all the Mizo alcoholic beverages and is not considered as real alcoholic drink. The rakzû sample collected from Tuirial area, Aizawl district, is found to contain 20.6% (v/v) of ethanol with 0.826% (w/v) of residue on evaporation and 0.198% (w/v) ash content (Devi 2012). The ethanol content of rakzû is quite high as compared to other rice beer from Northeast India whose ethanol content ranges from 12 to 13% but is low when compared to international standard.

16.7 Conclusion

Preservation methods for many of the traditional food items are not available mainly due to unavailability of scientific in-depth studies. Most of the indigenous foods are seasonal and not available throughout the year which makes development of food preservation process necessary. Traditional food processing techniques of Mizo, mainly fermentation, are developed not only to improve the taste of food but also to preserve it. It is always the case that, when the season for certain vegetable/food is over, the demand for such vegetable/food becomes very high as is with the price. Fermentation allows such vegetable/food to be preserved for certain amount of time prolonging their availability. It is wonderful to learn that the Mizo forefathers somehow utilised the minimal available resources such as fire and sun and devised their own way of food preservation. It is indeed quite intriguing that our forefathers practised the science of biotechnology without knowing it. However, most of the fermented products are still in the dark without proper scientific studies. A study on the nutritive values, microorganisms involved, physical and chemical changes brought about by fermentation, etc. of the traditionally fermented products of Mizo would be highly significant. It is also of utmost importance to study the possible effect, whether beneficial or harmful, of the fermented products on the health and well-being of consumers. Scientific study on the traditional fermentation process is a must in order to improve the technique which will have a positive impact on the quality and safety of the final fermented products. By utilising the current scientific knowledge and technologies, one can be innovative about many of the foods produced using fermentation and indigenous knowledge systems, and they must be used to add value to such products, such as increased shelf life, improved flavour and appealing packaging and labelling. This will definitely help in promoting ethnic fermented foods and beverages that will result in improving the economy of the state. While applying innovative techniques in producing such fermented products, documentation of the traditional indigenous technologies must be done for future generations. It will also help in creating a reference database to be utilized by future generations for the benefit of society in the long run.