Ethnic Fermented Foods Help Preserve Some Bacteria and Fungi

The technique involved help keep alive important bacteria and fungi found in India's northeast, and which would otherwise disappear with time.

Monika Kundu Srivastava writes for India Science Wire.

New Delhi: Fermented foods from jalebi to dosa are common across India. Scientists are now focusing on them because they also harbour a diverse array of microbes.

A study of ‘starters’ that are used to prepare ethnic fermented foods in Sikkim and Meghalaya has revealed that they have rich microbial diversity. The study was undertaken to find out the types of bacteria and fungi present in two traditionally prepared starters: marcha and thiat, used to ferment a variety of starchy substances and produce a sweet alcoholic beverage that popular in the two northeastern states.

Marcha and thiat are traditionally-prepared starters similar to the jamun people use to prepare curd. In curd, the bacteria help in changing milk sugar, which is a simple sugar, into lactic acid. In marcha and thiat, the fungi convert the starch, which is a complex sugar, present in rice into alcohols.

The traditional practice of using marcha and thiat starters in the process of fermentation is an integral part of the socio-cultural heritage of Sikkim and Meghalaya, respectively. The technique involved also help keep alive important bacteria and fungi found in the area, and which would otherwise disappear with time.

The researchers used next-generation genome sequencing to develop an accurate profile of fungal and other microbial communities present in marcha and thiat. They found that marcha had more quantities as well as varieties of fungi than thiat. Thiat, on the other hand, had more bacteria. Both starters contained ProteobacteriaFirmicutes and Actinobacteria, in descending order of quantity. The main fungus found was Ascomycota. Yeasts are mainly found in marcha whereas mold was more prevalent in thiat.

The results of the study were published in the journal Scientific Reports on September 8, 2017.

“Ethnic fermented beverages and alcoholic drinks have the potential to grow in beverage industry if proper scientific and technical support is provided to indigenous practices of home-based alcoholic fermentation,” said Jyoti Prakash Tamang, of the school of life sciences at Sikkim University, Gangtok, who led the study. “These practices also preserve vast biological genetic resources, which otherwise may disappear over time.”

He added that “fermented beverages produced by using starch and sugar-digesting starters are generally [mildly alcoholic], 4-5%, have a sweet taste and several health benefits. They are high source of calories and contain some vitamins and minerals.”

Marcha is prepared from soaked rice with some wild herbs, ginger and dry red-chilli and a bit of previously crushed marcha powder. The resulting dough cakes are fermented at room temperature for 24 hours, Sun-dried for three to five days and then used as starters for preparing cereal-based fermented beverages. Thiat is prepared by soaking ‘sticky’ or ‘sweet’ rice along with the leaves and roots of a black cardamom variety, a bit of old thiat, mixed and turned into dough by adding water. It is then fermented and Sun-dried, just as with marcha.

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