Biosynthesis of food ingredient by fermentation

Jasmin Ara Farhana :

Fermentation is a biological process which is driven by a biological agent, microorganisms and their enzymes, and at the end yields a food product having desirable properties.

For instance, fermentation could enhance the taste, nutritional value and color of food or change the consistency of a food product to make it more ropy or more solid.

So, fermentation can add new functionalities to a food product.

The common theme is of course the microbes because these are the engines that drive the process.

Consumption of fermented food products is preferred over raw products because:
i Fermentation improves microbial safety and can extend the shelf life of foods to extremely long periods at low cost, because it usually does not need refrigeration to keep fermented products stable.

Fermented product like cheese can be stored for over years at room temperature and still its microbial composition remain stable and safe. Food fermentation is not monodisciplinary.

It evolves from many different disciplines. But it always starts with food safety. In history the main reason of fermenting food products was to preserve them, to make them safe .

Otherwise, they may be spoiled and might contain food pathogens.
ii. It reduces toxic compounds of plant materials.
iii. It improves the digestibility
iv. It imparts flavour, taste, texture and appearance. Therefore, fermented products usually have enhanced organoleptic properties.
v. It provides opportunities for product diversification.
Although fermentation is a process that people must already practice for centuries or millennia, there is still room for innovation because now there is more available information about the microbes that are involved.

So, new product development is possible. Many times this is an important driver to also innovate fermentation process.

Fermentation can be seen as second chance for primary production. Primary production indicates the first time production.
With the unique feature of fermentation processes, new products can be produced by in situ biosynthesis of food ingredients. Let’s look at this chain of events.

The sun is powering the growth of green plants, which serve as a food source for cattle, in this case the cow.

Then the cow converts it for instance into milk and finally it can be fermented. But what is happening there? One of the ingredients that is produced during primary production, so during the production of plant material (grass in this occasion), is the vitamin folic acid. It is produced by plants but not by cows.

However, cows require it as a vitamin for growth.

That means that cows already absorb and utilize some of that folic acid and folic acid levels drop. Also we cannot make it and we need to extract it from our diet.

So if this food chain is longer, those plant compounds gradually decrease in levels.

They become poorer in terms of the nutritional value along the food chain.

However, with fermentation certain vitamin levels can be boosted because not only plants can make vitamins of that particular type, many bacteria also can do that, in contrast to for instance cows.

Therefore, because of the activity of bacteria, the folic acid level in yogurt is higher compared to milk.

By learning more and more about i) the bacteria and ii) their capacity to produce different types of vitamins, these bacteria can be used to increase the nutritional value of fermented food products. And the good news is, there are many examples like this, such as the increased concentration of vitamin B-complex in Cheese compared to milk.

(The writer is an Associate Professor, Department of Human Nutrition and Dietetics, Patuakhali Science and Technology University)