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Probiotics for dairy & functional foods and beverages

Wednesday, 01 February, 2023, 16 : 00 PM [IST]

Ganesh Gaikwad & Dr R. B. Kshirsagar

The increasing research on science and innovation has shifted consumer awareness from conventional to functional foods that are more nutritious and healthier. The ideation of functional food is based on the addition of probiotics that promote cognitive response, improved immune system, and general wellbeing.

At a time when there is no proven therapy for global pandemic Sars-CoV-2 causing infectious viral disease Covid-19, alternative food and nutritional interventions through diet are studied like never before to limit the infection.

Probiotics are live microorganisms that have the potential to modulate the human immune system and prevent such infection, which is why several safety issues during its administration must be addressed. While at the same time, it is necessary to update, reform, and tighten the policies and regulations for the food manufacturers dealing with such functional foods to protect consumers from false and misleading claims.

Yogurt, fermented milks (both drinkable and spoonable), and to a much lesser extent, cheese have long been used as probiotic carrier dairy foods. Yogurt has long been associated with longevity and wellbeing of the people. Up until now, many efforts have been made to give conventional yogurt additional beneficial properties by adding value added ingredients such as probiotics, prebiotics and various plant extracts.

Among such value-added fermented products, probiotic yogurt has reached a great market success during the last two decades or more. Although solid texture, high fat content and pH values of cheese offer better protection of probiotic cells against undesirable environmental conditions, probiotic cheese market is far below its market potential.

Probiotic dairy beverages have also long been available in the global beverages markets. The concept of a healthy intestine for a disease-free life was first designed early 19th century, was first isolated from feces of bottle-fed infants and named ‘Bacillus acidophilus'.

This bacterium was later demonstrated to have a beneficial role in correcting disorders of human digestive tract in 1922. Since then, products containing Lb. acidophilus, have become increasingly popular. Milk fermented by Lb. acidophilus, for therapeutic applications, i.e., tuberculosis treatment. Later, Dr Minoru Shirota-a Japanese microbiologist- discovered Lactobacillus casei strain Shirota in 1930 and launched the commercial probiotic milk beverage, named Yakult in 1935.

The probiotic means simply life for originating from the Greek words ‘pro’ and 'bios’. The most commonly quote meaning was made by Fuller in 1989. The probiotics are live microbial feed supplement which beneficially affects the host animal by improving its intestinal balance. This correct definition is still commonly referred to, despite continual contention.

Today, probiotics are quite every day in health-promoting ‘functional foods’ for humans, as well as therapeutic, prophylactic growth supplements in animal production human health. Other commonly studied probiotics include the spore-forming Bacillus spp. Bacillus spp holds an added interest in probiotics as they can be kept in the spore form and therefore stored indefinitely on the shelf.

It is often reported that a probiotic must be adherent and colonise within the gastrointestinal tract (GIT), it must replicate to high numbers, it must produce antimicrobial substances, and it must withstand the acidic environment of the GIT. The most commonly used probiotic is LAB, namely, lactobacilli spp. are usually characterised by Gram-positive, nonmotile, nonsporulating bacteria that produce lactic acid as their main by-product due to fermentation.

Some features of bacterial species as probiotics

Type of probiotic bacteria	Benefits
B. animalis/bifidus regularis	Gut health, digestion
B. longum	Digestion, irritable, bowel syndrome
B. animalis	Immune system, digestion, irritable bowel, colds
L. acidophilus	Irritable bowel, diarrhea, antibiotic-induced diarrhea, lactose intolerance, immune system, pollen allergies
L. paracasei	Travelers diarrhea, ulcers
L. plantarum	Irritable bowel, immune system, colds
L. casei immunitas	Immune system, colds and flus, diarrhea
L. casei shirota	Immune system, digestion
L. lactis	Immune system
P. acidilactici	Ulcerative colitis
S. boulardii	Antibiotic-induced diarrhea, acne, irritable bowel

Starter cultures
Food fermentation has been used for centuries as a method to preserve perishable food products. The raw materials traditionally used for fermentation are as diverse as: fruits, cereals, honey, vegetables, milk, meat and fish. It is possible to obtain a large variety of different food products by selecting different raw materials, starter cultures and fermentation conditions. The diversity covers, but is not limited to products as: wine, beer, vinegar, bread, soy sauce, kochujang, sauerkraut, kimchi, pickled olives, fermented milk products as buttermilk and yoghurt, a variety of cheeses and sausages.

Starter culture is a microbial preparation of large numbers of cells of at least one microorganism to be added to a raw material to produce a fermented food by accelerating and steering its fermentation process. The group of lactic acid bacteria (LAB), occupies a central role in these processes, and has a long and safe history of application and consumption in the production of fermented foods and beverages.

They cause rapid acidification of the raw material through the production of organic acids, mainly lactic acid. Also, their production of acetic acid, ethanol, aroma compounds, bacteriocins, exopolysaccharides, and several enzymes is of importance. In this way they enhance shelf life and microbial safety, improve texture, and contribute to the pleasant sensory profile of the end product.

The production of lactic acid, by fermenting lactose is the major role of dairy starters. The acid is responsible for development of characteristic body and texture of the fermented milk products, contributes to the overall flavour of the products, and enhances preservation. Diacetyl, acetaldehyde, acetic acid, also produced by the lactic starter cultures, contribute to flavour and aroma of the final product.

Most of the cultured dairy products are produced using commercial starter cultures that have been selected for a variety of desirable properties in addition to rapid acid production. These may include flavor production, lack of associated off flavors, bacteriophage tolerance, ability to produce flavour during cheese ripening, salt tolerance, exopolysaccharide production, bacteriocin production, temperature sensitivity.

Types of fermented foods and their starter cultures

Product	Raw material	Starter culture
Beer	Cereals	Yeast
Wine	Grape juice	Yeast, lactic acid bacteria
Bread	Grains	Yeast, lactic acid bacteria
Soy sauce	Soybeans	Mould (Aspergillus), lactic acid bacteria
Sauerkraut, Kimchi	Cabbage	Lactic acid bacteria
Fermented Sausages	Meat	Lactic acid bacteria
Pickled vegetables	Cucumbers, olives	Lactic acid bacteria
Fermented milks	Milk	Lactic acid bacteria
Cheese	Milk	Lactic acid bacteria

The manufacturers of fermented foods have the choice of either acquiring the starter culture in a ready to-use, highly concentrated form, or to make a propagation of the culture in the factory. The choice between the two types of process will be influenced by a number of factors as: the number of different products produced, degree of automation, presence of expertise in microbiology and finally the economy. The highest level of safety and flexibility is achieved by using a commercial starter culture for direct inoculation. Such cultures are supplied either as frozen or freeze-dried highly concentrated and highly active cultures.

(Gaikwad is research scholar, College of Food Technology, VNMKV, Parbhani; Dr Kshirsagar is head, Department of Food Engineering, College of Food Technology, VNMKV, Parbhani. They can be reached at ganeshpg107@gmail.com)