Fermented Foods

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Kluyveromyces marxianus, Torula kefir, Saccharomyces exiguus, Candida lambica, ..... the global sale of probiotic products is $15.9 billion in 2019 as compared.
Food Biology Series

Fermented Foods Part II: Technological Intervention

Editors

Ramesh C. Ray Principal Scientist (Microbiology) ICAR - Central Tuber Crops Research Institute Bhubaneswar, Odisha, India and

Didier Montet Food Safety Team Leader UMR Qualisud, CIRAD Montpellier, France

A SCIENCE PUBLISHERS BOOK

Fermented Food—Part II: Technological Interventions Ramesh C. Ray and Didier Montet (eds.) ISBN 978-1-1386-3784-9

Not for Circulation

18 Kefir and Koumiss Origin, Health Benefits and Current Status of Knowledge Sunil K. Behera,1,* Sandeep K. Panda,2 Eugenie Kayitesi 2 and Antoine F. Mulaba-Bafubiandi 1

1. Introduction Milk constitutes an important ingredient of healthy balanced diet of our daily life. It is an important source of vitamins, minerals, and proteins for human nutritional requirement, hence regarded as a complete food. Throughout the world, milk and milk products are valued as natural and traditional food. However, milk is extremely perishable and many means have been adapted to preserve it. The earliest one which has been used for many thousands of years is the process of fermentation (Parveen and Hafiz 2003). Milk can be fermented by inoculating fresh milk with the appropriate bacteria and incubating it at a temperature that favors their growth. As the bacteria grow, they convert milk sugar (lactose) to lactic acid through the process of fermentation. The lactic acid generated during milk fermentation decreases the pH of milk and as a result it prevents the growth of putrefactive and/or pathogenic microorganisms that do not survive in acidic environment. Since the time immemorial the process of Department of Metallurgy, Faculty of Engineering and the Built Environment, University of Johannesburg, P.O. Box 17911, Doornfontein Campus, 2028, Johannesburg, South Africa. 2 Department of Biotechnology and Food Technology, Faculty of Science, University of Johannesburg, Doornfontein Campus, Johannesburg, South Africa, P.O. Box 17011. * Corresponding author: [email protected] 1

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fermentation has been adapted as a tool for food preservation. With due course of time, it has been noticed that many fermented foods have better nutritional and functional values when compared to their unfermented counterparts (Hasan et al. 2014). Hence the fermentation processes have become the most popular food processing techniques for preservation of foods along and for the addition of better nutritional value (Panda et al. 2014a, 2014b). Worldwide, the known fermented milk products are yogurt, kefir, koumiss, sour cream, cheeses, etc. The primary function of fermenting milk was, originally, to extend its shelf life. Further the fermentation process brought numerous changes to the nutritional property of milk, such as an improved taste and flavor and enhanced digestibility of the milk. Historically, the fermentation of milk can be traced back to around 10,000 B.C. (Dhewa et al. 2015). Fermentation takes place through the natural microflora present in milk. With the advent of scientific methods the different classes of microorganisms present in the fermented dairy products have been detected. The most common microorganisms observed in fermented milk products belong to the strains of lactic acid bacteria (LAB), Lactobacillus, Leuconostoc, Lactococcus, etc. (Liu et al. 2014). These microorganisms prevent the spoilage of milk and inhibit the growth of other pathogenic microorganisms. Today the fermentation processes are controlled with specific starter cultures and conditions to obtain a wide range of milk products like milk cream, cultured buttermilk, kefir, koumiss, yogurt and amasi. Different starter cultures are used for each fermented dairy product. They consist of microorganisms added to the milk to provide specific characteristics in the final fermented milk product with desired properties. The vital function of lactic acid starters is for fermentation of lactose into lactic acid. In addition, they also contribute to flavor, aroma and alcohol production, while inhibiting interference of spoilage microorganisms. A single strain of bacteria may be added, or a mixture of several microorganisms may be introduced. Bacteria, yeasts and molds perform the process of fermentation at specific range of optimum temperatures. The optimum temperature for thermophilic lactic acid fermentation is about 40 to 45°C, while mesophilic lactic acid fermentation occurs at moderate temperatures ranging from 30 to 40°C (Carminati et al. 2010). Microbial fermentation is the biochemical conversion of carbohydrates into alcohols or acids (Panda et al. 2013, Panda et al. 2016). In fermented milk products both alcohol and lactic acid may be produced, e.g., kefir and koumiss, or only lactic acid, e.g., sour milk cream. The bacteria convert the lactose to lactic acid and raise the acidity of the milk. The rise in acidity causes denature of milk proteins thus inhibiting the growth of other organisms that are not acid tolerant. Following the completion of fermentation process, the fermented dairy products are marketed with added flavors.

402  Fermented Foods—Part II: Technological Interventions In addition to extending the shelf life of milk products, the fermentation process gives probiotic properties to the milk products (Amara and Shibl 2015). After invention of the microscope, the microbiological studies revealed that the fermented milk products contain live microorganisms and the microbial metabolites that are highly beneficial for human health (Fernandez et al. 2015). Further development of scientific knowledge has made it clear that the human intestinal microflora consists of trillions of microbial cells. These microorganisms play a vital role in several physiological activities, metabolic activities and immune functions (Guinane and Cotter 2013). Historically the fermented milk products have health benefits and have a good taste which enables their consumption, hence milk was the first probiotics food adapted by the men (Amara and Shibl 2015). Men knew how to prepare different types of fermented milk products even before the invention of the microscope (Amara and Shibl 2015). The different types of the microorganisms used as starter culture induce different reactions and as a result it produces different types of fermented products like yogurt, kefir, koumiss, sour cream, etc. The knowledge of such traditional processes for food preservation is transferred from generation to generation. Looking to the importance of the beneficial properties of kefir and koumiss, this chapter describes the nutritional importance and health promoting properties of kefir and koumiss.

2. Kefir Kefir is a fermented milk drink which is traditionally produced by fermenting cow, goat and sheep milk by using “kefir grains” as starter culture (Farnworth 2005). The kefir grains contain active microorganisms and when added to fresh milk, they produce kefir. Kefir grains consist of protein and polysaccharide matrix containing different species of yeasts, LAB, acetic acid bacteria, and mycelial fungi (Witthuhn et al. 2005). Kefir produced through the fermentation of milk by the microorganisms is a white or yellowish colored, sour, carbonated and a mild alcoholic beverage. It has yeasty aroma with acidic taste (Irigoyen et al. 2005). Kefir is sometimes commercially available without carbonation and alcohol (when yeast is not added to the starter culture), resulting in a product that is very similar to yogurt. The flavor, taste, nutritional composition of kefir varies with the type of milk and microbial strains used for kefir production.  Kefir originated from the Caucasian mountains and then it became popular in central and Eastern Europe (Assadi et al. 2000). It is important food stuff in Russia. Traditionally kefir is produced in the households of the Caucasian Mountains and Tibetian region of China. They used the kefir grains which were inherited from their ancestors for kefir preparation.

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Generally, kefir is prepared from cow, sheep and goat milk; however soya milk is also known to be used for kefir preparation (Farnworth 2005). In the later part of the nineteenth century, the benefit of kefir was highlighted when it helped for effective treatment of tuberculosis, intestinal and chronic diseases in the Caucasus region. The benefits of kefir were first reported by the Russian doctors working in this region. Kefir has been reported for its healing effects on the high blood pressure, anaemia, obesity control, gall bladder problem, etc. (Bellamy and MacLean 2005). Due to its abundant health benefits, kefir has gained popularity as a functional healthy probiotic food throughout the world. 2.1 Kefir production Kefir production started from the indigenous process by incubating the kefir grains with milk of cow, sheep or goat. Later the process was refined scientifically to produce it on a commercial scale. 2.1.1 Kefir grains Microorganisms present in kefir grains are responsible for the fermentation of milk. The original kefir grains are slightly yellowish in colour and they resemble a cauliflower (Nielsen et al. 2014). There is no scientific evidence about the origin of kefir grains. Kefir grains are yellowish-white, cauliflower shaped, semi hard granules containing different yeast and bacterial stains, which exist in symbiotic association (Fig. 1). When the grains are added to sterilized milk and incubated the microorganisms are activated to ferment milk. Kefir grains are made up of a complex microbial biomass matrix composed of polysaccharide, fat and protein of kefir microorganism

Figure 1. Kefir grain. (source: https://julietwhev.files.wordpress.com/2013/03/kefir-grains.jpg).

404  Fermented Foods—Part II: Technological Interventions origin (Rea et al. 1996). Microorganisms involved in kefir production secrete exopolysaccharides that accumulate along with proteins and fat molecules to form kefir grains. Further, growth of kefir grains occur by the accumulation of microbial biomass on the pre-existing kefir grains during kefir production. The major constituent of kefir grain matrix is composed of polysaccharide “kefiran” (La Riviere et al. 1967). The kefiran is a heteropolysaccharide made from glucose and galactose. Lactic acid bacteria are the main exopolysaccharide producing microorganisms in kefir that give the rheological and texture properties to the kefir formed from the fermented milk (Frengova et al. 2002). 2.1.2 Traditional/Indigenous process of kefir production The traditional process for kefir preparation is described as follows: (a) Incubation of milk (cow, sheep or goat) with kefir grains at room temperature for 24 hr; (b) At the end of the incubation period kefir grains are separated from milk by filtration process; (c) the fermented milk, i.e., the kefir is preserved for further consumption. The kefir grains separated from the kefir can be further reused as a starter culture for preparation of kefir from fresh batch of milk. 2.1.3 Modern process of kefir production The kefir can be prepared from the milk of sheep, cow or goat. For large scale production of kefir, kefir grains are not used but rather sterilized milk is incubated with selected microorganisms directly. At the industrial scale, at first the milk is sterilized by the process of homogenization and pasteurization. After sterilization the milk is kept for cooling down up to 20°C and the milk is incubated with specific strains of microorganisms for 24 hr further to prepare kefir (Assadi et al. 2000, Otles and Cagindi 2003). The nutritional and sensory qualities of kefir vary with the type of milk and microbial strain used. The taste, flavor and aroma of kefir differ from other milk products because it is a produced through a combination of eukaryotic and prokaryotic (yeast and bacteria) fermentation process. A typical process of kefir production is graphically presented in Fig. 2. Kefir resembles yogurt to some extent. Many people believe that kefir and yogurt are similar, but in reality they have many significant differences based on biochemical and organoleptic properties. Both kefir and yogurt are cultured milk products but they contain different strains of microorganisms. Generally, yogurt contains bacterial strains that belong to the genera of Lactobacillus and Streptococcus, while kefir contains several other bacterial

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Figure 2. A typical process of Kefir production.

strains such as Lactobacillus, Leuconostoc, Acetobacter, Streptococcus and Pseudomonas spp. Apart from the bacterial strains, kefir contains different yeast strains belonging to Saccharomyces, Candida and Kluyveromyces genus, hence kefir is a fermented milk product of combined action of yeast and bacterial fermentation process. Appearance of kefir is not as creamy as yogurt. Generally, kefir has a sourer or tart taste due to lactic acid content. It has a little effervescence, due to the carbon dioxide and alcohol content released by alcoholic fermentation. The acidity generated drops the pH of milk up to 4 to 4.5, and it varies depending on the type of milk and fermentation conditions.

3. Koumiss Koumiss is a traditional milk beverage produced from fermentation of mares’ milk by indigenous microorganisms (Montanari et al. 1996). Koumiss is also known by other names like koumiss, kumiss, kumis, kymis, kymmyz. It is a fermented drink traditionally made from the milk of horses by people in Central Asia and China, where it is one of the most important basic foodstuffs. Koumiss is similar to the kefir; however it is prepared by a liquid starter culture in contrast to the solid kefir grains used in kefir production. Koumiss is also widely produced in Russia, Kazakhstan in Western Asia. In Mongolia, it has been adapted as the national drink and is known as Airag (Uniacke-Lowe et al. 2010).

406  Fermented Foods—Part II: Technological Interventions 3.1 Preparation of Koumiss In the traditional process, koumiss is prepared by incubating fresh mare’s milk with a part of the previous day’s batch of koumiss as a starter culture. The previous day’s batch of koumiss containing indigenous native microorganisms is inoculated to fresh mares’ milk and kept for about 8 hr of incubation (Cagno et al. 2004). The milk is fermented by the LAB and yeast to produce lacto-alcoholic rich beverage. The preparation of koumiss is presented in Fig. 3. unlike kefir, which is prepared from the milk of cow, sheep or goat, the mare and camel milk used for koumiss production gives the product its distinctive character. The higher lactic acid and alcoholic content observed in koumiss in comparison to kefir is attributed to the higher sugar content of mare’s milk used in koumiss preparation (Uniacke-Lowe et al. 2010, Bornaz et al. 2010). The average chemical composition of mare’s milk and bovine milk shows that the mare’s milk has a distinct composition. The noticeable differences between these milks shows that the mares milk contain lower fat (12.1 g/kg) and higher lactose (63.7 g/kg) content compared to bovine milk (Uniacke-Lowe et al. 2010). The predominant microbial strains used for koumiss are LAB and yeast strains of Saccharomyces (Wouters et al. 2002). The lactic acid produced by the lactic acid bacterial strains gives the koumiss an acidic characteristic and the yeasts generate alcohol in koumiss through alcoholic fermentation process. Thus the koumiss obtained by the fermentation of mare’s milk is a milky grey, fizzy liquid with a sharp alcohol and acidic taste. Since the mare’s milk has higher lactose content, the final fermented product, i.e., koumiss has comparatively higher lactic acid and

Figure 3. A typical process of Koumiss production.

Figure 3. A typical process of Koumiss production

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alcoholic content when compared with kefir. Koumiss contains alcohol up to 2%, and therefore, it is also called milk wine. Although the koumiss is a popular fermented milk beverage, the availability of the mare’s milk is the limiting factor for its large scale production. Presently, the large scale production of koumiss is performed from cow’s milk supplemented with the additional sugar to make it approximate with the composition of mare’s milk (Zhang and Zhang 2012).

4. Microorganisms Associated With Kefir and Koumiss The microbial diversity of kefir and koumiss is very complex. However, several reports have described the microbial diversity with these two products. The microorganisms entrapped in the protein and polysaccharide matrix of the kefir grains live symbiotically (Lopitz-Otsoa et al. 2006). The microbial populations presented in the grains mostly belong to LAB, acetic acid bacteria (AAB), yeasts, and mycelia fungi (Marshall 1984, Witthuhn et al. 2005). A brief list of microorganisms detected in different kefirs is described in the Table 1. The notable bacterial strains found in kefir are Lactobacillus acidophilus, Lb. brevis, Lb. casei, Lb. fermentum, Lb. helveticus, Lb. kefir, Lb. parakefiri, Lactococcus lactis, Leuconostoc mesenteroides, Lb. delbrueckii, Acetobacter sicerae sp. nov, Streptococcus, etc. (Witthuhn et al. 2005, Simova et al. 2002, Li et al. 2014). Several strains of yeasts have also been reported in kefir such as Kluyveromyces marxianus, Torula kefir, Saccharomyces exiguus, Candida lambica, Candida kefir, Saccharomyces cerevisiae, Candida krusei and Candida famata (Lopitz-Otsoa et al. 2006, Witthuhn et al. 2005). Yeast cells provide flavor and aroma to kefir (Simova et al. 2002). In addition, they provide essential nutrients (vitamins and amino acids) for bacteria growth and thus assist growth of bacterial strains present in kefir (Farnworth 2005, Irigoyen et al. 2005). Furthermore, they inhibit growth of pathogenic microorganisms by decreasing the pH of the medium through the production of ethanol, carbon dioxide and organic acids. The notable microorganisms present in the starter culture used for koumiss preparation belong to the bacterial strains of Lactobacillus and Lactococcus, and fungal strains of Kluyveromyces and Saccharomyces (UniackeLowe et al. 2010). Cagno et al. (2004) reported the use of bacterial strains Lactobacillus delbrueckii and Streptococcus thermophillus in starter culture for the preparation of koumiss from mare’s milk. Brief lists of microorganisms detected in different koumiss are described in the Table 2.

408  Fermented Foods—Part II: Technological Interventions Table 1. Microorganisms associated with Kefir. Microorganisms Lactococcus spp., Lactobacillus spp. Lactobacillus keranofaciens Lactobacillus buchneri Lactobacillus plantarum Lactobacillus kefiri Acetobacter aceti Kluyveromyces marxianus Saccharomyces turicensis Pichia fermentans Kazachstaniaunispora Dekkeraanomala Yeast

References Cui et al. 2013, Chen et al. 2008, Simova et al. 2002 Chen et al. 2008 Garofalo et al. 2015 Wang et al. 2015 Chen et al. 2008 Li et al. 2014 Wang et al. 2012 Chang et al. 2014 Wang et al. 2012 Wang et al. 2012 Garofalo et al. 2015 Garofalo et al. 2015 Soupioni et al. 2013

Table 2. Microorganisms associated with Koumiss. Microorganisms

References

Lactobacillus spp. Lb. acidophilus

Guo et al. 2015

Lb. helveticus

Miyamoto et al. 2015

Lb. salivarius

Danova et al. 2005

Lb. buchneri

Danova et al. 2005

Lb. plantarum

Danova et al. 2005

Lb. delbrueckii

Cagno et al. 2004

Streptococcus spp. Str. thermophiles

Kozhahmetova et al. 2013

Leuconostoc

Guzel-Seydim et al. 2009

Yeasts Torula kumiss

El-Ghaish et al. 2011

Saccharomyces lactis

Kosikowski 1982

Saccharomyces unisporus

Montanari et al. 1996

Kluyveromyces lactis

Kucukcetin et al. 2003

El-Ghaish et al. 2011

Cagno et al. 2004

Kosikowski 1982

5. Biochemical Mechanisms Involved in The Production of Kefir and Koumiss The biochemistry of kefir and koumiss production depends upon the type of lactic acid fermentation occurred, namely homo fermentation and hetero fermentation. The homo fermentative microorganisms produce only lactic

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acid as the final product whereas the hetero fermentative microorganisms produce ethanol and CO2 along with lactic acid. The details of the homo and hetero lacto-fermentation have been described in the previous chapter of this book (see Chapter 17). The characteristic flavor of kefir and koumiss are due to the presence of various biochemical compounds formed during fermentation process, such as organic acids (lactic, propionic, citric, acetic, pyruvic and succinic acids, etc.). These acids are produced due to the metabolism of milk by the microorganisms involved in milk fermentation (Guzel-Seydim et al. 2000). The microorganisms present in kefir, metabolise the milk sugar to produce energy through the biochemical process of glycolysis and other metabolic pathways (alcoholic and lactic acid fermentation and Krebs cycle). The final product formed in glycolysis is pyruvic acid. Further, metabolic process depends on the availability of the oxygen for the microorganisms present in kefir. In presence of oxygen, the aerobic microbes metabolize the pyruvate through the Krebs cycle. In the Krebs cycle the pyruvate is converted into different organic acids like citric, oxalic, succinic acid, etc. However, in absence of oxygen the pyruvic acid is fermented to either alcohol or lactic acid. The organic acids produced by microbial metabolism have several functional properties. Acetic acid is a weak acid used as a preservative and a food additive. It is soluble in lipids and therefore it can diffuse through the plasma membrane of a microbial cell and affect its internal pH, causing the death of food spoiling or pathogenic microorganisms (Giannattasio et al. 2013). Citric acid is a preservative and flavoring agent generally used in food and pharmaceutical industries. This acid acts as a chelating agent for the metal ions present in the medium and inhibit microbial growth. Pyruvic acid is also applied as a flavoring agent and as a preservative agent (Nielsen et al. 2014, Theron and Lues 2011). Lactic acid is also a preservative and a pH regulating agent (Theron and Lues 2011). Propionic acid is used as a preservative and as a flavoring agent (Nielsen 2004). Hence, due to the production of the above organic metabolites during milk fermentation, the fermented milk products have long shelf life. In addition to the above metabolites, exopolysaccharides are also formed by the microorganisms found in kefir and koumiss. The microorganisms belonging to the genera of Lactobacillus and Lactococcus are the mostly exopolysaccharide producing bacterial strains in kefir (Welman and Maddox 2003, Irigoyen et al. 2005, Miguel et al. 2010). Kefir and koumiss contain complex microbial community which include bacterial strains dominated by LAB, acetic acid bacteria and yeast strains. The bacteria and yeast symbiotically exist in kefir, and the yeast strains play the major role in the development of specific aroma and flavor. Lactic acid bacteria are the prevalent bacterial strain found in the kefir grains.

410  Fermented Foods—Part II: Technological Interventions The yeast cells do not grow efficiently when the bacteria are separated from the kefir grain (Leite et al. 2013). Since some strains of yeasts such as Saccharomyces cerevisiae, Saccharomyces turicensis, Torulaspora delbrueckii, Kazachstania unispora, etc. found in kefir are unable to metabolize lactose (Leite et al. 2013). This inability makes them dependent on the lactic acid bacteria, which are capable of metabolizing the milk sugar lactose. Kefir is usually made from partially skimmed cow’s milk. The final product contains live bacteria and yeasts that produce carbon dioxide gas. This gas production gives kefir a “sparkling” sensation on the tongue when consumed. Kefir has been referred to as the champagne of fermented dairy products. Koumiss is a milk drink with a sharp alcohol and acidic taste (Salimei and Fantuz 2012). The lactic acid content of koumiss varies from 0.7 to 1.8% and the ethanol content varies between 0.6 to 2.5%. Koumiss is categorized into mild, medium and strong depending upon the degree of lactic acid and ethanol content. Due to higher alcoholic content the koumiss is referred as milk wine.

6. Health Beneficial Properties of Kefir and Koumiss Kefir and koumiss are microbial fermented milk products. The fermentation process induces changes in the nutritional value, flavor, aroma and color, etc. of the milk. The intake of kefir and koumiss promote wide range of health benefits. Primarily, they are rich probiotic food for human consumption. In addition to their probiotic nature they possess a wide range of health benefits such as anti-bacterial and anti-fungal properties, regulate immunity, maintain healthy gastrointestinal system, regulate cholesterol and sugar levels, regulate blood pressure, help to get rid over the lactose intolerance, induce production of some essential vitamins, etc. (Bakir et al. 2015, Apostolidis et al. 2007). Recent studies that have focused on the importance of probiotic food materials have enumerated the following points to describe the health benefits achieved from kefir and koumiss consumption. 6.1 Kefir and Koumiss as potential source of probiotics According to The Food and Agriculture Organization of the United Nations/ World Health Organization (FAO/WHO 2001), the term probiotics can be defined as “live microorganisms administered in an adequate quantity that continue to exist in the intestinal environment, to perform a health positive effect on the host” (Reid et al. 2003). The kefir and koumiss are excellent source of probiotic microorganisms. The microbes present in the kefir and koumiss live symbiotically, yet the microbial population composition in them may differ due to the origins,

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methods and substrates used for preparation of these products. However, there are common species of microorganisms such as bacterial strains of Lactobacillus acidophilus, Lb. brevis, Lb. casei, Lb. fermentum, Bifidobacterium bifidum, B. adolescentis, Streptococcus lactis, Str. alivarius, Str. thermophilus, Bacillus, Enterococcus and yeast and mold strains of Saccharomyces cerevisiae, S. bourlardii, Aspergillus niger, A. oryzae, Candida pintolopesii, etc. Most of the probiotic bacterial strains colonize in the digestive tract of our body. The widely known probiotic microorganisms belong to bacterial strains of Lactobacillus and Bifidobacterium, however, bacterial strains belonging to Pediococcus, Lactococcus, Bacillus and several strains of yeasts are also reported for their probiotic nature (Soccol et al. 2010, Blaiotta et al. 2013). The bacterial strains of Lactobacillus, i.e., LAB strains are dominant microorganisms distributed throughout the gastrointestinal and genital tracts of man and higher animals. They are non-pathogenic and produce lactic acid by their metabolism; as a result they lower the pH of the gastric and genital tract of human body. This class of microorganisms also produce hydrogen peroxide, ethanol and/or acetic acid, thus inhibiting the proliferation of unwanted pathogenic microorganisms in the gastric and genital tract of the body. That is why these microorganisms are called natural living protectors of the human body. 6.2 Kefir and Koumiss has potent antimicrobial properties The nutritional and organoleptic properties of the probiotic milk kefir and koumiss offer the potential to combat against pathogenic microbial infections (Franco et al. 2013, Carasi et al. 2014, Silva et al. 2009). Recent scientific studies have confirmed the antimicrobial properties of traditional kefir and koumiss. In a study, Chifiriuc et al. (2011) evaluated the antimicrobial properties of kefir by in vitro analysis. The authors investigated the antimicrobial activity of kefir against the bacterial strains of the Bacillus subtilis, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Salmonella enteritidis, Pseudomonas aeruginosa and Candida albicans. They compared the antimicrobial properties of the kefir fermented for 24 hr and 48 hr, as well as 7 day old preserved kefir by in vitro disk diffusion method. The authors compared the antimicrobial activities of the kefir with those of the antibiotics ampicillin and neomycin and observed higher antimicrobial potential of kefirs against the bacterial strains used for the study. The authors claim that the kefir has higher antibacterial properties when compared to control antibiotics (ampicillin and neomycin) taken for the study. A recent study of the antimicrobial properties of the koumiss was conducted by Chen et al. (2015). The authors used koumiss from Inner Mongolia, China and evaluated the anti-bacterial properties of the mycotoxin secreted by the yeast cell of koumiss by in vitro and in vivo

412  Fermented Foods—Part II: Technological Interventions analysis. Through genomic analysis, the authors identified three strains of S. cerevisiae, and two strains of Kluyveromyces marxianus producing mycocin in the traditional Koumiss from Inner Mongolia. The in vitro and in vivo study on mice confirmed the anti-bacterial properties of the mycotoxin isolated from the yeast cells of koumiss against the pathogenic E. coli bacteria. Hence, the study shows that the traditional fermented milk beverages have potential antimicrobial properties. 6.3 Kefir and koumiss as a substitute for lactose intolerant people Lactose is a naturally occurring sugar in milk. Most of the adult populations of the world are unable to digest the lactose content of the milk properly. Such condition of lactose indigestion is called lactose intolerance. The LAB present in kefir and koumiss ferment lactose to lactic acid, and as a result these dairy foods are much lower in lactose content than raw milk. Hence, in general kefir and koumiss are well tolerated by the people with lactose intolerance in comparison to regular raw milk products (Fox et al. 2015, Zubillaga et al. 2001). 6.4 Kefir and koumiss stimulate expression of growth factors In the recent in vivo study conducted on mice model by Bakir et al. (2014) it was revealed that the probiotic dairy products positively affect the release of growth factors and stimulates the increase in body weight of mice. The authors conducted immune-histochemical studies on the liver and kidney cells on the mice nourished with kefir and koumiss and observed the expression of the platelet derived growth factor-c (PDGF-C) and platelet derived growth factor receptor-alpha (PDGFR-α). The authors found that PDGF-C and PDGFR-α were expressed more in the kidney cells and hepatic cells and stimulated increase in live weights of the mice models used for the study. The platelet derived growth factor receptor-alpha (PDGFR-α) is a member of the PDGF receptor and they play a vital role for activation of platelet derived growth factor (Andrae et al. 2008). The platelet derived growth factors (PDGF) are a class of growth factors that influence growth and development of body. From the above report it may be concluded that the probiotic dairy products kefir and koumiss act as growth and development promoters. 6.5 Kefir may be protective against cancer Cancer is one of the world’s leading causes of death. It occurs when there is an uncontrolled growth of abnormal cells in the body such as a tumor. The probiotics in fermented dairy products are believed to inhibit tumor

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growth by reducing formation of carcinogenic compounds, as well as by stimulating the immune system (Leite et al. 2013). 6.6 Trends in transformation of traditional Kefir and Koumiss to commercialization According to a market survey conducted by Transparency Market Research, the global sale of probiotic products is $15.9 billion in 2019 as compared to $11.6 billion in 2012. Although kefir is not known in all corners of the world, still it has a stake among the probiotic products. A company named Lifeway Foods, Inc, recently named one of Fortune Small Business Fastest Growing Companies, is known to sell of $100 million annually. In 2013 the company introduced the products to the UK and subsequently to Canada. The products are available in different flavors such as vanilla, raspberry, strawberry and mango flavors. Some of the kefir products of Lifeway Foods have been displayed in Fig. 4. More than 1000 leading stores such as Kroger, Wegmans and Whole Foods are known to sell kefir in the US. However the

Figure 4. Kefir with different flavours marketed by Lifeway industries. (source: http://lifewaykefir.com/).

414  Fermented Foods—Part II: Technological Interventions commercialization of koumiss is not clearly documented. Unlike kefir the commercialization of koumiss is difficult as the substrate for the koumiss, i.e., mare’s milk is rarely available.

7. Conclusion Fermented dairy products such as kefir and koumiss have numerous functional properties. It is a convenient and traditional process of food preservation.  Fermentation lowers down the pH of milk and inhibits the growth of food spoilage microorganisms. The microbial metabolites like different organic acids, exopolysaccharides produced during kefir and koumiss production enhances their flavor, aroma and texture, which are attractive for the consumer. This chapter has described the history, microbiology and biochemistry of kefir and koumiss. The current market status of the two products has been mentioned. Popularization of kefir and koumiss can be expedited through deliberation and discussion of the health beneficial properties of the products in different forums such as social media, internet, etc. Future research should be directed to upscale and for the commercialization of kefir and koumiss, keeping in view the health beneficial properties and unique organoleptic properties of the products. Keywords: Kefir, koumiss, milk, fermentation, probiotics

References Amara, A.A. and Shibl, A. (2015). Role of Probiotics in health improvement, infection control and disease treatment and management. Saudi Pharmaceutical Journal 23: 107–114. Andrae, J., Gallini, R. and Betsholtz, C. (2008). Role of platelet-derived growth factors in physiology and medicine. Genes & Development 22: 1276–1312. Apostolidis, E., Kwon, Y.I., Ghaedian, R. and Shetty, K. (2007). Fermentation of milk and soymilk by Lactobacillus bulgaricus and Lactobacillus acidophilus enhances functionality for potential dietary management of hyperglycemia and hypertension. Food Biotechnology 21: 217–236. Assadi, M.M., Pourahmad, R. and Moazami, N. (2000). Use of isolated kefir starter cultures in kefir production. World Journal of Microbiology & Biotechnology 16: 541–543. Bakir, B., Sari, E.K., Aydin, B.D. and Yil, S.E. (2015). Immunohistochemical examination of effects of kefir, koumiss and commercial probiotic capsules on platelet derived growth factor-c and platelet derived growth factor receptor-alpha expression in mouse liver and kidney. Biotechnic & Histochemistry 90: 190–196. Bellamy, I. and MacLean, D. (2005). Radiant Healing: The many paths to personal harmony and planetary wholeness: Joshua Books, Queensland, Australia, pp. 272. Blaiotta, G., Gatta, B.L., Capua, M.D., Luccia, A.D., Coppola, R. and Aponte, M. (2013). Effect of chestnut extract and chestnut fiber on viability of potential probiotic Lactobacillus strains under gastrointestinal tract conditions. Food Microbiology 36: 161–169. Bornaz, S., Guizani, N., Sammari, J., Allouch, W., Sahli, A. and Attia, H. (2010). Physicochemical properties of fermented Arabian mares’ milk. International Dairy Journal 20: 500–505. Cagno, R.D., Tamborrino, A., Gallo, G., Leone, C., Angelis, M.D., Faccia, M., Amirante, P. and Gobbetti, M. (2004). Uses of mares’ milk in manufacture of fermented milks. International Dairy Journal 14: 767–775.

Kefir and Koumiss: Origin, Health Benefits and Current Status of Knowledge 415 Carasi, P., Diaz, M., Racedo, S.M., Antoni, G.D., Urdaci, M.C. and Serradell, M.A. (2014). Safety characterization and antimicrobial properties of kefir-isolated Lactobacillus kefiri. BioMed Research International 2014: 1–7. Carminati, D., Giraffa, G., Quiberoni, A., Binetti, A., Suarez, V. and Reinheimer, J. (2010). Advances and trends in starter cultures for dairy fermentations. In: F. Mozzi, R.R. Raya and G.M. Vignolo (eds.). Biotechnology of Lactic Acid Bacteria: Novel Applications, Wiley-Black well, USA. Chang, J., Ho, C., Mao, C., Barham, N., Huang, Y., Ho, F., Wu, Y., Hou, Y., Shih, M., Li, W. and Huang, C. (2014). A thermo-and toxin-tolerant kefir yeast for biorefinery and biofuel production. Applied Energy 132: 465–474. Chen, Y., Aorigele, C., Wang, C., Simujide, H. and Yang, S. (2015). Screening and extracting mycocin secreted by yeast isolated from koumiss and their antibacterial effect. Journal of Food and Nutrition Research 3: 52–56. Chen, H., Wang, S. and Chen, M. (2008). Microbiological study of lactic acid bacteria in kefir grains by culture-dependent and culture-independent methods. Food Microbiology 25: 492–501. Chifiriuc, M.C., Cioaca, A.B. and Lazar, V. (2011). In vitro assay of the antimicrobial activity of kephir against bacterial and fungal strains. Anaerobe 17: 433–435. Cui, X., Chen, S., Wang, Y. and Han, J. (2013). Fermentation conditions of walnut milk beverage inoculated with kefir grains. LWT - Food Science and Technology 50: 349–352. Danova, S., Petrov, K., Pavlov, P. and Petrova, P. (2005). Isolation and characterization of Lactobacillus strains involved in koumiss fermentation. International Journal of Dairy Technology 58: 100–105. Dhewa, T., Mishra, V., Kumar, N. and Sangu, K.P.S. (2015). Koumiss nutritional and therapeutic values. In: A.K. Puniya (ed.). Fermented Milk and Dairy Products. CRC Press, Boca Raton. El-Ghaish, S., Ahmadova, A., Hadji-Sfaxi, I., Mecherfi, K.E.E., Bazukyan, I., Choiset, Y., Rabesona, H., Sitohy, M., Popov, Y.G., Kuliev, A.A., Mozzi, F., Chobert, J. and Haertle, T. (2011). Potential use of lactic acid bacteria for reduction of allergenicity and for longer conservation of fermented foods. Trends in Food Science & Technology 22: 509–516. Farnworth, E.R. (2005). Kefir-a complex probiotic. Food Science and Technology Bulletin: Functional Foods 2: 1–17. Fernandez, M., Hudson, J.A., Korpela, R. and de los Reyes-Gavilan, C.G. (2015). Impact on human health of microorganisms present in fermented dairy products: an overview. BioMed research international 412714. Fox, P.F., Uniacke-Lowe, T., Mc Sweeney, P.L.H. and O’Mahony, J.A. (2015). Dairy Chemistry and Biochemistry, Springer, Heidelberg, New York. Franco, M.C., Golowczyc, M.A., de Antoni, G.L., Perez, P.F., Humen, M. and Serradell, M.D.L.A. (2013). Administration of kefir-fermented milk protects mice against Giardia intestinalis infection. Journal of Medical Microbiology 62: 1815–1822. Frengova, G.I., Simova, E.D., Beshkova, D.M. and Simov, Z.I. (2002). Exopolysaccharides produced by Lactic Acid Bacteria of kefir grains. Z. Naturforsch 57c: 805–810. Garofalo, C., Osimani, A., Milanovi, V., Aquilanti, L., Filippis, F.D., Stellato, G., Mauro, S.D., Turchetti, B., Buzzini, P., Ercolini, D. and Clementi, F. (2015). Bacteria and yeast microbiota in milk kefir grains from different Italian regions. Food Microbiology 49: 123–133. Giannattasio, S., Guaragnella, N., Zdralevic, M. and Marra, E. (2013). Molecular mechanisms of Saccharomyces cerevisiae stress adaptation and programmed cell death in response to acetic acid. Frontiers in Microbiology 4: 33–42. Guinane, C.M. and Cotter, P.D. (2013). Role of the gut microbiota in health and chronic gastrointestinal disease: understanding a hidden metabolic organ. Therapeutic Advances in Gastroenterology 6: 295–308. Guo, C., Zhang, S., Yuan, Y., Yue, T. and Li. J. (2015). Comparison of lactobacilli isolated from Chinese suan-tsai and koumiss for their probiotic and functional properties. Journal of Functional Foods 12: 294–302.

416  Fermented Foods—Part II: Technological Interventions Guzel-Seydim, Z., Koktas, T. and Greene, A.K. (2009). Kefir and Koumiss: microbiology and technology. Development and manufacture of yogurt and other functional dairy products. Fatih Yildiz (ed.). CRC Press, Boca Raton. Hasan, M.N., Sultan, M.Z. and Mar-E-Um, M. (2014). Significance of fermented food in nutrition and food science. Journal of Scientific Research 6: 373–386. Irigoyen, A., Arana, I., Castiella, M., Torre, P. and Ibanez, F.C. (2005). Microbiological, physicochemical, and sensory characteristics of kefir during storage. Food Chemistry 90: 613–620. Kosikowski, F. (1982). Cheese and Fermented Milk Foods, F. V. Koskiowski and Associates, New York, U.S.A. Kozhahmetova, Z. and Kasenova, G. (2013). Selection of lactic acid bacteria and yeast for koumiss starter and its impact on quality of koumiss. ATI—Applied Technologies & Innovations 9: 138–142. Kucukcetin, A., Yaygin, H., Hinrichs, J. and Kulozik, U. (2003). Adaptation of bovine milk towards mares’ milk composition by means of membrane technology for koumiss manufacture. International Dairy Journal 13: 945–951. La Riviere, J.W., Kooiman, P. and Schmidt, K. (1967). Kefiran, a novel polysaccharide produced in the kefir grain by Lactobacillus brevis. Archives of Microbiology 59: 269–278. Leite, A.M.O., Miguel, M.A.L., Peixoto, R.S., Rosado, A.S., Silva, J.T. and Paschoalin, V. M. F. (2013). Microbiological, technological and therapeutic properties of kefir: a natural probiotic beverage. Brazilian Journal of Microbiology 44: 341–349. Li, L., Wieme, A., Spitaels, F., Balzarini, T., Nunes, O.C., Manaia, C.M., Landschoot, A.V., Vuyst, L.D., Cleenwerck, I. and Vandamme, P. (2014). Acetobacter sicerae sp. nov., isolated from cider and kefir, and identification of species of the genus Acetobacter by dnaK, groEL and rpoB sequence analysis. International Journal of Systematic and Evolutionary Microbiology 64: 2407–2415. Liu, S., Holland, R. and Crow, V.L. (2004). Esters and their biosynthesis in fermented dairy products: a review. International Dairy Journal 14: 923–945. Lopitz-Otsoa, F., Rementeria, A., Elguezabal, N. and Garaizar, J. (2006). Kefir: A symbiotic yeast-bacteria community with alleged healthy capabilities. Revista Iberoamericana DeMicologia 23: 67–74. Marshall, V.M.R.E. (1984). The microflora and production of fermented milks. In: M.R. Adams (ed.). Progress in Industrial Microbiology. Vol. 23. Microorganisms in the production of food. Elsevier, Amsterdam. Miguel, M.G.C.P., Cardoso, P.G., Lago, L.A. and Schwan, R.F. (2010). Diversity of bacteria present in milk kefir grains using culture-dependent and culture-independent methods. Food Research International 43: 1523–1528. Miyamoto, M., Ueno, H.M., Watanabe, M., Tatsuma, Y., Seto, Y., Miyamoto, T. and Nakajima, H. (2015). Distinctive proteolytic activity of cell envelope proteinase of Lactobacillus helveticus isolated from airag, a traditional Mongolian fermented mare’s milk. International Journal of Food Microbiology 197: 65–71. Montanari, G., Zambonelli, C., Grazia, L., Kamesheva, G.K. and Shigaeva, M.K. (1996). Saccharomyces unisporaas the principle alcoholic fermentation microorganism of traditional koumiss. Journal of Dairy Research 63: 327–331. Nielsen, B., Gurakan, G.C. and Unlu, G. (2014). Kefir: A Multifaceted Fermented Dairy Product. Probiotics & Antimicrobial Protection 6: 123–135. Otles, S. and Cagindi, O. (2003). Kefir: A Probiotic Dairy-Composition, Nutritional and Therapeutic Aspects. Pakistan Journal of Nutrition 2: 54–59. Panda, S.K., Behera, S.K., Sahu, U.C., Ray, R.C., Kayitesi, E. and Mulaba-Bafubiandi, A.F. (2016). Bioprocessing of jackfruit (Artocarpus heterophyllus L.) pulp into wine: Technology, proximate composition and sensory evaluation. African Journal of Science, Technology, Innovation and Development 8: 27–32. Panda, S.K., Sahu, U.C., Behera, S.K. and Ray, R.C. (2014b). Bio-processing of bael (Aegle marmelos L.) fruits into wine with antioxidants. Food Bioscience 5: 34–41.

Kefir and Koumiss: Origin, Health Benefits and Current Status of Knowledge 417 Panda, S.K., Sahu, U.C., Behera, S.K. and Ray, R.C. (2014a). Fermentation of sapota (Achras sapota linn.) fruits to functional wine. Nutrafoods 13: 179–186. Panda, S.K., Swain, M.R., Singh, S. and Ray, R.C. (2013). Proximate compositions of a herbal purple sweet potato (Ipomoea batatas L.) wine. Journal of Food Processing and Preservation 37: 596–604. Parveen, S. and Hafiz, F. (2003). Fermented cereal from indigenous raw materials. Pakistan Journal of Nutrition 2: 289–291. Rea, M.C., Lennartsson, T., Dillon, P., Drina, F.D., Reville, W.J., Heapes, M. and Cogan, T.M. (1996). Irish kefir-like grains: their structure, microbial composition and fermentation kinetics. J. Appl. Microbiol. 81: 83–94. Reid, G., Sanders, M.E., Gaskins, H.R., Gibson, G.R., Mercenier, A., Rastall, R., Roberfroid, M., Rowland, I., Cherbut, C. and Klaenhammer, T.R. (2003). New scientific paradigms for probiotics and prebiotics. Journal of Clinical Gastroenterology 37: 105–118. Salimei, E. and Fantuz, F. (2012). Equid milk for human consumption. International Dairy Journal 24: 130–142. Silva, K.R., Rodrigues, S.A., Filho, L.X. and Lima, A.S. (2009). Antimicrobial activity of broth fermented with kefir grains. Appl. Biochem. Biotechnol. 152: 316–325. Simova, E., Beshkova, D., Angelov, A., Hristozova, T., Frengova, G. and Spasov, Z. (2002). Lactic acid bacteria and yeasts in kefir grains and kefir made from them. Journal of Industrial Microbiology & Biotechnology 28: 1–6. Soccol, C.R., Vandenberghe, L.P.S., Spier, M.R., Medeiros, A.B.P., Yamaguishi, C.T., Lindner, J.D.D., Pandey, A. and Thomaz-Soccol, V. (2010). The potential of probiotics: A review. Food Technology and Biotechnology 48: 413–434. Soupioni, M., Golfinopoulos, A., Kanellaki, M. and Koutinas, A.A. (2013). Study of whey fermentation by kefir immobilized on low cost supports using 14C-labelled lactose. Bioresource Technology 145: 326–330. Theron, M.M. and Lues, J.F. R. (2011). Organic acids and food preservation, 1st edition, chapter 1 and 2, CRC Press, Taylor & Francis Group, Boca Raton. Uniacke-Lowe, T., Huppertz, T. and Fox, P.F. (2010). Equine milk proteins: chemistry, structure and nutritional significance. International Dairy Journal 20: 609–629. Wang, J., Zhao, X., Tian, Z., Yang, Y. and Yang, Z. (2015). Characterization of an exopolysaccharide produced by Lactobacillus plantarum YW11 isolated from Tibet Kefir. Carbohydrate Polymers 125: 16–25. Wang, S., Chen, K., Lo, Y., Chiang, M., Chen, H., Liu, J. and Chen, M. (2012). Investigation of microorganisms involved in biosynthesis of the kefir grain. Food Microbiology 32: 274–285. Welman, A.D. and Maddox, I.S. (2003). Exopolysaccharides from lactic acid bacteria: perspectives and challenges. Trends in Biotechnology 21: 269–274. Witthuhn, R.C., Schoeman, T. and Britz, T.J. (2005). Characterisation of the microbial population at different stages of kefir production and kefir grain mass cultivation. International Dairy Journal 15: 383–389. Wouters, J.T.M., Ayad, E.H.E., Hugenholtz, J. and Smit, G. (2002). Microbes from raw milk for fermented dairy products. International Dairy Journal 12: 91–109. Zhang, W. and Zhang, H. (2012). Fermentation and koumiss. In: Y.H. Hui (ed.). Handbook of Animal-Based Fermented Food and Beverage Technology, Second Edition, CRC press, Boca Raton. Zubillaga, M., Weill, R., Postaire, E., Goldman, C., Caro, R. and Boccio, J. (2001). Effect of probiotics and functional foods and their use in different diseases. Nutrition Research 21: 569–579.