2Chemical, Master and PhD Student in Chemistry. Department of Chemistry, Federal University of Lavras (UFLA), Campus Universitário, 37.200-000, Lavras, MG, Brazil
3Agronomist, PhD in Microbiology. Department of Biology, Federal University of Lavras (UFLA), Campus Universitário, 37.200-000, Lavras, MG, Brazil
Keywords: Nutrition; Probiotic; Beverage
The microorganisms present in kefir carried out three types of fermentation during the fermentation process: lactic, alcoholic and acetic. [12,13,14]. The kefir beverages contains vitamins, minerals and essential amino acids that help the body with healing and maintenance functions [5,13,14,15,16,20,21].
The objective of this review is to report chemical and therapeutic characteristics of kefir.
In our studies, we find the microbiota of the Brazilian kefir (for isolation and PCR-DGGE methods) composed of yeast and bacteria’s. Lactic acid bacteria were the major isolated group identified, followed by yeasts and acetic acid bacteria’s such as Lactobacillus kefir, Lactobacillus lactis, Lactobacillus sp., Lactococcus sp., Leuconostoc sp., Acetobacter acetic, Acetobacter lovaniensis, Acetobacter sp.,, Saccharomyces cerevisiae , Kluyveromyces marxianus, Pichia sp., Candida sp., Kazachstania aerobia and Lachancea meyersii [13,14,15,16].
The microorganisms present in kefir carried out three types of fermentation during the fermentation process: lactic, alcoholic and acetic [12,13,14]. The compounds formed are divided in two groups: major and minor end-products (secondary metabolites).
O lactic acid, acetaldehyde, diacetyl, acetoin, acetone are originates from fermentation of homofermentative and heterofermentative lactic acid bacteria’s present in kefir grains.
Biosynthesis of acetic acid may be from various amino acids, e.g. Streptococcus genus are able to form acetic acid from glycine, alanine and leucine . Acetate may also be formed from pyruvate by Acetobacter genus .
Studies have shown that kefir have antimicrobial activity [4,5,6,21]. These studies indicate that kefir antimicrobial activity is associated with the production of organic acids, bacteriocins, carbon dioxide, hydrogen peroxide, ethanol and diacetyl.
The nutritional/chemical composition of kefir is variable. It depends on the source fat content of milk, the microbial composition and the technological process of kefir. The nutritional/chemical composition of kefir is composed mainly of protein, mineral content (Calcium, Phosphor, Magnesium, Potassium, Sodium, Chloride), essential amino acids (tryptophan, Leucine, Lysine, Valine), vitamins (A, Carotene, B1, B2, B6, B12, C, D, E), aromatic compounds (Acetaldehyde, Diacetyl, Acetoin) and trace elements (Iron, Copper, Molybdenum, Manganese, Zinc) .
The anticarcinogenic role of kefir can be attributed to cancer prevention by activation of the immune system [6,23]. Lactic acid Bacteria’s present in kefir may involve the inhibition of the cholesterol absorption in the small intestine . Lactic acid Bacteria’s also have the ability to decrease lactose concentrations by presence of β-galactosidase activity in fermented process, make them suitable for consumption by people classified as lactose intolerant [7,23]. Kefir has also been shown effective against hypertension .
The polysaccharide matrix, called kefiran Figure 2, is produced by lactic acid bacteria and usually associated to the therapeutic properties of kefir . Kefiran has frequently been claimed to be effective against a variety of diseases, antitumor activity, antibacterial and antifungal activities . kefiran was modulate key steps in the virulence of Bacillus cereus in intestinal infections .
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