Evaluation of Antioxidant Activity of Non-alcoholic Water Kefir and Its Metabolic Effects on Wistar Rats

Abstract

Water Kefir is a symbiotic product made by sugar solution fermentation using a culture of bacteria and yeast held in a polysaccharide matrix called (kefir grains). It is believed to contain many bioactive substances, and it may contribute in human health improving. By optimize the fermentation conditions (Time, pH, Temperature), we tried to produce nonalcoholic kefir. Furthermore we aimed to investigate antioxidant and metabolic effects of this product. Microorganisms were isolated and identified on the basis of morphology and biochemical tests. We Also, determined the nutrients and minerals contents of this product. Antioxidant activity in vitro evaluated using five methods: DPPH, inhibition of ascorbate autoxidation, reducing power, hydroxyl radicals, and total antioxidant capacity. Diabetes was induced in adult Wistar rats by intraperitoneal injection of streptozotocin, and they were given kefir in drinking water for five weeks. Body weight, glucose and lipids levels were then measured. The parameters of oxidative stress, Malondialdehyde, catalase, protein carbonyl, hydroperoxides, vitamin C. were also examined. Three distinct microbial populations were identified in water kefir beverage including, lactic acid bacteria, Acetic acid bacteria, and yeasts.The results showed important amounts of nutrients and minerals in water kefir. Water kefir exhibited an excellent antioxidant activity. It also demonstrated significant improvement in body weight, glucose, lipids profiles, and oxidative stress biomarkers of treated rats comparing with diabetic and control ones. These results conduce to conclude that water kefir could be promisor symbiotic of beneficial microorganisms, bioactive compounds, and natural antioxidants with excellentcapability in health developingand maintenance. Water kefir can potentially be useful functional food for diabetics to control glucose lipids levels, and enhancing of defenses system against oxidative stress. Key words: Nonalcoholic Water Kefir, anti-hyperglycemic, anti-hyperlipidimic, Antioxidant activity, Symbiotic, Wistar ratsuniversity of tlemcen