摘要：Background: Hyaluronic acid (HA) is a natural carbohydrate that promotes proper joint function and tissue repair. Hyaluronic acid is an essential nutrient that effectively strengthens eyes, skin, collagen and immunity. So, elder people needs extra help and supplement with hyaluronic for maintaining collagen production, promoting skin elastin, hydrating damaged or chapped skin and reversing signs of aging. It is better to provide them their needs from natural and efficient ingredients or supporting some common foods with hyaluronic acid. Materials and Methods: To reialize the objectives of the present study the molecular characterization of HA produced bacteria was performed, followed by isolation and purification of HA and then the x-ray diffraction, scaning electronic microscope, HPLC analysis and antioxidant capacity were performed. Results: The molecular data emphasized that the ability of Streptococcus thermophilus BLM 58 to produce hyaluronic acid more than Streptococcus thermophilus TH-4. The FT-IR and x-ray diffraction confirmed the identity of purified HA with the profile obtained by standard which confirmed the non-crystalline structure of HA and its appearance as semi-hydrated fibers. Scanning electronic microscope indicated that the HA consists of many layers of cylindrical fibers with blined ended. Moreover, considerable antioxidant activity (IC50 = 493.58±0.48 μg mL1) with no cytoxicity of HA were observed. The hyaluronic acid-fortified yogurt showed a good overall acceptabilty without any adverse effect on the rheological properties. Conclusion: Hyaluronic acid can be safely used as a food supplement to support the nutritive value of food products (as a yogurt) without any negative effect on the rheological and organoleptic properties.
