title: Characterization of a novel galactan produced by Weissella confusa KR780676 from an acidic fermented food.
abstract: An exopolysaccharide (EPS) producing strain PUFSTM055 isolated from Idli batter (an Indian traditional cereal-legume based fermented food) was identified as Weissella confusa KR780676. The strain was shown to produce 17.2g/L (dry weight) of EPS in 2% sucrose supplemented MRS broth and the EPS was characterized. HPTLC analysis confirmed the presence of galactose monomers, indicating the homopolysaccharide nature of EPS. Fourier-transform infrared spectroscopy and nuclear magnetic resonance analysis revealed that the EPS was found to be a novel linear galactan containing α-(1→6)-linked galactose units. Scanning electron microscopy of the EPS revealed the presence of porous and spongy starch-like granules. Topographical examination of EPS by atomic force microscopy revealed that the EPS formed densely packed mesh-like structure with irregular spherical lumps. The EPS also showed high thermal stability with a degradation temperature of 287.5 °C and melting point at 274.65 °C. EPS was semi-crystalline with crystallinity index of 0.23 and showed 100% water solubility index. These characteristics of the EPS would make it a promising hydrocolloid for food industries as bio-thickeners, stabilizers and also as an encapsulating material for delivery of food bioactive compounds. This is the first study reporting the galactan compose of the EPS from lactic acid bacteria.
authors.affiliation: Department of Food Science and Technology, Pondicherry University, Pondicherry 605014, India.
authors.forename: Digambar
authors.initials: D
authors.lastname: Kavitake
authors.affiliation: Department of Food Science and Technology, Pondicherry University, Pondicherry 605014, India.
authors.forename: Palanisamy Bruntha
authors.initials: PB
authors.lastname: Devi
authors.affiliation: Department of Food Science and Technology, Pondicherry University, Pondicherry 605014, India.
authors.forename: Sanjay Pratap
authors.initials: SP
authors.lastname: Singh
authors.affiliation: Department of Food Science and Technology, Pondicherry University, Pondicherry 605014, India. Electronic address: pkshalady@yahoo.co.uk.
authors.forename: Prathapkumar Halady
authors.initials: PH
authors.lastname: Shetty
mesh_terms: D005285:Fermentation; D005516:Food Microbiology; D005685:Galactans / Q000096:biosynthesis* / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D012995:Solubility; D013696:Temperature; D014867:Water / Q000737:chemistry; D058836:Weissella / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D005685:Galactans; D014867:Water
keywords: Exopolysaccharides; Galactan; Idli batter; Weissella confusa