Gelling properties of kefiran, a food grade polysaccharide obtained from kefir grains

PIERMARIA, JUDITH; DE LA CANAL, M; ABRAHAM, ANALIA G

FOOD HYDROCOLLOIDS

Lugar: doi: 10.1016/j.foodhyd.2007.10; Año: 2008 vol. 22 p. 1520 - 1527

0268-005X

Food industry is always searching for new food components to improve texture and mouthfeel of food; besides, a health promoting capacity is also required. Polysaccharide of kefir, named kefiran, is a water-soluble glucogalactan which has been reported to have antibacterial and antitumour activity, modulates gut immune system and protects epithelial cells against Bacillus cereus exocelullar factors. Taking into account that the extraction method of kefiran from grains was simple, and that deproteinised whey could be utilised as substrate for kefir grain biomass production, further application could be considered for this biopolymer. The aim of the present work was to evaluate some of the physicochemical properties of kefiran solution such as intrinsic viscosity, flow behaviour and the ability of kefiran to perform cryogels. Besides, rheological properties of gels were also determined. Kefiran has a newtonian behaviour in diluted solutions which becomes pseudoplastic at higher concentrations. The mechanical spectrum of solution has behaviour of an entanglement network. After freeze- thaw treatment of the solution a transition of the rheological behaviour from a liquid-like system to a gel was observed. The increment in storage modulus (G´) in cryogels was 35 times higher than the value obtained for the solution. As the polymer concentration is increased, a higher number of interactions are evident for the increment in loss modulus (G´´). The behaviour of kefiran cryogels at 37°C determines its ability to melt at mouth temperature and is an interesting alternative for the application of kefiran cryogels in food formulations