Guar gum is a hydrocolloid extracted from the seed of a leguminous
plant, Cyamopsis tetragonolobus ( Gupta, Shah, Sanyal, Variyar, & Sharma, 2009). It is a galactomannan formed of linear chains of d-mannopyranosyl units connected to each other by β (1→4) bonds, and d-galactopyranosyl units connected to each other by α (1→6) bonds ( Munhoz, Weber, & Chang, 2004). Guar is one of the most important thickeners used in food and drink industries ( Richardson, Willmer, & Foster, 1998), since it produces highly viscous solutions even at low concentrations ( Lapasin, Pricl, & Tracanelli, 1991), is cheap, and improves food stability ( Bobbio & Bobbio, 1992). It is widely used in products such as salad dressings or as a suspension agent and crystallization inhibitor in ice-creams ( Chenlo, Moreira, & Silva, 2011). selleck It is also used in applications where viscosity control, suspension and body formation, as well as modification of texture, consistency or water retention are required. The rheological behavior of guar gum solutions is pseudoplastic, showing good stability during freezing and thawing cycles. The effects of adding co-solutes such as sucrose, glucose, trehalose and sodium chloride on the steady-shear flow behavior of guar have been reported by various authors (Chenlo et al., 2011; Galmarini, Baeza, buy RAD001 Sanchez,
Zamora, & Chirife, 2011; Richardson et al., 1998). Mechanical spectra determined by small-amplitude oscillatory shear flow can also yield very useful information on the solution structure and the nature of the interactions between the biopolymer and other food constituents. FTIR spectroscopy is widely used in food industry to provide valuable information on the structure and on concentration of chemical functional groups within the material. The fundamental requirement for infrared activity, leading to absorption of infrared radiation, is that there must be a net change in dipole moment during the vibration for the molecule or the functional group under study. Considering
Amisulpride that other components present in a determined formulation can have a marked influence on the functional properties of hydrocolloids, studies on the interactions of the gums with co-solutes are of fundamental importance. Knowledge on such interactions may be useful to promote elaboration of healthy foods and which can attend the needs of individuals who have food restrictions, maintaining the sensory and technological properties of the product. Based on these considerations, the objective of this work was to study the interactions between polyols and guar gum by analyzing the rheological, also evaluating the systems after applying freezing and thawing cycles considering its potential use in ice cream or frozen desserts. Spectroscopic analyzes were performed to evaluate the structural changes of macromolecules depending on the composition of the systems.