Hydrated starch alone and in composition with nanosilica A-300 and quercetin (natural antioxidant) was studied in the form of powders (mechanical mixture) and gels using H-1 NMR (at 200-280 K), FTIR (293 K), TG (293-573 K), TSDC (90-265 K) and quantum chemistry methods. Influence of weakly polar (chloroform-d, CDCl3\) and polar ((CD3)(2)SO, DMSO) deuterated solvents on bound water structure in these systems was also analysed at 200-280 K. The energetic and structural boundaries between weakly (unfrozen at 250-260 < T < 273 K) and strongly (unfrozen at 200 < T < 250-260 K) bound waters become nonabrupt after the addition of these solvents to quercetin/starch/nanosilica composites because of the differences in water interaction with these substances differently affecting its freezing point depression. (C) 2009 Elsevier B.V. All rights reserved.