Effects of phenolic compounds on gelation behavior of gelatin gels

The effects of phenolic additives on the gelation behavior of gelatin gels were investigated using thermomechanical analysis (TMA) for study of gel-me lting temperature, dynamic mechanical analysis (DMA) for study of gel-stora ge modulus and gel-aging stability, viscometry for study of gelation time, and texture analyzer for study of gel strength and gel melting. Thermodynam ically, the addition of 1,3-benzenediol, 1,4-benzenediol or 1,3,5-benzenetr iol favored the gelation process of gelatin solutions (increases in T-m and aging stability) due to the introduction of extra physical crosslinks amon g gelatin chains through hydrogen bonding, while the addition of 1,2-benzen ediol had a negative effect (decreases in T-m and aging stability) possibly due to intra-hydrogen bonding of the additive molecule itself. All the phe nolic compounds had little effect on gel moduli. Kinetically, the introduct ion of 1,2-benzenediol or 1,4-benzenediol slowed the gelation process, whil e introduction of catechin, a polyphenol, accelerated the first stage of th e gelation process. (C) 2000 John Wiley & Sons, Inc.