Rheological and Thermal Behavior of Mixed Gelatin/Konjac Glucomannan Gels

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Abstract
Mixed konjac glucomannan/gelatin gels were mechanically characterized in the linear and large deformation regimes. Differential scanning calorimetry revealed no effect of konjac addition on gelling and melting of gelatin. The elastic moduli increased with increasing konjac content, but fracture stress slightly decreased. The rheological results and confocal laser scanning microscopy support segregative phase separation, where rigid polysaccharide domains act as bound fillers which are not separated by the solvent from the matrix and increase the Young's modulus, but the fracture stress is only weakly dependent on the concentration of the filler. The melting temperature of konjac‐modified gels remains below body temperature, indicating konjac addition does not increase danger of choking. The addition of konjac to gelatin gels with or without sucrose decreased sensory hardness and stickiness. For both types of gels, the addition of konjac made mastication and swallowing easier, making konjac/gelatin mixed gels an interesting alternative for gelatin gels.Practical Applications: Mixed polysaccharide and protein gels are gaining popularity in the food industry. This study investigated the rheological consequences of konjac glucomannan addition to gelatin. The mixed gels had lower sensory hardness compared with pure gelatin gels, which led to lower perceived difficulty of mastication and swallowing. The mixed gels also retained their melt‐in‐mouth properties, as konjac did not affect the thermal properties.
Funding Information
  • Agriculture Forestry and Fisheries (22026)

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