Rheological Properties of Mixed Gels

Abstract

The rheological properties of carrageenanlgelatin and agarlgelatin mixed gels were investigated by measuring the rupture properties, the texture parameters and the dynamic viscoelasticities. f i e melting point, transparency and syneresis of these gels were measured in order to obtain the relationship with the rheologicalproperties. The physical properties of the two mixed gels were slightly dgferent. The agarlgelatin mixed gels generally showed the hindered effect of gelatin. f i e brittleness of agar gel disappeared on mixing with gelatin. It then became aflexible, cohesive and transparent gel. Carrageenanlgelatin mixed gels showed a decrease in the values of almost all of the mechanical properties when compared with carrageenan gels. However, the rupture properties of the C0.5 mixed gel were much higher than those of simple carrageenan gels.

Effect of heating temperature, pH, concentration and starch/whey protein ratio on the viscoelastic properties of corn starch/whey protein mixed gels

“…12 A synergistic effect in mixed gels can occur when either the two components are structurally compatible with each other or one component acts as an active ®ller. 12,13 On the other hand, structural incompatibilities can also occur in mixed gels, such as carrageenan/gelatin or agar/gelatin gels, which showed inhibitory gelation effects when compared to the parent gels, 14 or WPI/corn starch gels, in which disrupted corn starch granules apparently act as an inactive ®ller. 12 WP forms different network structures depending on pH: aggregated particulate networks at intermediate pH (4±6) and ®ne-stranded networks at high or low pH away from the isoelectric point.…”

Instrumental Texture Profile Analysis With Particular Reference to Gelled Systems

“…These authors employed a plunger 0.64 cm in diameter on samples 2.3 cm in diameter, so that in this case, too, puncture tests were performed. Kobayashi and Nakahama (1986) using a Rheolometer (Iio Denki Co.) evaluated several TPA parameters (hardness, cohesiveness, brittleness and adhesiveness) of two types of mixed gels consisting of carrageenadgelatin and agarlgelatin in comparison with the properties of the individual ones, but also employing a plunger with a diameter smaller than that of the sample, so that it was a puncture test, not a true compression (Table 2). They concluded that agarlgellftin gels were elastic and cohesive, and that the brittleness of agar gel disappeared on mixing with gelatin.…”

Microstructure and elastic modulus of phase-separated gelatin–starch hydrogels containing dispersed oil droplets

“…There has been a vast amount of research on hydrogels consisting of gelatin combined with polysaccharides, e.g., with agar (Clark, Richardson, Ross-Murphy, & Stubbs, 1983;Kobayashi & Nakahama, 1986), agarose (Gotlieb, et al, 1988;Sharma, George, Button, May, & Kasapis, 2011), alginate (Muchin, Streltsova, Vajnerman, & Tolstoguzov, 1978), sodium alginate (Voron'ko, Derkach, & Izmailova, 2002), methylcellulose (Nishinari et al, 1993), maltodextrin (Kasapis, Morris, Norton, & Clark, 1993a), gellan (Lau, Tang, & Paulson, 2000;Papageorgiou, Kasapis, & Richardson, 1994), ɩ-carrageenan (Michon, Cuvelier, Launay, & Parker, 1996), konjac glucomannan (Harrington & Morris, 2009b), starch (Abdulmola, Hember, Richardson, & Morris, 1996), pectin (Al-Ruqaie, Kasapis, & Abeysekera, 1997), low-methoxy pectin (Gilsenan, Richardson, & Morris, 2003), k-carrageenan (Antonov & Goncalves, 1999;Haug, Draget, & Smidsrod, 2004), locust bean gum (Alves, Antonov, & Goncalves, 2000) and dextran (Butler & Heppenstall-Butler, 2003). Such studies have highlighted the dependence of gel microstructure and rheology on the mixing behaviour of gelatin with the polysaccharide present in the system.…”