Hot water extraction, a big number of fibers had been dispersed inside the agar option and filtered out using the agar within the approach of stress filtration. In addition, the presence of sulfate groups in the structure could possibly result in electrostatic repulsion amongst the D-Fructose-6-phosphate disodium salt custom synthesis polysaccharide chains. The decreased entanglement from the polysaccharide chain possibly resulted inside the decreased viscosity. Just after alkaline pretreatment, the degree of chain entanglement enhanced using the raise of your 3,6-AG content, as a result leading towards the greater viscosity. Moreover, the viscosity of agar answer also is determined by the molecular weight or the chain length of molecules [26]. Yarnpakdee et al. [14] found that viscosity of agar from G. tenuistipitata pretreated with NaOH at all concentrations employed was higher than those pretreated with KOH mainly because the polysaccharide chain might be additional degraded by KOH. Meanwhile, agar extracted from G. tenuistipitata with high alkaline concentration (7 NaOH, w/v) showed a decreased viscosity. Similarly, Praiboon et al. [11] reported that the lower in viscosity of agar pretreated with 5 NaOH was as a result of hydrolysis in the polysaccharide chain by alkaline. In general, the viscosity could reflect the purity or high quality in the product. In production, the viscosity of agar could also be adjusted by diverse pretreatment solutions according to the actual requirements. Dissolving, gelling, and melting temperatures of agars with distinct treatment options are presented in Table 1. The native agar from G. tenuistipitata showed decrease DNQX disodium salt Neuronal Signaling gelling and melting temperatures of 30.four C and 82.8 C, respectively. It was discovered that native agars from G. corticata from collected from Kenya, G. tenuistipitata collected from the Philippines, and G. blodgettii and G. crassissima collected from the Yucatan Peninsula showed diverse gelling and melting temperatures, and their gelling and melting temperatures are inside the variety of 425 C and 868 C, respectively [279]. The gelling and melting temperatures vary depending on the area where the algae are harvested. Also, each gelling and melting temperatures are affected by distinct extraction processes. For agar with alkaline pretreatment through alkali extraction (7 NaOH, w/v) and enzyme-assisted extraction (three NaOH, w/v), those with NaOH pretreatment formed gel at temperature of 42.4 C and 34.8 C, respectively, plus the corresponding gels molt at 86.4 C and 84.four C. That is certainly, agar with greater gelling and melting temperatures may be extracted from G. tenuistipitata just after alkaline pretreatment. The high melting temperature is attributed to the high energy necessary to cleave the network, indicating that the alkali pretreated agar gels were more steady than native agar. The higher melting temperature is ascribed towards the higher power needed to break down the network, indicating that the agar gel with alkaline pretreatment have been a lot more steady than native agar [30]. Villanueva et al. [30] reported that the gelling and melting temperatures of native agar from G. vermiculophylla were the 21.66.4 C and 62.70.0 C, respectively; however, both gelling and melting temperatures rose to 31.05.eight C and 73.60.4 C, respectively, when G. vermiculophylla was treated with 4 NaOH. Moreover, the substitution degree of methoxy group on the agar polysaccharide chain was also certainly one of significant variables affecting the gelling temperature. The quantity and location of sulfate groups were also believed to inhibit or delay the gelation mecha.
