Study On The Rhelolgecal Properties And Compatibility Of Low-Concentration Carrageenan

The rheological properties of low-concentration carrageenan with different concentration, shearing rate, temperature, constant temperature heating time, freezing-thawing time, stirring time, standing time, pH, electrolytes or non-salt material which would affect the viscosity and gel strength of gum solution were studied in this paper, and the compound of carrageenan with konjac gum, gelatine, agar were studied also. The result showed:The viscosity of low-concentration (0.05%～0.5%) carrageenan was increased with concentration.It became pseudo-plas ticity fluid and its viscosity was gradually reduced with temperature and constant temperature heating time. The viscosity of 0.1% concentration carrageenan was increased with stirring time under stated stirring velocity first, but it was reduced fast when the stirring time over 90min.With the standing time increased, the viscosity of low-concentration carrageenan was reduced and stabilized after 3 days. The viscosity of 0.1% concentration carrageenan was increased with refrigeration but decreased with freezing time. The 0.5% concentration carrageenan formed gel after refrigerated 12 hours and its viscosity was fluctuated with freezing time. With the 11% concentration salt acceded to,the viscosity of carrageenan was increased and stabilized after 3 days.With 0.1% concentration electrolyte joined, the viscosity of solution was reduced. When the concentration of electrolyte reached 0.5%, potassic salt induced carrageenan formed gel but natrium salt couldn't. Opposite to sucrose, ethanol made the viscosity of 0.1% concentration carrageenan increased. Citric acid and soluble amylum had no effect to viscosity of low-concentration carrageenan. At low concentration, the viscosity of carrageenan solution was distinctly increased when its pH value was below 5.0. The viscosity of low-concentration gum solution was constant when its pH value was in range of 5.0～9.0 and its viscosity was gradually reduced when its pH value was over 9.0.The gel strength of low-concentration (0.5%～1.0%) carrageenan was increased with concentration under 0.8%, and then it reduced rapidly. The gel strength was increased with standing time and refrigeration, with freezing time went on, it was gradually reduced. The gel strength of carrageenan was influenced with stirring action, and it was decreased sharply with temperature below 65℃. After constant temperature heating 30 minutes at 75℃, the gel strength was distinctly reduced, and then stabilized in short order. When the 11% concentration salt was added in the gel, its strength was reduced shaply and stabilized after 2 days. The potassic salt could increase the gel strength of low-concentration carrageenan contrary to natrium salt, and the effect was improved with the content of potassic salt. The gel strength was reduced with pH when its value was under 5.5, and it was constant when pH value in range of 5.5-9.5. Then, the gel strength was evident reduced till pH value to 11.0, and it was increased sharply later. Four kinds of non-salt materials all made the gel strength of low-concentration carrageenan decrease badly, and the effect was foreign to its concentration.There was distinct synergistic interaction between carrageenan (CAR) and konjac gum (KM). The viscosity of mixed solution of 0.1% concentration CAR and 0.2% concentration KM reached to maximum when the proportion of CAR/KM was 7:3. The mixed solution had better heat-resistant and freeze-resistant capability than single gum solution. Compounded with the gel of CAR and KM according to stated proportion, the mixed gel strength was greatly higher than CAR. With the mixed gum density 1%, the best proportion of CAR/KM was 5:5. There was synergistic interaction between CAR and gelatine (Gel) also. The best proportion of 0.1% concentration CAR and 0.1% concentration Gel was CAR/Gel 5:5. The viscosity of mixed solution was influenced by temperature and freezing-thawing time, but not affected by stirring action. The 0.1% concentration CAR solution and the 0.1% concentration agar (AG) solution had synergistic interaction when the proportion was 7:3. There wasn't synergistic interaction between 0.1% concentration CAR gel and 0.1% concentration AG.