Effect of temperature and incubation time on gelatin viscosity decline
Viscosity decline is an important quality index in gelatin, which is strictly required by hard capsule manufacturers. Some customers require less than or equal to 7%, while others require less than or equal to 5%. In light industry standard QB2354-2005, it is clearly stipulated that the viscosity decrease should be less than or equal to 10% when the concentration of 6.67% glue is incubated at 37 ~C for 24 hours. Bacterial contamination in the production process is not the only cause of high viscosity decline, but it is also the main cause.
In order to determine the viscosity drop value in a short time, shorten the detection time, and grasp the decline of the viscosity, which has a certain guiding role in guiding the production and blending of gelatin. For this reason, the experiment and comparison of the viscosity drop value at 37 and 60 have been carried out, and the viscosity drop value has been measured at different time, and the influence of temperature on the viscosity has been analyzed.
1 experimental part
1.1 experimental instruments
(1) Bosch viscometer (ND-1);
(2) incubator (the temperature can be controlled at 37 1 C);
(3) Electrothermal constant temperature water bath (adjustable to 65 + 1 C);
1.2 test solution
A certain amount of commercial dry glue was weighed and 6.67% of the glue was prepared into 300 ml. The viscosity and viscosity drop value were determined.
1.3 experimental method
(1) Contrast of viscosity decline at different temperatures.
(2) Sample collection: 21 samples were randomly obtained over a period of time.
(3) Collected samples were prepared into 6.67% glue according to the method of viscosity determination in QB2354-2005. After measuring the viscosity, the samples were incubated in a incubator at 37 for 24 hours and in a incubator at 60 for 18 hours. Then the viscosities were measured and the decline values were calculated.
1.4 results and discussion
The viscosities of 21 samples were decreased after incubation in incubator at 37 for 24 h and in incubator at 60 for 18 h.
In order to investigate the relationship between the decrease of viscosity and culture time, 6.67% glue was used to culture at 37 C according to the method of viscosity determination in QB2354-2005. It was measured after 3 hours of culture and every 3 hours.
According to the contrast value and results of viscosity decrease, the viscosity decrease value of colloidal solution with agreed concentration (6.67%) is different after incubation at two different temperatures, which may be related to the entropies, enthalpies and microorganisms of the colloidal solution.
From the analysis of the results, the viscosity decline value measured at 60 C for 18 h was less than 20%, and that at 30 C for 24 h was less than 10%. If the semi-finished gelatin is cultured at 60 for 18 hours, the viscosity drop value is determined, which can shorten 6 hours in practice. This not only guides the production needs, but also meets the requirements of gelatin blending.
The decrease value of viscosity increases with time. And the rate of increase is slower. However, more experiments are needed to determine whether the decrease of viscosity will change more with the increase of time.