Bloom Strength is an important physical property of gelatin. It is usually expressed in grams Bloom (g-Bloom), commonly referred to as the Bloom value.
In gelatin manufacturer production quality control, Bloom testing is used to check whether the actual test result meets the specified test method and customer specifications. It is also an important way to control consistency between batches.
This article focuses on how gelatin Bloom strength is tested, the relevant GB 6783 testing requirements, and the factors that may cause variations in Bloom test results.
Why Is Gelatin Bloom Strength Testing Needed?
Gelatin Bloom strength testing has practical value in production, quality control, and purchasing.
Quality Control
Standardized Bloom testing helps check whether test results remain stable between different production batches, helping maintain batch-to-batch consistency.
Product Development
During product development, Bloom testing is used to confirm whether the actual performance of the gelatin meets the required application specifications.
Compliance
Depending on the product and market requirements, gelatin testing may need to follow standards or test methods such as GB 6783, USP, or GME.
Customer Specifications
For gelatin suppliers, Bloom testing can be used to verify whether the test result of the delivered product meets the technical specifications agreed with the customer.
Gelatin Bloom Strength Testing and Gelatin Purchasing
Bloom strength is also an important technical factor in the pricing and purchasing of commercial gelatin.
In general, the price of commercial gelatin increases as the Bloom value increases.
The industrial gelatin, pharmaceutical gelatin, and food gelatin exported by EKING are purchased and priced based on technical specifications such as Bloom strength.
Therefore, accurate and consistent Bloom testing is not only used for internal quality control. It also helps suppliers and customers confirm that the product meets the agreed specifications and provides consistent performance in use.
History of Gelatin Bloom Strength Testing
The gelatin Bloom testing method used today can be traced back to the testing method developed by Bloom in 1925.
Although testing instruments and equipment have continued to improve over the years, the basic testing approach has remained standardized:
A gelatin solution is prepared at a concentration of 6.67% and held at 10°C for 16–18 hours before testing with a Bloom tester.
During the test, a plunger with a surface diameter of 1/2 inch (1/2") is pressed 4 mm into the gel. The force required to press the plunger into the gel is measured and expressed as g-Bloom.
Therefore, gelatin Bloom testing is not simply a matter of pressing a probe into a gel and reading a "hardness number." The test must be carried out under controlled conditions, including the sample concentration, temperature, time, probe size, and penetration depth.
EKING's Standardized Bloom Strength Testing
As early as 1987, in order to standardize gelatin product testing and improve the accuracy and repeatability of test results between buyers and sellers, EKING gelatin factory introduced advanced international Bloom testing equipment.
With standardized testing equipment and test conditions, gelatin Bloom test results can be controlled more consistently, providing a reliable basis for production quality control and customer specification checks.
How Is Gelatin Bloom Strength Tested? — China Standard GB 6783
Gelatin Bloom testing in China can be carried out according to the relevant national standards.
GB 6783 is China's national food safety standard for food additive gelatin. It covers raw material requirements, physical and chemical specifications, and related test methods.
The testing requirements include:
- Raw material requirements
- Physical and chemical specifications
- Bloom strength
- Viscosity
- Moisture
- Ash
- Heavy metals and other parameters
- Other related test methods
Therefore, when gelatin quality is controlled according to GB 6783, Bloom testing is one important part of the overall quality testing system.
Gelatin Bloom Strength Testing Video
To learn more about the actual gelatin Bloom testing process, you can watch the testing video for a closer look at the procedure.
Why Can Gelatin Bloom Test Results Vary?
In actual laboratory testing, even when the same gelatin batch is tested, differences in sample preparation, equipment condition, or test conditions can lead to different results.
Common factors include:
- Solution preparation
- Solvent and water quality
- Gelatin weighing method
- Gelatin solution concentration
- Air bubbles in the solution
- Condition of the Bloom tester probe
- Probe speed and penetration depth
- Temperature control accuracy of the water bath
- Bloom tester aging
- Gel setting temperature and time
Therefore, test conditions should be kept as consistent as possible when carrying out gelatin Bloom testing.
1. Solution Preparation
Gelatin Bloom testing starts with preparing a gelatin solution at the specified concentration.
Therefore, the amount of gelatin weighed, moisture content, and final solution concentration can all affect the test result.
The moisture content of the gelatin particles themselves is one factor that needs particular attention during actual testing.
2. Solvent: How Water Quality Affects Gelatin Bloom Testing
The water used to dissolve gelatin is generally distilled water or deionized water.
If untreated tap water is used, higher levels of components such as sodium chloride and calcium lactate may cause the measured gelatin Bloom value to be lower than the actual value.
Therefore, to reduce the effect of water quality differences on test results, standardized Bloom testing should use water that meets the testing requirements.
3. How Gelatin Weighing Can Affect Test Results
Gelatin particles contain a certain amount of moisture.
Therefore, when preparing a 6.67% gelatin solution, the actual amount of gelatin added may differ depending on the weighing and moisture correction method used.
The main methods for sampling and weighing gelatin include:
1. Weighing Based on Dry Gelatin
After removing the moisture contained in the gelatin particles, the absolute dry gelatin weight is used as the basis for preparing a 6.67% gelatin solution.
2. Commercial Gelatin Method
Without taking differences in the moisture content of gelatin particles into account, consistently weigh 8 g of commercial gelatin and then add water to a total weight of 120 g.
3. Correction Based on 12% Moisture
The calculation is adjusted based on an assumed moisture content of 12%, and water is then added to a total weight of 120 g.
Why Does Different Moisture Content Lead to Different Gelatin Weights?
Depending on the moisture content of the gelatin particles, the amount of gelatin that needs to be weighed when preparing a 6.67% gelatin solution will also be different.
For example, when preparing the same 120 g gelatin solution, if the moisture content of the gelatin particles is 10%:
| Weighing Method | Gelatin to Be Weighed |
|---|---|
| Based on the absolute dry gelatin method | 8.89 g |
| Commercial gelatin method | 8.00 g |
| 12% moisture correction method | 7.82 g |
Then add water to a total weight of 120 g.
As shown above, different calculation methods can result in a significant difference in the actual amount of gelatin weighed.
As the actual amount of gelatin weighed increases, the test result also increases.
Therefore, the weighing and calculation method used for the sample must be clearly defined during Bloom testing. Otherwise, test results from different laboratories may not be directly comparable.
4. Gelatin Solution Concentration
Gelatin solution concentration is a very important test condition in Bloom testing.
Under standard test conditions, the gelatin solution is usually prepared at a concentration of 6.67%.
If the actual concentration differs from the specified value, it can change the condition and firmness of the resulting gel, which can then affect the Bloom test result.
Therefore, accurate weighing and control of the final solution concentration are important for achieving repeatable test results.
5. Air Bubbles in the Solution
Air bubbles in the gelatin solution can also affect the test result.
If air bubbles remain inside the gel, they may create weak spots, make the gel structure uneven, and affect the force measured when the test probe is pressed into the gel.
Therefore, when preparing test samples, avoid creating large amounts of air bubbles and minimize the amount of air trapped in the gel.
6. Equipment and Instrument Factors
In addition to sample preparation, the condition of the Bloom tester and related equipment can also cause variations in test results.
1. Loose Bloom Tester Probe
If the probe of the Bloom tester becomes loose, it can interfere with the test result.
At the same time, the probe speed and penetration depth must be precisely controlled by the instrument to ensure good repeatability between tests.
2. Penetration Depth
Penetration depth also affects the test result.
The greater the penetration depth, the higher the measured result may be.
Therefore, the specified penetration depth must be strictly controlled during testing.
3. Water Bath Temperature Control Accuracy
Gel formation is affected by temperature conditions.
If the actual temperature of the water bath differs significantly from the set temperature, the gel formation process may change, which can affect the Bloom test result.
4. Bloom Tester Aging
After long-term use, aging of the Bloom tester or reduced accuracy of its measurement system may also cause variations in test results.
Therefore, Bloom testing equipment should be regularly inspected, maintained, and calibrated when necessary.
7. Gelatin Solution Setting Temperature and Time
The temperature and time used for gelatin solution to form a gel under controlled conditions can also affect the Bloom test result.
If the temperature is too high or the setting time is too short, the resulting gel may be too soft, leading to a lower test result.
Why Does Setting Time Affect Bloom Test Results?
During gelatin gel formation, gelatin chains gradually change from a disordered state into a more ordered helical structure.
This process requires a suitable temperature and enough time.
At higher temperatures, gelatin molecules move more actively. When the temperature falls below the gelatin setting point, more bonds can form between the molecules and gel formation can take place.
As time passes, the connections between the molecules and the gel structure gradually become more stable, giving the gelatin gel a certain level of strength.
Therefore, if the cooling and setting time of the gelatin solution under controlled conditions is too short, the gel structure may not have fully formed, which can lead to a lower test result.
This is why standardized gelatin Bloom testing requires strict control of temperature and time.
Key Conditions for Gelatin Bloom Strength Testing
In general, a repeatable gelatin Bloom test requires several conditions to be controlled at the same time:
| Test Factor | What Needs to Be Controlled |
|---|---|
| Gelatin concentration | Usually 6.67% |
| Test temperature | 10°C |
| Setting time | 16–18 hours |
| Test probe | 1/2" diameter plunger |
| Penetration depth | 4 mm |
| Solvent | Usually distilled water or deionized water |
| Sample weighing | Clearly define the weighing and moisture correction method used |
| Gel condition | Avoid air bubbles and abnormal gel structure |
| Testing equipment | Keep probe, displacement, and force control accurate |
| Temperature equipment | Ensure accurate temperature control of the water bath |
Any significant change in these conditions may affect the final Bloom test result.
Gelatin Bloom Strength Testing FAQ
Are the GB 6783, USP, and GME test methods the same?
The basic testing principles are similar, but different standards or test methods may have differences in sample concentration, probe size, setting conditions, and specific test parameters.
Therefore, when comparing Bloom test results from different sources, always specify the testing standard and the exact test conditions used.
Bloom values obtained using different test methods should not be directly compared without knowing the testing conditions.
Can gelatin Bloom strength be tested without a Bloom tester?
If a Texture Analyzer is equipped with a suitable probe and software, and meets the required force and distance specifications, it can also be used for gelatin gel strength testing.
However, if the test result is intended for official compliance testing, it is recommended to use a dedicated Bloom tester, or a Texture Analyzer that has been validated and meets the requirements of the relevant test method.
Conclusion: Standardized Testing Is the Basis for Consistent Gelatin Quality
Gelatin Bloom testing is not simply a matter of pressing a probe into a gel and reading a number.
From sample weighing, gelatin concentration, and water quality to the temperature and time used for gel formation, as well as the condition of the Bloom tester, penetration depth, and equipment performance, every step can affect the final test result.
Therefore, for gelatin manufacturers and buyers, clearly defining the test method, keeping test conditions consistent, and maintaining stable testing equipment are the basis for obtaining accurate and repeatable Bloom test results.
For B2B gelatin purchasing, the Bloom value provided by a supplier should also be understood and compared together with the testing standard and test conditions used.
Need Professional Gelatin for Your Production Line?
If you are sourcing industrial gelatin, pharmaceutical gelatin, or food gelatin for your production line, you can share your application, technical specifications, and target Bloom value with EKING.
We can provide suitable gelatin product information based on your requirements and arrange samples with the Bloom value you need for testing and evaluation.
Contact EKING