Bloom (test)

For other uses, see Bloom (disambiguation).

Bloom is a test used to measure the strength of a gel, most commonly gelatin. The test was originally developed and patented in 1925 by Oscar T. Bloom.^[1] The test determines the weight in grams needed by a specified plunger (normally with a diameter of 0.5 inch) to depress the surface of the gel by 4 mm without breaking it at a specified temperature.^[2] The number of grams is called the Bloom value, and most gelatins are between 30 and 300 g Bloom. The higher a Bloom value, the higher the melting and gelling points of a gel, and the shorter its gelling times.^[2] This method is most often used on soft gelatin capsules ("softgels"). To perform the Bloom test on gelatin, a 6.67% gelatin solution is kept for 17–18 hours at 10 °C prior to being tested.

Various gelatins are categorized as "low Bloom", "medium Bloom", or "high Bloom", but there are not universally defined specific values for these subranges. Gelatin is a biopolymer material composed of polypeptide chains of varying length. The longer the chain, the higher the Bloom number:^[3]

Gelatin classes

Category	Bloom number (Bloom strength)	Average molecular mass	Examples
Low Bloom	30–150[4]	20,000–25,000	Beef hide low Bloom gelatin (USP-NF)[5]
Medium Bloom	150–225	40,000–50,000	Gelatin type B[6]
High Bloom	225–325	50,000–100,000	Gelatin type A[6]

See also

• Durometer

References

1. "US1540979 Machine for testing jelly strength of glues, gelatins, and the like". Google Patents. Retrieved 1 September 2016.
2. Schrieber, Reinhard; Gareis, Herbert (27 June 2007). Gelatine Handbook: Theory and Industrial Practice. Wiley. ISBN 978-3-527-61097-6.
3. "Gelatins—product information sheet" (PDF). Sigma-Aldrich. Retrieved 24 August 2017.
4. "Gelatin - an overview | ScienceDirect Topics". www.sciencedirect.com. Archived from the original on 15 December 2023. Retrieved 15 December 2023.Link to original publication
5. "GELATIN - LOW BLOOM - BEEF-HIDE - NF by Vyse Gelatin Company - Food, Beverage & Nutrition". www.ulprospector.com. Archived from the original on 15 December 2023. Retrieved 15 December 2023.
6. Felix, Pascal G. (18 November 2003). Characterization and correlation analysis of pharmaceutical gelatin (Thesis). Digital Commons @ University of South Florida. Archived from the original on 15 December 2023. Retrieved 15 December 2023.

External links

• Phillips, Glyn O.; Williams, Peter A. (2000). "6.3.1. Bloom strength—standard method for characterizing gel strength". Handbook of Hydrocolloids. Taylor & Francis. ISBN 9780849308505.