Bloom (test)

{{Short description|Test to measure strength of a gel}} {{Other uses|Bloom (disambiguation)}} {{Use dmy dates|date=August 2017}}

'''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.<ref>{{cite web|title=US1540979 Machine for testing jelly strength of glues, gelatins, and the like|url=https://patents.google.com/patent/US1540979|website=Google Patents|access-date=1 September 2016}}</ref> 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.<ref name="GelatineHandbook">{{cite book|last1=Schrieber|first1=Reinhard|last2=Gareis|first2=Herbert|title=Gelatine Handbook: Theory and Industrial Practice|date=27 June 2007 |publisher=Wiley|isbn=978-3-527-61097-6}}</ref> 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.<ref name="GelatineHandbook"/> This method is most often used on soft gelatin capsules ("softgels"). To perform the Bloom test on gelatin, a lab keeps a 6.67% gelatin solution for 17–18 hours at 10 °C prior to testing it.

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:<ref>{{cite web |url= https://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/Sigma/Product_Information_Sheet/2/g9382pis.pdf |publisher= Sigma-Aldrich |title= Gelatins—product information sheet |accessdate= 2017-08-24 }}</ref> {|class=wikitable |+Gelatin classes !Category !Bloom number (Bloom strength) !Average molecular mass !Examples |- |Low Bloom |30–150<ref>{{cite book |last1=Hanani |first1=Z.A. Nur |title=Encyclopedia of Food and Health |chapter=Gelatin |date=2016 |pages=191–195 |doi=10.1016/B978-0-12-384947-2.00347-0 |isbn=978-0-12-384953-3 |quote=Gel strength and viscosity are the most important physical properties of gelatin. Gel strength, also known as ‘bloom’ value, is a measure of the strength and stiffness of the gelatin, reflecting the average molecular weight of its constituents, and is usually between 30 and 300 bloom (< 150 is considered to be a low bloom, 150–220 a medium bloom, and 220–300 a high bloom). Higher bloom value indicates greater gelatin strength. Based on the type of product required and its function, a different bloom value for gelatin is applied. }}</ref> |20,000–25,000 |Beef hide low Bloom gelatin (USP-NF)<ref>{{cite web |title=GELATIN - LOW BLOOM - BEEF-HIDE - NF by Vyse Gelatin Company - Food, Beverage & Nutrition |url=https://www.ulprospector.com/en/na/Food/Detail/3844/109618/GELATIN---LOW-BLOOM---BEEF-HIDE---NF#:~:text=Gelatin%20-%20Low%20Bloom%20-%20Beef-Hide%20-,a%20pH%20level%20of%205.60%20+%200.60. |access-date=2023-12-15 |url-status=live |archive-date=2023-12-15 |archive-url=https://web.archive.org/web/20231215133833/https://www.ulprospector.com/en/na/Food/Detail/3844/109618/GELATIN---LOW-BLOOM---BEEF-HIDE---NF#:~:text=Gelatin%20%2D%20Low%20Bloom%20%2D%20Beef%2DHide%20%2D,a%20pH%20level%20of%205.60%20+%200.60. |website=www.ulprospector.com}}</ref> |- |Medium Bloom |150–225 |40,000–50,000 |Gelatin type B<ref name="Felix2003">{{cite thesis |last1=Felix |first1=Pascal |title=Characterization and Correlation Analysis of Pharmaceutical Gelatin |date=18 November 2003 |url=https://digitalcommons.usf.edu/etd/1365/ }}{{pn|date=August 2025}}</ref> |- |High Bloom |225–325 |50,000–100,000 |Gelatin type A<ref name="Felix2003" /> |}

==See also== * Durometer

==References== {{Reflist}}

==External links== * {{cite book |title=Handbook of Hydrocolloids |date=2021 |doi=10.1016/C2018-0-04245-0 |isbn=978-0-12-820104-6 |editor1-first=Glyn O. |editor1-last=Phillips |editor2-first=Peter A. |editor2-last=Williams }}

Category:Gels Category:Hardness tests