Gels are commonly used within the food industry as they form an extremely versatile and effectively processed ingredient. Gels as a thickener, binding agent, adhesive property, stabilizer and whipping agent among other functions. Every food sector is influenced by the use of gels in their products and cannot be easily replaced by any other ingredient. Gelatin (or gelatine) has industry standard Bloom strength tests to grade and qualify its gelling properties and other agents (hyrocolloids) may be tested in similar ways.
Gelling agents are also used in the pharmaceutical and cosmetics industries to provide desirable texture.
Typical gel products tested include:
Instrumental measurements are used to assess the functional properties of hydrocolloid gels, usually relating to its firmness and eleasticity, by compression (or occasionally penetration) of the surface. The measurement of gelatin and other gelling agent strength, for example, is an integral part of its quality assessment and grading. Gel strength has been shown to directly relate to the functional performance of the product, independent of its application. Preparation of the sample and test conditions imposed are of critical importance and directly influence the response of the sample being tested. The importance of accuracy and reproducibility of results is compounded when we consider that the majority of hydrocolloid systems are sold based upon their functional properties.
A key example of standardized gel testing is the long established gelatin Bloom strength test. Originally established within the British Standards Method (B.S. 757:1975), this test method has since been modified by the Gelatine Manufacturers of Europe (GME). This technique strictly defines the preparation of the gelatin sample, the test conditions (speed, trigger point, deformation distance, test probe etc.) and instrument specification used to make the test, which performs a controlled compression of the surface. The end result is an empirical test method that follows fundamental principles for standardization and control. The principle reason for gelatin producers to establish a standardized technique is that gelatin is graded by its Bloom value, where higher values mean higher prices, hence uniformity in its quantification is critical in a world market. The Bloom strength relates to the force required to deform the gel, typically in the range 50 Bloom gelatin to 300 Bloom gelatin. Values below 120 are graded as low, those above 200, high and those in betweentermied medium strength.
Read our Gelatine Bloom strength test case study.
Specific fixtures and accessories are required for Bloom strength testing. The gel sample bottle and probes have exact specifications in terms of dimensions and materials. Food Technology Corporation's gel industry fixtures conform to ISO 9665, GME, AOAC 1985 and BS757 standards.