Gum Acacia senegal is defined as the gummy exudate from the branches of the acacia tree. However, many species of acacia exist and not all species generate Acacia senegal of the highest quality and therefore not of the same price. The problem is that differentiating between the species, once the gum is processed, is difficult and those people who might be blending lower quality gum  are certainly not willing to tell you how to weed out the impostors.

Importers Service will not sell gum blends without the explicit knowledge and approval of the customer. We also believe that laboratory time should be spent developing processes to provide the highest quality pure gum arabic, not to attempt to provide a 'substitute' or combination of gums that might work today but not tomorrow. We would like to inform anyone who is purchasing Acacia senegal how to find out if they are getting maximum value for your purchasing dollar by providing the following information to help you characterize your material:

Test 1: Specific rotation. The highest quality gum arabic has a specific rotation of -26 to -32. If you have a rotation of under -26 it is possible that you have a blend of gums or you have an inferior acacia senegal. If your gum rotates in a different range than this, continue to test 2 to determine the nature of the impurity that you have. If it does fall into this range, it is likely that you have pure material. However if you are experiencing difficulties, the potential exists that improper processing has damaged the gum. Contact ISC for free samples to test in your application.

Test 2: Decolorized Grade #2 test. #2 gum acacia, as it is also known, in its pure form will have a color in solution similar to that of black coffee. In order to make this material more useful in color sensitive applications, the gum arabic industry (led by ISC in the early 80's) has discovered how to remove the colorants from this material. However, even without the color, grade #2 gum acacia has very different properties from #1 grade and a lower cost. To determine if you have a material containing decolorized #2 simply produce a 20% solution of the gum. Add NaOH solution to bring the pH of the solution to about 10 (it need not be exact). If decolorized #2 is present, the solution will darken upon addition of the base. Contact ISC and let us determine the percentage of #2 gum in your sample to allow you to determine the actual quality of this material or to reassess your needs and provide a pure product for your application.

Test 3: Residual oxidation agents. Firms will utilize oxidizing agents in the production of decolorized #2 gum acacia. This is acceptable provided they then take steps to remove these chemicals. Residual oxidizer can result in the degradation of your expensive oils and flavors. Identification of the residual is simple, produce a 20% solution of the gum and test it with any of the oxidizing agent test strips available through the major laboratory supply houses or contact ISC and we will provide these to you.

Test 4: Starch. The presence of starch can be assessed through the well known potassium iodide methods. However, this is not effective when the starch being used is a malto dextrin or some of the other inexpensive modified food starches. Fortunately for us, the use of these materials leave a distinctive foot print. First, the starches typically have a very positive rotation if you have found a positive rotation but not decolorized #2 gum you may suspect starch. Second, the mono and di saccharides that are present in malto dextrins can easily be identified via HPLC, mono and di saccharides are never present in pure acacia of any species. This test can be performed by many labs throughout the country or contact ISC for the one we recommend. Inclusion of starch dramatically decreases the price of the material and may present a labeling issue, be very careful with this impurity.

We hope that this information provides you with the knowledge to purchase materials that fit the requirements of your individual process and enables you to be cost effective. We will always be happy to assist you with any of these tests or to do the entire evaluation in our laboratory without any commitment on your part to purchase anything from ISC.

Contact Dave Hulmes at 201-332-6970 with any technical concerns you may have.