New Method of DNA Isolation from Two Food Additives Suitable for Authentication in Polymerase Chain Reaction Assays

Abstract

Locust bean gum and guar gum are galactomannans used as additives (E 410 and E 412, respectively) in the food industry as stabilizing agents. Analytical discrimination between the two additives in gums and foods is now feasible by molecular techniques. However, only complex and time-consuming DNA isolation protocols are available to date. We have developed simple improved protocols to obtain enough DNA suitable for PCR amplification from a few milligrams of commercial E 410 and E 412 additives (containing more than 75% polysaccharides). The suspension of additives in water or 10 mM Tris-HCl, pH 8.5, efficiently recovers DNA suitable for authentication in PCR assays. However, the Tris method was much more efficient for the extraction of DNA from E 410 than for E 412 additives. Conversely, the water method was the most suitable for detecting DNA extracted from E 412 or from E 410/E 412 mixtures. Combined with the use of the two specific ribosomal primer pairs previously designed, our methods are well-suited for a fast and simple high-throughput sample treatment of commercial gums for molecular certification.

Re‐evaluation of guar gum (E 412) as a food additive

“…With both methods, guar and locust bean gum can be detected in ice cream and fresh cheese at levels < 0.1% (Meyer et al., ). A similar PCR‐based method is reported for the identification of guar and locust bean gum in 22 finished food products (ice cream, dehydrated desserts, milk derivatives, dehydrated soups, salad dressing, marmalade and meat) (Urdiain et al., , ). The described PCR‐based methods are useful for the qualitative but not for quantitative determination of guar gum in foodstuff.…”

Certain Rheological Aspects of Functionalized Guar Gum

“…Guar gum is a high molecular weight polysaccharide (generally more than 2 million g/mol) that can form extensive intermolecular H-bonding resulting in high solvation and thereby increased viscosity [2]. These attributes of guar gum find it varied applications in the industry [3][4][5][6][7][8][9][10][11]. Guar gum functions as a thickener, emulsion stabilizer, gelling agent, film former, or texture modifier.…”