This research (purchase required) set out to design a rapid point-of-use test to detect cassava starch as an adulterant in higher-value starches. The test method used Proofreading enzyme-mediated probe cleavage (Proofman) coupled with ladder-shape melting temperature isothermal amplification (LMTIA). The optimal detection temperature of this Proofman-LMTIA method was 62℃ and the reaction could be finished within 20 minutes with a detection sensitivity of 100 pg/μL of genomic cassava DNA. Nine different species were collected and verified for the specificity of cassava ITS primers and probes. The detection limit of cassava DNA derived from artificially premixed starch powders was 1 % (w/w).
As a proof-of-concept, the researchers used their Proofman-LMTIA assay to test 33 commercial products from the food and medicine sectors. They report that – based on their assay - 16 samples contained undeclared cassava components.
Photo by Daniel Dan on Unsplash
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