Development of a Ladder-Shape Melting Temperature Isothermal Amplification (LMTIA) Assay for the Identification of Cassava Component in Sweet Potato Starch Noodles

Food authenticity has become increasingly important as a result of food adulteration. To identify the authenticity of sweet potato starch noodles, the ladder-shape melting temperature isothermal amplification (LMTIA) method of determining cassava (Manihot esculenta Crantz) DNA in sweet potato starch noodles was used. A set of primers targeted at the internal transcription spacer (ITS) of cassava was designed, genomic DNA was extracted, the LMTIA reaction temperature was optimized, and the specificity of the primer was verified with the genomic DNAs of cassava, sweet potato (Ipomoea batatas L.), Solanum tuberosum L., Zea mays L., Vigna radiate L., Triticum aestivum L., and Glycine max (L.) Merr. The sensitivity with the serially diluted genomic DNA of cassava and the suitability for the DNA extracted from sweet potato starch adulterated with cassava starch were tested. The LMTIA assay for identifying the cassava component in sweet potato starch noodles was established. At the optimal temperature of 52 degrees C, the primers could specifically distinguish a 0.01% (w/w) cassava component added to sweet potato starch. Additionally, the LMTIA method was applied to the cassava DNA detection of 31 sweet potato starch noodle samples purchased from retail markets in China. Of these, 14 samples were positive. The LMTIA assay could be a reliable method for the rapid detection of cassava components in sweet potato starch noodles, to protect the rights of consumers and to regulate the sale market order of starch noodles.

Automated summary

Food authenticity is increasingly important due to food adulteration. Researchers developed a reliable method using ladder-shape melting temperature isothermal amplification (LMTIA) to identify the authenticity of sweet potato starch noodles by detecting the presence of cassava DNA. The method successfully identified the cassava component in sweet potato starch noodles and could be used to regulate the sale market order of starch noodles.