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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 °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. [ABSTRACT FROM AUTHOR]

When old corrugated cardboard (OCC) is returned to the paper mill for repulping and reuse, the starch, which is added to the paper surface as a reinforcement agent, is dissolved into the pulping wastewater. Most of the OCC pulping wastewater is recycled to save precious water resources; however, during the water recycling process, the accumulation of dissolved starch stimulates microbial reproduction, which causes poor water quality and putrid odor. This problem seriously affects the stability of the papermaking process and product quality. In this study, phosphomolybdic acid (H3PMo12O40, abbreviated as PMo12) was utilized to catalyze the waste starch present in papermaking wastewater to monosaccharides, realizing the resource utilization of waste starch. The results showed that the optimized yield of total reducing sugar (78.68 wt%) and glycolic acid (12.83 wt%) was achieved at 145 °C with 30 wt% PMo12 at pH 2, which is equivalent to 91.51 wt% starch recovered from wastewater for resource utilization. In addition, the regeneration of the reduced PMo12 was realized by applying a potential of 1 V for 2 h. Overall, this study has theoretical significance and potential application value for resource utilization of waste starch in OCC pulping process and cleaner management of OCC waste paper. [ABSTRACT FROM AUTHOR]

[Display omitted] • First report a duplex LMTIA method targeting ITS for sweet potato and maize detection. • The duplex method can detect sweet potato and maize simultaneously at 61 ℃ in 20 min. • Sensitivity of sweet potato and maize detection is 10 pg/μL and 1 pg/μL, respectively. • Detection limit of sweet potato and maize in artificially adulterated samples is 1%. • The duplex Proofman-LMTIA method can be applied in commercial food authentication. To simultaneously detect sweetpotato and maize components in starch products, this study develops a rapid analysis method based on ladder-shape melting temperature isothermal amplification (LMTIA) coupled with proofreading enzyme-mediated probe cleavage (Proofman). Internal transcription spacer (ITS) gene sequences were targeted to design species-specific primers linked with Proofman probes. The detection of this duplex Proofman-LMTIA method could be completed in 20 min under the optimal temperature of 61 ℃. The specificities of sweetpotato and maize ITS primers were verified with seven other species. The sensitivities of sweetpotato and maize DNA extracts were 10 pg/μL and 1 pg/μL, respectively. The detection limits of sweetpotato and maize DNA samples extracted from artificially adulterated starch powders were both 1 %. To demonstrate the effectiveness of the established duplex Proofman-LMTIA method, a total of 19 commercial sweetpotato noodles and 14 starch products were collected and tested for sweetpotato and maize authentication. Taken together, the LMTIA method is suitable for rapid and accurate detection of sweetpotato and maize components in starch products. The popularization of this method will provide guidelines for ingredients authentication and market supervision of products. [ABSTRACT FROM AUTHOR]