Effects of energy-gathered and energy-divergent ultrasound on structure, DNA extraction and adulterated quantification of sweet potato vermicelli and its starch

Background: The identification of adulterated sweet potato vermicelli faces significant challenges, seriously hindering the development of the vermicelli industry. Herein, we investigate effects of energy-gathered ultrasound (EGU) and energy-divergent ultrasound (EDU) (30, 40 and 50 W L^-1) on structure, DNA extraction and adulterated quantification of sweet potato vermicelli and its starch, thereby exploring their potential in adulteration of sweet potato vermicelli.

Results: EGU-assisted modified cetyltrimethylammonium bromide (CTAB) protocol with β-mercaptoethanol significantly improved DNA extraction from sweet potato vermicelli (223.7-249.2 ng μL^-1) and its starch (133.4-186.4 ng μL^-1), followed by EDU-assisted DNA extraction from sweet potato vermicelli (115.1-209.3 ng μL^-1) and its starch (33.4-61.0 ng μL^-1). Both EGU and EDU treatments resulted in the destruction of microstructure and crystalline structure, as well as changes in pasting and thermal properties of sweet potato vermicelli and its starch. Real-time polymerase chain reaction (PCR) amplification results revealed that EGU and EDU enhanced the efficiency of DNA amplification, and EDU showed smaller cycle threshold (C_t) values than EGU. In addition, EDU-assisted CTAB protocol combined with real-time PCR could detect levels of less than 1% of cassava and maize starches in sweet potato vermicelli.

Conclusion: EDU-assisted CTAB protocol combined with real-time PCR shows promise as a sensitive and reliable analytical tool for vermicelli adulteration. © 2024 Society of Chemical Industry.