Chloroplast markers for detecting rice grain-derived food ingredients in commercial mixed-flour products

Development of a SYBR Green Real-Time PCR method for the detection of Coffea arabica and C. canephora using chloroplast genes

Coffea arabica (Arabica) and C. canephora (Robusta) are valuable agricultural products traded worldwide. In this study, we designed specific primer pairs for Arabica and Robusta using chloroplast genes to distinguish and quantify the two types of coffee beans. We assessed the specificity, sensitivity, and applicability of the qRT-PCR assay using all the primer pairs. The six designed primer pairs (three for Arabica and three for Robusta) exhibited a correlation coefficient higher than 0.99 and a slope of approximately - 3.21 to - 3.52. The efficiency ranged from 92.09 to 104.79%. The Real-Time quantitative PCR (qPCR) assay had a detection limit of 0.001 ng DNA and a quantitative detection limit of 0.01% (w/w). Additionally, the specificity of the primer pairs was confirmed by analyzing 12 non-target plant species and verifying their practicality using 10 commercials. This study highlights the effectiveness of the SYBR-based qPCR assay in detecting adulteration in commercial coffee products.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-024-01636-7.

Development of real-time PCR-based markers for differentiation of Oplopanax elatus and Aralia cordata in commercial food products

Oplopanax elatus and Aralia cordata, commonly referred to as "Dureub" in Korea, are generally used as medicinal or food raw materials. Although O. elatus, a rare and endangered plant, is typically sold at high prices, the more abundant A. cordata is comparatively inexpensive. Given their common names and morphological root similarities, both plants can easily be confused, thereby providing potential opportunities for fraudulent use in food products. Species-specific molecular markers that can be used for quantitative real-time PCR (qPCR) analysis were developed. Verification of the six primer pairs revealed a correlation coefficient greater than 0.99, with a slope between -3.33 and -3.56. The assay confirmed specificity based on an analysis of 14 non-target plant species and verified its practicality using 10 commercial products with reliability based on a blind test. Thus, qPCR assays can contribute to food safety and protect consumer rights and interests.

Supplementary Information

The online version of this article contains supplementary material available 10.1007/s10068-023-01313-1.

Establishing DNA markers to differentiate Agastache rugosa and Pogostemon cablin, which are confusedly used as medicinal herbs, using real-time PCR

Agastache rugosa and Pogostemon cablin are used as medicinal herbs and aromatic plants and belong to the family Lamiaceae. Despite differences in composition and physicochemical properties, both plants are frequently sold as the medical substance "Kwakhyang" in some Asian countries. Molecular markers were established to distinguish between the two plants using quantitative real-time PCR. Species-specific primers were designed in the nuclear internal transcribed spacer region of ribosomal DNA and in the chloroplast genes matK, rbcL, and rpoB. Six primer sets were tested, the correlation coefficient was higher than 0.99, and the slope was approximately - 3.36 to - 3.58. Efficiency ranged from 90.13 to 98.52%. The developed real-time PCR assay was validated with 14 off-target species, and its reliability was verified through blind testing of 14 commercial products. The assay developed here may help protect consumer rights, and the designed primers can be used to distinguish between the target species.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01176-y.

Development of real-time PCR based molecular markers for two medicinal herb Artemisia species A. capillaris and A. iwayomogi

Artemisia capillaris and Artemisia iwayomogi are well-known herbal medicines which are used as hepatotherapeutic drugs. These two herbal species can be confused with each other, owing to their morphological similarity and similar Korean common names of "Injinho" and "Haninjin," respectively. Molecular markers to distinguish between the two plants were developed. Six primer sets were designed and verified, and their efficiencies were found to range from 90.28 to 98.29%. The developed primer sets had significant correlation coefficient values between the cycle threshold values and the logarithm of DNA concentration for their target species (R2 > 0.98), with slopes ranged from - 3.3637 to - 3.5793. The specificity of the quantitative polymerase chain reaction (qPCR) was confirmed with 14 other species. Additionally, 16 commercial medicinal herbs and 40 blind samples were tested to evaluate their reliability. Collectively, the findings indicate that developed qPCR-based target-specific primer sets have potential applicability toward protection of consumers' rights.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01166-0.