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In recent years, interest in healthy and natural food products has increased, particularly in fresh fruits and their derivatives, which are important sources of bioactive compounds. However, due to the high cost of fruits and the economic incentives of producers, adulteration of fruit-based products is frequently observed. This study aimed to develop and apply DNA-based methods to verify the authenticity of Rubus idaeus (red raspberry) and its derived products. DNA was extracted from fresh fruits, dried fruits, and industrially processed products (teas, juices, jams and smoothies). A commercial DNA isolation kit was used, yielding pure and concentrated DNA suitable for PCR (Polymerase Chain Reaction) analysis. Specific primers targeting the ITS1 (Internal Transcribed Spacer 1) region were designed to enable reliable differentiation of raspberry from closely related species (eg. blackberry, strawberry). DNA extracts were subjected to PCR-HRM (High-Resolution Melting) analysis. The method successfully detected raspberry DNA across all sample types, with dried and minimally processed products producing the strongest signal and the clearest melting curves. Juice samples exhibited lower signal intensity and slightly shifted curves due to industrial processing and lower DNA concentration, while dense products with high sugar and additive content (jams and smoothies) generated weaker, less specific curves. Electrophoresis confirmed the specificity of the amplicons, showing a product of approximately 220 bp for raspberry and distinct amplicons for related species. These findings demonstrate the high selectivity, sensitivity, and applicability of PCR-HRM as a reliable tool for fruit product authentication and adulteration detection, with strong potential for routine quality control and consumer protection.
Keywords: Rubus idaeus, food authenticity, PCR-HRM, DNA barcoding, electrophoresis
Acknowledgements: We gratefully acknowledge the grant support from University Student Assembly of the „Ss. Cyril and Methodius” University in Skopje for the project titled „Determining the authenticity of fruit products using PCR methods“.
