Quantitative PCR analysis for fruit juice authentication using PCR and laboratory-on-a-chip capillary electrophoresis according to the Hardy-Weinberg law.
DNA-based analysis for the authentication of fruit juices was evaluated using the Polymerase Chain Reaction (PCR) and laboratory-on-a-chip capillary electrophoresis (LOC). A PCR restriction fragment length polymorphism (RFLP) assay demonstrated the detection of grapefruit juice in orange juice, although the assay was relatively insensitive with a limit of detection of 10% v/v. A PCR heteroduplex assay for detecting mandarin juice in orange juice was successfully applied to the LOC system and demonstrated greater sensitivity with a limit of detection of 2.5% v/v. Results for both assays using authentic juice mixtures were consistent with that expected following the random reannealing of PCR-amplified DNA at PCR plateau according to the principles of the Hardy-Weinberg law. Calculations of theoretical and expected yields of homoduplex and heteroduplexes indicated that the heteroduplexes were underestimated by 1.5-fold on the LOC. Although the LOC can provide good quantitative end-point analytical data from PCR methods, care must be taken in data interpretation because different data interpretation applies dependent on the attainment of the PCR plateau.
Leatherhead Food International, Randalls Road, Leatherhead, Surrey, United Kingdom.
Mary
M
Scott
Angus
A
Knight
D001628:Beverages / Q000032:analysis*; D002957:Citrus / Q000737:chemistry* / Q000235:genetics; D046209:Electrophoresis, Microchip / Q000379:methods*; D016133:Polymerase Chain Reaction / Q000379:methods*; D011786:Quality Control