Facile and accelerated method for detection of adulteration in commercially available lime juice products in Iranian market

Abstract

Background: The present study was aimed to introduce a rapid, simple and cost-effective method to detect adulterated lime juice products commercially available in the Iranian market. Methods: Twelve different brands of marketed lime juice products were randomly purchased from the local stores in Tabriz, Iran. Fresh lime juice, as a control, was prepared by squeezing lime fruits using a plain hand juicer. Ehrlich’s reagent was used for a colorimetric analysis; solid phase extraction-thin layer chromatography (SPE-TLC) technique was utilized for fingerprinting of methanol/water fractions of samples on the silica gel plates at two wavelengths of 366 and 254 nm, before and after spraying aluminum chloride reagent; and attenuated total reflectance-infrared spectroscopy (ATR-IR) was used for further studies. Results: The obtained results from colorimetric analysis indicated appearance of orange-brown color indicating presence of limonoids in fresh lime juice and only five commercially available products. Regarding SPE-TLC fingerprinting, except for five products with identical or comparable TLC patterns to the fresh lime juice, other samples represented completely different TLC patterns, suggesting the presence of adulterants in these products. Therefore, the developed colorimetric and SPE-TLC techniques revealed some extents of adulteration in half of the studied products (58.3%). However, in the case of ATR-IR analysis, the obtained spectra were not illustrating enough to be applied for the detection of adulterated samples. Conclusion: It can be concluded that the described colorimetric method in combination with the developed SPE-TLC technique could be utilized for the preliminary screening of adulterated lime juice products.