Analytical method development and validation based on a paper analytical device (PAD) for the detection of adulteration in Teff Injera (Ethiopian flatbread)
摘要
A novel, simple, affordable, portable, and easy-to-use method based on a paper analytical device has been developed that helps to determine adulteration of teff injera (Ethiopian flatbread) qualitatively. The developed paper analytical device test card generated a red-orange colour on lane B (ferric detection), red on lane D (ferrous detection), Prussian blue on lane F (ferric detection), and Turnbull’s blue colour on lane H (ferrous detection) for pure teff injera. The colour barcodes generated by pure teff injera quite differ from those produced by teff injera that contain the common adulterants; gesso or cassava. While the colours generated by teff injera containing gesso and teff injera containing cassava were almost the same, except for lane J (Ca detection). The blue colour was noted during the run on lane J in teff injera containing cassava, but this colour was not produced even after five minutes in teff injera containing gesso. The test card colour result was less intense or inactive for injera samples purchased from the local market. It indicates that inexpensive cereals might be used in place of authentic teff flour or blending of it happened before baking. The developed method was confirmed by analysing the elemental composition of samples using microwave plasma atomic emission spectrometers.