Detection and quantification of adulteration of durum wheat flour by flour from common wheat using reverse phase HPLC

Abstract

When common wheat (Triticum aestivum L ) gliadins were separated by RP-HPLC, a major doublet peak eluted at 47.20 and 47.94 min. This peak was consistently found to be absent in Durum wheat (Triticum durum Desf) gliadins separated under identical conditions. In Durum wheat gliadins a characteristic small peak eluted at 48-30 min followed at 50.47, 51.37, 52.80 min by larger peaks. The peak area ratio of the peaks eluting at 50.47 and 51-37 min was found to be 2.18 (+0-14). This ratio was found to decrease proportionally on contamination of Durum wheat flour with flour @om some common wheat varieties. This ratio alone was not enough to detect and quantify adulteration by all varieties of common wheat. An alternative method was found whereby the peak emerging between 47 and 49 min in the Durum wheat gliudin elution profile was expressed as a ratio of the total protein applied. This ratio was shown to increase when Durum wheat flour was adulterated with flour @om common wheat thus enabling quantitative estimation of the level of adulteration. A third method of detecting adulteration of Durum wheat flour is also proposed in which the peak emerging between 47 and 49 min is collected and the protein separated by PAGE. The presence of more than one band of y/B-gliadins is indicative of adulteration.

Compared Use of HPLC and FZCE for Cluster Analysis of Triticum spp and for the Identification of T. durum Adulteration

“…The data presented in this study indicate that both the RP-HPLC and the FZCE method are close to satisfying these conditions. The presented RP-HPLC method is basically similar to the other RP-HPLC methods (based on the analysis of gliadin fractions) proposed in the last years by several authors (27,31). In contrast, the presented FZCE method is based on analysis of water-extractable wheat proteins and could be considered similar to the official Italian method of Resmini and De Bernardi (35), consisting in the separation of wheat albumins on Native-PAGE.…”

A novel approach to authenticity control of whole grain durum wheat (Triticum durum Desf.) flour and pasta, based on analysis of alkylresorcinol composition

“…Electrophoretic methods are used, whereby D-genome encoded proteins like gliadins (Bonetti et al, 2004;Burgoon, Ikeda, & Tanner, 1985) or specific polyphenoloxidases (Feillet & Kobrehel, 1974) are separated and detected by gel electrophoresis. McCarthy, Scanlon, Lumley, and Griffin (1990) reported the use of RP-HPLC for the detection of common wheat flour in durum wheat flour/semolina, based on the separation and detection of specific gliadins, and the method has been extended for application to pasta products (Barnwell, McCarthy, Lumley, & Griffin, 1994). Specific D-genome encoded proteins have also been detected by free zone capillary electrophoresis (FZCE); however the method was only applied for blends of durum wheat and common wheat flour and has not been validated for quantitative analysis so far (Bonetti et al, 2004).…”

Common wheat determination in durum wheat samples through LC/MS analysis of gluten peptides

“…With the development of high-performance liquid chromatography and free-zone capillary electrophoresis, new methods for the detection of common wheat were generated. The extraction and subsequent HPLC analysis of gliadins from wheat can be used to detect adulteration with common wheat [11]; this approach can also be applied to pasta when it is dried at high temperature [12]. The chromatogram and the electropherogram of proteic extracts from common wheat both contain some peaks that are not detectable in durum wheat; this makes it possible to construct a calibration curve using samples of known composition [13].…”