Examination of Tracing Techniques for the Geographical Origin of Durum Wheat Semolina Used in Pasta by Stable Isotope Analysis and SDS-PAGE

<p>We verified the possibility of tracing the geographical origin of durum wheat semolina used in pasta by examining the stable carbon, nitrogen, and oxygen isotope ratios (δ¹³C, δ¹⁵N, and δ¹⁸O) of wheat proteins. We determined the δ¹³C, δ¹⁵N, and δ¹⁸O values of the durum wheat semolina and pasta samples from Canada, Turkey, and Japan. The δ¹³C and δ¹⁵N values of the pasta made from Japanese durum wheat were lower than those of the other samples (p < 0.001 in both δ¹³C and δ¹⁵N). On the other hand, the δ¹⁸O values of the pasta made from Canadian durum wheat semolina were lower than those of the other samples (p < 0.001). These results show that stable isotope analysis is a potentially useful tool for tracing the geographical origin of durum wheat semolina in pasta. Furthermore, we examined an easier and more reasonable method of tracing the geographical origin of durum wheat semolina in pasta by using Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) of wheat protein fraction (glutenin fraction) extracted from pasta. SDS-PAGE of durum wheat semolina and pasta suggested that the manufacturing process of pasta had little influence on the proteins in the glutenin fraction extracted from pasta. Moreover, as a result of SDS-PAGE of durum wheat semolina and pasta made from Canadian, Turkish, and Japanese durum wheat semolina, each characteristic band was found in the glutenin fraction of Japanese samples (around 40 kD) and Turkish samples (around 110 kD). These results suggest that SDS-PAGE is also a potentially useful tool for tracing the geographical origin of durum wheat semolina in pasta.</p>