Control of Origin of Sesame Oil from Various Countries by Stable Isotope Analysis and DNA Based Markers—A Pilot Study

Abstract

The indication of origin of sesame seeds and sesame oil is one of the important factors influencing its price, as it is produced in many regions worldwide and certain provenances are especially sought after. We joined stable carbon and hydrogen isotope analysis with DNA based molecular marker analysis to study their combined potential for the discrimination of different origins of sesame seeds. For the stable carbon and hydrogen isotope data a positive correlation between both isotope parameters was observed, indicating a dominant combined influence of climate and water availability. This enabled discrimination between sesame samples from tropical and subtropical/moderate climatic provenances. Carbon isotope values also showed differences between oil from black and white sesame seeds from identical locations, indicating higher water use efficiency of plants producing black seeds. DNA based markers gave independent evidence for geographic variation as well as provided information on the genetic relatedness of the investigated samples. Depending on the differences in ambient environmental conditions and in the genotypic fingerprint, a combination of both analytical methods is a very powerful tool to assess the declared geographic origin. To our knowledge this is the first paper on food authenticity combining the stable isotope analysis of bio-elements with DNA based markers and their combined statistical analysis.

Stable isotope composition of cocoa beans of different geographical origin

“…). Particularly high δ 2 H values were previously also reported in sesame oil from Uganda . As shown in Fig.…”

“…between Tanzania and Uganda in East Africa ( P < 0.05). It is worth noting that the particularly high δ 13 C values in Uganda were also recently described in sesame probably in relation to the geographical characteristics of this country (most of Uganda is on a plateau at an altitude of 1000–1200 m, with a mean temperature of 21–23 °C and limited changes during the year).…”

“…Particularly high δ 2 H values were previously also reported in sesame oil from Uganda. [19] As shown in Fig. 2b, there is a good correlation (P < 0.01) between the δ 2 H of cocoa and the weighted annual δ 2 H of world precipitation reported in the GNIP database.…”

“…More recently, 1 H NMR spectra of traded cocoa beans were used to characterise fermented cocoa beans on the basis of the variety and geographical origin. [15,16] H, C, N, O and S stable isotope ratios measured using Isotope Ratio Mass Spectrometry (IRMS) have been shown to be a reliable tool for establishing the authenticity of a wide variety of food products, such as wine, [17] olive [18] and sesame oils, [19] orange juice, [20] honey, [21] beef, [22] fish, [23,24] shrimps [25] and prawns, [26] ham, [27] milk, [28] rice, [29] lentils. [30] This is due to particular isotopic fractionation processes, which reflect both climatic phenomena (e.g.…”

Metabolite Profiling and Chemometric Study for the Discrimination Analyses of Geographic Origin of Perilla (Perilla frutescens) and Sesame (Sesamum indicum) Seeds

“…In particular, more than 90% of sesame seeds were imported from China (50%) and India (40%) [19]. The price of perilla and sesame seeds is influenced by their places of origin; therefore, identification of the geographic origin of these seeds is important [21]. Forging or mislabeling domestic seeds as imported seeds to gain economic benefits has increasingly become a crucial issue for both producers and consumers, and it affects food quality assurance and safety [22].…”