Simultaneous determination of fatty acid composition in the samples of tahini and tahini halva sold in the market with GC/FID-MS device and determination of adulteration by chemometric approaches

Tahini is a semi-fluid consistency, rich in nutritional value, obtained by roasting sesame and then peeling and grinding it. Tahini halva is known as Turkish honey or Turkish dessert in Western countries, by boiling sugar at about 150 °C and adding gypsum root (Saponaria officinalis) juice; It is a traditional product obtained by adding white tahini to the white sugar wax obtained by whipping and kneading until it reaches the desired consistency. The approximate chemical composition of tahini consists of a high percentage of fat (58.9%) and protein (24.7%), a low percentage of crude fiber (2.3%) and moisture (<1.0%), and a significant amount of ash (3.0%). Tahini oil is highly unsaturated (82%). Oleic (42.4%) and linoleic (39.7%) acid constitutes the majority of unsaturated fatty acids. Among the saturated fatty acids, palmitic acid (9.8%) and stearic acid (6.4%) are dominant. Oleic acid, linoleic acid, palmitic and stearic acid make up 98% of the total fatty acids in tahini. The characteristics that tahini halva must have are reported in the TGK Tahini Halva Communique (2015/28) published in the Official Gazette No. 29385. Samples are taken in accordance with the rules specified in the Turkish Food Codex Regulation, and national or internationally accepted analysis methods are applied. White sesame, which is the highest quality sesame produced in our country, is used in the production of tahini halva, whose production and consumption has increased rapidly in recent years. However, due to the decline in sesame production, different oils such as sunflower oil, peanut oil, soy protein, soybean oil are used in the production of tahini halva. This is an indication that imitation and adulteration are used in foods. Food fraud is generally carried out with economic motivation and it is aimed to increase the profit margin by ignoring consumer safety. Detection of adulteration using cheaper oils is difficult with current methods. In this study, the oils of various halva and tahini samples collected from the market were extracted by the Soxhelet method. A GC device with MS and FID detectors was used to look at the fatty acid composition and amount of the extracted oils. Simultaneously, the fatty acids detected in MS and FID detectors were verified in MS detector and calculated in FID detector. Fatty acid composition and their obtained from pure sesame oils and mixtures were made. A total of 12 different fatty acid types were detected in the samples taken from the market. From essential fatty acids; Palmitic Acid (C16:0), Stearic Acid (C18:0), Oleic Acid (C18:1), Linoleic Acid (C18:2) Arachidic Acid (C20:0), Behenic Acid (C22:0) and Lignoceric Acid (C24:0) was found to be numerically high in quantity. PCA analysis was used to examine data distribution patterns based on PCA analyzes of the models created by mixing 5 samples of suspected adulteration, as well as 6 different oil samples and sesame oil at the rates of 10 %, 25 % and 50 %, were made and interpretations were made about which oils could be. As a result of all these studies, it was determined that 5 of 31 samples were adulterated.