Sesame (Sesamum indicum), is a significant oilseed crop with great economical and nutritional value, encompassing a plethora of primary and secondary metabolites that exhibit pharmacological and therapeutic merits. The present study, using untargeted comparative metabolomics, aims to authenticate and classify sesame seed accessions from different countries of origin i.e., Egypt, Sudan and Nigeria, based on their metabolite variations and in relation to their biological activity and nutritional value such as mineral content. Also, to further assess the impact of processing on sesame’s nutritional value and biological activity using the industrial production of sesame paste as a case study. To achieve such results, data sets generated from different analytical platforms GC-MS post-silylation, HS-SPME-GC-MS and UPLC-MS were coupled to chemometrics to aid in providing chemical information for better quality control and nutritional assessments. The identified metabolite profiles for raw accessions and processed sesame samples belonged to a myriad of chemical classes including sugars, sugar alcohols and acids, polyphenolic compounds, amino acids, nitrogenous compounds, fatty acids, fatty alcohols, aldehydes, ketones, esters, phytosterols, heterocyclic compounds and organic acids. GC-MS analysis comprising 85 peaks for raw accessions and 114 peaks for processed samples, in addition to HS-SPME results comprising 134 peaks for raw and laboratory-roasted seeds, revealed variation in fatty acid composition among raw sesame accessions, such as Nigerian sesame, which was abundant in oleic and linoleic fatty acids. Moreover, a total of 139 peaks were identified using UPLC-MS, which lead to the tentative identification of novel compounds in sesame i.e., 1- linoleoylglycerophosphoinositol, 1-palmitoylglycerophosphoinositol and sesaminol 2,6- dicatechol monomethyl ether. Discriminatory markers based on UPLC-MS data belonging to coumarins, lignans, phenolic and organic acids were also revealed among raw accessions, whereas roasted and unroasted seeds were distinguished by their sugar, peptide/amino acid, and organic acid contents. Furthermore, the mineral content of sesame seeds revealed the negative impact of processing on its overall content, and the impact of cultivation region, which was indicated by the low mineral content in Egyptian sesame compared to others. The antioxidant capacity assays also revealed strong scavenging activity for raw accessions in DPPH and β-carotene-lineolate assays and declined antioxidant capacity as a result of processing


School of Sciences and Engineering


Chemistry Department

Degree Name

MS in Chemistry

Graduation Date

Fall 11-30-2022

Submission Date


First Advisor

Mohamed Ali Farag

Committee Member 1

Mostafa Hassan Abdel Hamid

Committee Member 2

Ehab El Sawy


133 leaves

Document Type

Master's Thesis

Institutional Review Board (IRB) Approval

Not necessary for this item

Available for download on Sunday, September 29, 2024