Effect of Roasting Process on Total Phenolic Compounds and γ-tocopherol Contents of Iranian Sesame Seeds (Sesamum indicum)

Jannat, Behrooz; Oveisi, Mohammad Reza; Sadeghi, Naficeh; Hajimahmoodi, Mannan; Behzad, Massomeh; Nahavandi, Bahman; Tehrani, Shirin; Sadeghi, Fatemeh; Oveisi, Morvarid

doi:10.22037/ijpr.2013.1399

Effect of Roasting Process on Total Phenolic Compounds and γ-tocopherol Contents of Iranian Sesame Seeds (Sesamum indicum)

Document Type : Research article

Authors

¹ Food and Drug Laboratory Research Center, Ministry of Health and Medical Education, Tehran, Iran.

² Department of Drug and Food Control, School of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.

³ Islamic Azad University of Pharmaceutical Sciences, Tehran, Iran.

10.22037/ijpr.2013.1399

Abstract

Sesame (Sesamum indicum L.) seed and oil have long been used widely as healthy foods to supply energy and prevent aging. Some of the main active anti-oxidative constituents in sesame seeds are γ-tocopherol and phenols. The purpose of this study was to investigate the relationship between roasting temperature and time with γ-tocopherol and total phenolic compounds (TPC) of sesame seeds when roasted in a domestic electric oven.
Eight cultivars of sesame seeds in this study were Darab, Dezful, Karaj, Moghan, Naz-Branching, Naz-NonBranching, Siah and Varamin. Each cultivar was divided into ten group based on the roasting time (10, 15 and 20 min) and temperatures (180, 200 and 220°C)andunroasted one. The high-performance liquid chromatography (HPLC) and spectrophotometeric methods were used for γ-tocopherol (n = 80) and TPC (n = 80) analysis, respectively.
The γ-tocopherol content ranged from 329 ± 5 mg/L in Naz-Branching sesame oil to 1114±7 mg/L in Siah sesame oil and 169±6 to 577±1 mg/kg in sesame seed respectively. γ-tocopherol content of six cultivars increased significantly (p < 0.05) as the roasting temperature and time; until 200°C for 10 min, but they were decreased by roasting at 220 °C in longer time.
Also TPC increased significantly as the roasting temperature. The amount of TPC varied in different sesame cultivars from 20.109 ± 3.967 µM to 129.300±3.493 in Varamin and Naz-Branching sesame seed cultivars, respectively, also TPC increased from 70.953 ± 5.863 µM in unroasted Naz-Branching sesame seed to 129.300 ± 3.493 µM after roasting in 200°C for 20 min.
The present study showed that Iranian sesame seed can be considered as a good source of natural antioxidant specially after roasting. The optimum temperature and time roasting to obtain the most γ-tocopherol and total phenolic content was 200°C for 10 and 20 min, respectively.

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