Effect of roasting on tocopherol and total phenolic content of hemp seeds

Hemp is a single-year herbaceous plant of the Cannabinaceae family. As an economical valuable plant, its different parts are used in many different industries. In this study, some chemical components of hemp seeds, which consumed as snack food, obtained from Samsun Vezirköprü were determined. In addition, the effects of different roasting temperatures (140ºC, 160ºC and 180°C) and times (0 - 60 min, at 5 min. intevals) on the oxidative stability of hemp seed oil were investigated. The dry matter, ash, oil, protein, total tocopherol and total phenolic content of hemp seed were 91.49%, 5.06%, 37.27%, 26.13%, 798.86 mg/kg oil and 1022.11 mgGA eq./kg defatted fraction, respectively. Hemp seed is an important source of linoleic acid (54.85 %) as an essential fatty acid, and contains a high level of γ-linolenic acid (18.13%). The roasting process did not significantly affect the fatty acid composition of hemp seed (p>0.05). The peroxide and p-anisidine values of the samples roasted varied from 1.33 to 3.09 meq O2 /kg oil, and 1.65 to 43.27, respectively. The effects of roasting temperature and time on the peroxide, p-anisidine and totox values of the samples were significant (p <0.05). It was concluded that the hemp seeds contained significant amounts of linoleic acid, an essential fatty acid, and roasting process caused significant changes in lipid oxidation parameters. Keywords: Antioxidant, Roasting, Hemp seed, Chemical composition, Oxidation