Cyanide content, nutrient composition, physicochemical properties and sensory quality of flaxseed oil bodies prepared from flaxseeds (Linum usitatissimum L.) treated with different heat treatment methods

Abstract

Flaxseeds (Linum usitatissimum L.) were pre-treated with different heat treatment methods including steaming (100 °C for 10 min, 20 min or 30 min), roasting (120 °C for 10 min, 20 min or 30 min) and microwave (560 W for 1 min, 2 min or 3 min). Flaxseed oil bodies were prepared from the flaxseeds with and without heat treatment, and the cyanide content, yield rate, nutritional composition, physico properties, rheological behavior, and sensory characteristic were evaluated. These three types of heat treatment methods could effectively reduce the content (1.87-13.98 mg/kg) of toxic cyanide in flaxseed oil bodies. In addition, compared with the flaxseed oil bodies in steaming and roasting treated groups, the flaxseed oil bodies in microwave treated group exhibited higher yield rate (36.37-39.71 %), lower level of lipid oxidation (peroxide value, 6.10-7.10 mmol/kg lipid; thiobarbituric acid reactive substances, 1.99-2.20 mg MDA/kg lipid), higher content of polyunsaturated fatty acids (PUFAs, 63.33-64.22 %), better viscoelasticity, and better appearance color. Therefore, microwave treatment at 560 W with less than 3 min is a suitable preheating method of flaxseeds, thus improving the quality of the obtaind oil bodies.

Keywords: Flaxseed oil body; Heat treatment; Lipid oxidation; Safety; Sensory quality; Stability.