Effect of hot oven and microwave roasting on garden cress (<i>Lepidium sativum</i>) seed flour quality and fatty acid composition, thermal and dielectric properties of extracted oil

Abstract

Summary The effect of roasting (microwave and oven) on functional properties of garden cress ( GC ) ( Lepidium sativum ) seed flour, oil yield and fatty acid composition, colour, melting and crystallisation of oil were investigated. The obtained results revealed that roasting significantly influenced the physicochemical properties of the flour, and doubled the oil yield. The GC oil was rich in α‐linolenic acid (31.05%) and oleic acid (22.1%) along with the presence of other fatty acids including linoleic acid, erucic, stearic and arachidic acid. No significant difference in MUFA content and the U/S fatty acid ratio of GC oil was observed due to roasting. The oil sample exhibited two distinct endothermic melting transitions (≈ −35 °C and −19 °C) and one crystallisation peak (≈ −54 °C), those peaks were unaffected by the roasting. These observations were confirmed by FTIR spectroscopy. Therefore, roasting pretreatment is a promising technique to improve GC oil yield while preserving oil quality.