Oven roasting effects on the physicochemical and chemosensory characteristics of hemp seeds (Cannabis sativa L.)

Physicochemical properties and flavor characteristics of hemp seeds (HS) were analyzed by roasting temperature (140 °C, 160 °C, 180 °C) and time (initial, 3, 6, 9, 12 min). HS with roasting showed a lightness (L*) with increasing roasting time. Total flavonoid content (TFC) decreased significantly with roasting compared to initial, and total phenolic content (TPC) tended to decrease with increasing roasting time at low temperatures (140 °C), but relatively high temperatures (160 °C and 180 °C), TPC increased significantly with increasing roasting time. The electronic tongue (E-tongue) analysis showed that the sweetness tended to increase with increasing roasting temperature and time, but the bitterness also tended to increase sharply when roasted at 180 °C. The electronic nose (E-nose) analysis showed that the main terpenes like d-limonene, α-pinene, caryophyllene, and β-pinene that exhibit fresh, herbal, and lemon-like aromas were decreased with increasing roasting time. But the volatile compounds with a sweet aroma produced like 2.5-dimethylpyrazine, 2,3-dimethylpyrazine and 2-methyl propanal were increasing with high temperatures (160 °C and 180 °C). This study will provide basic information for developing products using HS.