Impact of microwave roasting on physicochemical properties, maillard reaction products, antioxidant activity and oxidative stability of nigella seed (Nigella sativa L.) oil

In this study, oils extracted from nigella seeds (NS) subjected to microwave roasting at 180, 360, 540 and 720 W for 5 and 10 min were evaluated for quality and stability characteristics. The impact of microwave powers on oil yield, pigment content, Maillard reaction products (MRPs), radical scavenging activity (RSA), color, viscosity, total phenolic content (TPC), oxidative stability index (OSI) and fatty acid composition (FAC) of oil was studied. TPC, RSA, OSI, MRPs, viscosity, chlorophyll and carotenoid contents were higher in oil of NS heated at 720 W for 10 min while maximum oil yield and low acid value was observed for NS heated at 540 W for 10 min. FAC was slightly influenced by microwave roasting and FTIR spectra exhibited a minor difference in intensities of peaks at 3009, 2925, 2854, 1745 and 1161 cm-1. The results of the study indicated that microwave roasting improves NS oil quality characteristics.

Automated summary

The study showed that high power microwave roasting (720 W) for 10 minutes resulted in black seed oil with higher total phenolic content, radical scavenging activity, and oxidative stability index, while the highest oil yield and low acid value were observed for black seed oil roasted at 540 W for 10 minutes. Microwave roasting had a slight influence on the fatty acid composition.