Physico-functional and quality attributes of microwave-roasted black pepper (Piper nigrum L.)

Abstract The present study was focused on microwave-roasting (300–600 W for 5–15 min) on the quality attributes of black pepper. The increase in roasting power and time decreased the lightness, L * (51.85–25.64), and a visible color change from medium light to dark was observed. Roasting reduced the powder density (bulk density – 0.51–0.41 g/cm 3 ; tapped density – 0.70–0.53 g/cm 3 ), flowability, and crystallinity and showed a higher Hausner’s ratio (1.29–1.42), carr’s index (22.43–29.38), compressibility index (0.22–0.30), cohesion index (13.96–34.80 g mm/g), and caking strength (5225.79–12040.44 g mm). All the samples showed stable flow, and the stability was in the range of 1–1.11. Sample roasted at lower roasting levels had higher antioxidant properties viz. , phenolic content (36.20–79.62 mg GAE/100 g), flavonoid content (350.52–566.45 mg QE/100 g), % DPPH scavenging activity (53.97–85.12 %), and ABTS assay (2.33–4.81 mmol TE/100 g), whereas the higher roasting conditions reduced the TFC and % DPPH inhibition. The principal component analysis (PCA) and a simple least square method (SLSM) with maximum desirability were used to develop the correlation and optimize the roasting condition, respectively. Results showed that the roasting time had a prominent effect on different quality attributes compared to roasting power, and the optimum roasting condition for BP is 300 W, 15 min.