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

Abstract

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/cm3; tapped density – 0.70–0.53 g/cm3), 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.