Comparative study of the bioactive compounds, flavours and minerals present in black pepper before and after removing the outer skin

Black pepper is one of the most widely used spices due to its characteristic pungency and bioactive abilities. This spice is made from the ripened fruits of pepper plants, and sometimes the outer layer is removed for use in light-coloured foods. The piperine, total phenols, total flavonoids, volatile flavours and minerals in black pepper were determined before and after removing the outer skin and their advantages were characterized. The total flavonoid and total phenol concentrations in white pepper after removing the skin were 24.0 and 23.9% lower than those in black pepper before removing the skin while the piperine content was 8.2% higher after removing the skin. The radical scavenging activity of the DPPH and ABTS were decreased by 66.2% and 54.3%. Most flavour compounds in black pepper were reduced by removing the outer skin while some in the low peak areas were increased. Removing the outer skin led to a more delicate flavour and higher bioactivity in black pepper.