Modulating the phenolic content and biological activity of pear pomace powder by granulation and extraction pre-treatment

Abstract The aim of this study was to determine the effect of the degree of granulation of the pear ( Pyrus L.) pomace powder, and the method of pre-treatment on the phenolic content and bioactivities. The dried pear pomace was fractionated into granulations: 1 mm, 710 µm, 180 µm, 75 µm, 53 µm, then treated with methanol extraction and two-step extraction with Soxhlet method. The results obtained confirmed the possibility of modulating the phenolic profile and biological activities through the selection of particle size and extraction methods. Total phenolic compounds was 375.0 to 512.9 mg gallic acid/100 g dw and total flavonoid compounds was 24.7 to 34.6 mg quercetin/100 g dw. Two-step extraction (1 - Soxhlet extraction, 2 - MeOH extraction) provided antioxidant activity of up to 418.8 (FRAP) and 340.0 mg Trolox/100 g dw (DPPH). The lowest granulation of pear pomace powder indicated the highest inhibitory activity of α-amylase, β-glucosidase (as antidiabetic activity), angiotensin-converting enzyme (as antihypertensive activity). Antibacterial activities against Gram (-) bacteria ( E. coli ) and Gram (+) ( S. aureus ) were also very significant in the pomace samples, but most noticeably in those extracts from Soxhlet technique. The study not only highlights the potential for pear pomace but also points towards the use of different processing techniques in designing products with enhanced health-promoting potential while supporting waste-free production.