Amylase and Helicobacter pylori inhibition by phenolic extracts of pineapple wastes bioprocessed by Rhizopus oligosporus

This study focused on the potential functional activity of phenolic-enriched pineapple wastes bioprocessed by Rhizopus oligosporus. Using the phenolic-enriched bioprocessed extracts, amylase inhibition relevant to Type 2 diabetes and Helicobacter pylori inhibition linked to stomach ulcer were investigated. Two treatments were studied: 9 g of pineapple residue plus 1 g of soy flour (P9) and 5 g of pineapple residue plus 5 g of soy flour (P5). Extracts obtained after 2 and 10 days of growth were selected to represent early and late stages of bioprocessing based on phenolic content. Potent alpha-amylase inhibition was found in P9 treatment at 2 days. of fungal growth and was maintained after subsequent boiling, freeze-drying and/or autoclave treatment. Amylase inhibitory activity did not correlate with the DPPH radical scavenging antioxidant activity of the extracts and therefore it is likely linked to the structure of the phenolic compounds. H. pylori inhibitory activity was found in P5 treatment after 10 days of R. oligosporus growth and may be linked to phenolic compounds present at this stage.