Effects of high pressure processing on activity and structure of soluble acid invertase in mango pulp, crude extract, purified form and model systems

The effects of high pressure processing (HPP) on the activity of soluble acid invertase (SAI) in mango pulp, crude extract, purified SAI and purified SAI in model systems (pectin, bovine serum albumin (BSA), sugars and pH 3-7) were investigated. The activity of SAI in mango pulp was increased after HPP, and that in crude extract stayed unchanged. The activity of purified SAI was decreased after HPP at 45 and 50 degrees C. Pectin exhibited a concentration-dependent protection for purified SAI against HPP at 50 degrees C/600 MPa for 30 min. Pectin that had an esterification degree (DE) of 85% exhibited a greater protection than pectin that had a DE of 20-34%. BSA, acidic pH (3-6) and sucrose also exhibited protection for purified SAI against HPP. HPP at 50 degrees C/600 MPa for 30 min disrupted the secondary structure and tertiary structure of purified SAI, but no aggregation of purified SAI was observed after HPP. (C) 2017 Elsevier Ltd. All rights reserved.