Preservation of five edible seaweeds by high pressure processing: effect on microbiota, shelf life, colour, texture and antioxidant capacity

Abstract

Edible seaweeds Chondrus crispus (CC, Irish moss), Codium fragile (CF, green sea fingers), Himanthalia elongata (HE, sea spaghetti), Ulva lactuca (UL, sea lettuce) and Undaria pinnatifida (UP, wakame) were high pressure processed (HPP) at 400 or 600 MPa for 5 min and stored at 4 °C for up to 180 days. Viable bacterial counts on day 1 ranged from 4.24 log cfu/g for UP to 6.14 for CC. Estimated shelf life of control CC, CF, HE, UL and UP seaweeds, with the threshold set at 7 log cfu/g, was 7, 30, 60, 3 and 30 days, respectively. HPP treatments extended shelf life of seaweeds until at least day 180, except for CC treated at 400 MPa, until day 90. Most microbiological, physicochemical, colour, texture and enzymatic characteristics of seaweeds varied significantly with HPP treatment and storage time. HPP treatments generally preserved total polyphenol content and antioxidant capacity of seaweeds until day 180. Exceptions were total polyphenol content of HE and UP and antioxidant capacity of CC and UP, which suffered losses close to half of the initial values. HPP showed to be a valid processing technology for extending the shelf life of edible seaweeds under refrigerated storage.