Volatile compounds and odour characteristics of five edible seaweeds preserved by high pressure processing: Changes during refrigerated storage

Abstract

Edible seaweeds Chondrus crispus, Codium fragile, Himanthalia elongata, Ulva lactuca and Undaria pinnatifida, without any treatment (control seaweeds), were stored at 4 °C for 15, 30, 60, 15 and 30 days, respectively, until microbial counts exceeded 7 log cfu/g. High pressure processed (HPP) seaweeds, treated at 400 or 600 MPa for 5 min on day 2 after collection, were held at 4 °C until day 180. At the start of storage, 133 volatile compounds were detected in control seaweeds, with 89, 31, 45, 79 and 69 compounds found in C. crispus, C. fragile, H. elongata, U. lactuca and U. pinnatifida, respectively. Chemical groups including the highest number of compounds were aldehydes (24), alcohols (23), ketones (18), hydrocarbons (17) and benzene compounds (14). At the end of storage, 131 compounds were detected in control seaweeds, including 18 aldehydes, 28 alcohols, 23 ketones, 14 hydrocarbons and 13 benzene compounds, and 164 compounds in HPP-treated seaweeds, including 23 aldehydes, 31 alcohols, 19 ketones, 23 hydrocarbons and 15 benzene compounds. Increases in the levels of alcohols, benzene compounds and S-compounds and decreases in hydrocarbons, aldehydes and acids were recorded during storage of some control seaweeds, and increases in the levels of alcohols, acids and N-compounds and decreases in aldehydes, ketones and furans during storage of some HPP-treated seaweeds. Odour acceptance fell below rejection threshold as early as on day 15 for control U. lactuca while it remained acceptable until day 60 for control H. elongata and until day 180 for all the HPP-treated seaweeds. HPP treatment at 400 to 600 MPa for 5 min, in combination with refrigerated storage, is a useful tool for seaweed preservation, given its beneficial effects on microbial quality and sensory characteristics.