Impact of Monascus purpureus combined with Lactobacillus plantarum and Saccharomyces cerevisiae fermentation on nutritional and flavor characteristics of Pyropia yezoensis

Fermentation can promote various properties of food. This study investigated the impact of fermentation by Monascus purpureus combined with Lactobacillus plantarum and Saccharomyces cerevisiae on the physicochemical and flavor characteristics of Pyropia yezoensis . Results indicate that the protein and free amino acid content increased threefold. A total of 62 volatile flavor compounds were identified by GC-IMS. Alcohols, ketones and esters were enhanced with 2- to 6-fold, while aldehydes were reduced by 76.56 %, contributing to the enhancement of pleasant fragrances and the reduction of fishy and seawater odors. As for the non-volatile properties, the content of organic acids and free amino acids increased from 2.18 mg/g and 0.19 mg/g to 46.03 mg/g and 4.93 mg/g, respectively, as assessed by HPLC and amino acid analyzer. The metabolic pathways of non-volatile substances were speculated upon. This work provides a basic theory and a practical reference for fermentation food processing of P. yezoensis .