The Controlled Semi-Solid Fermentation of Seaweeds as a Strategy for Their Stabilization and New Food Applications

Abstract

For centuries, macroalgae, or seaweeds, have been a significant part of East Asian diets. In Europe, seaweeds are not considered traditional foods, even though they are increasingly popular in Western diets in human food applications. In this study, a biological processing method based on semi-solid fermentation was optimized for the treatment of the seaweed Gracilaria gracilis. For the first time, selected lactic acid bacteria and non-conventional coagulase-negative staphylococci were used as starter preparations for driving a bio-processing and bio-stabilization of raw macroalga material to obtain new seaweed-based food prototypes for human consumption. Definite food safety and process hygiene criteria were identified and successfully applied. The obtained fermented products did not show any presence of pathogenic or spoilage microorganisms, thereby indicating safety and good shelf life. Lactobacillus acidophilus-treated seaweeds revealed higher α-amylase, protease, lipase, endo-cellulase, and endo-xylanase activity than in the untreated sample. This fermented sample showed a balanced n-6/n-3 fatty acid ratio. SBM-11 (Lactobacillus sakei, Staphylococcus carnosus and Staphylococcus xylosus) and PROMIX 1 (Staphylococcus xylosus) treated samples showed fatty acid compositions that were considered of good nutritional quality and contained relevant amounts of isoprenoids (vitamin E and A). All the starters improved the nutritional value of the seaweeds by significantly reducing the insoluble indigestible fractions. Preliminary data were obtained on the cytocompatibility of G. gracilis fermented products by in vitro tests. This approach served as a valid strategy for the easy bio-stabilization of this valuable but perishable food resource and could boost its employment for newly designed seaweed-based food products.

Liquid submerged fermentation by selected microbial strains for onion skins valorization and its effects on polyphenols

“…A spectrometric method was also performed for the measurement of lipase activity using p-nitrophenyl palmitate (p-NPP) as a substrate (Park et al 2007 ). The assay was performed on 1 mL of crude enzyme solution properly diluted as described by Maiorano et al ( 2022 ). One unit (U) of lipase activity was defined as the amount of lipase required to release 1 µmol of p -nitrophenol from p -NPP in 1 min under the corresponding conditions.…”

“…This assay specifically detects the activity of endo-xylanase and not the activity of the enzyme xylosidase or exo-xylanase. The endo-xylanase activity of the supernatants was assayed using Xylanase Assay kits (XylX6 method) (Megazyme, Bray, Ireland), by following the manufacturer’s instructions as described by Maiorano et al ( 2022 ). The endo-xylanase activity (one unit) was defined as 1 µmol of pNP released from XylX6 per minute.…”

“…The catalytic activity of microbial cellulases was tested using a cellulase assay kit (CellG5, Megazyme, Bray, Ireland), as the method provided by the manufacturer, and as described by Maiorano et al ( 2022 ). The cellulase activity (one unit) was defined as 1 µmol of pNP released from CellG5 per minute.…”

Combination of Solid State and Submerged Fermentation Strategies to Produce a New Jellyfish-Based Food

“…Yeasts and bacteria strains were individually inoculated as starters at a final concentration of about 10 7 CFU/g (as already used for starter formulations in fermentation of vegetables from terrestrial and marine origin by Tufariello et al [ 35 ], Maiorano et al [ 36 ]) into the sterilized Jelly paste. The bacterial and yeast strains individually used as candidate starters, all belonging to the CNR ISPA-LE microbial collection, were Bacillus amyloliquefaciens MS3, Lactiplantibacillus plantarum C 180-11, Leuconostoc mesenteroides KT 5-1, Saccharomyces cerevisiae LI 180-7 and Debaryomyces hansenii BC T3-23.…”

An overview of fermentation in the food industry - looking back from a new perspective

“…The fermentation of seaweeds increased antioxidant and antimicrobial activity (Fatmawati et al 2022 ). The increase in antimicrobial activity implicated the protection of seaweeds from pathogenic and spoilage bacteria and improved the seaweeds' nutritional value by reducing the insoluble and indigestible fractions (Maiorano et al 2022 ). Figure 2 shows the fermentation process.…”