Citation: Ramires, F.A.; Bleve, G.; De Domenico, S.; Leone, A. Combination of Solid State and Submerged Fermentation Strategies to Produce a New Jellyfish-Based Food. Foods 2022, 11, 3974. https://doi.org/10.3390/ foods11243974 Academic Editors: Haohao Wu, Yanbo Wang and Na Sun Received: 10 November 2022 Accepted: 5 December 2022 Published: 8 December 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). foods Article Combination of Solid State and Submerged Fermentation Strategies to Produce a New Jellyfish-Based Food Francesca Anna Ramires 1 , Gianluca Bleve 1, * , Stefania De Domenico 1,2 and Antonella Leone 1,3,4 1 Consiglio Nazionale delle Ricerche, Istituto di Scienze delle Produzioni Alimentari, Unità Operativa di Lecce, 73100 Lecce, Italy 2 Dipartimento di Biologia e Scienze Biologiche e Ambientali (DiSTeBA), Campus Ecotekne, Università del Salento, 73100 Lecce, Italy 3 Consorzio Nazionale Interuniversitario per le Scienze del Mare (CoNISMa), Local Unit of Lecce, 73100 Lecce, Italy 4 National Biodiversity Future Center (NBFC), 90133 Palermo, Italy * Correspondence: gianluca.bleve@ispa.cnr.it Abstract: This study describes the set-up and optimization of a fermentation strategy applied to a composite raw material containing jellyfish biomass as the principal ingredient. New fermented food was developed by combining fresh jellyfish Rhizostoma pulmo and the sequential solid-state submerged liquid fermentation method used in Asian countries for processing a high-salt-containing raw material. Aspergillus oryzae was used to drive the first fermentation, conducted in solid-state conditions, of a jellyfish-based product, here named Jelly paste. The second fermentation was performed by inoculating the Jelly paste with different selected bacteria and yeasts, leading to a final product named fermented Jellyfish paste. For the first time, a set of safety parameters necessary for monitoring and describing a jellyfish-based fermented food was established. The new fermented products obtained by the use of Debaryomyces hansenii BC T3-23 yeast strain and the Bacillus amyloliquefaciens MS3 bacterial strain revealed desirable nutritional traits in terms of protein, lipids and total phenolic content, as well as valuable total antioxidant activity. The obtained final products also showed a complex enzyme profile rich in amylase, protease and lipase activities, thus making them characterized by unique composite sensory odor descriptors (umami, smoked, dried fruit, spices). Keywords: fermentation; edible jellyfish; safety assessment; quality traits; nutritional traits; odor profile; novel foods 1. Introduction Since ancient times, fermentation has been used as a process generally able to modify and produce foods. A number of raw meats, fish, milk, grains, fruits and vegetables can be fermented, producing a variety of preserved foods [1]. They are currently increasing in popularity since fermentation changes the nutrient content, digestibility and sensory characteristics of these products [2]. To our knowledge, the fermentation process has not yet been applied to jellyfish as raw material, with the exception of a Chinese patent related to the application of lactic acid bacteria to alum-treated jellyfish for the production of a fermented version of this product [3] and in the study of Wang et al. [4], where the effects of the inoculation of Lactobacillus strains into desalted alum-treated jellyfish were studied to enhance the flavor of this product and reduce the use of other preservatives. Asian countries are big producers and consumers of jellyfish, which represents a favorite and popular seafood. Indeed, jellyfish is regarded as a high-quality diet marine product [5]. In recent years, much attention has been paid to jellyfish, with the exploitation of new and more sustainable marine resources as food. The main products commercially Foods 2022, 11, 3974. https://doi.org/10.3390/foods11243974 https://www.mdpi.com/journal/foods