D'Elia, Luigi (2021) MICROALGAL BIOREFINERY FOR FOOD APPLICATION: PROCESS DEVELOPMENT FOR THERMO-RESISTANT ANTIOXIDANTS PRODUCTION. [Tesi di dottorato]

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Item Type: Tesi di dottorato
Resource language: English
Title: MICROALGAL BIOREFINERY FOR FOOD APPLICATION: PROCESS DEVELOPMENT FOR THERMO-RESISTANT ANTIOXIDANTS PRODUCTION
Creators:
Creators
Email
D'Elia, Luigi
luigi.delia@unina.it
Date: 12 July 2021
Number of Pages: 240
Institution: Università degli Studi di Napoli Federico II
Department: Biologia
Dottorato: Biotecnologie
Ciclo di dottorato: 33
Coordinatore del Corso di dottorato:
nome
email
Moracci, Marco
marco.moracci@unina.it
Tutor:
nome
email
Monti, Daria Maria
UNSPECIFIED
Date: 12 July 2021
Number of Pages: 240
Keywords: Algae, biorefinery, green chemistry, antioxidants
Settori scientifico-disciplinari del MIUR: Area 05 - Scienze biologiche > BIO/10 - Biochimica
Date Deposited: 22 Jul 2021 16:04
Last Modified: 07 Jun 2023 10:42
URI: http://www.fedoa.unina.it/id/eprint/13679

Collection description

Due to the toxicity of synthetic antioxidants used as food additives, nowadays the request for naturals ones is mandatory. Moreover, many natural antioxidants lose their biological activity after food thermal process treatment. Among natural sources, microalgae and cyanobacteria emerged in the last years as good antioxidants producers. The aim of the present PhD project was the production of thermo-resistant antioxidants from microalgae and cyanobacteria to be applied in the food industry, obtained with green extraction processes and/or solvents. First, a screening on twenty-five strains between microalgae and cyanobacteria, obtained from the Algal collection of University Federico II (ACUF), was carried out. The biomass was extracted in ethanol, considered a GRAS (Generally Recognized As Safe) solvent. Based on growth rate and in vitro antioxidant activity of the extracts, Enallax sp., Synechococcus bigranulatus and Galdieria sulphuraria were selected and their biocompatibility was assessed. Then, extracts were validated also for their ability to protect human keratinocytes from UVA induced oxidative stress, before and after the pasteurization process. Then, the secondary amine N-Ethylbutylamine (EBA) switchable solvent was used to extract antioxidants from biomass obtained from microalgae grown in bubble column photobioreactors (1L) and in thin layer photobioreactor (15L). Switchable solvents are particular liquids that can be converted from hydrophobic to hydrophilic form and viceversa, as a response to an external stimulus. The yields of antioxidants molecules obtained with EBA were similar to the yields obtained with a conventional method, Bligh e Dyer (B&D), on the same amount of biomass. Moreover, EBA extraction allowed to selectively extract a β-carotene enriched fraction and a zeaxanthin enriched fraction. The biocompatibility and antioxidants activity of both fractions, either before and after thermal treatment, open the way to use microalgae and cyanobacteria in food preservation.

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