Valorization of marine biomass for the development of biopolymeric materials and additives with functional properties
- Autores: Vera Cebrian Lloret
- Directores de la Tesis: Amparo Lopez Rubio (dir. tes.), Marta Martínez Sanz (dir. tes.), Antonio Martínez Abad (dir. tes.), Pau Talens Oliag (tut. tes.)
- Lectura: En la Universitat Politècnica de València ( España ) en 2024
- Idioma: inglés
- Tribunal Calificador de la Tesis: Koro de la Caba Ciriza (presid.), Amparo Ribes Greus (secret.), Marta Fernández García (voc.)
- Programa de doctorado: Programa de Doctorado en Ciencia, Tecnología y Gestión Alimentaria por la Universitat Politècnica de València
- Materias:
- Enlaces
- Tesis en acceso abierto en: RiuNet
- Resumen
This doctoral thesis focused on the valorization of different sources of marine biomass with the main purpose of developing biopolymeric materials and ingredients for the food industry. Thus, in the first part of the thesis, the valorization of biomass from different algae species was carried out to identify compounds of interest and assess their potential to produce biopolymeric materials and protein-rich food ingredients. Among these species was Ruguloperyx okamurae, an invasive brown seaweed that poses a threat to marine ecosystems. However, this species was shown to have significant potential as a sustainable source of bioactive compounds, transforming its role as a threat into a valuable opportunity.
Red seaweed biomass was also highlighted for its potential in a variety of applications, including the development of cost-effective and environmentally friendly materials for food applications obtained through minimal processing. In this context, the composition and structure of the algal cell walls played a crucial role in understanding how each species behaves during processing and in the properties of the resulting films. In addition to the production of biopolymeric materials, red seaweeds were also studied as a source of proteins for human consumption. Although native seaweeds had low digestibility, this was improved through processing. However, it is important to note that, despite the improvement in digestibility, processing could induce the degradation of more labile amino acids, having a negative impact on the nutritional quality of the proteins.
In the second part of this thesis, several species of red seaweeds were explored to extract agar more efficiently by simplified methods, and the suitability of the extracts obtained to develop biopolymeric materials and hydrogels for food applications was evaluated. It could be observed that the degree of agar purification had a significant impact on the final properties of both films and hydrogels. In the case of films, those made of pure agar exhibited superior properties; however, they underwent significant changes in their semicrystalline structure during storage. In contrast, those films derived from less purified agar extracts showed greater stability over time, suggesting the potential of less purified agars as additives to reduce costs and improve the stability of pure agar films. Regarding the hydrogels, agar purification led to the formation of hydrogels with significantly higher strength and hardness. On the other hand, the simplified extraction protocol produced less purified agar fractions containing other compounds such as proteins, polyphenols, and minerals. Although this resulted in less rigid and resistant hydrogels, this feature could be advantageous for the production of hydrogels with bioactive properties.
In the third and last part of the thesis, the valorization of industrial wastes generated after alginate extraction was addressed, with the purpose of obtaining cellulosic fractions by simplified methods for their application in the production of biopolymeric materials. In this context, it was observed that the residues of Alaria esculenta and Saccharina latissima were suitable for the extraction of cellulosic fractions, while Ascophyllum nodosum might be more interesting for the production of fucoidan-rich extracts. Cellulosic fractions with higher purity produced films with more desirable mechanical properties and visual appearance. Conversely, less purified fractions presented a greater barrier to water vapor. According to the results, it was determined that the simple application of an alkaline treatment could produce cellulosic fractions that resulted in films with an optimal balance between functional properties and economic and environmental efficiency in biopolymeric material production.
