Molecular profile of polysaccharides from upcycled products: digestive, physiological, biological, and prebiotic properties
- Autores: Julio Estebán Salazar Bermeo
- Directores de la Tesis: Nuria Martí Bruñá (dir. tes.), Manuel Valero Roche (codir. tes.)
- Lectura: En la Universidad Miguel Hernández de Elche ( España ) en 2025
- Idioma: español
- Tribunal Calificador de la Tesis: Luis Pérez García-Estañ (presid.), Manuel Lainez Andres (secret.), Farah Hosseinian (voc.)
- Programa de doctorado: Programa de Doctorado en Biología Molecular y Celular por la Universidad Miguel Hernández de Elche
- Materias:
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- Resumen
Upcycling fruit by-products demands careful monitoring of processing technologies to yield physiologically active molecules, such as (poly)phenols and dietary fibre (DF) prebiotics , with proved bioactive potential. Upcycling by-products must ensure besides consumer acceptability, appropriate digestibility, and fermentability, contributing to gut microbiota modulation and intestinal health. Additionally, bioactive compounds must be metabolized through efficient biochemical pathways to confer health benefits and mitigate disease risks. Persimmon (Diospyros kaki Thunb.) fruit by-products offer a distinctive profile as a model system for upcycling bioactive compounds research.
Persimmon by-products, rich in (poly)phenols, carotenoids, and DF, represent a valuable resource for biotechnological, nutraceutical, pharmaceutical, and food applications. Across this thesis, we have revealed, in four chapters, the potential of persimmon upcycled DF for applications ranging from epithelial modulators to nutraceutical delivery systems through the optimization of novel extraction technologies, the bioactive potential of extracted fractions, and their molecular interactions.
In the first chapter, we studied the health benefits of persimmon processed by-products, particularly its prebiotic properties and impact on gut health. Through in vitro digestion and fermentation with probiotic strains like Lactobacillus casei and Bifidobacterium bifidum, persimmon fibres promoted the production of short-chain fatty acids, particularly butyrate; short fatty acids are studied for maintaining gut health, as they support intestinal epithelial integrity and reduce inflammation. Further studies using Caco-2 cell monolayers demonstrated the fibre's ability to enhance intestinal barrier function by increasing trans-epithelial electrical resistance (TEER) values. The antioxidant properties of persimmon obtained fibres were another focal point of this thesis. Rich in (poly)phenols and carotenoids, the extracted fractions exhibited strong radical-scavenging activity when measured by DPPH. and ABTS.+ radical assays.
Novel extraction technologies played a pivotal role in the second and third chapter. Ultrasound assisted extraction (UAE), Natural deep eutectic solvents (NADES) and Vacuum instantaneous expansion (USEX), were employed to maximize the extraction of bioactive compounds while preserving their structural integrity. These techniques yielded polysaccharides and phenolic compounds with enhanced antioxidant activity and fermentability. USEX was combined with UAE to optimize the processing of rhamnogalacturonan-I (RG-I) polysaccharides. This coupling significantly optimized antioxidant activity and Zeta-potential, creating a stable and functional polysaccharide matrix for various applications. Structural and biochemical profiling of these polysaccharides using mass spectrometry, infrared spectroscopy, and microscopy analyses revealed information about their composition and properties.
In the second chapter, persimmon fibre's bioactive potential studies extended beyond health benefits into functional applications. We incorporated DF fractions into prototype functional beverages, including isotonic and dairy-based drinks. Enriched beverages not only met consumer preferences for taste and texture but also delivered enhanced nutritional benefits.
