VALORISATION OF YELLOW PEA BY-PRODUCTS THROUGH Lactobacillus plantarum AND Kluyveromyces marxianus SOLID-STATE FERMENTATION

The global increase in food waste, particularly from agro-industrial processing, demands sustainable solutions. Pulses, including yellow peas (Pisum sativum L.), play a key role as plant-based protein sources but often generate by-products with limited applications due to structural and sensory limitation. This thesis investigates the valorisation of yellow pea seed by-products, specifically seeds discarded during industrial selection, through solid-state fermentation (SSF) using Lactobacillus plantarum and Kluyveromyces marxianus. Initial pre-trials were conducted to evaluate fermentation feasibility and pre-treatment strategies. Following this, an optimized experimental design was applied, incorporating different thermal pre-treatments and microbial inoculum levels. Fermentation effectiveness was assessed through pH monitoring, while structural and aromatic modifications were analysed using FTIR spectroscopy and GC-MS coupled with multivariate data analysis (PCA). The application of multivariate data analysis revealed distinct clustering patterns and provided clear insights into the discriminative effects of pre-treatment conditions and fermentation strategies. Results demonstrated a good synergic metabolism of lactic acid bacteria and yeasts which enhance acidification, modifications in protein secondary structures detected by amide-related bands (e.g., Amide I and Amide II) and saccharides band changes, concluding with the reduction in off-flavour volatiles (e.g., hexanal, 1-pente-3ol) and promotion of more desirable and positive aromatic notes (e.g., esters). These findings highlight the potential of SSF as a sustainable and effective method for upcycling yellow pea by-products into value-added functional ingredients. Furthermore, they underscore the need to optimise pre-treatment protocols and to deepen the investigation through quantitative analyses of the resulting bioactive and nutritional compounds.