Fungi, including filamentous organisms such as yeasts, play essential roles in various processes such as nutrient exchange in ecosystems, the cultivation of mushrooms, and solid-state fermentation (SSF). SSF involves microbial growth on solid substrates without free water, leading to the production of enzymes, bioactive compounds, and biofuels. This fermentation method offers advantages like lower production costs, reduced waste disposal issues, and the efficient utilization of agricultural residues and fruit and vegetable by-products. Filamentous fungi excel in SSF due to their enzyme secretion capacity and ability to produce valuable compounds. The process is influenced by biological, physico-chemical, and environmental factors, requiring careful optimization for optimal results. Fruit and vegetable by-products are increasingly recognized as valuable substrates for SSF, offering rich sources of bioactive compounds and high nutritional value. The optimization of SSF processes, compatibility with various substrates, and potential for producing diverse value-added products make SSF a promising method for sustainable resource utilization and enhanced product development. Future research should focus on improving process efficiency, expanding the substrate range, enhancing product quality and yield, and integrating SSF with other technologies for enhanced production capabilities.

Carrot pomace (CP) represents a promising source of dietary fiber with potential applications in functional food systems. This study investigated the effects of enzymatic hydrolysis (Pectinex^® Ultra Tropical, Celluclast^® 1.5 L, and Viscozyme^® L) on the chemical composition, technological, and functional properties of CP. The untreated CP was characterized by a high total dietary fiber (TDF) content, predominated by insoluble dietary fiber (IDF), with a soluble dietary fiber (SDF)/IDF ratio of 1:1.6. Enzymatic treatment significantly reduced TDF and IDF (up to 54.1% and 58.5%, respectively) while increasing reducing sugars by 2.3–3.4-fold and changing the SDF/IDF ratio to 1:1.2–1.5. Technological properties were altered, with decreased oil-retention capacity and color intensity, whereas water-solubility index increased, and water-swelling capacity was enzyme-dependent. Emulsion stability was enhanced in enzymatically treated samples. Total phenolic content increased in the soluble fraction (up to 21.8%). Functional properties, including cholesterol-binding, sodium cholate-binding, and glucose-adsorption capacities, were significantly influenced by enzymatic modification and pH conditions (for cholesterol-binding capacity). Prebiotic activity varied depending on enzyme treatment, and Celluclast^®-modified CP demonstrated the highest prebiotic index, exceeding that of inulin for selected strains. Overall, enzymatic hydrolysis effectively modulated the structural and functional properties of CP, highlighting its potential as a value-added ingredient for the formulation of functional and prebiotic food products.

Carrot pomace (CP) is a fibre-rich by-product of juice production whose application in food products is limited by the predominance of insoluble dietary fibre. This study aimed to evaluate differences in dietary fibre composition and technological and functional properties between untreated and enzyme-treated CP and to assess its potential application in food supplement formulations. CP was treated with the commercial enzyme preparation Sternzym^® Oilex, containing pectinase and hemicellulolytic side activities. Soluble (SDF) and insoluble (IDF) dietary fibre contents, technological and functional properties, phenolic compounds, and antioxidant activity were determined. Bacterial growth promotion was evaluated in vitro using the prebiotic index (PI). Untreated and enzyme-treated CP were subsequently evaluated as carriers for Lactiplantibacillus plantarum in freeze-dried food supplement formulations, and bacterial viability was monitored during three months of storage. Compared with untreated CP, enzyme-treated CP contained less SDF and IDF and exhibited a different SDF:IDF ratio. Pomace modification increased water- and oil-retention capacities, solubility index, and the content of soluble phenolic compounds, but decreased water swelling capacity. The enzymatically modified CP exhibited higher PI values than inulin in assays with both L. plantarum and L. acidophilus. Enzymatic treatment also improved cholesterol- and sodium cholate-binding capacities under neutral pH conditions, while glucose adsorption decreased. During storage, the highest L. plantarum viability was maintained in the sample containing untreated CP and remained at approximately 8 log₁₀ CFU/g after three months. Overall, CP is a promising source of dietary fibre and bioactive compounds and may serve as a carrier for probiotic bacteria in food supplements.