Abstract
The increasing global demand for sustainable protein sources, driven by population growth, environmental challenges and shifting dietary habits has heightened the need for innovative functional foods that can provide both nutrition and health benefits. This thesis addressed this challenge by encouraging the consumption of alternative protein sources through the development of novel fermented foods. By upcycling agri-food by products and utilizing fermentation driven processes, this research focused on transforming underutilized resources such as whey milk, olive oil mill wastewater OMWW, and wine pomace into functional ingredients. These ingredients are not only rich in proteins and bioactive compounds, but also contribute to sustainable food systems and a circular economy.
The first study investigated the recycling of whey milk by products a protein source into fruit smoothies a source of phenolic compounds through starter assisted fermentation. Five lactic acid bacteria LAB strains were selected as optimal starters for improving antioxidant activity, protein digestibility, and phenolic release, particularly anthocyanins. The fermentation process enhanced the nutritional profile of the smoothies, providing a valuable method for upcycling whey, a major by product of dairy production, into functional foods that offer health promoting benefits and address protein demand in balanced diets.
The second study focused on the valorization of OMWW, a challenging waste product from olive oil production, by combining it with Chlorella vulgaris, a protein rich microalgae. The fermentation of this mixture using LAB and yeast starters not only facilitated microbial growth but also unlocked valuable polyphenolic compounds and bioactive metabolites with antifungal and nutritional properties. When incorporated into wheat bread as a functional ingredient, the fermented OMWW CHL mixture enhanced the breads sensory attributes, extended its shelf life and offered an alternative source of protein to support dietary needs.
The third study explored the synergistic fermentation of C. vulgaris and wine pomace, another underutilized by product of the wine industry. By leveraging the metabolic potential of LAB and yeast strains, the fermentation process improved sugar utilization and enhanced the bioavailability of phenolic compounds. Additionally, fermentation generated potential bioactive peptides, enhanced antioxidant activity and protein quality. This study demonstrated the potential of combining plant based protein sources with polyphenol rich by products to develop novel functional ingredients that promote human health and meet the rising demand for alternative proteins.
Together, these studies highlight the role of fermentation in transforming agri-food by products into valuable, protein rich functional ingredients, offering innovative solutions for sustainable food production and addressing critical protein demands in modern diets.