Protective Effects of Polysaccharides on Antifungal Activity of Bread Waste-derived Bioactive Peptides During Freeze Drying

Abstract Bioactive peptides (BPs) derived from agri-food side-streams display great potential as functional ingredients and nutraceuticals. However, BPs can be susceptible to environmental stressors and food processing conditions and typically exist as an aqueous mixture of various peptides, making their storage and use in foods very challenging. Microencapsulation offers a solution, utilizing suitable wall materials to create a protective matrix and transform them into powders for improved stability and application versatility. Here, we investigated the possibility of creating freeze-dried microencapsulated BP powders from bread waste using maltodextrin as the wall material to maintain their antifungal properties against Penicillum albocoremium , Eurotium herbariorum and Penicillium roqueforti fungi. The results were compared to those obtained from galactoglucomannans (GGM) and glucuronoxylans (GX) sourced from forest industry side-streams, aiming to explore their potential suitability as innovative materials for microencapsulating BPs. Maltodextrin microcapsules exhibited the highest inhibition rate on the tested fungi (10 − 44%), followed by GX (26 − 39%) and then GGM (9 − 14%) counterparts. Interactions between wall materials and BPs, as illustrated by FTIR analyses, were found to be the cause of variations in antifungal activities among BP microcapsules. The use of wall materials, especially wood hemicelluloses, facilitated freeze drying of BPs. However, their application in food products is restricted by the decline in the BP bioactivity resulting from the freeze drying process. For this reason, additional research on alternative drying methods is needed. The results of this study are expected to open new ways of production of stable functional ingredients from side-streams of the forest and food industries.