The Entrapment of Bioactive Compounds of Olive Leaf Extracts into a Sucrose Matrix by Co-Crystallization Process: Structural Characterization and Stability

Olive leaf is one of the richest sources of phenolic compounds with antioxidant properties. Use of these compounds as food and pharmaceutical ingredients face challenges like protecting them during storage and food processing. In this study, bioactive compounds of olive leaf aqueous extract were encapsulated into a sucrose matrix using co-crystallization process. The co-crystallized powders were characterized in terms of their morphology, thermal behavior, chemical structure and also polyphenols and antioxidant activity retention rate, under various storage conditions such as light, moisture and temperature for period of 4 months. DSC thermograms for all samples, indicated the peaks around 190 C typical of sucrose melting behavior. FT-IR analysis for all samples showed typical bands of sucrose molecule. At the end of storage time, co-crystallized products containing 10% extract which were stored at dark condition, showed the highest preservation rate of polyphenols around 92% and antioxidant activity around 77.35%. A significant decrease (P˂0.05) was observed in preservation rate of polyphenols and antioxidant activity for powders stored in artificial light and RH=75% conditions compared to storage at dark and 4 °C conditions.