Development of Biopolymeric Microparticles as Anthocyanin Stabilizers

The objective of this research was to evaluate the feasibility of stabilizing anthocyanins (AC) through their encapsulation in sodium caseinate (NaCAS) microgels. To investigate this, a comprehensive examination of the formation of complexes between AC from blueberries and blackberries and NaCAS was conducted utilizing fluorescence spectroscopy and Fourier Transform Infrared spectroscopy (FTIR). This study was conducted in both the absence and presence of tara gum (TG), due to the established formation of NaCAS microgels at specific concentrations of both biopolymers during the acid gelation process. The extracts from both berries caused static fluorescence quenching of NaCAS and altered the peak position and/or intensity of the ─OH, C─H, amide I, amide II, and COO^- protein bands. These results indicate that hydrogen bonding and hydrophobic interactions play a role in the formation of AC-NaCAS complexes. The formation of these complexes leads to conformational changes in NaCAS, which are further enhanced by the presence of TG. The increase in the random coil content of NaCAS, along with the presence of TG, enhances protein-protein interactions, resulting in the formation of NaCAS microgels that incorporate AC, as confirmed by confocal microscopy. PRACTICAL APPLICATIONS: The stabilization of AC from berries through AC-NaCAS/TG microgels (∼6-15 µm) offers an innovative approach to incorporate natural antioxidants into foods such as yogurts, dairy and non-dairy desserts, spreadable cheeses, and baked goods, or as functional ingredients in beverages. These microgels can enhance nutritional value, improve sensory properties such as texture and creaminess, and contribute to the overall stability of food products during processing and storage. Future studies could further explore interactions with other food components to optimize functional and sensory performance in real food systems.