Encapsulation of Plant Extracts in a Psyllium/Starch Matrix: Synthesis and Functional Properties.

Area of Science:

• Food Science and Technology
• Materials Science
• Biochemistry

Background:

• Plant extracts are rich in bioactive compounds but often unstable and difficult to incorporate into food matrices.
• Polysaccharide-based carriers offer potential for stabilizing and delivering these sensitive compounds.
• Developing effective encapsulation methods is crucial for functional food innovation.

Purpose of the Study:

• To develop and characterize a binary polysaccharide carrier (starch/psyllium) for encapsulating plant extracts (Sambucus nigra, Aronia melanocarpa, Echinacea purpurea).
• To evaluate the physicochemical, rheological, and functional properties of the resulting biocomposites for food applications.
• To assess the impact of encapsulation on extract stability, bioactivity, and material properties.

Main Methods:

• Encapsulation of plant extracts using a stepwise starch/psyllium matrix workflow.
• Characterization using Scanning Electron Microscopy (SEM) and Fourier-Transform Infrared Spectroscopy (FTIR).
• Assessment of rheological behavior, thermal properties, surface energy, antioxidant capacity, and antimicrobial activity.

Main Results:

• SEM confirmed uniformly distributed, extract-loaded spherical structures within a porous matrix.
• FTIR indicated hydrogen bonding and hydrophobic interactions contributing to system stability.
• Biocomposites exhibited shear-thinning behavior, preserved color, altered thermal properties, and showed increased hydrophobicity.
• Encapsulation maintained or enhanced antioxidant capacity and modulated antimicrobial activity, with improved efficacy against Gram-negative bacteria.

Conclusions:

• The starch/psyllium matrix is a versatile platform for stabilizing plant extracts for food use.
• Encapsulation enhances physicochemical properties, such as moisture barrier potential and thermal stability.
• The developed biocomposites offer tunable functional attributes, including antioxidant and antimicrobial activities, suitable for functional food development.