Emulsion gels as delivery systems for phenolic compounds: Nutritional, technological and structural properties

Area of Science:

• Food Science and Technology
• Nutritional Science
• Materials Science

Background:

• Polyphenols possess antioxidant properties beneficial for disease prevention.
• Emulsion gels (EGs) are suitable delivery systems for multiple bioactive compounds.
• Soy protein and alginate-based EGs offer a promising matrix for polyphenol encapsulation.

Purpose of the Study:

• To develop and characterize emulsion gels (EGs) incorporating different polyphenol extracts.
• To evaluate the impact of grape seed, olive, and grape total polyphenol extracts on EG composition and properties.
• To assess the stability and physical characteristics of polyphenol-enriched EGs.

Main Methods:

• Four EGs were produced: one control (ES) and three with polyphenol extracts (grape seed (ESG), grape seed and olive (ESO), grape total (EST)).
• EGs were formulated using olive oil, soy protein, alginate, and water, processed via homogenization and chilling.
• Composition, phenolic metabolite concentrations, technological, and structural properties were analyzed.

Main Results:

• Hydroxytyrosol was detected in all EGs, with ESO exhibiting the highest concentration.
• Gallic acid, flavanol monomers, and derivatives were present, with ESG showing the highest content.
• EGs displayed good thermal stability, while color and texture were significantly affected by the polyphenol source.

Conclusions:

• Alginate-soy protein-based EGs can effectively incorporate diverse polyphenol extracts.
• The type of polyphenol extract significantly influences the chemical composition and physical attributes of the EGs.
• These polyphenol-enriched EGs represent a functional food ingredient with potential health benefits.