Spray-dried propolis extract. I: physicochemical and antioxidant properties

Area of Science:

• Food Science
• Natural Products Chemistry
• Chemical Engineering

Background:

• Green propolis is a natural resin with valuable bioactive compounds.
• Propolis extracts are susceptible to degradation during processing.
• Spray drying is a common method for producing dry extracts.

Purpose of the Study:

• To investigate the impact of spray drying on the chemical and biological properties of green propolis extract.
• To determine the optimal spray drying parameters for preserving bioactive compounds and antioxidant activity.
• To quantify polyphenol and flavonoid recovery and assess the antioxidant capacity of the spray-dried extract.

Main Methods:

• Spray drying of alcoholic green propolis extract.
• Determination of total polyphenol content using the Folin-Ciocalteu method.
• Determination of total flavonoid content using the aluminum chloride colorimetric method.
• Assessment of antioxidant activity via membrane lipid peroxidation inhibition assay.

Main Results:

• Polyphenol content was significantly influenced by drying air outlet temperature (p<0.005) and its square.
• Flavonoid content was significantly influenced by the square of the outlet temperature (p<0.05).
• Polyphenol recovery ranged from 45.1-54.9%, and flavonoid recovery from 30.6-40.8%.
• Antioxidant activity was affected by extract feed rate and air outlet temperature (p<0.1%).
• Spray-dried propolis extract exhibited significant antioxidant activity, with IC50 values between 2.5-5.0 μg/ml.

Conclusions:

• Spray drying parameters, particularly air outlet temperature, significantly affect the polyphenol and flavonoid content of green propolis extract.
• While recovery rates vary, the spray-dried extract retains significant antioxidant properties.
• Further optimization of spray drying conditions can enhance the yield and efficacy of propolis-based products.