Upcycling Walnut Green Husk: Polyphenol-Rich Extracts from Traditional vs. Organic Crops for Spray-Dried Vegan...

Area of Science:

• Agricultural Science
• Food Science
• Biotechnology

Background:

• Agro-industrial by-products like walnut green husk are often underutilized.
• Polyphenols from plant sources are recognized for their antioxidant properties.
• There is a growing demand for natural, plant-based antioxidants in the food industry.

Purpose of the Study:

• To valorize walnut green husk by extracting antioxidant polyphenols.
• To develop a stable, vegan antioxidant powder using chickpea protein encapsulation.
• To assess the antioxidant potential and safety of the derived extracts.

Main Methods:

• Ultrasound-assisted extraction was employed to obtain polyphenol-rich extracts from walnut green husk.
• Non-cytotoxicity of extracts was evaluated in the presence of common contaminants.
• Chickpea protein was used as a wall material for spray-drying encapsulation.
• Optimization of spray-drying parameters (protein concentration, temperature) was performed.

Main Results:

• Ultrasound-assisted extraction yielded polyphenol-rich extracts with significant antioxidant activity.
• Extracts showed non-cytotoxic effects, irrespective of contaminants or crop origin.
• Organic walnut husk produced extracts with higher polyphenol content (37 compounds) and antioxidant capacity compared to conventional sources (22 compounds).
• Spray-dried chickpea protein-encapsulated powder exhibited high antioxidant content and stability at low humidity (≤35%).

Conclusions:

• Walnut green husk is a viable source for extracting valuable polyphenols with antioxidant properties.
• Chickpea protein encapsulation provides a sustainable method for creating a stable, vegan antioxidant powder.
• The developed product shows potential as a natural, plant-based substitute for synthetic antioxidants in food systems.