Enhanced extraction of beetroot peel polyphenols using response surface methodology and their stabilization in W/O/W emulsions using whey protein isolates

Beetroot peels, often discarded as waste, hide a treasure trove of polyphenols—and scientists have found a green way to unlock them and keep them stable for future foods.

What if food waste could become a functional ingredient? Beetroot peels, a byproduct of the food industry, are packed with bioactive compounds like polyphenols and flavonoids. Researchers optimized their extraction using a green method, guided by response surface methodology. The Box-Behnken Design revealed that maximum polyphenol yield occurs at 21.72 minutes, 4.99% sample concentration, and 49.76 W power—achieving 46.5 mg GAE/g of polyphenols and strong antioxidant activity (66.3% DPPH, 89.6% ABTS).

But extraction was only half the battle. To protect these delicate compounds, the team encapsulated them in water-in-oil-in-water (W/O/W) emulsions using whey protein isolates (WPI) at three concentrations. Over 30 days at 4°C, they monitored creaming, viscosity, encapsulation efficiency, and droplet size. The winner? 3% WPI provided the best color retention, physical stability, and encapsulation efficiency.

This work demonstrates that optimizing green extraction and smart encapsulation can turn beetroot peel waste into a stable, value-added ingredient for future food applications. The circular economy just got a little more colorful.

Key Points

• Green extraction optimized with Box-Behnken Design
• Max polyphenols at 21.72 min, 4.99% concentration, 49.76 W
• 3% WPI emulsion best for stability and encapsulation