Eco-friendly valorization of espresso coffee grounds as a sustainable source of natural antioxidants in protein bar formulation

Your morning espresso leaves behind a treasure trove of antioxidants—if you know how to unlock them. Scientists just found a greener way to turn coffee grounds into a functional food ingredient.

Spent coffee grounds are the unwanted leftovers of a global caffeine habit, piling up in massive quantities. But they're also packed with bioactive compounds, especially phenolic antioxidants. This study compared three eco-friendly extraction methods—conventional, ultrasound-assisted, and microwave-assisted—to see which one best unlocks those hidden molecules.

Key Points

• Microwave extraction gave highest yield (25.31%) and phenolic content (74.8 mg GAE).
• Extract showed strong antioxidant activity (IC50 44.8 mg/L in DPPH test).
• At >0.5% in protein bars, taste acceptability dropped due to bitterness.