Beyond waste to bioactive potential: advances in olive by-product valorization and resource recovery

What if the discarded apple peels in your juice glass hold a molecule worth recovering? Scientists just optimized a way to pull a valuable bioactive compound from apple pomace in under two minutes.

Apple pomace—the leftover press cake from juice making—is usually treated as waste. But this study shows it is a hidden treasure chest. Researchers used microwave-assisted extraction (MAE) to recover ursolic acid, a bioactive compound with promising health benefits, from Hanfu apple pomace. Instead of trial-and-error, they applied response surface methodology (RSM) to map the process mathematically.

Three variables shaped the outcome: extraction time, sample-to-solvent ratio, and ethanol concentration. Time mattered most, followed by ethanol strength and the solid-liquid balance. The model predicted an optimal recipe: 118.25 seconds of microwaving, a 1:30.86 sample-to-solvent ratio, and 82.23% ethanol. That recipe promised an 89.92% ursolic acid yield.

When tested, the actual yield reached 88.87%—a tiny gap that confirms the model's reliability. A further purification step with XAD-7 resin significantly boosted the compound's purity. The takeaway? This green, energy-efficient method turns agricultural leftovers into a source of high-value bioactives, not just compost.

Key Points

• Microwave extraction recovers 88.87% ursolic acid from apple pomace
• Extraction time is the most influential process variable
• XAD-7 resin purification significantly boosts compound purity