Optimizing microwave-assisted extraction of ursolic acid from apple pomace using response surface methodology

Toss an apple core into the trash, and you might be throwing away a hidden treasure. Scientists have found a way to turn apple pomace—the leftover press cake—into a source of ursolic acid, a valuable bioactive compound.

Apple pomace, the fibrous leftovers from juicing and cider making, is usually discarded. But researchers in China and the UK have discovered a way to give it a second life. Using microwave-assisted extraction (MAE), they pulled ursolic acid—a compound with promising health benefits—from Hanfu apple pomace, and they did it with remarkable efficiency.

The team optimized three key variables: extraction time, sample-to-solvent ratio, and ethanol concentration. Through a Box-Behnken design and response surface methodology, they found that extraction time had the biggest impact on yield, followed by ethanol concentration and the sample-to-solvent ratio. The sweet spot was a quick 118.25 seconds, a 1:30.86 ratio, and 82.23% ethanol, predicting a yield of 89.92%.

When they tested these conditions in the lab, they got 88.87%—a close match, confirming the model's reliability. And by passing the extract through XAD-7 resin, they boosted purity significantly. This green, fast method turns waste into a valuable resource, offering a sustainable path for recovering bioactive compounds from food industry byproducts.

Key Points

• Microwave-assisted extraction recovers ursolic acid from apple pomace efficiently.
• Optimal conditions: 118.25 s, 1:30.86 ratio, 82.23% ethanol, 89.92% yield.
• XAD-7 resin purification significantly boosts ursolic acid purity.