Ethyl acetate’s intermediate polarity better extracts moderately polar phenols and flavonoids from orange and pineapple peels, resulting in higher yields compared to more polar methanol. This difference is due to solvent selectivity based on compound polarity rather than overall extraction capacity.

That’s actually a very reasonable and interesting finding. Even though methanol is commonly used for extracting phenols and flavonoids due to its high polarity, it doesn’t always give the best results for every plant material. In your case, orange and pineapple peels contain many flavonoids and phenolic compounds that are semi-polar in nature—compounds like hesperidin, naringenin, and quercetin derivatives. These tend to dissolve better in ethyl acetate, which is a moderately polar solvent, rather than methanol which is highly polar.

Also, since you used Soxhlet extraction, the choice of solvent becomes even more important. Ethyl acetate has a slightly higher boiling point than methanol, which means it may offer a better environment for extracting heat-sensitive compounds without degrading them during the continuous heating and condensation process. Ethyl acetate also tends to extract fewer unwanted polar substances like sugars or proteins, so your extract may be richer in the actual phenolics and flavonoids you’re targeting.

In short, your better yield with ethyl acetate is likely due to the better match between the solvent’s polarity and the nature of the compounds in fruit peels, as well as less interference from other substances that methanol might pull out. You’re not doing anything wrong—this is actually a good result and it makes sense chemically.