Summary: Recently, food chain production has become inefficient in terms of sustainability due to the use of pesticides, synthetic fertilizers, and byproducts generated.  The circular economy can be improved by the reuse of byproducts generated by the food industry in developing new functional foods. Byproducts such as grape pomace can be used for this purpose. Nevertheless, these new foods must demonstrate that they provide nutrients and benefit the consumer's health. Two different muffin formulations (15 and 20 %) were evaluated in a consumer acceptance test (n=119) and compared with a control muffin (CM). All samples were in the likeness region. However, the muffin enriched with 15 % grape pomace (M15) presented a better acceptance than that enriched with grape pomace at 20 % (M20). This was attributed to the presence of seeds and stalks in the grape pomace consumers perceived in the M20. The sample of M15 was characterized by its composition of micro, macronutrients, and phenolic compound content. In moisture, ash, lipids, and protein, M15 presented a similar content compared to CM. However, M15 presented a higher dietary fiber compared to CM (5.71 % and 3.39 %, respectively). This is attributed to the insoluble and soluble fiber from the grape pomace. The total phenolic content in M15 was similar (120 mgGAE/g muffin) to CM (110 mgGAE/g muffin). In vitro digestion shows that CM presented a higher release of phenolic compounds (13 mgGAE/g muffin) during the intestinal stage than M15 (7 mgGAE/g muffin). This phenomenon was explained by the high dietary fiber content that can bind phenolic compounds and diminish their release at this stage. Phenolic compounds that cannot be bioaccessible in this stage can be used as prebiotics during the colonic fermentation. Nevertheless, further studies on bioavailability and bioactivity should be performed to categorize this new food as functional.