From By-Products to Flavored Oils: Ultrasound-Assisted Enrichment of Refined Olive and Grape Seed Oils and Consumer Perception Under Blind and Informed Conditions.

The sustainable valorization of underutilized oils and plant by-products requires not only technological upgrading but also consumer acceptance. In this study, basil and chili pepper by-products were used to flavor refined olive oil and grape seed oil through ultrasound-assisted extraction (UAE). The resulting oils were characterized in terms of quality parameters, antioxidant activity, total phenolic content, and total carotenoid content to assess the overall enrichment achieved by UAE, while consumer perception was investigated under both blind and informed conditions. UAE effectively enhanced the bioactive profile of both refined olive and grape seed oils, yielding up to a twofold increase in total phenolic content compared with the corresponding unflavored oils. Chili pepper- and basil-flavored grape seed oils exhibited the highest antioxidant activity, reaching 3.9 μmol TE/g oil, whereas oxidative changes were influenced more by the flavoring matrix than by the lipid carrier. Sensory evaluation under blind conditions identified opportunities for product optimization, particularly by increasing basil aroma intensity and moderating chili pungency, as highlighted by Just-About-Right (JAR) and penalty analyses. More importantly, providing consumers with information about the enrichment process significantly improved product acceptance. Flavor liking and purchase intention increased under informed conditions, with improvements of up to 20.37% for basil-flavored grape seed oil. Considering that 77.14% of participants were unfamiliar with grape seed oil, these findings demonstrate that combining sustainable technological upgrading with effective consumer communication can substantially enhance the acceptance and market potential of underutilized lipid matrices and food industry by-products.