Consumer Acceptability and Flavor Attributes of Black Walnut Syrup: Tapping into a Climate-resilient and Profitable Alternative to Traditional Syrups

Black walnut ( Juglans nigra L.) is a climate-resilient species that presents underexplored opportunities for horticultural applications, including tapping for syrup production. This study evaluated consumer liking of black walnut syrup and characterized consumer descriptions of its flavor compared with maple syrup. Five syrups were evaluated: two grade A maple syrups (Maple1 and Maple2), a commercial black walnut syrup (PBW_commercial), two locally produced black walnut syrups (PBW_UMN1 and PBW_UMN2), and a black walnut–infused syrup (BW_infused). Participants (n = 106) evaluated six syrup samples and rated them on attributes such as color, overall liking, flavor liking, and the intensity of specific flavors (e.g., caramel, nutty, woody, maple, burnt, bitter). Statistical analyses revealed differences among syrups for all attributes. Darker syrups (PBW_commercial, PBW_UMN2) exhibited stronger woody, burnt, and bitter flavors, while lighter syrups (PBW_UMN1, BW_infused) had milder profiles. PBW_UMN2 closely resembled Maple2 for most attributes, while PBW_commercial differed, with lower overall liking and caramel scores and higher nutty, woody, burnt, and bitter attributes. Principal component analysis indicated that flavor liking and overall liking were negatively correlated with bitter and burnt flavors but positively correlated with maple and caramel flavors. Multiple linear regression models showed that caramel and maple flavors positively influenced liking, while bitterness negatively affected it. The blend of familiar flavors and distinctive black walnut characteristics indicated that PBW_UMN2 could be as liked as maple syrup. This study highlights the market potential of black walnut syrup, suggesting that balancing caramel, woodiness, and nuttiness while minimizing bitterness can enhance consumer acceptability.