Impact of ultrasound-assisted processing on the quality characteristics of quicklime-treated pumpkin dessert.

BACKGROUND: The characteristic texture of quicklime-treated pumpkin dessert is primarily due to Ca2+-mediated cross-linking of pectin in the plant cell walls. However, conventional processing requires prolonged soaking to promote this interaction. This study investigated the effects of ultrasound-assisted quicklime treatment on pectin-Ca2+ interactions and the resulting textural structure, as well as on physicochemical properties, bioactive compounds, and sensory acceptance. RESULTS: Pumpkin slices with two thicknesses (6.5 and 13 mm) were treated in a 0.5% CaO solution using ultrasound at 200 and 400 W for 15 and 30 min, with treatment codes defined as ultrasound power-slice thickness-treatment time (e.g., 200 W-13-30 indicates 200 W ultrasound power, 13 mm slice thickness, and 30 min treatment time). The control samples were coded as C-6.5 and C-13 according to slice thickness. The effects of ultrasound-assisted quicklime treatment on physicochemical properties, texture, color, carotenoid, total phenolic and flavonoid contents, antioxidant activity, and sensory characteristics were evaluated. Treatment reduced the conventional 16 h soaking period to 15-30 min. The highest total phenolic content was observed in the 200 W-13-30 treatment (339.60 mg GAE g-1 dry matter), whereas the 200 W-6.5-30 treatment exhibited the highest antioxidant activity and flavonoid content (397.34 mg TE 100 g-1 dry matter and 1497.92 mg QE kg-1 dry matter, respectively). The control C-13 sample retained the highest carotenoid content (99.31 mg CE kg-1). Hardness generally increased with ultrasound power, indicating ultrasound-induced changes in the textural structure associated with Ca2+-pectin interactions. Sensory evaluation revealed that the 200 W-6.5-15 treatment provided the most desirable color, while the 400 W-13-30 treatment achieved the highest overall acceptability. CONCLUSION: Ultrasound-assisted quicklime treatment reduced processing time while improving food quality and maintaining acceptable sensory quality, making it a promising alternative to conventional pumpkin dessert processing. © 2026 Society of Chemical Industry.