The effect of ultrasound pretreatment on oven and vacuum oven drying kinetics of blueberries

Taşçı Z. E., KIPÇAK E.

Bulgarian Chemical Communications, vol.55, no.3, pp.256-266, 2023 (Scopus) identifier

  • Publication Type: Article / Article
  • Volume: 55 Issue: 3
  • Publication Date: 2023
  • Doi Number: 10.34049/bcc.55.3.ncntc05
  • Journal Name: Bulgarian Chemical Communications
  • Journal Indexes: Scopus
  • Page Numbers: pp.256-266
  • Keywords: activation energy, Blueberries, effective moisture diffusivity, oven drying, ultrasonic pretreatment, vacuum oven drying
  • Yıldız Technical University Affiliated: Yes


Blueberries (Vaccanium corymbosum) are small, round fruits having vital nutritional and functional properties. However, they are seasonal fruits with short shelf lives, a feature which hinders their desired commercialization. This condition necessitates the investigation of efficient drying methods for their extensive preservation. In literature, although there are numerous articles focusing on the antioxidant capacities and nutritional contents of blueberries, studies investigating their drying kinetics and the effects of various pretreatments on the process are still scarce. Therefore, in this study, the effect of ultrasound pretreatment on the oven drying and vacuum oven drying of blueberries is investigated. During the experiments, drying temperatures were selected as 60, 70 and 80°C. For both methods, experiments were conducted with 30 s and 60 s ultrasound pretreatment and the results were compared with the untreated sample data. The kinetic parameters of effective moisture diffusivities (Deff) and activation energies (Ea) were calculated. Moreover, the drying curves were modeled with 14 mathematical modeling equations given in the literature. The drying times were seen to decrease by increasing the drying temperature and with the effect of vacuum. The lowest drying time (150 min), highest Deff (8.41×10-10 m2/s) and highest Ea (48.23 kJ/mol) were obtained at the vacuum oven drying experiment conducted without any pretreatments. Ultrasound pretreatment was seen to have an adverse effect on the drying of blueberries. The highest drying time (960 min), lowest Deff (1.57×10-10 m2/s) and lowest Ea (29.47 kJ/mol) were obtained at the oven drying experiment performed after 60 s of ultrasound pretreatment.