Effect of ethyl oleate pretreatment on blueberry (Vaccinium corymbosum L.): drying kinetics, antioxidant activity, and structure of wax layer

  • Kejing An
  • Manqin Fu
  • Hao Zhang
  • Daobang Tang
  • Yujuan Xu
  • Gengsheng XiaoEmail author
Original Article


Blueberry belongs to the genus vaccinium, which is rich in a variety of biologically active components beneficial to the human body. Drying of blueberry is a slow and energy-intensive process because of its waxy skin, which has low permeability to moisture. Therefore, chemical pretreatment of ethyl oleate (AEEO) was adopted to accelerate moisture diffusivity. The results showed that the drying rate of blueberries was increased significantly by AEEO treatment, and the drying time can be shortened by 17.17–40.70%. After AEEO dipping, the effective diffusion coefficient increased from 5.461 × 10−9 to 1.067 × 10−8 m2/s at 60 °C. Six semi-theoretical thin-layer models were used to estimate the curves of air-drying of blueberry, and Wang–Singh model was found to perform better than other models. Besides, the rehydration and retention of nutritional contents were also improved by AEEO dipping. The total phenolics, total flavonoids, total anthocyanin content, and ABTS*+ scavenging activity of blueberry were increased by 37.74%, 21.01%, 47.83%, and 30.75%, respectively. The result of SEM observation and cell-membrane permeability indicated that AEEO could break down the wax layer of blueberry, change the crystal structure of wax layer, and increase cell permeability, which resulted in shorter drying time and higher quality of blueberry.


Ethyl oleate Wax layer Anthocyanins Cell membrane permeability Modelling 



We thank the financial support of the National Key R&D Program of China (2017YFD0400900, 2017YFD0400904), National Natural Science Foundation of China (31501500), and Province Natural Science Fund of Guangdong (2015A030312001).

Supplementary material

13197_2018_3538_MOESM1_ESM.docx (14 kb)
Supplementary material 1 (DOCX 13 kb)


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Copyright information

© Association of Food Scientists & Technologists (India) 2019

Authors and Affiliations

  • Kejing An
    • 1
  • Manqin Fu
    • 1
  • Hao Zhang
    • 1
  • Daobang Tang
    • 1
  • Yujuan Xu
    • 1
  • Gengsheng Xiao
    • 1
    Email author
  1. 1.Sericulture and Agri-Food Research Institute Guangdong Academy of Agricultural Sciences/Key Laboratory of Functional Foods, Ministry of Agriculture/Guangdong Key Laboratory of Agricultural Products ProcessingGuangzhouPeople’s Republic of China

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