Drying Kinetics and Mass Transfer Characteristics of Walnut under Hot Air Drying

Xiaolan Man, Long Li, Xiuwen Fan (), Hong Zhang, Haipeng Lan, Yurong Tang and Yongcheng Zhang
Additional contact information
Xiaolan Man: College of Mechanical Electrification Engineering, Tarim University, Alar 843300, China
Long Li: College of Mechanical Electrification Engineering, Tarim University, Alar 843300, China
Xiuwen Fan: College of Mechanical Electrification Engineering, Tarim University, Alar 843300, China
Hong Zhang: College of Mechanical Electrification Engineering, Tarim University, Alar 843300, China
Haipeng Lan: College of Mechanical Electrification Engineering, Tarim University, Alar 843300, China
Yurong Tang: College of Mechanical Electrification Engineering, Tarim University, Alar 843300, China
Yongcheng Zhang: College of Mechanical Electrification Engineering, Tarim University, Alar 843300, China

Agriculture, 2024, vol. 14, issue 2, 1-19

Abstract: This study was conducted to investigate the drying kinetics and internal and external mass transfer characteristics of walnuts for an understanding of the drying mechanism. The drying characteristics, mass transfer characteristics, and color of walnut during hot air drying ( HAD ) were investigated under different initial moisture content ( IMC ) (0.35, 0.39, and 0.43 g water/g wet mass) and drying temperatures (50, 60, 70, and 80 °C). The results indicated that the IMC and drying temperature both have significant effects on the drying process of walnut, showing the higher the IMC , the longer the preheating time, the smaller the effective moisture diffusivity ( D eff ) and mass transfer coefficient ( h m ), and the longer the drying time, but reverse results for drying temperature. The values of D eff and h m for walnut ranged from 4.94 × 10 −10 to 1.44 × 10 −9 m 2 /s and 1.24 × 10 −7 to 3.90 × 10 −7 m/s, respectively. The values of activation energy for moisture diffusion and mass transfer ranged from 21.56 to 23.35 kJ/mol and 28.92 to 33.43 kJ/mol, respectively. Multivariate linear prediction models were also established for estimating the D eff and h m as a function of the HAD process parameters. The drying temperature has a greater effect on the walnut kernel lightness than the IMC . The Verma et al model could be used to describe the HAD process of the walnut. The findings contribute to the understanding of moisture transfer mechanisms in walnuts and have practical value for the evaluation and improvement of drying systems.

Keywords: walnut; drying; effective moisture diffusivity; mass transfer coefficient; activation energy; color; model (search for similar items in EconPapers)
JEL-codes: Q1 Q10 Q11 Q12 Q13 Q14 Q15 Q16 Q17 Q18 (search for similar items in EconPapers)
Date: 2024
References: View complete reference list from CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.mdpi.com/2077-0472/14/2/182/pdf (application/pdf)
https://www.mdpi.com/2077-0472/14/2/182/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jagris:v:14:y:2024:i:2:p:182-:d:1326344

Access Statistics for this article

Agriculture is currently edited by Ms. Leda Xuan

More articles in Agriculture from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().