Modeling Distribution and Dissipation Kinetics of Pesticides in Peel and Medulla Tissues of Postharvest Tuber Crops

• Published in: ACS food science & technology 2021-11, Vol.1 (10), p.1909-1919
• Main Author: Li, Zijian
• Format: Article
• Language: English
• ISSN: 2692-1944; 2692-1944
• DOI: 10.1021/acsfoodscitech.1c00246

To evaluate pesticide distribution and dissipation patterns in postharvest tubers, a peel model under open-environment conditions was developed, which could specify the fate of pesticides in the peel and medulla (pulp) compartments. The simulated results for over 700 pesticides in potatoes indicated that the pesticide degradability in crop tissues contributed the most to the overall dissipation in the medulla compartment than other physiochemical properties. The dissipation process in potato medullas was diminished by the peel compartment, indicating that the peel acts as a protective layer, particularly for highly lipophilic pesticides with high peel-to-medulla concentration ratios at harvest. In addition, the simulated results showed that the peel-to-medulla pesticide concentration ratios decreased significantly immediately after potatoes were harvested (e.g., 1 or 3 days after harvest), which was consistent with the field observations, indicating that pesticide distribution in the peel and medulla compartments achieved steady state if the source of the pesticide was blocked (i.e., pesticide residues in soil). Furthermore, the simulated reduction factors of pesticides in potato medullas were parametrized using the nonpeel model, which helped derive the equivalent half-lives of pesticides in potato medullas after accounting for the peel effect. It was concluded that the tuber peel can act as a protective layer to reduce residue dissipation in medulla tissues, and the dissipation half-lives of pesticides in cold storage (e.g., 5 °C) can be over two times longer than those at room temperature. The present study provides a modeling perspective on pesticide dissipation kinetics in postharvest tuber crops, and the simulated results can be combined with other food processing factors to evaluate the fate of pesticide residues in the tuber food supply chain.