(422a) Engineering Protein Delivery Systems to Protect Pyrethroids (?-Cyhalothrin) Against Photodegradation

Engineering Protein Delivery Systems to Protect Pyrethroids (λ-Cyhalothrin) against Photodegradation

Hyoungill Lee^a, Pranav P. Thirumalai^a, Hao Feng^a*

^a- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, USA-61801

^* Corresponding author and Associate Professor, Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, 382F-AESB, 1304 West Pennsylvania Avenue, Urbana, IL 61801, USA.

Phone: 01-217-244-2571; Fax: 01-217-333-9329; Email: haofeng@uiuc.edu

Abstract:

In recent years, Liu et al. have shown that pyrethroid pesticides have been widely used due to their long lasting stability and high insecticidal activity. Several studies have shown the adverse effects of chemical and/ or photodegradation of pesticides in food and water systems. A review by Legrini et al. shows Advanced Oxidation Processes (AOPs) as a potential in this area. In this work we have used soy protein stabilized nanoemulsions and nanocomplexes with pyrethroids, such as λ-Cyhalothrin, to protect the pesticides against UV exposure. Soluble Soy Protein Isolate (SPI) was prepared using pH shifting (pH 8, 9, 10, 11 and 12) and a combination of pH shifting and ultrasound (100% amplitude for 1, 2, 3, 4 and 5 minutes). The combination of pH shifting and ultrasound showed significantly greater recovery and surface hydrophobicity of soluble SPI, irrespective of the pH and ultrasound treatment time. The turbidity and the particle size (nm) of nanoemulsions increased from 0.6783 to 3.9445 and 85.1 nm to 241.9 nm respectively, with an increase in oil:protein (w:w) ratio from 0.25:1 to 2:1. Soy protein stabilized (pH 12 + sonication) nanocomplexes with λ-Cyhalothrin and nanoemulsions showed at least 40% more protection than λ-Cyhalothrin in distilled water, when exposed to UV radiation for 6 hours. Thus, both the nanocomplexes and nanoemulsions prepared from 90% soluble SPI with a combination of pH shifting and ultrasound showed greater protection of pesticide against photodegradation.

Keywords: Photodegradation, pyrethroids, ultrasound, nanotechnology, nanoemulsion, nanocomplex