A new fluorimetric method for simultaneous determination of lipid and protein hydroperoxides in muscle foods with the use of diphenyl-1-pyrenylphosphine (DPPP)

Janna Cropotova,Turid Rustad

doi:10.1016/j.lwt.2020.109467

Abstract

A new fluorimetric assay for simultaneous determination of lipid and protein hydroperoxides in muscle foods by the use of diphenyl-1-pyrenylphosphine (DPPP) was proposed in the study. Non-fluorescent DPPP that reacts with hydroperoxides stoichiometrically to yield fluorescent DPPP oxide, was used as a fluorescent dye to determine lipid and protein peroxidation in fish samples during frozen storage. The novel sensitive DPPP-assay developed for analysis under fluorescence microscopy conditions was based on this reaction. A good linear correlation between the amount of lipid hydroperoxides measured by the developed DPPP-assay and the peroxide value measured by iodometric titration was observed. Also, increase in fluorescence intensity from the reaction of DPPP with protein hydroperoxides in fish samples showed linear relation to the amount of cumene hydroxide added over a wide concentration range. The method was successfully applied on fish samples and can be used for fast assessment of primary oxidation stress in muscle foods.

Highlights

Unsaturated lipids are susceptible to oxidation reactions when exposed to different external factors including heat and light, as well as pro-oxidants such as enzymes, metals and metalloproteins (Frankel, 1998)
The method sensitivity and precision depend on the linearity region of the calibration curves and the relative standard deviation (RSD) of the fluorescence intensity signal arisen from DPPP-standard reacted with lipid and protein hydroperoxides within this linearity range
The present study has shown that a novel fluorimetric assay based on stoichiometric reaction of DPPP with lipid and protein hydroperoxides yielding fluorescent DPPP oxide, is a reliable, fast and sensitive method able to detect, visualize and quantify both lipo- and water-soluble hydroperoxides in muscle foods such as fish samples

Summary

Introduction

Unsaturated lipids are susceptible to oxidation reactions when exposed to different external factors including heat and light, as well as pro-oxidants such as enzymes, metals and metalloproteins (Frankel, 1998). The formation of primary lipid oxidation products, lipid hydroperoxides is produced during peroxidation chain reactions by free radicals and enzymes such as lipoxygenase. Besides generation of off-flavours, their breakdown in food products may result in a loss of nutrients leading to a decreased quality and nutritional value (Diplock et al, 1998; McClements & Decker, 2017; Shahidi & Zhong, 2010). The formation of secondary lipid oxidation products from the breakdown of primary oxidation products is the main reason for rancidity, generation of off-flavours and nutritional losses in foods (Frankel, 1998; Shahidi & Zhong, 2010). A prompt determination of lipid hydroperoxides is needed to take actions for retarding the progression of lipid oxidation in a product

Methods

Results

Conclusion