Quantitative Detection of Benzoyl Peroxide in Wheat Flour Using Line-Scan Macroscale Raman Chemical Imaging

Abstract

A high-throughput Raman chemical imaging method was developed for direct inspection of benzoyl peroxide (BPO) mixed in wheat flour. A 5 W, 785 nm line laser (240 mm long and 1 mm wide) was used as a Raman excitation source in a push-broom Raman imaging system. Hyperspectral Raman images were collected in a wavenumber range of 103-2881 cm from dry wheat flour mixed with BPO at eight concentrations (w/w) from 50 to 6400 ppm. A sample holder with a sampling volume of 150 × 100 × 2 mm was used to present a thin layer (2 mm thick) of the powdered sample for line-scan image acquisition with a spatial resolution of 0.2 mm. A baseline correction method based on adaptive iteratively reweighted penalized least squares was used to remove the fluctuating fluorescence signals from the wheat flour. To isolate BPO particles from the flour background, a simple thresholding method was applied to the single-band fluorescence-free images at a unique Raman peak wavenumber (i.e., 1001 cm) preselected for the BPO detection. Chemical images were created to detect and map the BPO particles. Limit of detection for the BPO was estimated in the order of 50 ppm, which is on the same level with regulatory standards. Pixel concentrations were calculated from the percentages of the BPO pixels in the chemical images. High correlation was found between the pixel concentrations and the mass concentrations of the BPO, indicating that the Raman chemical imaging method can be used for quantitative detection of the BPO mixed in the wheat flour.

Calibration and testing of a Raman hyperspectral imaging system to reveal powdered food adulteration

“…Compared with previous attempts regarding authenticity analysis of wheat flour using Raman imaging [ 22 , 24 ], the current study demonstrated the similar results with the advancement of simultaneous detection of two potential adulterants. Moreover, no study has been utilized Raman imaging technique for rapid authenticity analysis of paprika powder which is one of the most vulnerable powdered food to be adulterated with hazardous chemical adulterants.…”

“…However, majority of studies utilizing Raman imaging technique for authenticity analysis of powdered food deal with only one type of adulterants; whereas, two or more adulterants can be added for the same purpose. Moreover, the commercial software used for Raman image collection of BPO adulterated wheat flour [ 22 ] and detection of other adulterants in powdered food [ 23 , 24 ] seems not to be applicable for effective and real-time visualization of Raman chemical image of adulterant materials which if possible, can further be used to make instant decision on food quality and thus, ultimately accelerate the speed of quality analysis tests in industrial environment.…”

Rapid Detection of Adulterants in Whey Protein Supplement by Raman Spectroscopy Combined with Multivariate Analysis

“…Therefore, faster, low-cost and more accurate methods for detecting adulterants are urgently needed. Raman spectroscopy is a powerful analytical tool for rapid, nondestructive detection of solid or liquid samples, and has been successfully used to detect adulteration in a variety of complex foods [20,21]. In previous studies, Jianwei Qin proved that Raman chemical imaging with the help of a proper mixture of analysis algorithms could effectively detect multiple adulterated substances in food powder [21].…”

“…Raman spectroscopy is a powerful analytical tool for rapid, nondestructive detection of solid or liquid samples, and has been successfully used to detect adulteration in a variety of complex foods [20,21]. In previous studies, Jianwei Qin proved that Raman chemical imaging with the help of a proper mixture of analysis algorithms could effectively detect multiple adulterated substances in food powder [21]. Raman spectroscopy was also successfully applied to the rapid quantitative detection of adulterated urea in liquid milk and resulted an accuracy of over 90% [12].…”

Highly Sensitive Detection of Benzoyl Peroxide Based on Organoboron Fluorescent Conjugated Polymers

“…In recent years, a series of analytical methods for BPO detection, including chromatographic method [11], electrochemistry [9], capillary electrophoresis [2], Raman hyperspectral detection [12,13], and flow injection analysis [14] have appeared in succession. Although these methods are highly specific and sensitive for BPO detection, they still suffer from many problems such as tedious sample pre-treatment, large solvent consumption, expensive instrumentation, and professional operation [15].…”