Application of Vibrational Spectroscopy to Investigate Radiation‐Induced Changes in Food

Abstract

This chapter is mainly focused on the application of vibrational spectroscopy, namely mid‐infrared, near infrared and Raman spectroscopy, to irradiated food. The chapter begins with an introduction to the basis of radiation and the effects of radiation on biological systems; this is followed by a brief discussion on the usage of radiation in food science and the general spectroscopic methods used in the detection of irradiation. The applications of different chemometric techniques, such as principal component analysis (PCA), partial least squares regression (PLS), canonical variate analysis (CVA), linear discriminant analysis (LDA) and cluster analysis to vibrational spectroscopic data of irradiated food are presented. In addition, the discrimination of radiation dose in food using vibrational spectroscopy together with chemometric methods is described. The application of detailed molecular investigation, such as determination of content, structure, and function of macromolecules, is specifically illustrated in the analysis of hazelnut samples using mid‐IR spectroscopy. Determination of radiation‐induced lipid peroxidation and protein secondary structural alterations in food are discussed. Applications of NIR spectroscopy on irradiated food, such as determination of food quality and the effect of radiation on different food samples are also discussed.

Aspects of silver tolerance in bacteria: infrared spectral changes and epigenetic clues

“…To determine the changes in the amount and structure of the proteins of Ag-exposed bacteria, the intensities and positions of amide I band located at 1635 cm −1 emerging from proteins were evaluated [22]. The IR spectra of control and Ag-exposed bacteria including this band in the 1750-1350 cm −1 region are shown in Figure 1C and D. Moreover, the intensities and positions of this band are presented in Table 1.…”

Relationship between the v2PO4/amide III ratio assessed by Raman spectroscopy and the calcium content measured by quantitative backscattered electron microscopy in healthy human osteonal bone

“…(1). N PO 4 and N amide III are the numbers of the corresponding vibrational units (per unit volume). As a result of these definitions, wt.…”

“…Quantitative calculations of this slope are complex due to the parameters R amide III and R PO 4 , which include unknown contributions from the optical parameters, Raman tensors, and measurement geometry. Also, the estimations for m amide III require detailed information on the composition of the organic matrix.…”

“…%Ca values for three different values of K. K 2 was chosen to fit the results of our measurements. Resulting from the approximation that mineral consists of pure hydroxyapatite (Ca∕P ¼ 1.67), the range between the two dashed lines reflects the difference between a hypothetical 1∶1 mixture of hydroxyapatite and octacalciumphosphate (2Ca 4 …”

“…As a consequence, the application of Raman spectroscopy for analysis has increased dramatically over the last years [3][4][5][6] and has become a useful tool for the investigation of bone material, offering simultaneous information on the properties of its organic matrix and mineral phase. The mineral/matrix ratio [i.e., mineral phase (PO 4 ) normalized to organic matrix (amide)] is a frequently used parameter to describe the bone matrix mineralization, with several studies demonstrating that this ratio is altered due to disease or during treatment.…”