EPR Methods Applied on Food Analysis

Abstract

An overview of the different methodologies developed so far for the investigation of paramagnetic species in foods is presented. Electron paramagnetic resonance spectroscopy (EPR), also known as electron spin resonance spectroscopy (ESR), is the primary technique toward the development of methods for the exploration of EPR-sensitive species, such as free radicals, reactive oxygen species (ROS), nitrogen reactive species (NRS), and C-centered radicals and metal ions. These methods aim for: (a) quantification of radical species, (b) exploration of redox chemical reaction mechanisms in foods, (c) assessment of the antioxidant capacity of food, and (d) food quality, stability, and food shelf life. For these purposes, different radical initiations and detections have been used in foods depending on both the chemistry of the target system and the kind of information required, listed in: the induction of radicals by (a) microwave, UV, or γ-radiation; (b) heating; (c) addition of metals; and (d) use of oxidants.

UV‐irradiation influence on free radical formation and radical scavenging ability of caffeic acid—EPR, UV‐Vis, and colorimetric examination

“…In our research free radicals formation in caffeic acid and modification of its antioxidant interactions by after exposition to UV radiation, which often exist in foods, was proved by the use of EPR spectroscopy. Caffeic acid often exists in food (Kiokias, Proestos, & Oreopoulou, 2020) and from the studies of the others authors it is known that free radicals are also formed by UV radiation in foods (Drouza, Spanou, & Keramidas, 2018). Free radical formation in fruits of peaches, which contains different phenolic compounds, under UV‐B radiation was examined by the spin‐trapping technique (Sgherri, Scattino, Pinzino, Tonutti, & Ranieri, 2015).…”

Evaluasi Radikal Bebas dalam Kopi Robusta dan Arabika Toraja dengan metoda Electron Spin Resonance

“…Itu artinya sebagai studi awal Evaluasi alternatif paramater mutu kopi berbasis metoda ESR dapat menjadi dasar bagi pengembangan riset mutu kopi dalam perspektif variable fisika elementer yang sejauh ini untuk kopi Toraja belum pernah dilakukan. Selain fokus utama menemukan kadar radikal bebasdan aktivitas antioksidan dalam kopi Toraja, penelitian ini juga akan menemukan nilai faktor Lande (g-factor) dari kopi robusta dan arabika Toraja untuk setiap perlakuan variasi temperatur pemanggangan kopi yang berbeda (Drouza et al, 2019).…”

“…Karena biasanya ada lebih banyak elektron dalam keadaan lebih rendah, karena distribusi Maxwell-Boltzmann ada penyerapan energi bersih, dan penyerapan inilah yang dimonitor dan diubah menjadi spektrum. Spektrum atas di bawah ini adalah penyerapan tersimulasi untuk sistem elektron bebas dalam medan magnet yang bervariasi (Drouza et al, 2019).…”

“…Metode ini bertujuan untuk: (a) kuantifikasi spesies radikal, (b) eksplorasi mekanisme reaksi kimia redoks dalam makanan, (c) penilaian kapasitas antioksidan makanan, dan (d) kualitas, stabilitas, dan umur simpan makanan. Untuk tujuan ini, inisiasi dan deteksi radikal yang berbeda telah digunakan dalam makanan tergantung pada kimia sistem target dan jenis informasi yang diperlukan, tercantum dalam: induksi radikal oleh (a) gelombang mikro, UV, atau radiasi; (b) pemanasan; (c) penambahan logam; dan (d) penggunaan oksidan (Drouza et al, 2019).…”

Use of Spectroscopic Techniques to Monitor Changes in Food Quality during Application of Natural Preservatives: A Review

“…Raman spectroscopy provided data correlating with TBARS values and allowing a better understanding of the structural changes in RTC pork chops during refrigerated storage [ 207 ]. The effect of adding several antimicrobial and antioxidant additives (sodium citrate tribasic, E331, ascorbic acid, E300, and sodium ascorbate, E301 on meat drip from defrosted yellowfin tuna fish loins was studied by Howes et al [ 208 ]. Different bands of Raman spectra, especially those located at 570 and 578 cm −1 allowed to gain insight into the nature of the complex formed in the presence of these additives.…”