Screening and detection of electron beam-irradiated mandarin oranges during storage by e-tongue, PSL, and ESR techniques

Abstract

Food irradiation is an effective quarantine treatment for fresh agricultural commodities. This study aimed to use different analytical methods, such as the electronic tongue (e-tongue), photostimulated luminescence (PSL), and electron spin resonance (ESR), to determine the screening and/or detection properties of electron beam-irradiated mandarin oranges at 0, 0.4 and 1 kGy during 15 days of storage at 4°C. Principal component analysis (PCA) based on e-tongue profiles could potentially discriminate irradiated orange samples from nonirradiated ones for up to 10 days of storage. Calculating PSL ratios also aided in screening the irradiation status of the oranges until 15 days of storage. ESR spectroscopy with various pretreatments (freeze drying/FD, vacuum drying/VD, ethanol extraction & vacuum drying/EVD) increased the signal intensity of radiation-induced cellulose radicals in the samples. Such a process enabled their detection for up to 5 days of storage for 0.4 kGy-irradiated orange samples and 15 days for 1 kGy-irradiated samples, respectively, where the irradiated orange samples showed superior detection results in the order of EVD ⟩ VD ⟩ FD in the pretreatment method.