Inside the Egg—Demonstrating Provenance Without the Cracking Using Near Infrared Spectroscopy

Predicting Egg Storage Time with a Portable Near-Infrared Instrument: Effects of Temperature and Production System

“…The absorbance around 1170 nm (between 1160 to 1180 nm) might be associated with C-H and C-H 3 bonds [38][39][40]. This region can be associated with the absorption of fatty acids containing cis double bonds (second overtones C-H) as reported by Sato and collaborators (1991) [29,41]. However, the main differences in the NIR spectra of the egg samples collected from the different days and storage treatments were observed around 1440 nm (O-H bonds).…”

“…Other authors also indicated that the absorbance around 1450 nm might be associated with the first overtone of O-H stretching bonds. An increase in the absorbance values at this wavelength might be directly related to changes in protein structure during egg storage [22,29]. A recent study by Chen and co-workers [42] stated that the wavelength region between 1400 and 1500 nm might also be associated with the presence of N-H secondary bonds corresponding to amine groups [42].…”

“…The NIR spectra of the intact egg samples were collected at two points of the equatorial line of the egg separated by 180 • . This was achieved by using a portable NIR spectrophotometer (Micro-NIR 1700, Viavi, Milpitas, CA, USA) working in the 950-1600 nm wavelength range, with a spectral resolution of 10 nm with no moving parts (Viavi Solutions, 2015, Milipitas, CA, USA) [29]. The MicroNIR software was used to control the instrument and collect the spectra (MicroNIR Prov 3.1, Viavi, Milpitas, CA, USA).…”

“…The parameters for spectral data acquisition were configured with an integration time of 50 ms and an average of 50 scans (MicroNIR Prov 3.1, Viavi, Milpitas, CA, USA). To calculate absorbance/reflectance, reference spectra of a Spectralon ® were collected every 20 samples [29]. Figure 1 shows the set-up utilized to collect the NIR spectra of the egg samples analyzed.…”

“…Consequently, assessing the authenticity and quality (e.g., freshness) of eggs at various stages of the supply chain (from farm to supermarket) using reliable, rapid, non-destructive, and cost-effective technologies has become paramount for the food manufacturing industry [5,27]. The use of NIR to authenticate the provenance of eggs laid by hens from different production systems has been shown to be a viable option [26,28,29]. It has been reported that a common fraudulent practice in the chicken egg supply chain is related to mislabeling the laying date to increase its expiration date (e.g., stale egg sold as fresh) [26,28].…”