Investigating the properties of egg white pasteurised by ultra-high hydrostatic pressure and gamma irradiation by evaluating their NIR spectra and chemosensor array sensor signal responses using different methods of qualitative analysis

Abstract

Nowadays there is an increasing consumer demand for high quality, minimally processed, additive-free and microbiologically safe foods. The future implication of non-thermal food processing techniques, such as ultra-high hydrostatic pressure and gamma irradiation develop rapidly in the food industrial area. Being non-thermal treatments, components involved in the sensory and nutritional quality remain unaffected. In order to gain experience on feasibility of non-thermal pasteurisation of egg, the effects of ultra-high hydrostatic pressure (UHP) treatment and gamma irradiation levels were investigated. In the present study fresh liquid egg white samples were subjected to ultra-high hydrostatic pressure of 400 MPa for 15 min at 4 °C and gamma irradiation of 3 kGy doses. Near infrared spectroscopy and chemosensor array measurements (electronic nose) were performed in order to monitor the quality changes caused by the applied treatments compared to untreated control samples. The recorded near infrared spectra and the sensor signal responses of the chemosensor array were classified by our self-developed qualitative evaluation method the polar qualification system (PQS) and the spectra recognition tool (SRT). The results of PQS were compared to traditional qualitative mathematical statistical methods such us principal component analysis (PCA), linear discriminant analysis (LDA) and to their combination using the first few principal components in calculation of the discriminant functions (PCA + CDA).