Investigating the effects of mild preservation technology on perishable foods by volatolomics: The case study of ready-to-cook tuna-burgers

Volatile organic compounds (VOCs) in ready-to-cook tuna-burgers, prepared with and without a protective microbial strain (Lactobacillus paracasei) and in combination with modified atmosphere packaging (MAP, 5% O2 and 95% CO2), were analysed during their shelf life by headspace solid-phase microextraction coupled with a gas chromatography-mass spectrometry (HS-SPME-GC-MS). The results, processed by a statistical multivariate approach (Analysis of Variance, Principal Component Analysis obtained for compounds and chemical classes, and Pearson analysis), proved that the application of both L. paracasei microbial inoculation and MAP significantly influenced the aroma profile of fish-burgers during storage, showing marked differences in almost all the compound classes. In particular, a decrease of aldehyde contents, together with an increase of acids and ketones were observed in L. paracasei samples with respect to the control samples, while the samples under MAP differed from the others in the higher content in alcohols. Furthermore, positive and negative correlations among compounds during the storage time were found by means of Pearson correlation coefficients, suggesting in some cases the existence of specific chemical pathways. The proposed volatolomic approach has proved to be an easy and efficient tool to study the effects of the preservation strategies on perishable food.