Applications of gas chromatography for air and food quality assessment, and for monitoring health-related biomarkers.

Gas chromatography has been applied in a wide range of fields: from environmental analysis to culture heritage sector, from biochemical field to food analysis, because of its high versatility and its availability in many laboratories. In this work, gas chromatography (GC) coupled to flame ionization detector (FID) or mass-spectrometry (MS) was exploited in various sectors related to food chemistry, demonstrating its high performance and versatility. In the first study, GC-MS has been exploited for the assessment of the efficiency of kitchen hoods filters, and to monitor volatile organic compounds (VOCs) development in different cooking systems and foods, thus contributing to assess air quality in indoor environments. In particular, a new method involving the sampling of the air during a cooking process by a polyethylene terephthalate (PET, Nalophan) bag and the subsequent analysis by solid-phase microextraction (SPME) and GC-MS, was applied for the first time to the study of VOCs developed in different cooking systems (deep-frying of French fries, grilling of a hamburger, boiling of cauliflower and heating of sunflower oil). The same method was applied for the efficiency test of odor filters used in domestic kitchen hoods and also to develop and validate an alternative method to the one proposed by current legislation EN IEC 61591. The second study exploited again a new SPME-GC-MS, but in a different field: the study of food shelf-life. The first objective was the study of the efficiency of a new biopackaging (BP), based on biopolymers, to preserve the quality of organic chicken meat under modified atmosphere (MAP) in comparison with a polyethylene terephthalate (PET) material, during storage at 2°C. The second purpose regarded the comparison of the shelf-life of organic and traditional chicken meat (of the same species) in a cellophane packaging under aerobic conditions at 2°C. The results were promising and this study contributed to encourage the use of new biodegradable materials and the consumption of sustainable and organic products. In chapter 3, the presented study applied GC-FID, for the valorisation of food products and by- products, by analysing a bioactive compound, squalene, in vegetable oils and apple by-products (seeds and peels), after developing and validating a new, rapid and simple analytical method. Squalene has been demonstrated to have several beneficial properties; in the present study, its content in different extra virgin olive oils and olive oils were investigated. Squalene was also monitored during the refining process of different vegetable oils: olive, soybean, grapeseed, sunflower, sunflower with high oleic content and maize oils, in order to evaluate possible losses during the process. The proposed method was applied also to the study of squalene in two apple by-products (peels and seeds) to evaluate their possible exploitation in food, cosmetical or pharmaceutical fields. In the future, the method could be exploited in the study of squalene in many different food matrices, reducing time, solvents and costs respect other analytical methods present in literature. In the study presented in the last chapter, GC was exploited for a different purpose again. The aim was the determination of analytes, short chain free fatty acids (SCFAs), in biological samples as faeces and fermentation fluids, where their measurement gives an indication of the effect of a special diet or environmental condition, where higher content is in general associated with positive effects. A new GC-FID method was developed and exploited in two different projects in collaboration with the School of Biosciences and Veterinary Medicine of the University of Camerino for the determination and quantification of eight SCFAs (acetic, propionic, i-butyric, butyric, i-valeric, valeric, i-caproic and caproic acids) in different biological samples (rat, mice and human faeces and in fermentation fluids samples). Indeed, in the last decades SCFAs were recognized for their beneficial effects on the host health status and their analysis contributed to the to investigate for instance the effect of diet supplementation in the people health or to study the adaptation of gut microbiota during geographical, habits and diet changes. These works represent some examples of the possible exploitation of gas chromatography in food chemistry and in close fields. Important information and analytical tools have been obtained, that contributed to assess the quality of a food, or air quality, or the effect of a diet, or environmental conditions, on the overall health status of an individual.