Development and validation of mass spectrometry-based methods for food quality and food safety assessment

Abstract

In this PhD thesis, analytical chemistry plays a significant role in the assessment of food quality and safety; in particular, three different topics have been addressed to and they are presented into three chapters in which different analytical methodologies have been developed, validated and applied successfully in different topics of food chemistry research. The first chapter is focused on an innovative analytical technique, capillary zone electrophoresis coupled to tandem mass spectrometry. This technique was exploited for the first time for the determination of two products of the Maillard reaction: N-ε-furoylmethyl-L-lysine (furosine) and 5-hydroxymethylfurfural (HMF), which are widely used as markers of food process as well as markers of the nutritional quality of food. The potentiality of this methodology has been investigated as it appears very interesting from different points of view: low consumption of solvents and sample, short time of analysis and high specificity due to mass spectrometry detection. The validated method for furosine analysis was applied to the study of furosine behavior against maltose:maltulose ratio, previously investigated and proposed as a marker of thermal treatment in flour-derived products and infant formulas. Object of the research was a model bread submitted to different cooking procedures by combining different times and temperatures and two different ovens (a low-emissivity oven a conventional one). Thermal treatment entity was expressed in terms of cook value index and other parameters such as colour, weight loss and surface temperature were investigated and correlated to each other. The concurrent evaluation of several markers could be considered as the best way for obtaining information retrospectively about the heat treatment applied during processing and also about the storage conditions of commercial food products. Moreover, the potentiality of capillary zone electrophoresis coupled to tandem mass spectrometry was also investigated for the detection and quantification of a neutral molecule, HMF, in different kind of food products. The topic of the second chapter is the study of different chili peppers varieties grown in the Parma district by Azienda Agraria Sperimentale Stuard, with the aim of the creation of a controlled food supply chain in northern Italy in order to reduce importation of chili pepper from oriental countries. 44 Capsicum genotypes (Capsicum annuum, Capsicum frutescens, Capsicum chinense) were characterized in terms of pungency through evaluation of the capsaicinoids profile by high performance liquid chromatography coupled to a photodiode-array detector. Berries were also classified according to shape, dimension and colour. Thereafter, six genotypes were selected in order to achieve the ideal requirements for industrial purpose, and for the cultivation on a large scale. Besides, the evaluation of the changes occurring in terms of colour, furosine, capsaicinoids and carotenoids, during one year of shelf-life of the pepper powders was performed, with the aim of optimizing the powder characteristics and obtaining a stable product from a commercial point of view. The third chapter describes the exploitation of high resolution mass spectrometry in the field of food-contact materials. In particular, a new line of hybrid mass spectrometer, namely Q-Exactive, was employed, for the first time, for characterization of polycarbonate intended to come in contact with food. The safety of materials in contact with food must be evaluated as molecules could migrate from materials into food. The materials should be manufactured in compliance with EU regulation, which also require good manufacturing practices, so that any potential transfer to foods does not raise safety concerns, change the composition of the food in an unacceptable way or have adverse effects on the taste and odour of foods. This work has to be contextualized as a supporting job for food companies which have obtained declarations of conformity for plastic material involved in food processing but are not aware of its composition. Recently, polycarbonate has been taken into account from European Commission from safety point of view on the basis of recent scientific report about estrogenic activity of its monomer, bisphenol A. Another important point is the coloration of these plastics. No scientific data are reported about the organic colourants effectively used for the coloration of food-contact plastics. High-resolution mass spectrometry is decisive for the identification of unknown molecules like organic colourants, non-intentionally added substances (NIAS), degradation products and plastic additives. Moreover, until now, no methods employing high resolution mass spectrometry for the multitarget determination of the above cited substances have been developed.