Foods that provide medical and health benefits or have a role in disease risk prevention are termed functional foods. The functionality of functional foods is derived from bioactive compounds that are extranutritional constituents present in small quantities in food. Bioactive components include a range of chemical compounds with varying structures such as carotenoids, flavonoids, plant sterols, omega-3 fatty acids (n-3), allyl and diallyl sulfides, indoles (benzopyrroles), and phenolic acids. The increasing consumer interest in natural bioactive compounds has brought about a rise in demand for these kinds of compounds and, in parallel, an increasing number of scientific studies have this type of substance as main topic. The principal aim of this PhD research project was the study of different bioactive and toxic compounds in several natural matrices. To achieve this goal, chromatographic, spectroscopic and sensorial analysis were performed. This manuscript reports the main results obtained in the six activities briefly summarized as follows: • SECTION I: the influence of conventional packaging on lipid oxidation of pasta was evaluated in egg spaghetti. • SECTION II: the effect of the storage at different temperatures of virgin olive oil was monitored by peroxide value, fatty acid activity, OSI test and sensory analysis. • SECTION III: the glucosinolate and phenolic content of 37 rocket salad accessions were evaluated, comparing Eruca sativa and Diplotaxis tenuifolia species. Sensory analysis and the influence of the phenolic and glucosinolate composition on sensory attributes of rocket salads has been also studied. • SECTION IV: ten buckwheat honeys were characterised on the basis of their pollen, physicochemical, phenolic and volatile composition. • SECTION V: the polyphenolic fraction, anthocyanins and other polar compounds, the antioxidant capacity and the anty-hyperlipemic action of the aqueous extract of Hibiscus sabdariffa were achieved. • SECTION VI: the optimization of a normal phase high pressure liquid chromatography–fluorescence detection method for the quantitation of flavanols and procyanidins in cocoa powder and chocolate samples was performed.

Lipids are important components that contribute very significantly to nutritional and technological quality of foods because they are the least stable macro-components in foods, due to high susceptibility to oxidation. When rancidity take place, it makes food unhealthy and unacceptable for consumers. Thus, the presence of antioxidants, naturally present of added to foods, is required to enhance shelf life of foods. Moreover, antioxidant like phenolic compounds play an important role in human health enhancing the functionality of foods. The aim of this PhD project was the study of lipid quality and lipid oxidation in different vegetable foods focusing on analytical and technological aspects in order to figure out the effects of lipid composition and bioactive compounds (phenolic compounds, omega-3 fatty acids and dietary fiber) addition on their shelf life. In addition, bioavailability and antioxidant effects of phenolic compounds in human and animals, respectively, were evaluated after consumption of vegetable foods. The first section of the work was focused on the evaluation of lipid quality impact on technological behaviour of vegetable foods. Because of that, cocoa butter with different melting point were evaluated by chromatographic techniques (GC, TLC) and the sample with the higher melting point showed the presence of fatty acids, triglycerides, 2-monoglycerides and FT-IR profile different from genuine cocoa butter, meaning an adding of foreign fat (lauric-fat) not allowed by the law. Looking at lipid quality of other vegetable foods, an accelerated shelf life test (OXITEST®), was used to evaluate of lipid stability to oxidation in tarallini snacks made up using different lipid matrices (sunflower oil, extravirgin olive oil and a blend of extravirgin olive oil and lard). The results showed a good ability of OXITEST® to discriminate between lipid unsaturation and different cooking times, without any samples fat extraction. In the second section, the role of bioactive compounds on cereal based food shelf life was studied in different bakeries by GC, spectrophotometric methods and capillary electrophoresis. It was examined the relationships between phenolic compounds, added with flour, and lipid oxidation of tarallini and frollini. Both products showed an increase in lipid oxidation during storage and antioxidant effects on lipid oxidation were not as expected. Furthermore, the influence of enrichment in polyunsaturated fatty acids on lipid oxidation of pasta was evaluated. The results proved that LC n-3 PUFA were not significantly implicated in the onset of oxidation in spaghetti stored under daylight and accelerated oxidation in a laboratory heater. The importance of phenolic compounds as antioxidant in humans and rats was also studied, by HPLC/MS in the latter section. For this purpose, apigenin and apigenin glycosides excretion was investigated in six women’s urine in a 24 hours study. After a single dose of steamed artichokes, both aglicone and glucuronide metabolites were recovered in 24 h urine. Moreover, the effect of whole grain durum wheat bread and whole grain Kamut® khorasan bread in rats were evaluated. Both cereals were good sources of antioxidants but Kamut® bread fed animals had a better response to stress than wheat durum fed, especially when a sourdough bread was supplied.

Researches performed during the PhD course intended to assess innovative applications of near-infrared spectroscopy in reflectance (NIR) in the production chain of beer. The purpose is to measure by NIR the "malting quality" (MQ) parameter of barley, to monitor the malting process and to know if a certain type of barley is suitable for the production of beer and spirits. Moreover, NIR will be applied to monitor the brewing process. First of all, it was possible to check the quality of the raw materials like barley, maize and barley malt using a rapid, non-destructive and reliable method, with a low error of prediction. The more interesting result obtained at this level was that the repeatability of the NIR calibration models developed was comparable with the one of the reference method. Moreover, about malt, new kinds of validation were used in order to estimate the real predictive power of the proposed calibration models and to understand the long-term effects. Furthermore, the precision of all the calibration models developed for malt evaluation was estimated and statistically compared with the reference methods, with good results. Then, new calibration models were developed for monitoring the malting process, measuring the moisture content and other malt quality parameters during germination. Moreover it was possible to obtain by NIR an estimate of the "malting quality" (MQ) of barley and to predict whether if its germination will be rapid and uniform and if a certain type of barley is suitable for the production of beer and spirits. Finally, the NIR technique was applied to monitor the brewing process, using correlations between NIR spectra of beer and analytical parameters, and to assess beer quality. These innovative results are potentially very useful for the actors involved in the beer production chain, especially the calibration models suitable for the control of the malting process and for the assessment of the “malting quality” of barley, which need to be deepened in future studies.

Osmotic Dehydration and Vacuum Impregnation are interesting operations in the food industry with applications in minimal fruit processing and/or freezing, allowing to develop new products with specific innovative characteristics. Osmotic dehydration is widely used for the partial removal of water from cellular tissue by immersion in hypertonic (osmotic) solution. The driving force for the diffusion of water from the tissue is provided by the differences in water chemical potential between the external solution and the internal liquid phase of the cells. Vacuum Impregnation of porous products immersed in a liquid phase consist of reduction of pressure in a solid-liquid system (vacuum step) followed by the restoration of atmospheric pressure (atmospheric step). During the vacuum step the internal gas in the product pores is expanded and partially flows out while during the atmospheric step, there is a compression of residual gas and the external liquid flows into the pores (Fito, 1994). This process is also a very useful unit operation in food engineering as it allows to introduce specific solutes in the tissue which can play different functions (antioxidants, pH regulators, preservatives, cryoprotectants etc.). The present study attempts to enhance our understanding and knowledge of fruit as living organism, interacting dynamically with the environment, and to explore metabolic, structural, physico-chemical changes during fruit processing. The use of innovative approaches and/or technologies such as SAFES (Systematic Approach to Food Engineering System), LF-NMR (Low Frequency Nuclear Magnetic Resonance), GASMAS (Gas in Scattering Media Absorption Spectroscopy) are very promising to deeply study these phenomena. SAFES methodology was applied in order to study irreversibility of the structural changes of kiwifruit during short time of osmotic treatment. The results showed that the deformed tissue can recover its initial state 300 min after osmotic dehydration at 25 °C. The LF-NMR resulted very useful in water status and compartmentalization study, permitting to separate observation of three different water population presented in vacuole, cytoplasm plus extracellular space and cell wall. GASMAS techniques was able to study the pressure equilibration after Vacuum Impregnation showing that after restoration of atmospheric pressure in the solid-liquid system, there was a reminding internal low pressure in the apple tissue that slowly increases until reaching the atmospheric pressure, in a time scale that depends on the vacuum applied during the vacuum step. The physiological response of apple tissue on Vacuum Impregnation process was studied indicating the possibility of vesicular transport within the cells. Finally, the possibility to extend the freezing tolerance of strawberry fruits impregnated with cryoprotectants was proven.

Lo studio condotto durante il Dottorato di Ricerca è stato focalizzato sulla valutazione e sul monitoraggio delle diverse degradazioni termossidative in oli da frittura. Per raggiungere tale obiettivo si è ritenuto opportuno procedere mediante uno screening dei principali oli presenti sul mercato italiano e successiva messa a punto di due miscele di oli vegetali che sono state sottoposte a due piani sperimentali di frittura controllata e standardizzata in laboratorio, seguiti da due piani di frittura eseguiti in due differenti situazioni reali quali mensa e ristorante. Ognuna delle due miscele è stata messa a confronto con due oli di riferimento. A tal fine è stata identificato il profilo in acidi grassi, la stabilità ossidativa ed idrolitica, il punto di fumo, i composti polari, il contenuto in tocoferoli totali, ed i composti volatili sia sugli oli crudi che sottoposti ai diversi processi di frittura. Lo studio condotto ha permesso di identificare una delle miscele ideate come valida alternativa all’impiego dell’olio di palma ampiamente utilizzato nelle fritture degli alimenti, oltre a fornire delle indicazioni più precise sulla tipologia e sull’entità delle modificazioni che avvengono in frittura, a seconda delle condizioni impiegate. / The study conducted during the PhD research was focused on the assessment of various thermoxidative degradations in frying oils. To achieve this objective, it was considered appropriate to firs proceed with a screening of the major frying oils present in the Italian market, followed by the development of two frying blends, which were subjected to two different experimental frying plans at lab-scale, under controlled and standardized conditions. The same frying blends were also utilized under two different catering frying situations (cafeteria and restaurant). Each frying blend was compared with two reference frying oils (palm olein and extra virgin olive oil). To evaluate the frying performance of each frying oil and blend, different analytical determinations were carried out; such analysis were performed before, during and at the end of the frying process. The study led to the identification of one of the mixtures here developed as a valid alternative to palm oil, which is widely used for food frying at catering level; in addition, this research allowed a better definition of the modifications (type and entity) that occur during food frying, according to the conditions used. The determination of polar compounds generated during frying were analyzed by both the official method and a high-performance size-exclusion chromatographic method (HPSEC). In the last part of the PhD period, the stability and usage of a special marinade, made of grape seed phenolic extracts encapsulated in liposomal systems, was tested on beef patties. The objective was to evaluate the ability of phenol-enriched liposomes to inhibit the formation of heterocyclic aromatic compounds generated by pan-frying.

Nell’attuale contesto, caratterizzato da un’elevata attenzione alla qualità e alla sicurezza degli alimenti e alle soluzioni tese a garantirli, l’implementazione di sistemi microelettronici per il controllo del prodotto attraverso supporti miniaturizzati e a basso costo può risultare un’opportunità strategica. Oggetto della ricerca di dottorato sono stati lo studio dell’utilizzo di sensori e strumentazione innovativi per la misurazione ed il controllo di parametri ambientali di conservazione di prodotti alimentari e per la loro identificazione mediante la tecnologia della radiofrequenza. Allo scopo è stato studiato il contesto in cui operano gli attori principali della filiera agroalimentare ed è stata sviluppata un’idea di etichetta progettata per essere in grado di emettere attivamente segnale di allarme in caso di necessità (etichetta RFID intelligente semi-passiva). Il prototipo di chip, realizzato in via sperimentale, è stato validato positivamente, sia come strumento di misura, sia in termini di prestazione nel caso studio del monitoraggio della conservazione di un prodotto alimentare in condizioni controllate di temperatura e radiazione luminosa. Le significative evidenze analitiche di reazioni di degradazione dello stato qualitativo del prodotto, quali analisi di pH e colore, raccolte durante il periodo di osservazione di 64 giorni, hanno trovato riscontro con le misure rilevate dal chip prototipo. I risultati invitano ad individuare un partner industriale, con il quale sperimentare l’applicazione della tecnologia proposta. / In the actual context, characterized by a high attention to quality and safety of foods and to the solutions designed to guarantee them, the implementation of microelectronic systems for the control of the product through miniaturized and low cost devices, can be a strategic opportunity. Subject of this PhD course were the study of the use of innovative sensors and instrumentation for the measurement and control of environmental parameters of preservation of food products and for their identification by means of radio frequency technology. With this aim, the context in which they operate the main actors in the food industry has been studied and has been developed an idea of label designed to be capable of emitting an active alarm signal in case of need (intelligent semi-passive RFID tag). The prototype chip, has been tested both as a measuring instrument, both in terms of performance in the case study of the monitoring of the preservation of a food product. The prototype has been validated positively for measures and reliability was confirmed in the study case of monitoring the quality conditions of cheese samples stored under controlled conditions of temperature and light exposure. The significant evidences of analytical degradation of the quality of the product, such as changes of pH and color, collected during the observation period of 64 days, reflected the measurements taken by the prototype chip. The results invite to find an industrial partner with whom to experience the application of the proposed technology.

Il presente lavoro ha avuto lo scopo di identificare le caratteristiche di filtrabilità della birra attraverso lo svolgimento di prove tecnologiche di filtrazione in scala di laboratorio e su scala pilota, utilizzando diverse tipologie di sistemi filtranti e sperimentando diversi materiali di membrana. La fase preliminare della caratterizzazione della filtrabilità della birra è stata condotta presso i laboratori del Campden-BRI – The Brewing Research International, Inghilterra, mentre le prove tecnologiche su scala pilota si sono svolte presso il CERB – Centro di Eccellenza per la Ricerca sulla Birra. Le prove di filtrazione e le analisi sui campioni hanno permesso di verificare le performance delle diverse membrane utilizzate in risposta alla variazione dei principali parametri del processo di filtrazione tangenziale. Sono stati analizzati diversi parametri di qualità della birra filtrata attraverso il monitoraggio del processo e lo svolgimento di prove analitiche sul prodotto volte ad evidenziare gli effetti delle differenti tecnologie adottate. Per quanto riguarda le prove di laboratorio per la caratterizzazione della filtrabilità della birra, l’analisi della PCS (Photon Correlation Spectroscopy) è stata utilizzata per verificare l’influenza di diversi trattamenti enzimatici sulla efficienza del processo di filtrazione e la loro influenza sulla stabilità colloidale della birra filtrata. Dai risultati ottenuti è emerso che il PCS è un valido strumento per determinare la distribuzione in classi di diametro e il diametro medio effettivo delle particelle solide in sospensione nella birra e può essere utilizzato sia per predire la stabilità della birra filtrata, sia per monitorare il processo di filtrazione in tempo reale. / The purpose of this work was to identify the characteristics of filterability of beer throughout different filtration tests on a laboratory scale and on a pilot scale, using different types of filter systems and experimenting with different membrane materials. The preliminary characterization of beer filterability with the particle size analysis was conducted at the laboratories of Campden-BRI - The Brewing Research International, United Kingdom, while the pilot-scale filtration tests were conducted at the CERB – The Italian Brewing Research Centre, Italy. The filtration tests and the analysis on the samples allowed to verify the performance of the different membranes used in response to the variation of the main process parameters of cross-flow filtration. Several quality parameters were monitored on both filtered and unfiltered beer samples, to highlighting the effects of the different technologies used. With regard to the laboratory tests for the characterization of beer filterability, the analysis of the PCS instrument (Photon Correlation Spectroscopy) was used to verify the influence of various enzymatic treatments (Protease and Cellulase) on the efficiency of the filtration process and their influence on the colloidal stability of filtered beer The results showed that the PCS instrument is a reliable tool for determining the size distribution of suspended particles in beer and can be used to predict the colloidal stability of the filtered beer and to monitor the process filtration in real time.

Over the past years fruit and vegetable industry has become interested in the application of both osmotic dehydration and vacuum impregnation as mild technologies because of their low temperature and energy requirements. Osmotic dehydration is a partial dewatering process by immersion of cellular tissue in hypertonic solution. The diffusion of water from the vegetable tissue to the solution is usually accompanied by the simultaneous solutes counter-diffusion into the tissue. Vacuum impregnation is a unit operation in which porous products are immersed in a solution and subjected to a two-steps pressure change. The first step (vacuum increase) consists of the reduction of the pressure in a solid-liquid system and the gas in the product pores is expanded, partially flowing out. When the atmospheric pressure is restored (second step), the residual gas in the pores compresses and the external liquid flows into the pores. This unit operation allows introducing specific solutes in the tissue, e.g. antioxidants, pH regulators, preservatives, cryoprotectancts. Fruit and vegetable interact dynamically with the environment and the present study attempts to enhance our understanding on the structural, physico-chemical and metabolic changes of plant tissues upon the application of technological processes (osmotic dehydration and vacuum impregnation), by following a multianalytical approach. Macro (low-frequency nuclear magnetic resonance), micro (light microscopy) and ultrastructural (transmission electron microscopy) measurements combined with textural and differential scanning calorimetry analysis allowed evaluating the effects of individual osmotic dehydration or vacuum impregnation processes on (i) the interaction between air and liquid in real plant tissues, (ii) the plant tissue water state and (iii) the cell compartments. Isothermal calorimetry, respiration and photosynthesis determinations led to investigate the metabolic changes upon the application of osmotic dehydration or vacuum impregnation. The proposed multianalytical approach should enable both better designs of processing technologies and estimations of their effects on tissue. / Negli ultimi anni l'industria di trasformazione al minimo ha mostrato un crescente interesse verso i trattamenti di disidratazione osmotica e di impregnazione sottovuoto per le loro caratteristiche basse temperature di processo e per le relativamente contenute esigenze energetiche. La disidratazione osmotica, che consiste nell'immersione di tessuti vegetali in soluzioni ipertoniche, consente all’acqua presente nei tessuti di diffondere nella soluzione osmotica ed ai soluti in soluzione di diffondere, in direzione opposta, all'interno dei tessuti. L'impregnazione sottovuoto prevede l’immersione del tessuto vegetale in una soluzione di processo e consiste di due fasi successive. Durante la prima fase, la riduzione della pressione agente sul sistema solido-liquido provoca l'espansione ed il parziale rilascio nella soluzione del gas contenuto nei pori del tessuto. La seconda fase di ripristino della pressione atmosferica determina l’espansione del gas residuo nel tessuto con conseguente richiamo della soluzione esterna all'interno dei pori. L’impregnazione sottovuoto rappresenta un’interessante operazione tecnologica poiché può permette l’introduzione nei tessuti di specifiche molecole quali antiossidanti, regolatori di pH, stabilizzanti o crioprotettori. Il presente studio si è proposto di valutare, seguendo un approccio multianalitico di indagine, le principali modificazioni a carico di tessuti vegetali assoggettati a trattamenti di disidratazione osmotica o impregnazione sottovuoto. Misurazioni di tipo macro- (risonanza magnetica nucleare), micro- (microscopia ottica) ed ultrastrutturali (microscopia elettronica a trasmissione) sono state affiancate ad analisi di texture e di calorimetria a scansione differenziale. Sono stati valutati i principali effetti sulle interazioni aria-liquido in reali condizioni, sullo stato dell'acqua del tessuto e sui compartimenti cellulari. Misurazioni di calorimetria in isoterma e determinazioni dell'attività respiratoria e fotosintetica hanno infine permesso un'indagine dei cambiamenti metabolici. Tale approccio multianalitico, permettendo una valutazione complessiva delle modificazioni a carico della materia prima, può essere applicato nell’ottimizzazione dei parametri di processo sulla base delle caratteristiche ricercate nel prodotto finito.

This Ph.D. thesis focuses on the investigation of some chemical and sensorial analytical parameters linked to the quality and purity of different categories of oils obtained by olives: extra virgin olive oils, both those that are sold in the large retail trade (supermarkets and discounts) and those directly collected at some Italian mills, and lower-quality oils (refined, lampante and “repaso”). Concurrently with the adoption of traditional and well-known analytical procedures such as gas chromatography and high-performance liquid chromatography, I carried out a set-up of innovative, fast and environmentally-friend methods. For example, I developed some analytical approaches based on Fourier transform medium infrared spectroscopy (FT-MIR) and time domain reflectometry (TDR), coupled with a robust chemometric elaboration of the results. I investigated some other freshness and quality markers that are not included in official parameters (in Italian and European regulations): the adoption of such a full chemical and sensorial analytical plan allowed me to obtain interesting information about the degree of quality of the EVOOs, mostly within the Italian market. Here the range of quality of EVOOs resulted very wide, in terms of sensory attributes, price classes and chemical parameters. Thanks to the collaboration with other Italian and foreign research groups, I carried out several applicative studies, especially focusing on the shelf-life of oils obtained by olives and on the effects of thermal stresses on the quality of the products. I also studied some innovative technological treatments, such as the clarification by using inert gases, as an alternative to the traditional filtration. Moreover, during a three-and-a-half months research stay at the University of Applied Sciences in Zurich, I also carried out a study related to the application of statistical methods for the elaboration of sensory results, obtained thanks to the official Swiss Panel and to some consumer tests. / Questa tesi di Dottorato si focalizza sullo studio di parametri analitici chimici e sensoriali legati a qualità e purezza di diverse categorie di oli ottenuti da olive: oli extravergini di oliva, sia venduti presso la grande distribuzione organizzata (supermercati e discount) che reperiti direttamente presso diversi frantoi italiani ed oli di qualità inferiore (raffinati, lampanti e “repaso”). In parallelo all’applicazione di metodologie tradizionali e già consolidate, quali gascromatografia e cromatografia liquida ad elevate prestazioni, è stata realizzata la messa a punto di tecniche d’indagine innovative, rapide e a basso impatto ambientale. Ad esempio, sono stati sviluppati approcci analitici basati sulla spettroscopia nel medio infrarosso a trasformata di Fourier e la riflettometria nel dominio del tempo, abbinate ad una robusta elaborazione chemiometrica dei risultati. Sono stati indagati anche indici chimici di qualità e freschezza non inclusi fra i parametri “ufficiali” stabiliti dalla normativa italiana e comunitaria: l’adozione di un piano analitico completo ha permesso di avere interessanti informazioni sul grado di qualità dell’olio extravergine di oliva, in particolare all’interno del mercato italiano. Qui il range di qualità è risultato molto vasto, in termini di parametri chimici, sensoriali e classi di prezzo. Grazie alla collaborazione con altri gruppi di ricerca italiani e stranieri, sono stati realizzati studi riguardanti la shelf-life degli oli ottenuti da olive e gli effetti dell’applicazione di trattamenti termici sulla qualità di questi prodotti. Anche un trattamento tecnologico innovativo ed alternativo rispetto alla filtrazione tradizionale, come la chiarificazione con gas inerti, è stato studiato. Inoltre, durante un periodo di ricerca di tre mesi e mezzo svolto presso l’Università di Scienze Applicate di Zurigo, è stato realizzato uno studio relativo all’ applicazione di metodiche statistiche per l’elaborazione dei risultati sensoriali, derivanti sia dall’attività del Panel ufficiale svizzero di assaggio di oli vergini di oliva che da consumer test.

This research work is aimed at the valorization of two types of pomace deriving from the extra virgin olive oil mechanical extraction process, such as olive pomace and a new by-product named “paté”, in the livestock sector as important sources of antioxidants and unsaturated fatty acids. In the first research the suitability of dried stoned olive pomace as a dietary supplement for dairy buffaloes was evaluated. The effectiveness of this utilization in modifying fatty acid composition and improving the oxidative stability of buffalo milk and mozzarella cheese have been proven by means of the analysis of qualitative and quantitative parameters. In the second research the use of paté as a new by-product in dietary feed supplementation for dairy ewes, already fed with a source of unsaturated fatty acids such as extruded linseed, was studied in order to assess the effect of this combination on the dairy products obtained. The characterization of paté as a new by-product was also carried out, studying the optimal conditions of its stabilization and preservation at the same time. The main results, common to both researches, have been the detection and the characterization of hydrophilic phenols in the milk. The analytical detection of hydroxytyrosol and tyrosol in the ewes’ milk fed with the paté and hydroxytyrosol in buffalo fed with pomace showed for the first time the presence in the milk of hydroxytyrosol, which is one of the most important bioactive compounds of the oil industry products; the transfer of these antioxidants and the proven improvement of the quality of milk fat could positively interact in the prevention of some human cardiovascular diseases and some tumours, increasing in this manner the quality of dairy products, also improving their shelf-life. These results also provide important information on the bioavailability of these phenolic compounds.