Minor components are of particular interest due to their antioxidant and biological properties. Various classes of lipophilic minor components (plant sterols (PS) and α-tocopherol) were selected as they are widely used in the food industry. A Fast GC-MS method for PS analysis in functional dairy products was set up. The analytical performance and significant reduction of the analysis time and consumables, demonstrated that Fast GC-MS could be suitable for the PS analysis in functional dairy products. Due to their chemical structure, PS can undergo oxidation, which could be greatly impacted by matrix nature/composition and thermal treatments. The oxidative stability of PS during microwave heating was evaluated. Two different model systems (PS alone and in combination) were heated up to 30 min at 1000 W. PS degraded faster when they were alone than in presence of TAG. The extent of PS degradation depends on both heating time and the surrounding medium, which can impact the quality and safety of the food product destined to microwave heating/cooking. Many minor lipid components are included in emulsion systems and can affect the rate of lipid oxidation. The oxidative stability of oil-in-water (O/W) emulsions containing PS esters, ω-3 FA and phenolic compounds, were evaluated after a 14-day storage at room temperature. Due to their surface active character, PS could be particularly prone to oxidation when they are incorporated in emulsions, as they are more exposed to water-soluble prooxidants. Finally, some minor lipophilic components may increase oxidative stability of food systems due to their antioxidant activity. á-tocopherol partitioning and antioxidant activity was determined in the presence of excess SDS in stripped soybean O/W emulsions. Results showed that surfactant micelles could play a key role as an antioxidant carrier, by potentially increasing the accessibility of hydrophobic antioxidant to the interface.

Virgin olive oil(VOO) is a product characterized by high economic and nutritional values, because of its superior sensory characteristics and minor compounds (phenols and tocopherols) contents. Since the original quality of VOO may change during its storage, this study aimed to investigate the influence of different storage and shipment conditions on the quality of VOO, by studying different solutions such as filtration, dark storage and shipment inside insulated containers to protect it. Different analytical techniques were used to follow-up the quality changes during virgin olive oil storage and simulated shipments, in terms of basic quality parameters, sensory analysis and evaluation of minor components (phenolic compounds, diglycerides, volatile compounds). Four main research streams were presented in this PhD thesis: The results obtained from the first experimental section revealed that the application of filtration and/or clarification can decrease the unavoidable quality loss of the oil samples during storage, in comparison with unfiltered oil samples. The second section indicated that the virgin olive oil freshness, evaluated by diglycerides content, was mainly affected by the storage time and temperature. The third section revealed that fluctuation in temperature during storage may adversely affect the virgin olive oil quality, in terms of hydrolytic rancidity and oxidation quality. The fourth section showed that virgin olive oil shipped inside insulated containers showed lower hydrolytic and oxidation degradation than those without insulation cover. Overall, this PhD thesis highlighted that application of adequate treatment, such as filtration or clarification, in addition to a good protection against other external variables, such as temperature and light, will improve the stability of virgin olive oil during storage.

Minimally processed fruit (MPF) are products that have to maintain their quality similar to those of fresh ones. Being metabolic active tissues, they show physical and physiological response to minimal processing (wounding), that negatively influence their shelf-life. In the last decades, novel non-thermal processing methods have attracted the interest of food scientists, industries and consumers as technologies useful for shelf-life extension or increasing product functionality, with a minimal impact on the nutritional and sensory properties of foods. The main aim of this PhD thesis was to investigate qualitative, metabolic and nutritional aspects of different MPF, submitted to traditional and innovative non-thermal processes. This issue was addressed considering the product as a dynamic system, both in terms of endogenous physiological activity and porous matrix interacting with the surrounding ambient (during processing and storage), through the application of multi-analytical approach. The most consistent results related to the applied non-thermal techniques confirmed their different potentiality in the optic of processing and product innovation, but the need of their modulation in relation to the different raw material susceptibility to degradation and final product target. Cold plasma treatment effects on fresh-cut fruit, characterized by different kind of stability criticisms, resulted mainly bound to the inactivation of degradative enzymes and microbial cells, without evidencing functional modifications in the final products. The study of osmotic dehydration and vacuum impregnation highlighted as these techniques can be successfully applied for cold formulation/enrichment of MPF, but also the necessity to carefully account for the metabolic and structural modifications induced by the processing on the vegetable tissues. An induction of metabolic stress response was also evidenced as a consequence of pulsed electric fields treatment related to electric field strength. Below the threshold limit of irreversible damages to cell membranes, the treatment promoted only slight and reversible modifications of the metabolic profiles.

The topic of wine oxidation and the need of innovative strategies to prevent its extent were the subject of this PhD thesis. The complexity of the oxidative chemical reactions occurring in wine during its conservation were highlighted, and multiple analytical approaches were used to provide a more comprehensive understanding of wine oxidation and to plan tailored strategies to avoid its occurrence. The complexity of wine oxidation could be in a simplified manner attributed to the following main factors: wine composition, storage conditions, and oxygen exposure. An integrated theoretical and experimental approach was used, including study of chemical, physical and technological variables involved in wine production and storage. Standard protocols currently used to analyse the wine composition were implemented, if needed, and the lab scale trials were coupled with monitoring real case study along the supply chain. In particular, the effectiveness of plant extracts (tannins) commonly used in oenology was also evaluate in order to better understand their antioxidant properties and to encourage an harmonized regulation of their use in winemaking. The information provided and the scientific approach proposed in this thesis work may be useful in future work aimed to study practical implications and effective strategies to control oxidation in wine.

No description available.

No description available.

Lipolysis and oxidation of lipids in foods are the major biochemical and chemical processes that cause food quality deterioration, leading to the characteristic, unpalatable odour and flavour called rancidity. In addition to unpalatability, rancidity may give rise to toxic levels of certain compounds like aldehydes, hydroperoxides, epoxides and cholesterol oxidation products. In this PhD study chromatographic and spectroscopic techniques were employed to determine the degree of rancidity in different animal products and its relationship with technological parameters like feeding fat sources, packaging, processing and storage conditions. To achieve this goal capillary gas chromatography (CGC) was employed not only to determine the fatty acids profile but also, after solid phase extraction, the amount of free fatty acids (FFA), diglycerides (DG), sterols (cholesterol and phytosterols) and cholesterol oxidation products (COPs). To determine hydroperoxides, primary products of oxidation and quantify secondary products UV/VIS absorbance spectroscopy was applied. Most of the foods analysed in this study were meat products. In actual fact, lipid oxidation is a major deterioration reaction in meat and meat products and results in adverse changes in the colour, flavour and texture of meat. The development of rancidity has long recognized as a serious problem during meat handling, storage and processing. On a dairy product, a vegetal cream, a study of lipid fraction and development of rancidity during storage was carried out to evaluate its shelf-life and some nutritional features life saturated/unsaturated fatty acids ratio and phytosterols content. Then, according to the interest that has been growing around functional food in the last years, a new electrophoretic method was optimized and compared with HPLC to check the quality of a beehive product like royal jelly. This manuscript reports the main results obtained in the five activities briefly summarized as follows: 1) comparison between HPLC and a new electrophoretic method in the evaluation of authenticity of royal jelly; 2) study of the lipid fraction of a vegetal cream under different storage conditions; 3) study of lipid oxidation in minced beef during storage under a modified atmosphere packaging, before and after cooking; 4) evaluation of the influence of dietary fat and processing on the lipid fraction of chicken patties; 5) study of the lipid fraction of typical Italian and Spanish pork dry sausages and cured hams.

No description available.

No description available.

No description available.