Chemical characterization of nutraceutical components in vegetable products

Recent interest in reducing the environmental impact of agricultural and agro-industrial waste is leading to the development of innovative natural products with added healthy qualities, such as novel foods, nutraceuticals, cosmetics and biocides, containing bioactive compounds recovered from what is today considered waste. Presently, agricultural and agro-industrial residues have marginal use and they are often disposed in the fields or used as a source of energy with low enthalpy processes. In this framework, the main target of the thesis focused to maximize the recovery of bioactive molecules (i.e. polyphenols, glycoalkaloids, terpenoids, glucosinolates and secoiridoids), from side streams of agriculture and agro-industrial activities, in the perspective to produce bioactive compounds. Thus, the thesis aimed to study specific, sustainable and cost-effective methodologies to obtain phytocomplexes for food, feed, pharmaceutical, nutraceutical and cosmetic industries, applying the concept of a whole-by-products biorefinery. Different vegetables, the cultivation and the industrial processing of which produce a considerable amount of by-products (i.e. green tomatoes, potato leaves and vegetable belonging to the Brassicaceae family), were studied, particularly in terms of their secondary metabolite profiles. Lab-scale procedures for extraction of bioactive complexes have been defined and validated, in agreement with the main principles of the “green analytical chemistry”, taking advantages from non-conventional extraction methodologies (i.e. ultrasound-assisted extraction), able to overcome the limits of the solid/liquid and liquid/liquid conventional techniques, among which longer extraction time, need of huge amount of solvents, low selectivity, thermal decomposition of thermolabile compounds. Since one of the main problems of secondary metabolite intake for health-promoting purposes is related to their low bioavailability, another part of this thesis is dedicated to the application of liposomes as nutraceutical delivery systems of tyrosol, hydroxytyrosol and oleuropein, which are among the major phenolic compounds in the olive tree. A high number of by-products and residues derived from both olive tree cultivation and olive processing industry are obtained yearly (e.g. olive leaves and pomace) and they are promising sources of these bioactive compounds. The limitation of the use of secondary metabolites in nutraceutical and cosmetic industry is due to several factors, i.e. non-standardization, high effective dose and lacking sound scientific data for efficacy and safety. Moreover, little knowledge is available about their mechanism of action. Nuclear magnetic resonance spectroscopy is a straightforward technique for studying molecular dynamics and in this thesis a study related to highlight the behavior of capsaicin in solution is presented in order to acquire information about its mechanism of action and potential pharmacological effects. Cereal grains, legumes and their food derived products have gained more and more popularity in contributing to healthy eating behaviors. In fact, they contain a wide range of phytochemicals (e.g. carotenoids, phenolic acids) and other minor components associated with protection against many chronic diseases. Therefore, another part of this thesis was dedicated to the characterization of phytochemical profile in different types of flour obtained from whole cereals and legumes. The data obtained were also discussed considering the different processing techniques used in the pre-treatments of cereals and legumes to enhance their breadmaking characteristics. The results obtained in the present work provide an overview on the recovery, the applications and thus the potential use of nutraceuticals for human health.