NUTRITIONAL QUALITY AND FOOD SAFETY OF FOOD SOURCES AND FOOD PROCESSING BY-PRODUCTS

In the area of functional foods and dietary supplements, peptides that confer health benefits, also called bioactive peptides, are increasingly recognized as useful tools for improving health and preventing chronic diseases (Udenigwe and Aluko 2012). In fact, food proteins do not only supply nutrients, but also provide numerous health benefits through their impact on specific biochemical pathways. The importance of plant proteins has been underlined by numerous clinical studies performed on grain protein. Most of these activities are due to peptides encrypted in the parent protein sequences, which are delivered by digestion, absorbed by intestinal cells, and transported to the target organs, where they can exert their biological activity (Rutherfurd- Markwick 2012). Actually, bioactive peptides have become a hot research topic, since they provide a large spectrum of health benefits with minimal side effects compared to other chemicals. These health benefits are particularly in the area of hypercholesterolemia and hypertension prevention. Plant-based diet and plant proteins are becoming more and more important to meet nutritional requirements of the growing human population and simultaneously to reduce the negative impacts of food production on the environment. With the aim to boost the environmental sustainability, the valorization of byproducts is certainly one of the main challenges. Some food by-products, such as those deriving from oat, rice, almond, soy okara and coconut processing, are currently among the most interesting by-products of food industries due to their high nutritional potential. Another issue I have addressed in my thesis is the valorization of underutilized species of the genus Lupinus. belonging to the Fabaceae family, whose seeds are characterized by a high protein content. In particular, I have focused the attention on some wild Mexican lupin beans. In fact, a recent review collects data on the nutritional and bioactive compounds of these plants presenting data on proteins, lipids, minerals, dietary fiber, and other bioactive compounds (Ruiz-Lopez, Barrientos-Ramirez et al. 2019), but a characterization of the protein profile is still pending. The information of the protein profile of wild Lupinus species will be beneficial for fundamental and applied studies concerning the storage proteins of the seeds. Based on these considerations, the main aims of my PhD thesis were focused on the discovery, quantification and functional analysis of plant proteins or peptides. These objectives were reached by use of different tools, comprising advanced analytical techniques, such as mass spectrometry (MS) coupled to biochemical and bioinformatics tools, in order to improve the understanding of their mechanism of action at cellular level, their intestinal absorption profile as well as to forecast their potential bioactivities. Briefly, the main aims of the present study were: • To evaluate whether the treatment with some food-grade enzymes, such as amylase, cellulase/xylanase, protease, and their combination, may be useful to achieve this goal. • To valorizing the press cakes deriving from almond and coconut drinks production by using ultrasound- assisted extraction (UAE) to obtain protein ingredients for human use. • To characterize the potential pleotropic activity of two commercially available soybean and pea protein hydrolysates, respectively. • To investigate the composition of the seed proteins of four lupin species: Lupinus aschenbornii, Lupinus campestris, Lupinus hintonii, and Lupinus montanus. The thesis contains three parts: Part I introduces the state of art of proteins and peptides from food and food by-product. Chapter 1 discusses Recovering and obtaining bioactive peptides based on ultrasound-assisted extraction as well as enzymatic methods. Part II presents my scientific contributions in the PhD period. Chapter 2 is the investigation of the use of multiple pre-enzymatic treatments for obtaining valuable protein concentrates and polyphenols extracts from an oat press cake, since these seeds are considered highly nutritional. The food protein hydrolysates are attracting particular interests because of their various functional and biological properties. In spite of their valuable composition, the press cakes of these foods have been only rarely investigated and mainly used in low-value applications, such as feeds, or considered wastes. The recovery and reuse, instead, may allow to obtain additional economic benefits and reduce the waste of natural resources. Besides the proteins and peptides, also phenolic profile and phytic acid, a main antinutritional factor, were quantified. Chapter 3 presents the valorization of the press cakes deriving from almond and coconut drinks production by using ultra sound assisted extraction (UAE) to obtain protein ingredients for human use. The quality of the extracted protein ingredients were assessed in term of phytic acid content, protein profile, techno-functional features, and antioxidant properties. The effect on digestibility of sonication was also evaluated. Chapter 4 is the integrated evaluation of the multifunctional DPP-IV and ACE inhibitory effect of soybean and pea protein hydrolysates. Finally, Part III presents my contributions to another project related to an investigation of the proteome of four wild lupin species with the goal of providing useful information to integrate other chemical, molecular, and morphological data to improve the taxonomic identification of these species. The investigation was performed by integrating classical analysis methods, such as SDS-PAGE and 2D-electrophoresis, with chromatographic purification and mass spectrometry analysis by comparing the results with proteomic data of domesticated species.