Olive (Olea europaea L.) leaves are an abundant byproduct in the olive oil industry characterized by high quantities of phenols. The content of these molecules in olive leaves may vary according to several factors, including cultivar, olive tree alternate bearing cycle, and seasonal variations. In the present study, leaves belonging to five Italian cultivars (‘Biancolilla’, ‘Nocellara Etnea’, ‘Nocellara Messinese’, ‘Nocellara Siracusana’, ‘Zaituna’), cultivated in the same area, were collected from January to August and individually subjected to an appropriate extraction assay. Each extract was analyzed by means of HPLC/DAD/ESI-MS to determine its phytochemical profile and assess inter cultivar and seasonal variations. Moreover, total phenolics, ORAC, and DPPH assays were performed, in order to evaluate the Total Polyphenol Content and antioxidant potential. Seventeen different metabolites belonging to the subclasses of simple phenols, secoiridoids, hydroxycinnamic acids, and flavonoids were identified, quantified, and used as markers to monitor profile variations. The data obtained have shown that secoiridoids, particularly oleuropein, can be regarded as key molecules to discriminate among different cultivars and to assess variability in olive leaves during the flower and fruit development stage. All of the samples evidenced a remarkable antioxidant activity in terms of Radical Scavenging Activity, and as expected, some differences were observed among cultivars and depending on the harvest period through ORAC assay.

Pomegranate peel and mesocarp, considered as wastes of fruit processing, are rich sources of beneficial phytochemicals, including hydrolyzable tannins and flavonoids, with proven antimicrobial and antioxidant activity, which can be employed for improving the overall quality of food products. In the present study, extracts from pomegranate peel (PPW) and mesocarp (PMW) were obtained through a water extraction method and evaluated for in vitro antimicrobial activity and polyphenol content. The two extracts were then added during the cheese-making process in order to create a new functional cheese with improved microbiological and physico-chemical characteristics. Antimicrobial in vitro assays evidenced a substantial efficacy of both extracts against Staphylococcus aureus, which often causes staphylococcal food poisoning outbreaks linked to the consumption of raw milk cheeses and artisanal cheeses. For this reason, a simulated cheese contamination was carried out in order to assess if pomegranate extracts can exert antimicrobial activity towards this pathogen even when incorporated into the cheese matrix. Milk enriched with pomegranate extracts (PPW and PMW) was used to produce two different experimental cheeses, which were then evaluated for yield, polyphenol content, and microbiological as well as physico-chemical traits throughout the refrigerated storage. Despite the low concentration of the extracts, the treated cheeses showed an increase in firmness and a slight decrease in S. aureus counts, of more than one log unit in comparison to the control cheese, for up to 12 d of cold storage. Such results support the reuse of agro-food byproducts, in substitution to chemical food preservatives, as the key to a circular economy.

Mango (Mangifera indica L.) has been an important plant in traditional medicine for over 4000 years, probably because of its remarkable antioxidant activity. In this study, an aqueous extract from mango red leaves (M-RLE) was evaluated for its polyphenol profile and antioxidant activity. The extract was used as brine replacement (at 5%, 10% and 20% v/v) in fresh mozzarella cheese for improving its functional properties. During storage (12 d at 4 ± °C), compositional analysis performed on mozzarella has shown a progressive increase of iriflophenone 3-C-glucoside and mangiferin, the compounds most present in the extract, with a noticeable preference for the benzophenone. At the same time, the antioxidant activity of mozzarella peaked at 12 d of storage, suggesting a binding action of that matrix for the M-RLE bioactive compounds. Moreover, the use of the M-RLE has not negatively influenced the Lactobacillus spp. population of mozzarella, even at the highest concentration.

Glucosidases are important enzyme largely used in food industry; for this reason, different research studies have been aimed at investigating new producing microorganisms and cheap growth medium that can help to minimize their production costs and time. Food by-products and wastes are considered low-cost substrates that can play an important role from the perspective of a circular economy concept. Brewer’s spent grain (BSG) is the most abundant by-product of beer production that, thanks to its chemical and nutritional composition, has recently been re-evaluated for its application in various sectors. The aim of the present study was to induce the production of β-glucosidase in Wickerhamomyces anomalus BS91 using BSG as the main component. The results obtained during our research show that BSG is an attractive by-product of beer industry that can be used for the production of glucosidase. Enzyme activity obtained using this microorganism was equal to 369.7 ± 8.0 U/mL, six time greater than that observed in conventional nutritional medium (59.0 ± 5.7 U/mL). Also, we conducted additional research concerning β-glucosidase localization, and the obtained results show that the enzyme is tightly bound to the yeast cell wall, and this can probably greatly affect its stability since it is being protected by the cell wall itself.