Studio delle caratteristiche nutraceutiche e salutistiche degli oli di oliva extravergine e delle olive da tavola CV Tonda di Cagliari, possibile utilizzo di comuni cibi da tavola nella modulazione del microbioma orale umano

In recent years it has increased the interest in the role that certain foods have on some chronic diseases in particular against free radicals. Furthermore, certain foods show positive effects on one or more specific functions of the body, in addition to the normal nutritional role, so as to improve the health and well-being and/or reduce the risk of diseases. In the olives and its derivatives it has been recognized antioxidant capacity and beneficial properties against degenerative diseases induced by oxidative stress, due to the particular fatty acid composition, the important concentration of phenolic compounds and the Vitamin E content. The phenolic content of olives and their transformation products may be influenced by several factors: variety (type of cultivar), processing methods, soil conditions, climatic and technological processes. In table olives functional characteristics and antioxidants are strongly influenced by the fermentation process mediated by microbial starters. The type of inoculum may conditioning the final characteristics of the product. This work is divided in two part. In the first part it were evaluated the nutraceutical characteristics of some monocultivar extravirgin olive oils from Italy by means of their phenolic and Vitamin E composition, and antioxidant capacity. Furthermore the technological performances, during the processing of table olives, of two starters were evaluated: a Single Strain LAB (SSL) starter culture and a Selected Inoculum Enrichment (SIE), made up of an undefined number of strains, taking natural fermentation (NF) as control. Fermentation profile has been traced monitoring microbial counts, pH, titratable acidity and volatile acidity development. Phenolic profile, antioxidant capacity, along with instrumental texture analyses and sensory evaluations have been carried out to define the impact of the technologies employed on the quality features during the processing and in the final products. In the second part of this thesis it were evaluated the antimicrobial and antibiofilm effects of some common foods typical of the Mediterranean diet (Allium sativum L .; Allium cepa L .; Ocimum basilicum, L .; Petroselinum crispum) and shiitake mushroom (Lentinula edodes) extracts. Actually this is an important topic of study within the renewed philosophy of “more natural life” and environmentally friendly. The Olive oils tested showed excellent quality characteristics. SIE resulted more efficient in supplanting the spoilage microbiota (Enterobacteriaceae) compared to SSL and NF. Both starters were able to lower the pH at security levels in a shorter time compared to NF driven fermentation that resulted in higher final pH levels and lower titratable acidity. Texture analyses showed that NF samples retained more cohesiveness and elasticity than inoculated samples. However, SIE samples texture resulted more firm and elastic, compared to SSL texture. Microbial starters efficiently debittered the olives in 5 months, while NF samples resulted not yet debittered at the end of the sampling period. The results obtained in the second part of the thesis shown an activity profile of the extract of garlic for most of the tested strains. The results obtained from the experiments on the biofilm showed the oppositive trend to expected, in contrast to the antimicrobial action of the extract. The foods we studied could produce increased activity in the commensal (greater biofilm physiological) reducing pathogenicity. The most important fact, concerning the extract of Lentinula edoses, is the increase of the biofilm of the probiotic compared to the pathogen (inhibited). This could allow the use of the shiitake mushroom in the treatment of periodontal disease.