Characterization and exploiment of Microbial Strains to be used in Meat Processing and Fermentation

The principal aim of this research project has been the evaluation of the specific role of yeasts in ripening processes of dry-cured meat products, i.e. speck and in salami produced by adding Lactobacilli starter cultures, i.e. L. sakei, L. casei, L. fermentum, L. rhamnosus, L.sakei + S.xylosus. In particular the contribution of the predominant yeasts to the hydrolytic patterns of meat proteins has been studied both in model system and in real products. In fact, although several papers have been published on the microbial, enzymatic, aromatic and chemical characterization of dry-cured meat e.g. ham over ripening, the specific role of yeasts has been often underestimated. Therefore this research work has been focused on the following aspects: 1. Characterization of the yeasts and lactic acid bacteria in samples of speck produced by different farms and analyzed during the various production and ripening phases 2. Characterization of the superficial or internal yeasts population in salami produced with or without the use of lactobacilli as starter cultures 3. Molecular characterization of different strains of yeasts and detection of the dominant biotypes able to survive despite environmental stress factors (such as smoke, salt) 4. Study of the proteolytic profiles of speck and salami during the ripening process and comparison with the proteolytic profiles produced in meat model systems by a relevant number of yeasts isolated from speck and salami 5. Study of the proteolytic profiles of Lactobacilli starter cultures in meat model systems 6. Comparative statistical analysis of the proteolytic profiles to find possible relationships between specific bands and peptides and specific microorganisms 7. Evaluation of the aromatic characteristics of speck and salami to assess relationships among the metabolites released by the starter cultures or the dominant microflor

Hydrolysis of pea and lupin proteins by microorganisms to produce bioactive peptides

Small peptides and free amino acids have the advantage of being absorbed in the intestine without any digestion in the stomach. This explains their use in many formulas such as diets for nursing infants or sick adults and as stimulants for people liable for allergy development. The production of peptides through hydrolytic reactions seems to be the most promising technique to form proteinaceous antioxidants since peptides have higher antioxidant activity than raw proteins. In the present study, proteins extracted from flours of peas and lupin were hydrolyzed with microbial enzymes from whole cells of Lactobacillus fermentum MR13 and Lactobacillus rhamnosus C249. The products of the hydrolysis further separated by Size Exclusion Chromatography and the main fractions purified were analyzed for their antioxidant activity by DPPH assay. The results showed that both the total fractions, both the single fractions enhanced the antioxidant activity of the not hydrolyzed substrates. The antioxidant activities of hydrolyzed vegetal proteins seemed to be in relation to their molecular weight distribution. The peptides present in the fractions with highest antioxidant activity were identified with nanoLC-qTOF MS/MS analysis. As emerged from the present study, hydrolyzed vegetal proteins have the potential to become good ingredients and supplements in new food formulas

LC-ESI-QTOF-MS identification of novel antioxidant peptides obtained by enzymatic and microbial hydrolysis of vegetable proteins

Bioactive antioxidant peptides are more and more attracting the attention of food manufacturers for their potential to transform food in functional food, able to prevent a variety of chronic diseases associated with oxidative stress. In the present study proteins extracted from different vegetable sources (KAMUT khorasan wheat, emmer, lupine and pea) were hydrolyzed with commercial enzymes and Lactobacillus spp. strains. Hydrolysates were separated by size exclusion chromatography and purified fractions were analyzed for their antioxidant activity. Peptides from the fractions with the highest activity were identified by nanoLC-ESI-QTOF-MS and thirteen peptides were selected for synthesis on the basis of their sequence. Four peptides (VLPPQQQY, TVTSLDLPVLRW, VTSLDLPVLRW, FVPY) were found able to scavenge superoxide anion and hydroxyl radicals, organic nitro-radicals (ABTS, DPPH) and to inhibit lipid peroxidation. The impact of this work is targeted to add hydrolysed vegetable proteins to reformulated functional food or to produce health-promoting ingredients and nutraceuticals

Exploitation of starch industry liquid by-product to produce bioactive peptides from rice hydrolyzed proteins

Small peptides show higher antioxidant capacity than native proteins and may be absorbed in the intestine without further digestion. In our study, a protein by-product from rice starch industry was hydrolyzed with commercial proteolytic enzymes (Alcalase, Neutrase, Flavourzyme) and microbial whole cells of Bacillus spp. and the released peptides were tested for antioxidant activity. Among enzymes, Alcalase was the most performing, while microbial proteolytic activity was less efficient. Conversely, the antioxidant activity was higher in the samples obtained by microbial hydrolysis and particularly with Bacillus pumilus AG1. The sequences of low molecular weight antioxidant peptides were determined and analyzed for aminoacidic composition. The results obtained so far suggest that the hydrolytic treatment of this industrial by-product, with selected enzymes and microbial systems, can allow its exploitation for the production of functional additives and supplements rich in antioxidant peptides, to be used in new food formulas for human consumption

Descrittione de Costantinopoli

Map of Istanbul, on sheet with Italian text, printed both sides.Relief shown pictorially.Caption title.Page 131-132 of L'isole piu famose del mondo / descritte da Thomaso Porcacchi da Castiglione Arretino e intagliate da Girolamo Porro. In Venetia : Appresso Simon Galignani & Girolamo Porro, 1576.Shirley, R. Maps in the atlases of the British Library

Costantinopoli /

Relief shown pictorially.Oriented with north toward the upper right.Includes index.From: Raccolta di le più illustri et famose città di tutto il mondo / Francesco Valegio. Venice, ca. 1595.Shirley, R. Maps in the atlases of the British Library