0000000000496166
AUTHOR
N. Francesca
Combined approach for the investigation of dominant fermenting microbiota in two traditional sourdoughs produced in sicily
In order to explore the community of lactic acid bacteria (LAB) and yeasts present in two major typical Sicilian sourdoughs, seven mature sourdoughs for "Pane Nero di Castelvetrano" (CV1 - CV3 samples) and "Pane di Monreale" (MR1 - MR4 samples) were analysed through a culturedependent and culture-independent approach. The highest values of microbial counts were revealed in MR1 sourdough. In particular, LAB counts were at about 109 CFU/g in media specific for typical sourdough LAB, such as SDB and SFM, while levels of 106 CFU/g were registered for yeasts. The total DNA form each sourdough sample was extracted and subjected to a multiplex-PCR in order to recognize the major groups of LAB. Sev…
Development of an ad hoc starter culture for the production of functional raw ewes’ milk cheeses through the addition of grape pomace powder
The present work was carried out to select lactic acid bacteria (LAB) resistant to polyphenols in order to develop an ad hoc starter culture for the production of functional fresh ewes’ milk cheeses through the addition of grape pomace powder (GPP). To this purpose, raw ewes’ milk samples were inoculated with individual polyphenols belonging to five classes: flavanols (cathechin, epicatechin and epigallocathechin), flavonols (quercetin), flavones (rutin), hydroxyl-benzoic acid (vanillic acid and syringic acid) and hydroxyl-cinnamic acid (caffeic acid and cumaric acid). These polyphenols are commonly associated with the wine industry by-products and were added in milk to a final concentratio…
EFFECTS OF CITRUS ESSENTIAL OILS ON THE MICROBIOLOGICAL SAFETY OF PRIMO SALE CHEESE
In the last years, the consumers demanding foods with no chemical preservatives for food conservation, determined an interest by the food industries for the use of natural biopreservatives. Several essential oils from various plants and fruits have been characterized for their antibacterial activities in order to select new biopreservatives. The aim of this work was to evaluate the organoleptic effect of citrus essential oils to be applied in the processing of sheeps’ milk “Primo Sale” cheese and the inhibitory effect on the main bacterial pathogens of dairy interest. In order to better evaluate the antibacterial effect, the first approach was based on pasteurized milk, in view of the futur…
Microorganisms of food ice cubes and their transfer to drinks
The present work was carried out to investigate the microbiological characteristics of the ice cubes produced at different levels: 1) home-made (HM) from domestic freezers; 2) produced by ice machines in bars and pubs (BP); 3) produced by ice industries (IN). BP samples were collected from the box stocks. HM and BP samples were transferred into sterile stomacher bags. IN samples were provided in the manufacturers’ plastic bags. Samples were transported into thermal insulated boxes. Five samples per each production level, forming a total of 15 samples (HM1-HM5, BP1-BP5, IN1-IN5), were collected in duplicate in two consecutive months. Each ice sample was thawed in 1 L sterile Dhuram’s bottle …
Ecology and technological capability of lactic acid bacteria associated with Grillo grapevine used as base wine for Marsala production.
Lactic acid bacteria (LAB) have a defining role in winemaking process since their activities determine an important contribute to wine quality. Besides sulphur dioxide, lysozyme is becoming a common supplement in wine for bacterial growth inhibition (Sonni et al, 2009). It is a natural enzyme with muramidase activity working against a wide range of LAB, including Oenococcus spp., Pediococcus spp., Lactococcus spp. and Lactobacillus spp. (Cunningham et al, 1991). To obtain a first mapping of LAB inhabiting Marsala wine production area, grapes of “Grillo” variety were harvested from five vineyards different for climatic and agronomic parameters. A Marsala base wine large-scale process was fol…
Evoluzione della popolazione blastomicetica durante la produzione di olive da tavola di differenti cultivar siciliane monitorata attraverso l’analisi dell’ITS rDNA.
La popolazione blastomicetica di olive verdi da tavola, prodotte a partire da 4 diverse cultivar siciliane (Brandofino, Castriciana, Nocellara del Belice, Passulunara) e da una spagnola (Manzanilla), è stata monitorata durante l’intero processo di fermentazione. La tecnologia produttiva poteva definirsi di tipo semi-industriale, giacché il ruolo della microflora lattica era parzialmente sostituito dall’aggiunta di acido lattico e la fermentazione naturale avveniva in salamoia all’8% di NaCl. La popolazione di lieviti all’avvio del processo fermentativo è risultata, indipendentemente dalla cultivar di appartenenza, nell’ordine di 2.0 log UFC g-1. Viceversa nel prodotto al consumo le conte ha…
Il vino e la fermentazione alcolica
Il consumo di bevande alcoliche ha da sempre accompagnato la storia dell’uomo, riscontrandosi in tutte le civiltà, dalle meno evolute a quelle più progredite. Le scoperte scientifiche del XV secolo hanno messo in luce come tutti i popoli abbiano ampiamente sfruttato il fenomeno della fermentazione di cereali per produrre bevande. Lo stesso vino, inoltre, aveva assunto fin dai tempi più antichi un valore liturgico presso tutte le civiltà che si erano affacciate al Mediterraneo. Anche oggi, e in misura maggiore rispetto al passato, si fa largo uso di bevande alcoliche ottenute sia da fermentazione che da distillazione di liquidi zuccherini. Le bevande alcoliche fermentate sono caratterizzate …
Monitoraggio del ceppo starter Lactobacillus pentosus OM13 nella fermentazione delle olive da tavola (cv. “Nocellara del Belice”) con lavorazione sivigliana.
Obiettivo di questa ricerca . stato validare le attitudini tecnologiche alla trasformazione di olive da mensa cv. “Nocellara del Belice” da parte del ceppo Lactobacillus pentosus OM13. Lo starter Lb. pentosus OM13 ha dimostrato di dominare l’intero processo fermentativo e ha determinato un sensibile abbassamento del pH, inibendo cos. lo sviluppo di microrganismi potenzialmente patogeni e/o alterativi. All’inizio della sperimentazione e fino al 16¢X giorno di fermentazione, i lieviti hanno mostrato un incremento in entrambe le lavorazioni, con starter e di controllo, ma con un livello di carica microbica maggiore nella tesi di controllo. Nella fase di sperimentazione, successiva al 16¢X gior…
The effects of the traditional producing system on physicochemical, microbial and sensory properties of Caciocavallo Palermitano cheese
Caciocavallo Palermitano (CP) is a traditional cheese made with raw milk from cows of Sicilian local breeds fed pasture-based diets in extensive farms (EXT), processed by an artisanal technology (ART) based on wooden tools and the action of native microflora. CP is obtained also in intensive farms (INT) where milk from cows of specialized breeds fed dry diets is transformed by advanced procedures (ADV) using a stainless steel equipment and lactic acid starter cultures. This research was planned to investigate the changes in cheese properties due to production system and ripening., Milk was collected 3 times from an EXT and an INT farm and processed in ART and ADV conditions. The 12 produced…
Aproximaciones para mejorar el crecimiento de bacterias lácticas iniciadoras OM13 durante las primeras etapas de producción de aceitunas verdes de mesa estilo español
The present research aimed at determining the optimal conditions for the lactic acid fermentation of green Spanish-style table olives. The work is a follow-up, and focuses on the performance of the commercial starter strain Lactobacillus pentosus OM13 by applying an acclimatization step and the addition of nutrients, and concentrations of lactic acid that were previously investigated. The acclimatization of the cells warranted the dominance of the starter culture even at an inoculation level of 2 Log cycles lower than that commonly used in standard fermentation. A significant effect was found in terms of acidification kinetics within the first week of fermentation, with the highest decrease…