Search results for " batteri lattici"
showing 10 items of 19 documents
Description of lactic acid bacteria associated with wheat (Triticum durum) and non-conventional flours: focus on their bacteriocinogenic activity
2006
In situ activity of a bacteriocin-producing Lactococcus lactis strain. Influence on the interactions between lactic acid bacteria during sourdough fe…
2005
Aims: To biochemically characterize the bacteriocin produced by Lactococcus lactis ssp. lactis M30 and demonstrate its effect on lactic acid bacteria (LAB) during sourdough propagation. Methods and Results: A two-peptide bacteriocin produced by L. lactis ssp. lactis M30 was purified by ion exchange, hydrophobic interaction and reversed phase chromatography. Mass spectrometry of the two peptides and sequence analysis of the ltnA2 gene showed that the bacteriocin was almost identical to lacticin 3147. During a 20-day period of sourdough propagation the stability of L. lactis M30 was demonstrated, with concomitant inhibition of the indicator strain Lactobacillus plantarum 20, as well as the …
Rapid differentiation and in situ detection of 16 sourdough lactobacillus species by multiplex PCR.
2005
ABSTRACT A two-step multiplex PCR-based method was designed for the rapid detection of 16 species of lactobacilli known to be commonly present in sourdough. The first step of multiplex PCR was developed with a mixture of group-specific primers, while the second step included three multiplex PCR assays with a mixture of species-specific primers. Primers were derived from sequences that specify the 16S rRNA, the 16S-23S rRNA intergenic spacer region, and part of the 23S rRNA gene. The primer pairs designed were shown to exclusively amplify the targeted rrn operon fragment of the corresponding species. Due to the reliability of simultaneously identifying Lactobacillus plantarum , Lactobacillus…
THE USE OF LACTOBACILLUS PENTOSUS 1MO TO SHORTEN THE DEBITTERING PROCESS TIME OF BLACK TABLE OLIVES (CV. ITRANA AND LECCINO): A PILOT-SCALE APPLICATI…
2006
Fifty lactobacilli isolated from black table olive brines were evaluated for their salt tolerance, resistance to oleuropein and verbascoside, and ability to grow in modified filter-sterilized brines. A strain of Lactobacillus pentosus was selected and used as a starter to ferment, in pilot plant, black olives (Itrana and Leccino cv.) in brines modified for pH, carbohydrate, and growth factor concentrations, at 28 degrees C. The temperature-controlled fermentation of Leccino cv. olives resulted in obtaining ready-to-eat, high-quality table olives in a reduced-time process. HPLC analysis of phenolic compounds from fermented olives showed a decrease of oleuropein, a glucoside secoiridoid respo…
Identification of subdominant sourdough lactic acid bacteria and their evolution during laboratory-scale fermentations
2007
Abstract Presumptive lactic acid bacterial cocci were found in six sourdoughs (out of 20) from the Abruzzo region (central Italy) and subjected to phenotypic and genotypic characterization. A total of 21 isolates, recognized as seven strains by randomly amplified polymorphic DNA (RAPD)–polymerase chain reaction (PCR) typing, were identified by a polyphasic approach, consisting of 16S rRNA gene sequencing, multiplex PCR assays and physiological features, as Enterococcus faecium and Pediococcus pentosaceus. Four strains belonging to those species and previously isolated from wheat kernels were inoculated in sterile flour to verify their capacity to grow in sourdough environment. Doughs with s…
Ecologia delle popolazioni lattiche associate alle farine di frumento e studio delle attitudini tecnologiche per la produzione di impasti acidi
2013
Il presente lavoro ha previsto inizialmente l’isolamento, la tipizzazione e l’identificazione dei batteri lattici (BL) presenti in campioni di farine utilizzate per prodotti da forno a lievitazione naturale prelevati presso diversi panifici siciliani. Le conte in piastra dei BL sono state ottenute su tre differenti terreni colturali, generici e specifici. I risultati hanno evidenziato una concentrazione massima di BL di 4.75 Log UFC/g. Tutte le colonie diverse sono state isolate e purificate. Le colture sono state differenziate sulla base delle caratteristiche fenotipiche e dei profili generati mediante la tecnica randomly amplified polymorphic DNA (RAPD)-PCR che ha permesso il riconoscimen…
Studio retrospettivo sulla qualità igienico-sanitaria delle ricotte prodotte in Sicilia
2017
La ricotta è un prodotto lattiero caseario estremamente diffuso nei paesi del Mediterraneo ottenuto per termocoagulazione acida del siero. Scopo del lavoro è stato valutare la qualità igienico sanitaria delle ricotte siciliane mediante uno studio retrospettivo; sono stati analizzati i dati dei campioni conferiti all’ZS della Sicilia per controllo ufficiale, autocontrollo o progetti di ricerca. Dal 2002 ad oggi sono state esaminate 1295 ricotte fresche, nella maggior parte dei campioni sono stati ricercati L. monocytogenes (1156), Salmonella sp. (998), Brucella sp. (721), Stafilococchi coagulasi positivi (639) e E. coli (598). Su un numero di campioni variabile fra 98 e 371 è stata eseguita …