Fermentation of Nocellara Etnea table olives by functional starter cultures at different low salt concentrations

Nocellara Etnea is one of the main Sicilian cultivars traditionally used to produce both olive oil and naturally fermented table olives. In the present study, the effect of different salt concentrations on physico-chemical, microbiological, sensorial, and volatile organic compounds (VOCs) formation was evaluated in order to obtain functional Nocellara Etnea table olives. The experimental design consisted of 8 treatments as follow: fermentations at 4, 5, 6, and 8% of salt with (E1-E4 samples) and without (C1-C4 samples) the addition of starters. All the trials were carried out at room temperature (18 ± 2°C) and monitored for an overall period of 120 d. In addition, the persistence of the potential probiotic Lactobacillus paracasei N24 at the end of the process was investigated. Microbiological data revealed the dominance of lactic acid bacteria (LAB), starting from the 7th d of fermentation, and the reduction of yeasts and enterobacteria in the final product inoculated with starters. VOCs profile highlighted a high amount of aldehydes at the beginning of fermentation, which significantly decreased through the process and a concomitant increase of alcohols, acids, esters, and phenols. In particular, esters showed an occurrence percentage higher in experimental samples rather than in control ones, contributing to more pleasant flavors. Moreover, acetic acid, ethanol, and phenols, which often generate off-flavors, were negatively correlated with mesophilic bacteria and LAB. It is interesting to note that salt content did not affect the performances of starter cultures and slightly influenced the metabolome of table olives. Sensory data demonstrated significant differences among samples registering the highest overall acceptability in the experimental sample at 5% of NaCl. The persistence of the L. paracasei N24 strain in experimental samples, at the end of the process, revealed its promising perspectives as starter culture for the production of functional table olives with reduced salt content

Profiling of phenol content and microbial community dynamics during pâté olive cake fermentation

In this study, different microbial strains, as single and mixed-cultures, were used to ferment the pâté olive cake (POC), a by-product of olive oil processing. In particular, strains belonging to Candida boidinii, Wickerhamomyces anomalus and Lactiplantibacillus plantarum were used. The fermentation was carried out on diluted (3:2) POC without and with glucose (2% w/v) addition. Furthermore, phenolic compounds were monitored during fermentation in POC added with glucose differetly inoculated and the microbial community, at the end of fermentation, was evaluated by Next Generation Sequencing (NGS) techniques. Data highlighted that inoculated samples showed an hydroxytyrosol content higher than the un-inoculated controls. In particular, during fermentation the sample inoculated with C. boidinii, both in single and in mixed culture together with L. plantarum, increased the hydroxytyrosol content by 275 and 261 mg/L, respectively, after 8 days, to reach the highest content at the end of fermentation. Metagenomic analysis revealed a low abundance of 16S ribosomal RNA genes and fungal ITS in all samples at any sampling times. Furthermore, at the end of fermentation, all samples exhibited a different bacterial community with a decrease in acetic acid bacteria and an increase in Lactobacillaceae biodiversity. Finally, no effect was detected in any samples on fungal metagenomic profile, where Dipodascus geotrichum was found dominant both at initial and final fermentation. In conclusion, the present study confirmed that selected cultures can drive the fermentation and have an impact on the phenolic profile.This study was conducted within a Ph.D. research programme in Biotecnologie (XXXV cycle) by Paola Foti who received a grant ‘Dottorato innovativo con caratterizzazione industriale, PON RI 2014–2020’, titled ‘Olive oil by-products as a new functional food and source of nutritional food ingredients’ from the Department of Agriculture, Food and Environment (Scientific Tutors: C.C. Cinzia Caggia; Flora V. Romeo and Cinzia L. Randazzo). Authors thank the Azienda Olearia Consoli Pasquale & F.lli s.n.c (Adrano, CT), partner of the doctoral programme, to kindly supply the POC. The present study was partially supported by a regional funding Progetto di investimento 144511020025. P.O. FESR SICILIA 2014/2020, 2019–2021, Azione 1.1.3 - Sostegno alla valorizzazione economica dell’innovazione attraverso la sperimentazione e l’adozione di soluzioni innovative nei processi, nei prodotti e nelle formule organizzative, nonch ́e attraverso il finanziamento dell’industrializzazione dei risultati della ricerca: VERIFICO, Project number: 07TP1039000074info:eu-repo/semantics/publishedVersio

Hybridization of saccharomyces cerevisiae sourdough strains with cryotolerant saccharomyces bayanus nbrc1948 as a strategy to increase diversity of strains available for lager beer fermentation

The search for novel brewing strains from non-brewing environments represents an emerging trend to increase genetic and phenotypic diversities in brewing yeast culture collections. Another valuable tool is hybridization, where beneficial traits of individual strains are combined in a single organism. This has been used successfully to create de novo hybrids from parental brewing strains by mimicking natural Saccharomycescerevisiae ale 7 Saccharomyceseubayanus lager yeast hybrids. Here, we integrated both these approaches to create synthetic hybrids for lager fermentation using parental strains from niches other than beer. Using a phenotype-centered strategy, S. cerevisiae sourdough strains and the S. eubayanus 7 Saccharomyces uvarum strain NBRC1948 (also referred to as Saccharomyces bayanus) were chosen for their brewing aptitudes. We demonstrated that, in contrast to S. cerevisiae 7 S. uvarum crosses, hybridization yield was positively affected by time of exposure to starvation, but not by staggered mating. In laboratory-scale fermentation trials at 20 \ub0C, one triple S. cerevisiae 7 S. eubayanus 7 S. uvarum hybrid showed a heterotic phenotype compared with the parents. In 2 L wort fermentation trials at 12 \ub0C, this hybrid inherited the ability to consume efficiently maltotriose from NBRC1948 and, like the sourdough S. cerevisiae parent, produced appreciable levels of the positive aroma compounds 3-methylbutyl acetate (banana/pear), ethyl acetate (general fruit aroma) and ethyl hexanoate (green apple, aniseed, and cherry aroma). Based on these evidences, the phenotype-centered approach appears promising for designing de novo lager beer hybrids and may help to diversify aroma profiles in lager beer

Use of microbial pools for the enhancement of olive pâté by products

La valorizzazione dei sottoprodotti agroalimentari richiede la rispondenza a criteri di economicità ed innovazione che possono includere la progettazione di nuovi prodotti a medio e ad elevato valore aggiunto. In particolare, i sottoprodotti oleari rappresentano una fonte di molecole bioattive, la cui azione benefica è stata riconosciuta dall’EFSA. Recentemente, crescente interesse è rivolto al pâté, sottoprodotto ottenuto dall’estrazione olearia attraverso l’utilizzo del decanter multifase (DMF). Il pâté, caratterizzato da un’elevata umidità, dall’assenza di parti legnose e dalla presenza di composti bioattivi, rappresenta una matrice ideale per la formulazione di nuovi alimenti funzionali. Il presente studio ha avuto lo scopo di valorizzare e stabilizzare il pâté attraverso l’impiego di pool microbici. Fermentazioni guidate sono state allestite ed è stato determinato l’effetto di differenti inoculi microbici sulla cinetica di deamarizzazione. Ceppi appartenenti alle specie Candida boidinii, Wickerhamomyces anomalus e Lactiplantibacillus plantarum sono stati inoculati nel pâté ad una densità finale pari a 107 e 108 UFC/g per i lieviti e per L. plantarum, rispettivamente. Sono state disposte diverse tesi: tre inoculate con le singole culture, due inoculate con i ceppi combinati e una inoculata con la miscela dei tre ceppi. La fermentazione è stata monitorata a differenti tempi, attraverso analisi chimiche e microbiologiche. Inoltre, la cinetica di deamarizzazione della componente fenolica è stata monitorata in HPLC e, a fine fermentazione, la comunità microbica è stata caratterizzata attraverso analisi NGS. La fermentazione si è arrestata dopo 14 giorni, quando il pH ha raggiunto valori di 4.33 e 4.36, nei campioni inoculati con i due lieviti in monocoltura. Le analisi microbiologiche hanno evidenziato una densità cellulare costante dei lieviti, una riduzione della carica mesofila aerobia totale e dei lattobacilli in tutti campioni inoculati. La concentrazione di idrossitirosolo ha presentato una riduzione significativa nei campioni inoculati dopo 2 e 4 giorni, seguita da un incremento dopo 8 e 14 giorni. In particolare, un incremento significativo si è osservato, dopo 8 giorni, nei campioni inculati con C. boidinii in coltura singola, nei campioni inoculati con C. boidinii in associazione con L. plantarum, e nel campione inoculato con W. anomalus in coltura singola, raggiungendo concentrazioni di 275, 261 e 231 mg/L, rispettivamente, confermando una correlazione tra microbiota e processo di deamarizzazione. Le analisi NGS hanno rilevato una diminuzione delle Acetobacteraceae e la dominanza di Saccharomycetes in tutti i campioni. I risultati ottenuti confermano che la valorizzazione microbiologica del pâté può rappresentare una strategia per l'ottenimento di un prodotto funzionale ad alto valore aggiunto.info:eu-repo/semantics/publishedVersio

Effect of Sequential Inoculum of Beta-Glucosidase Positive and Probiotic Strains on Brine Fermentation to Obtain Low Salt Sicilian Table Olives

In the present study, the \u3b2-glucosidase positive strain Lactobacillus plantarum F3. 3 was used as starter during the fermentation of Sicilian table olives (Nocellara Etnea cultivar) at two different salt concentrations (5 and 8%), in order to accelerate the debittering process. The latter was monitored through the increase of hydroxytyrosol compound. In addition, the potential probiotic Lactobacillus paracasei N24 strain was added after 60 days of fermentation. Un-inoculated brine samples at 5 and 8% of salt were used as control. The fermentation was monitored till 120 days through physico-chemical and microbiological analyses. In addition, volatile organic compounds and sensorial analyses were performed during the process and at the end of the fermentation, respectively. Lactic acid bacteria and yeasts were, in depth, studied by molecular methods and the occurrence of the potential probiotic N24 strain in the final products was determined. Results highlighted that inoculated brines exhibited a higher acidification and debittering rate than control ones. In addition, inoculated brines at 5% of salt exhibited higher polyphenols (hydoxytyrosol, tyrosol, and verbascoside) content compared to samples at 8% of NaCl, suggesting a stronger oleuropeinolytic activity of the starter at low salt concentration. Lactobacilli and yeasts dominated during the fermentation process, with the highest occurrence of L. plantarum and Wickerhamomyces anomalus, respectively. Moreover, the potential probiotic L. paracasei N24 strain was able to survive in the final product. Hence, the sequential inoculum of beta-glucosidase positive and potential probiotic strains could be proposed as a suitable technology to produce low salt Sicilian table olives

Effect of Sequential Inoculum of Beta-Glucosidase Positive and Probiotic Strains on Brine Fermentation to Obtain Low Salt Sicilian Table Olives

In the present study, the b-glucosidase positive strain Lactobacillus plantarum F3. 3 was used as starter during the fermentation of Sicilian table olives (Nocellara Etnea cultivar) at two different salt concentrations (5 and 8%), in order to accelerate the debittering process. The latter was monitored through the increase of hydroxytyrosol compound. In addition, the potential probiotic Lactobacillus paracasei N24 strain was added after 60 days of fermentation. Un-inoculated brine samples at 5 and 8% of salt were used as control. The fermentation was monitored till 120 days through physico-chemical and microbiological analyses. In addition, volatile organic compounds and sensorial analyses were performed during the process and at the end of the fermentation, respectively. Lactic acid bacteria and yeasts were, in depth, studied by molecular methods and the occurrence of the potential probiotic N24 strain in the final products was determined. Results highlighted that inoculated brines exhibited a higher acidification and debittering rate than control ones. In addition, inoculated brines at 5% of salt exhibited higher polyphenols (hydoxytyrosol, tyrosol, and verbascoside) content compared to samples at 8% of NaCl, suggesting a stronger oleuropeinolytic activity of the starter at low salt concentration. Lactobacilli and yeasts dominated during the fermentation process, with the highest occurrence of L. plantarum and Wickerhamomyces anomalus, respectively. Moreover, the potential probiotic L. paracasei N24 strain was able to survive in the final product. Hence, the sequential inoculum of beta-glucosidase positive and potential probiotic strains could be proposed as a suitable technology to produce low salt Sicilian table olives

Effect of olive by-products feed supplementation on physicochemical and microbiological profile of Provola cheese

IntroductionWith the purpose to evaluate the effects of dietary olive cake, a source of bioactive phenolic compounds, as feed supplementation of lactating dairy cows on fatty acid composition, volatile organic compounds, and microbiological profiles of Provola cheese, we performed a two-arm study where control and experimental administered cows derived dairy have been compared.MethodsOur panel of analyses include metabolomics, physicochemical detected variables, culture dependent and independent analyses, and a stringent statistical approach aimful at disclosing only statistically significant results.Results and discussionLooking at the physicochemical variable’s profiles, a higher content of unsaturated fatty acids, polyunsaturated fatty acid, and conjugated linoleic acids as well of proteins were observed in experimental cheese samples, indicating the beneficial effect of dietary supplementation. Furthermore, based on volatilome composition, a clear cluster separation between control and experimental cheeses was obtained, mainly related to terpenes degradation, able of influencing their aroma and taste. Microbiological results showed a decrease of some spoilage related microbial groups in experimental cheeses, probably due to the inhibitory effect exerted by polyphenols compounds, that contrarily did not affect the core taxa of all cheese samples. This paper confirmed the promising utilization of olive by-product in farming practices to obtain more sustainable and safe dairy food products with lower environmental impact, mainly in Sicily and Mediterranean area, where waste disposal poses serious environmental and economic problems

Effect of Molasses and Dried Orange Pulp as Sheep Dietary Supplementation on Physico-Chemical, Microbiological and Fatty Acid Profile of Comisana Ewe's Milk and Cheese

The use of agro-industrial by-products for ruminant feed represents both an economical and environmental convenient way for reducing waste discharge and waste management costs for food industries. Large amounts of waste from citrus processing industries are available in Sicily, Italy. In the present study, the effect of dried citrus pulp as sheep dietary supplementation was evaluated on physico-chemical, microbiological and fatty acid composition of resulting milk and cheese. Pelleted feed integrated with molasses and blond orange pulp, replacing cane molasses, beet pulp and part of the maize and sunflower in ration, were administrated to ewes as an experimental treatment The experiment involved sixty Comisana breed sheep divided into two groups and two feeding trials (experimental and control). Ewe's milk and cheese samples were collected from January to April and analyzed for physico-chemical, microbiological and fatty acid profile composition. Results suggested that both the experimental milk and cheese were different from the controls. In particular, an increase of experimental milk yield and fat content were registered whilst the cheese samples exhibited a significant decrease of pH values and an increase in fat and protein contents. In addition, an increase of conjugated linoleic acids as well as of the oxidative stability were observed indicating the beneficial effect of dietary supplementation. Furthermore, among the main microbial groups, the experimental and control samples, no differences were detected. However, with the exception of streptococci, which was found higher in experimental cheeses, and staphylococci, which was significantly reduced by experimental feed. Moreover, the application of culture-independent methods highlighted the dominance of Lactobacillus rhamnosus/casei group in the experimental cheese, suggesting a driving role of the dietary supplementation in the cheese microbiota composition. The present study demonstrated that the inclusion of citrus by-products in the diet of small dairy ruminants is a promising feeding, which could positively affect milk composition and cheese manufacture

Comparative genomic and functional analysis of 100 Lactobacillus rhamnosus strains and their comparison with strain GG

Peer reviewe

Comparative genomic and functional analysis of 100 Lactobacillus rhamnosus strains and their comparison with strain GG

Peer reviewe