EFFECTIVENESS OF VACUUM DEVICES FOR HOME STORAGE OF RAINBOW TROUTS FROM GAME FISHING LAKES

The aim of this work was to study the effectiveness of vacuum devices for home storage of rainbow trouts from sport fishing lakes located near Avellino, in the South of Italy. The trout were divided in two groups: one was vacuum-packaged by using a "Food Vacuum System", while the other was stored in plastic trays covered with plastic wrap. Both the fish samples were stored at 4°C for 6 days. Rainbow trout purchased in a local supermarket were used as control. The trout quality was evaluated by microbiological, chemical and sensory analyses. Fatty acids and volatile compounds were characterized by GC and SPME-GC/MS. Results proved the efficiency of the vacuum system in preserving the quality characteristics of the trout, limiting the formation of off-odors and off-flavors related to spoilage and oxidative processes

Evolution of polyphenols, volatile aroma compounds and natural yeast flora of coda di volpe white grape

Wine is one of the main product of the agro-food products in Italy especially for its economic importance to local and regional level. The Campania region is excellent for the production of wine especially those of value, thanks to the presence of wide known varieties of native grapes. The aim of this work is been to characterize the chemical, biochemical and microbiological properties of Coda di Volpe grapes, cultivated in two areas, the hills and flat lands of Benevento. The name Coda di Volpe means tail of the fox, which was given in reference to the varieties of long, pendulous bunches of grapes, which resembles a fox's bushy tail. The polyphenols, pH, total acidity and °Brix were determined at different stages of maturation in order to identify the optimal time for the harvest. In particular, the total polyphenols content was evaluated with Folin-Ciocalteu method, while the specific polyphenols were determined by RP-HPLC. The grapes were harvested in sterile bag, sealed, pressed and incubated at 20°C for 1 month. During the fermentation it was isolated epiphytic microflora and characterized in order to analyse the physiological, oenological and technological properties. Three different yeast strains were assayed in their oenolegical ability, these were used in experimental fermentation with Coda di Volpe must. During alcholic fermentation have been evaluated yeast population, alcoholic grade and the volatile profile by the SPME-GC/MS technique. The data obtained have highlighted their ability to conduct the fermentation process, dominate the indigenous microflora and contribute to the definition of the flavour profile

Selection of Non-Saccharomyces Wine Yeasts for the Production of Leavened Doughs

Background: Non-conventional yeasts (NCY) (i.e., non-Saccharomyces) may be used as alternative starters to promote biodiversity and quality of fermented foods and beverages (e.g., wine, beer, bakery products). Methods: A total of 32 wine-associated yeasts (Campania region, Italy) were genetically identified and screened for decarboxylase activity and leavening ability. The best selected strains were used to study the leavening kinetics in model doughs (MDs). A commercial strain of Saccharomyces cerevisiae was used as the control. The volatile organic profiles of the inoculated MDs were analyzed by solid phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS). Results: Most of strains belonged to the NCY species Hanseniaspora uvarum, Metschnikowia pulcherrima, Pichia kudriavzevii, Torulaspora delbruekii, and Zygotorulaspora florentina, while a few strains were S. cerevisiae. Most strains of H. uvarum lacked decarboxylase activity and showed a high leaving activity after 24 h of incubation that was comparable to the S. cerevisiae strains. The selected H. uvarum strains generated a different flavor profile of the doughs compared to the S. cerevisiae strains. In particular, NCY reduced the fraction of aldehydes that were potentially involved in oxidative phenomena. Conclusions: The use of NCY could be advantageous in the bakery industry, as they can provide greater diversity than S. cerevisiae-based products, and may be useful in reducing and avoiding yeast intolerance

Active Edible Polysaccharide-Based Coating for Preservation of Fresh Figs (Ficus carica L.)

Fresh figs are very sensitive to microbial spoilage, even in cold storage conditions. Thus, fresh figs are high perishable products during postharvest with microbiological decay that induces an unpleasant taste and smell due to rot, and suitable conservation methods must therefore be applied. The fruit usually is consumed fresh locally, dried, or preserved longer term in other transformed forms. A sustainable approach to extend the shelf-life of figs can be constituted by application of an edible coating able to maintain the quality of the fruit during storage. A comparison between fresh figs in a commercial preservation system, with the figs preserved in an edible coating, and an active edible coating to preserve their quality characteristics was carried out. The coating efficacy was enhanced with the addition of pomegranate peel extract at two different concentrations. The inclusion of a component with high antioxidant activity in an edible coating proved to be an excellent method for preserving the quality of this highly perishable fruit. The application of natural products, obtained from renewable sources, represents a simple and economic strategy, but also a tool capable of preserving the quality of the fruit during the postharvest storage, which is often consumed in production areas due to shelf-life problems

<i>Lactobacillus acidophilus</i>—Rutin Interplay Investigated by Proteomics

<div><p>Dietary polyphenols are bioactive molecules that beneficially affect human health, due to their anti-oxidant, anti-inflammatory, cardio-protective and chemopreventive properties. They are absorbed in a very low percentage in the small intestine and reach intact the colon, where they are metabolized by the gut microbiota. Although it is well documented a key role of microbial metabolism in the absorption of polyphenols and modulation of their biological activity, molecular mechanisms at the basis of the bacteria-polyphenols interplay are still poorly understood. In this context, differential proteomics was applied to reveal adaptive response mechanisms that enabled a potential probiotic <i>Lactobacillus acidophilus</i> strain to survive in the presence of the dietary polyphenol rutin. The response to rutin mainly modulated the expression level of proteins involved in general stress response mechanisms and, in particular, induced the activation of protein quality control systems, and affected carbohydrate and amino acid metabolism, protein synthesis and cell wall integrity. Moreover, rutin triggered the expression of proteins involved in oxidation-reduction processes.This study provides a first general view of the impact of dietary polyphenols on metabolic and biological processes of <i>L</i>. <i>acidophilus</i>.</p></div

Immune-modulating effects in mouse dendritic cells of lactobacilli and bifidobacteria isolated from individuals following omnivorous, vegetarian and vegan diets

Lactobacilli and bifidobacteria play a primary role in modulation of gut immunity. By considering that microbiota composition depends on various factors, including diet, we asked whether functional differences could characterize faecal populations of lactobacilli and bifidobacteria isolated from individuals with different dietary habits. 155 healthy volunteers who followed omnivorous, ovo-lacto-vegetarian or vegan diets were recruited at four Italian centres (Turin, Parma, Bologna and Bari). Faecal samples were collected; lactobacilli and bifidobacteria were isolated on selective media and their immunomodulatory activity was tested in mouse dendritic cells (DCs). Pre-incubation with lactobacilli increased LPS-induced expression of the maturation markers CD80 and CD86, whereas pre-incubation with bifidobacteria decreased such expression. Analysis of the cytokine profile indicated that strains of both genera induced down-regulation of IL-12 and up-regulation of IL-10, whereas expression of TNF-α was not modulated. Notably, analysis of anti-inflammatory potential (IL-10/IL-12 ratio) showed that lactobacilli evoked a greater anti-inflammatory effect than did bifidobacteria in the omnivorous group (P < 0.05). We also found significantly reduced anti-inflammatory potential in the bacterial strains isolated from Bari’s volunteers in comparison with those from the cognate groups from the other centres. In conclusion, lactobacilli and bifidobacteria showed a genus-specific ability of modulating in vitro innate immunity associated with a specific dietary habit. Furthermore, the geographical area had a significant impact on the anti-inflammatory potential of some components of faecal microbiota.This study was supported by the Italian Ministry of University and Research (MIUR) PRIN 2010–2011 program (grant number 2010WZ2NJN; http://www.diet4microgut.it). The funders had no role in the design, analysis or writing of this article. We are grateful to Marco Gobbetti for the coordination of the diet4microgut project. Y. S. was supported by grant AGL2014-52101-P from the Spanish Ministry of Economy and Competitiveness (MINECO).Peer reviewe

Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry for the Discrimination of Food-Borne Microorganisms

A methodology based on matrix-assisted laser desorption ionization-time of flight mass spectrometry of intact bacterial cells was used for rapid discrimination of 24 bacterial species, and detailed analyses to identify Escherichia coli O157:H7 were carried out. Highly specific mass spectrometric profiles of pathogenic and nonpathogenic bacteria that are well-known major food contaminants were obtained, uploaded in a specific database, and made available on the Web. In order to standardize the analytical protocol, several experimental, sample preparation, and mass spectrometry parameters that can affect the reproducibility and accuracy of data were evaluated. Our results confirm the conclusion that this strategy is a powerful tool for rapid and accurate identification of bacterial species and that mass spectrometric methodologies could play an essential role in polyphasic approaches to the identification of pathogenic bacteria

Growth curves of <i>L</i>. <i>acidophilus</i> in control conditions and in the presence of rutin.

<p>(A) Growth curves of <i>L</i>. <i>acidophilus</i> obtained by plate counting. (B) Growth curves of <i>L</i>. <i>acidophilus</i> obtained measuring the optical density at 600 nm. Arrows indicate the times of bacterial cell collection for the further proteomic analyses. Values are the means of four independent experiments.</p