Antimicrobial and antibiofilm activities of procyanidins extracted from laurel wood against a selection of foodborne microorganisms

This study aimed to evaluate the antimicrobial and antibiofilm activities of two procyanidins isolated from an ethyl acetate extract of laurel wood against a selection of foodborne pathogens. The analysis of the extract by HPLC–DAD/ESI–MS allowed us to detect the presence of two procyanidins, which were selectively isolated and identified by chromatographic and spectroscopic means as cinnamtannin B‐1 ( 1 ) and procyanidin B‐2 ( 2 ). Procyanidins 1 and 2 exhibited two biological activities: inhibition of bacterial growth at high concentrations and prevention of biofilm formation at lower concentrations. Synergistic effect was also detected when both compounds were tested in combination against Listeria monocytogenes. Significant effects were also detected on disruption of preformed biofilm. The ability of procyanidins to inhibit microbial growth and biofilm formation and to synergistically work with each other may stimulate a market as natural food preservatives, and/or natural sanitisers for processing equipment where foodborne pathogens reside.     

Germin-like protein Cit s 1 and profilin Cit s 2 are major allergens in orange (Citrus sinensis) fruits

Oranges are clinically relevant allergenic foods. To date, orange allergens have not been characterized in detail. The study is aimed at analyzing the sensitization profile in orange-sensitized subjects with and without clinical allergy, and to identify orange allergens. Fifty-six sensitized subjects with self-reported reactions to orange were grouped into reactors (anaphylaxis or multiple episodes of immediate reactions and/or positive challenge tests) and non-reactors (negative open food challenge tests). Allergens were characterized by IgE immunoblotting, N-terminal sequencing, IgE-inhibition assays, and mediator release assays were performed to determine the allergenic potency of orange profilin. Of 56 subjects, 23 were classified as orange allergic showing mainly an oral allergy syndrome. Of 23 subjects classified as orange allergic, 22 were sensitized to profilin, Cit s 2. In patients with mono-sensitization to profilin in vitro histamine releases up to 75% from basophils were induced using orange extract and purified plant profilins. Of the allergic patients 78% were sensitized to germin-like protein, Cit s 1. Both allergens showed retained IgE reactivity in heat-processed orange juice. Interestingly, subjects with and without clinical allergy showed a comparable sensitization profile. Profilin and germin-like proteins are major orange allergens. The potential clinical relevance of orange profilin was indicated by its strong capacity to release histamine from basophils. However, a predominant sensitization to both allergens in subjects without symptoms also indicates a high frequency of clinically insignificant sensitization.     

HS-SPME/GC-MS Method to Characterise the Flavour of Italian Pasta: Potential Application to Assess the Quality of the Products

Food flavour, consisting of a large number of volatile compounds, has great influence on consumer acceptability and, when safety and nutritional value are guaranteed, sensory parameters become the discriminating factor in the product quality assessment which determines the differentiation on the market. The present work combines head space-solid phase micro-extraction and gas chromatography mass spectrometry techniques to analyse the volatile fraction of Italian durum wheat pasta. The aim was the optimization of an analytical method suitable to show possible differences in pasta flavour richness and identify compounds that could be used as food quality markers. Twenty-three odorants were identified and confirmed by comparing their mass spectra with those of 27 standard substances. The optimum conditions for extraction temperature and time, respectively, resulted from 70 °C and 90 min; the best recoveries were achieved with 10.5 g of sample. The developed method was applied for the relative quantitative analysis of different priced pasta to verify the technique capability to highlight possible quality differences.     

A new resource from traditional wines: characterisation of the microbiota of “Vino Santo” grapes as a biocontrol agent against Botrytis cinerea

The microflora of grapes involved in the production of a traditional Italian straw wine, “Vino Santo Trentino”, was evaluated as a biocontrol agent against Botrytis cinerea, one of the main diseases affecting fruit and grapes. The microbiota was described using plate counts and genotypic characterisation (sequencing of 16S rRNA for bacteria and 26s rRNA for yeast), allowing identification of yeasts belonging to the Hanseniaspora, Metschnikowia, Cryptococcus and Issatchenkia genera and bacteria (Bacillus, Microbacterium, Acetobacter and Gluconobacter spp.). The distribution of these species is related to the extent of B. cinerea infection. 7 isolates were able to halt the growth of B. cinerea in antagonistic cultures grown in Petri plates, using both synthetic growth and grape juice media. Technological characterisation of potential biocontrol agents, performed with the help of flow cytometry and HPLC-ECD, demonstrated that these microorganisms did not represent a risk for wine production due to their low resistance to ethanol, low pH and the absence of off-flavours. This ensures that the biocontrol agents disappear during winemaking and excludes a negative impact on the quality of wines. In conclusion, the microflora associated with dried grapes is a precious source of biocontrol agents against B. cinerea, both in terms of preventing disease in the vineyard and in control of the grape drying process for the production of straw wines.     

Functional stability of goats' milk yoghurt supplemented with Pistacia atlantica resin extracts and Saccharomyces boulardii

The present study describes the development of a functional goats' milk yoghurt, using Pistacia atlantica resin extracts and Saccharomyces boulardii, in an attempt to combine the beneficial effects of the milk, extract and probiotic microorganisms. Results demonstrated that Pistacia extracts promoted the survival of lactic acid bacteria and NMR spectra additionally revealed that the functional fatty acids can be retained during the shelf life of yoghurts, alongside with the other bioactive compounds. The organoleptic assessment revealed that there were no significant differences in flavour, body, texture and appearance between the different yoghurts.     

Effect of phytic acid degradation by soaking and exogenous phytase on the bioavailability of magnesium and zinc from Pisum sativum, L.

The effect of dephytinization of Pisum sativum, L. flour on the bioavailability of Mg and Zn was evaluated in growing rats. Processing of legume flours under optimal conditions for phytase activity (pH 5.5, 37 °C, 60 min) and subsequent removal of the soaking solution led to a 42 and 61% reduction in the content of Mg and Zn, respectively. Treatment with phytase led to an additional reduction in the concentration of the above-mentioned seed flour components, compared to the raw pea flour (69% and 74% for Mg and Zn, respectively). The considerable reduction in the content of inositol phosphates with high degree of phosphorylation attained under both processing conditions did not affect the digestive utilization of Mg, whereas the metabolic utilization of this mineral increased significantly. The digestive and metabolic utilization of Zn increased significantly in response to both processes assayed, reaching the highest values in the experimental group that was fed the phytase-treated pea flour diet. The amount of Mg retained by the experimental animals was reflected in the content of this mineral in the different tissues studied (femur, sternum, kidney, and heart), whereas no correlation was found in the case of Zn.