Effect of UV-C Treatment on Shelf Life of Soft Wheat Bread (Bun).

The effect of exposure of soft wheat buns to Ultraviolet-C radiation (UV-C, 253.7 nm) was studied as an alternative to conventional treatments to control fungal spoilage and prolong shelf life. To identify the most suitable operating conditions, the study included preliminary tests on the permeability of films to UV-C irradiation, and on treatment antifungal efficacy on target microorganisms (Penicillium digitatum and Saccharomycopsis fibuligera) in Petri dishes. A 125 µm T9250B film (Cryovac® Sealed Air S.r.l), commercially available for long-life bread treated with ethanol and conditioned in a modified atmosphere, was selected to pack buns before the UV-C treatment. The study was carried out along with the observation of the fungal growth of buns artificially inoculated with suspensions of P. digitatum and S. fibuligera, treated under UV-C at a distance of 25 cm between bread and the 15 W UV-C source, in comparison to untreated buns used as control. Estimation of fungal growth as well as sensory evaluation was made 2, 4, 7, 10 and 14 days after the treatment. UV-C treated buns showed a noticeable reduction of fungal spoilage and kept a tender texture for up to two weeks after packaging. UV-C treatment represents a good opportunity for the bakery industry, reducing costs and ensuring a prolonged shelf life of a commercial product, respecting the health and hedonistic expectations of the customers.

Biocontrol Efficacy of Metschnikowia spp. Yeasts in Organic Vineyards against Major Airborne Diseases of Table Grapes in the Field and in Postharvest.

The aim of this work was to evaluate the efficacy of two antagonistic yeasts, Metschnikowia pulcherrima strain MPR3 and M. fructicola strain NRRL Y-27328 (commercial product NOLI), applied in addition to the "on-farm biological treatments" (BIO) carried out during the production season, for the containment of powdery mildew and grey mould diseases on organic table grapes 'Italia'. The yeast strains were applied in the field three times, and their efficacy was evaluated during the production season and under postharvest conditions. Overall, M. pulcherrima MPR3 combined with BIO treatments reduced disease incidence caused by Erysiphe necator and disease incidence and severity caused by Botrytis cinerea with values between 67.8% and 86.2%, showing higher efficacy than BIO treatments applied alone and in combination with NOLI. Field treatments based on BIO+MPR3 maintained their performance also during fruit storage, protecting grape berries from grey mould development to a greater extent than the other treatments (disease reduction of about 98%). Thus, the presence of M. pulcherrima MPR3 seems to improve disease management both in the field and in postharvest environments, without negative impacts on grape microbial communities. These findings highlight the potential of M. pulcherrima MPR3 as a promising alternative strategy for disease control in organic vineyards and in postharvest, providing sustainable solutions to improve food quality and safety.

Mango (Mangifera indica L.) young leaf extract as brine additive to improve the functional properties of mozzarella cheese.

Mango (Mangifera indica L.) has been an important plant in traditional medicine for over 4000 years, probably because of its remarkable antioxidant activity. In this study, an aqueous extract from mango red leaves (M-RLE) was evaluated for its polyphenol profile and antioxidant activity. The extract was used as brine replacement (at 5%, 10% and 20% v/v) in fresh mozzarella cheese for improving its functional properties. During storage (12 d at 4 ± °C), compositional analysis performed on mozzarella has shown a progressive increase of iriflophenone 3-C-glucoside and mangiferin, the compounds most present in the extract, with a noticeable preference for the benzophenone. At the same time, the antioxidant activity of mozzarella peaked at 12 d of storage, suggesting a binding action of that matrix for the M-RLE bioactive compounds. Moreover, the use of the M-RLE has not negatively influenced the Lactobacillus spp. population of mozzarella, even at the highest concentration.

Efficacy and mechanism of action of food isolated yeasts in the control of Aspergillus flavus growth on pistachio nuts.

Due to its nutritional characteristics, dried fruit and in particular pistachio is considered an important component in the daily diet. Unfortunately, pistachio nuts can be contaminated during storage with a wide range of pathogenic fungi, including Aspergillus flavus. The present work has evaluated how the use of two yeast strains belonging to the species Wickerhamomyces anomalus and Metschnikowia pulcherrima can inhibit the in vitro and in vivo growth of A. flavus. Both yeast strains demonstrated a good in vitro antifungal activity attributable to a specific mechanism of action, although higher efficacy was evidenced by W. anomalus strain. The production of volatile organic compounds (VOCs) and lytic enzymes was hypothesized as the main mechanisms of action exerted by W. anomalus, while the nutritional competition for iron was assumed as the main biocontrol mechanism for M. pulcherrima. Moreover, from the results of the in vivo test carried out on artificially infected pistachio seeds, it was clear as M. pulcherrima strain showed the same efficacy of W. anomalus in inhibiting the growth and sporulation of A. flavus mold, despite W. anomalus was the most effective strain during in vitro assay. Altogether, these results indicate that both strains could be considered as potential biocontrol agents against A. flavus fungal growth, notwithstanding it is always important considering the tritrophic interaction (yeast-mold- host), which could play a crucial role in determining the final results.

Mangifera indica L. Leaves as a Potential Food Source of Phenolic Compounds with Biological Activity.

It is well recognized that functional foods rich in antioxidants and antiinflammation agents including polyphenols, probiotics/prebiotics, and bioactive compounds have been found to have positive effects on the aging process. In particular, fruits play an important role in regular diet, promoting good health and longevity. In this study, we investigated on biological properties of extract obtained from Mangifera indica L. leaves in preclinical in vitro models. Specifically, the profile and content of bioactive compounds, the antimicrobial potential toward food spoilage and pathogenic bacterial species, and the eventually protective effect in inflammation were examined. Our findings revealed that MLE was rich in polyphenols, showing a content exclusively in the subclass of benzophenone/xanthone metabolites, and these phytochemical compounds demonstrated the highest antioxidant capacity and greatest in vitro antibacterial activity toward different bacterial species such as Bacillus cereus, B. subtilis, Pseudomonas fluorescens, Staphylococcus aureus, and St. haemolyticus. Furthermore, our data showed an in vitro anti-inflammatory, antioxidant, and antifibrotic activity.

The Role of Plasma Membrane Pleiotropic Drug Resistance Transporters in the Killer Activity of Debaryomyces hansenii and Wickerhamomyces anomalus Toxins.

The killer strains of Debaryomyces hansenii and Wickerhamomyces anomalus species secrete antimicrobial proteins called killer toxins which are active against selected fungal phytopathogens. In our research, we attempted to investigate the role of plasma membrane pleiotropic drug resistance (PDR) transporters (Pdr5p and Snq2p) in the mechanism of defense against killer toxins. Saccharomyces cerevisiae mutant strains with strengthened or weakened pleiotropic drug resistance due to increased or reduced number of mentioned PDR efflux pumps were tested for killer toxin susceptibility. The present study demonstrates the influence of the Snq2p efflux pump in immunity to W.anomalus BS91 killer toxin. It was also shown that the activity of killer toxins of D. hansenii AII4b, KI2a, MI1a and CBS767 strains is regulated by other transporters than those influencing W. anomalus killer toxin activity. In turn, this might be related to the functioning of the Pdr5p transporter and a complex cross-talk between several regulatory multidrug resistance networks. To the best of our knowledge, this is the first study that reports the involvement of PDR transporters in the cell membrane of susceptible microorganisms in resistance to killer yeasts' toxins.

Killer yeasts isolated from olive brines: Technological and probiotic aptitudes.

Table olive brines, inoculated with six different starters of lactic acid bacteria (LAB) or spontaneously fermented, have been used as isolating source of killer yeasts throughout the fermentation process (120 d). Killer yeast isolates were identified and evaluated for technological and probiotic traits. Although the count of yeast population did not markedly vary among the different vessels and over time, the killer yeast phenotype was mainly present in yeast strains isolated from spontaneous fermentation; the number of killer isolates decreased over fermentation time. Killer phenotype was found in species identified as Pichia kluyveri, Zygoascus hellenicus, Wickerhamomyces anomalus, Pichia membranifaciens, Candida boidinii, Candida diddensiae and Saccharomyces cerevisiae. Among all tested isolates, W. anomalus strains evidenced the widest spectrum of enzymatic activities and the highest ß-glucosidase and phtytase activity. These strains evidenced also the best growth at low pH and increasing bile salt concentration, when grown at 37 °C, as well as the most constant viability index (%) during in vitro digestion.

Pomegranate Byproduct Extracts as Ingredients for Producing Experimental Cheese with Enhanced Microbiological, Functional, and Physical Characteristics.

Pomegranate peel and mesocarp, considered as wastes of fruit processing, are rich sources of beneficial phytochemicals, including hydrolyzable tannins and flavonoids, with proven antimicrobial and antioxidant activity, which can be employed for improving the overall quality of food products. In the present study, extracts from pomegranate peel (PPW) and mesocarp (PMW) were obtained through a water extraction method and evaluated for in vitro antimicrobial activity and polyphenol content. The two extracts were then added during the cheese-making process in order to create a new functional cheese with improved microbiological and physico-chemical characteristics. Antimicrobial in vitro assays evidenced a substantial efficacy of both extracts against Staphylococcus aureus, which often causes staphylococcal food poisoning outbreaks linked to the consumption of raw milk cheeses and artisanal cheeses. For this reason, a simulated cheese contamination was carried out in order to assess if pomegranate extracts can exert antimicrobial activity towards this pathogen even when incorporated into the cheese matrix. Milk enriched with pomegranate extracts (PPW and PMW) was used to produce two different experimental cheeses, which were then evaluated for yield, polyphenol content, and microbiological as well as physico-chemical traits throughout the refrigerated storage. Despite the low concentration of the extracts, the treated cheeses showed an increase in firmness and a slight decrease in S. aureus counts, of more than one log unit in comparison to the control cheese, for up to 12 d of cold storage. Such results support the reuse of agro-food byproducts, in substitution to chemical food preservatives, as the key to a circular economy.

Active Packaging-Releasing System with Foeniculum vulgare Essential Oil for the Quality Preservation of Ready-to-Cook (RTC) Globe Artichoke Slices.

Two globe artichoke genotypes, "Spinoso sardo" and "Opera F1", have been processed as ready-to-cook (RTC) slices and refrigerated at 4 °C for 12 days (i) to evaluate the suitability to be processed as RTC slices; (ii) to evaluate the effect of a Foeniculum vulgare essential oil (EO) emitter, within an active package system, to delay quality decay, thus extending shelf life; (iii) to estimate the impact of EO emitter on the sensory profile of the RTC slices after cooking. Results revealed that both globe artichoke genotypes possess a good attitude to be processed as RTC product. "Opera F1" showed the best performances for color parameters, texture and chemical indexes, while "Spinoso sardo" showed lower mass loss (ML) over the storage time. The addition of EO emitter slowed down the consumption of O2, better preserved texture when compared to the control and more effectively control polyphenol oxidase (PPO) activity and antioxidants' retention during the cold storage. Microbial counts in control globe artichoke RTC slices were significantly higher than those packed with EO emitter, confirming the inhibiting role played by EO of F. vulgare. In addition, the EO emitter did not influence negatively the sensory profile of RTC globe artichoke slices after microwave cooking.

Detrimental effect on the gut microbiota of 1,2-dicarbonyl compounds after in vitro gastro-intestinal and fermentative digestion.

This study investigated the stability of dicarbonyl compounds (DCs), 3-deoxyglucosone (3-DG), glyoxal (GO) and methylglyoxal (MGO) during simulated gastrointestinal digestion processes and the impact these compounds have on the gut microbiota. DCs pass almost unaltered through the in-vitro gastrointestinal digestion phases (concentration loss: 11% for 3-DG, 24% for GO and MGO) and have an effect on the fermentative digestion process, reducing the total gut bacterial population up to 6 Log10 units. Previous studies have shown no antimicrobial activity for 3-DG, however, for the first time it has been shown that when incubated with faecal bacteria 3-DG strongly depressed this microbial community. The influence of dicarbonyl compounds on the anaerobic fermentation processes was confirmed by the reduced production of short-chain fatty acids. Considering the modern Western diet, characterised by high consumption of ultra-processed foods rich in dicarbonyl compounds, this could lead to a reduction of bacteria important for the microbiome.

Combined application of antagonistic Wickerhamomyces anomalus BS91 strain and Cynara cardunculus L. leaf extracts for the control of postharvest decay of citrus fruit.

Combined use of biocontrol agents and plant extracts can be considered a viable and promising strategy for protecting plant tissues with different synergistic mechanisms of action that improve the antimicrobial activity of the mixtures. Treatments of citrus fruits with Wickerhamomyces anomalus BS91 have been previously reported as effective measures to reduce the incidence of green mold caused by Penicillium digitatum. On the opposite, the knowledge of the antifungal activity of cultivated cardoon (Cynara cardunculus L. var. altilis DC.) leaf extract, vegetable widespread in some Mediterranean areas, is still very limited. In this study, experimental trials were conducted to evaluate the effectiveness in vitro of leaf aqueous, methanolic and ethanolic extracts of C. cardunculus against seven fungal pathogens responsible for considerable food losses in the postharvest stage. In addition, biocontrol yeast W. anomalus BS91 and the three C. cardunculus extracts were tested in vivo both as a single treatment and in mixture, against Penicillium digitatum on 'Tarocco' oranges and 'Femminello' lemons. The combination of W. anomalus BS91 and leaf ethanolic extract reduced with the highest efficacy the incidence and severity of green mold on orange and lemon fruits with respect to the control, and was more effective than treatment with antagonistic yeast or leaf extracts applied alone. Incidence and severity of citrus decay were more consistently reduced when mixtures were applied 24 h before the inoculation of the pathogen, thus suggesting the relevance of preventive treatments. The mixtures of antagonistic W. anomalus BS91 and ethanolic leaf extract were more effective in controlling green mold decay on oranges than on lemons. These results indicate that biocontrol agents and leaf extracts, used in appropriate combination, can provide a stronger protection than when used singularly. However, compatibility between microbial antagonist and antimicrobial extract should be preliminary verified.

Characterization of Prickly Pear Peel Flour as a Bioactive and Functional Ingredient in Bread Preparation.

The aim of the present research was to evaluate the addition of prickly pear peel flour (PPPF) to bread dough as a source of nutrient and bioactive compounds. The PPPF's physical, chemical and nutritional composition was evaluated, as well as its content of bioactive compounds betalains, and flavonoids. The characterization evidenced high fiber and carbohydrate contents and an elevated amount of polyphenols and betalain compounds. The PPPF was then added at different concentrations (5, 10, 15, 20, 50%, w/w) to bread formulations as a potential functional ingredient. All concentrations, except 50% PPPF, evidenced good leavening dough properties and were then tested for baking. In relation to the content of added PPPF, the amount of betalains, representing bioactive compounds, remained high even after the baking process, suggesting a protective matrix effect. Among the different formulations, those containing PPPF at 10% showed the highest values in terms of the leavening dough capacity and bread specific volume and received the best sensory evaluation score.

Heterogenized Imidazolium-Based Ionic Liquids in Pebax®Rnew. Thermal, Gas Transport and Antimicrobial Properties.

Imidazolium-based ionic liquids (ILs) have interesting antimicrobial activity and their inclusion in a flexible film is ideal to take advantage of their properties in practical applications. Poly(ether-block-amide) (Pebax®Rnew) films were prepared by solution casting, loading two synthetized ILs (1-hexadecyl-3-methylimidazolium dimethyl-5-sulfoisophthalate [Hdmim][DMSIP], IL1 and 1-octyloximethyl-3-methylimidazolium hexafluorophosphate [OOMmim][PF6], IL2) up to 5 wt.%. The ILs were characterized by 1H NMR and MALDI-TOF spectroscopy. The films were investigated for miscibility, morphology, wettability, spectral properties and gas transport. The films display a good thermal stability (>200 °C). Differential scanning calorimetry (DSC) proves phase separation in the blends, that is consistent with FTIR analysis and with the island-like surface morphology observed in the micrographs. Gas permeability tests revealed that the IL-loaded films are dense and poreless, keeping the selectivity of the polymer matrix with a somewhat lessened permeability owing to the impermeable ILs crystals. The film antimicrobial activity, evaluated against Gram-negative and Gram-positive bacterial strains, was correlated to the structure of the incorporated ILs. The smaller IL2 salt did not modify the hydrophobic nature of the neat polymer and was readily released from the films. Instead, IL1, having a longer alkyl chain in the cation, provided a promising antimicrobial activity with a good combination of hydrophilicity, permeability and thermal stability.

Phytoremediation potential of Arundo donax (Giant Reed) in contaminated soil by heavy metals.

Soil pollution from heavy metals poses a serious risk for environment and public health. Phytoremediation is an eco-friendly and cheaper alternative compared to chemical-physical techniques. We carried out in vitro tests where three microorganisms Trichoderma harzianum, Saccharomyces cerevisiae and Wickerhamomyces anomalus were exposed to eight different heavy metals (one metal at a time) in order to evaluate resistance, growth and bioaccumulation capability for each metal (Ni, Cd, Cu, V, Zn, As, Pb, Hg). Taking into account the natural characteristics of T. harzianum, (resistance to environmental stress, resistance to pathogenic fungi, ability to establish symbiotic relationships with superior green plants) and the good bioaccumulation capacity for V, As, Cd, Hg, Pb shown after in vitro tests, it was chosen as a microorganism to be used in greenhouse tests. Controlled exposure tests were performed in greenhouse, where Arundo donax and mycorrhized Arundo donax with T. harzianum were exposed for 7 months at two different doses (L1 and L2) of a heavy metal mix, so as to assess whether the symbiotic association could improve the bioaccumulation capability of the superior green plant A. donax. Heavy metals were determined with ICP-MS. The average bioaccumulation percentage values of A. donax for L1 and L2 were, respectively: Ni (31%, 26%); Cd (35%, 50%); Cu (30%, 35%); As (19%, 27%); Pb (18%, 14%); Hg (42%, 45%); V (39%, 26%); Zn (23%, 9%). The average bioaccumulation percentage values of mycorrhized A. donax with T. harzianum for L1 and L2 were, respectively: Ni (27%, 38%); Cd (44%, 42%); Cu (36%, 29%); As (17%, 23%); Pb (37%, 54%); Hg (44%, 60%); V (16%, 20%); Zn (14%, 7%). A. donax showed the highest BAF (bioaccumulation factor) for Cd (0.50), Cu (0.35), As (0.27) and Hg (0.45) after exposure to L2; mycorrhized A. donax with T. harzianum showed the highest BAF for Ni (0.38), Cd (0.42), Pb (0.54) and Hg (0.60) after exposure to L2. A. donax showed the highest TF (translocation factor) values for Cd (0.28) and Hg (0.26) after exposition at L1 and L2 respectively; A. donax mycorrhized with T. harzianum showed the highest TF values for Cd (0.70), As (0.56), V (0.24), Pb (0.18) after exposition at L2, and Zn (0.30) after exposition at L1. Our study showed a good growth capability in contaminated soils and a good bioaccumulation capability of heavy metals, both for A. donax and mycorrhized A. donax with T. harzianum. Furthermore, for three metals (Ni, Pb and Hg) the bioaccumulation capability was improved by the symbiosis of T. harzianum with A. donax. So, these results proved the suitability both for A. donax and mycorrhized A. donax with T. harzianum for phytoremediation processes.

Antioxidant and Antimicrobial Properties of Semi-Processed Frozen Prickly Pear Juice as Affected by Cultivar and Harvest Time.

Consumer interest toward natural ingredients is creating a growing trend in the food industry and research for the development of natural products such as colorants, antimicrobials and antioxidants. Semi-processed frozen prickly pear (Opuntia ficus-indica (L.) Mill.) juices (PPJs), obtained from three cultivars with white, red and yellow pulp, with different harvest times ("Agostani" and "Bastardoni"), were characterized for betalains, total phenolics, flavonoids, carotenoids, antioxidant capacity (by 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH)) and antimicrobial potential against foodborne pathogenic bacteria. Through chemical assays, PPJs showed high contents of total polyphenols, flavonoids and betalains and marked antioxidant capacity. PPJs from the first harvest ("Agostani") revealed the significantly highest amount of polyphenols in white cultivar and of betacyanin and betaxanthin in yellow and red cultivars; antioxidant capacity was significantly higher in "Agostani" PPJs than in "Bastardoni" ones. Regarding antimicrobial potential, all PPJs revealed good antibacterial activity, particularly against Salmonella enterica as evidenced by the widest inhibition haloes. These results encourage the suitability of the first flowering prickly pear fruits, with low market value as fresh fruit but with high nutritional features, to be processed as semi-finished product. In particular, its use as ingredient in foods with high risk of Salmonella contamination may act as a natural preservative.

Antibacterial activity of 1,2-dicarbonyl compounds and the influence of the in vitro assay system.

The antibacterial activities of the dicarbonyl compounds glyoxal (GO), methylglyoxal (MGO), 3-deoxyglucosone (3-DG) were assessed against Gram-positive and Gram-negative pathogenic and food spoilage bacteria, both in agarised and liquid assay system. The kinetics of dicarbonyls' degradation at different antimicrobial assay conditions were studied, to determine the possible interference of the nutrient medium. In agarised assay system, GO and MGO exhibited antimicrobial activity, with higher efficacy against Gram-positive strains than Gram-negative ones. The nutrient medium reacted quickly both with GO and MGO, interfering with the antibacterial potential and the degradation kinetics indicated first-order reactions. In liquid assay system, both GO and MGO inhibited the target bacteria at concentrations significantly lower than those estimated in agarised assay system. Moreover, to the best of our knowledge, the antibacterial activity of GO and MGO against Listeria innocua, Pseudomonas fluorescens, Salmonella enterica and Bacillus cereus has not been previously reported.

Efficacy of different citrus essential oils to inhibit the growth and B1 aflatoxin biosynthesis of Aspergillus flavus.

Food contamination by aflatoxin B1 (AFB1), produced by mycotoxigenic strains of Aspergillus spp., causes severe medical and economic implications. Essential oils (EOs) are mixtures of eco-friendly natural volatile substances. Their ability to inhibit fungal growth has been investigated, while no data are available about their efficacy in inhibition of AFB1 biosynthesis. This study investigates the efficacy of five different citrus EOs to inhibit the growth and AFB1 synthesis of A. flavus through in vitro tests for a future application in food matrices. AFB1 detection was carried out by LC-ESI-TQD analytical approach. Lemon (Citrus limon (L.) Burm. f.), bergamot (Citrus bergamia Risso), and bitter orange (Citrus aurantium L.) EOs were the most effective causing a 97.88%, 97.04%, and 96.43% reduction in mycelial growth, respectively. Sweet orange and mandarin EOs showed the lowest percentage of mycelial growth reduction. Citrus EOs showed different capacity of AFB1 inhibition (lemon > bitter orange > bergamot > sweet orange > mandarin). Our results showed a dose-dependent antifungal activity of lemon, bitter orange, and bergamot EOs which at 2% (v/v) inhibited both mycelium growth and AFB1 genesis of A. flavus. Our results show that EOs' use can be a pivotal key to recovery and reuse of citrus fruit wastes and to be used as eco-friendly fungicides for improvement of food safety. The use of EOs obtained at low cost from the residues of citric industry presents an interesting option for improving the profitability of the agriculture.

Quality Maintenance of Beef Burger Patties by Direct Addiction or Encapsulation of a Prickly Pear Fruit Extract.

Beef burger patties are a very perishable food product with a maximum shelf life of 3 days at 4°C, due to a fast decrease of quality parameters and microbial growth. Although some additives listed in the Regulation EU 601 (2014) are allowed in fresh minced beef and meat preparations with antioxidant functionality, no additive with antimicrobial activity is permitted. In this study, a prickly pear extract (PPE) was added to beef burger patty formulations both by direct application and encapsulation in alginate beads. Beef burger patties were evaluated during refrigerated storage (up to 8 days at 4°C) in terms of microbial quality, pH, texture, and color variation. At the end of storage, burger samples incorporating PPE and encapsulated PPE showed significantly (p < 0.05) lower values of mesophilic bacteria, Enterobacteriaceae, and Pseudomonas spp. when compared to control samples added with sterile distilled water (SDW) or encapsulated SDW. Samples added with encapsulated PPE showed the smallest variations of color a* values (red) during the considered storage period, followed by samples added with PPE, suggesting a protective effect of the extract toward the myoglobin oxidation process. In addition, textural parameters (hardness, cohesiveness, and springiness) reached the highest levels, after 8 days of storage, in burger samples added both with PPE and encapsulated PPE, supporting the potentiality of PPE, encapsulated or not into alginate beads, to be used as a natural preservative of beef burger patty formulations for maintaining quality parameters.

Addition of Olive Leaf Extract (OLE) for Producing Fortified Fresh Pasteurized Milk with An Extended Shelf Life.

An olive leaf extract (OLE) has been tested in vitro for its antibacterial activity and ability to inhibit α-glucosidase enzyme. OLE was also evaluated for its potential, when added to pasteurized milk, to preserve nutritional parameters and to limit microbial growth, thus prolonging shelf life. In vitro assays demonstrated a strong antibacterial efficacy of OLE mainly against Bacillus cereus and the capacity to inhibit α-glucosidase enzyme (IC50) when used at 0.2 mg oleuropein/mL. The milk fortification with OLE at 3.6 mg of oleuropein/mL of milk reduced total mesophilic bacteria at undetectable level after 6 d (expiration date) and by 1 log CFU/mL after 10 d. Moreover, OLE addition at 1.44 and 3.6 mg of oleuropein/mL of milk significantly reduced fat and lactose losses up to 10 d. The results motivate the use of the OLE to make a new functional milk with an extended shelf life.

Role of biocontrol yeasts Debaryomyces hansenii and Wickerhamomyces anomalus in plants' defence mechanisms against Monilinia fructicola in apple fruits.

The role of killer yeasts of the species Debaryomyces hansenii and Wickerhamomyces anomalus in biocontrol of Monilinia fructicola, and their involvement in plant defence mechanisms against brown rot in apple fruits, were investigated. D. hansenii KI2a and W. anomalus BS91 strains showed the highest in vitro biocontrol activity, inhibiting mycelium growth by 69.53% and 66.08% respectively, as compared to control fungal cultures. Brown rot on apple fruits was significantly reduced by BS91 and two strains of D. hansenii KI2a and AII4b by 92.46%, 85.10% and 70.02%, respectively, in comparison to infected fruits, which did not receive any pre-treatment. In enzymatic tests, the most significant changes in peroxidase (POD) and catalase (CAT) activities were observed in fruits inoculated either with BS91 followed by M. fructicola infection or with AII4b yeast strain alone, where POD activities were significantly higher by 67% and 54%, respectively, and CAT activities were significantly lower by 65% and 68%, respectively, than in untreated control fruits. These results confirmed the ability of killer yeasts to influence host-defence related enzyme activities in apple fruit tissue and may suggest that AII4b killer strain has a potential as biocontrol agent prior to infection by triggering immune response mechanisms in plant tissue, whereas BS91 strain is the most effective during pathogen infection and could be used as biocontrol agent in postharvest disease onset. Accordingly, the antagonistic strains of W. anomalus BS91 and D. hansenii KI2a and AII4b could be proposed as active ingredients for the development of biofungicide against M. fructicola.