Penicillium Paneum Research Articles

Microbial Carriage of Shuttle Door Handles and Campus Bank’s Automated Teller Machines

Microorganisms are ubiquitous organisms that can cause microbial contamination in both indoor and outdoor settings, with frequently touched surfaces acting as environmental reservoirs that increase the ability of pathogens to be transferred from host to host. This study was aimed at isolating, identifying and characterizing bacteria and fungi present on frequently used Automated Teller Machines (ATMs) and campus shuttle bus handles at Adekunle Ajasin University, Akungba-Akoko, Ondo State. Swab samples were obtained from the keypads of ATMs and door handles of campus shuttle buses. Enumeration of total microbial counts was carried out using the pour plating technique. The bacterial isolates were identified using Bergey's Manual of Determinative Bacteriology based on the results obtained from microscopic examination, cultural and morphological examination and biochemical tests. Meanwhile, the fungal isolates were identified using the Atlas and Compendium of Soil Fungi, based on the results obtained from cultural and morphological examination, as well as microscopic examination. The antibiotic and antifungal susceptibility pattern of the isolated microorganisms was also determined. Results showed that the ATM keypads and shuttle door handles contained Staphylococcus aureus (8.82%), Bacillus spp. (32.35%), Proteus mirabilis (8.82%), Escherichia coli (5.88), Salmonella spp. (5.88%), Enterobacter cloacae (5.88%), Klebsiella pneumoniae (2.94%), Citrobacter freundii (2.94%), Vibrio cholerae (2.94%), Serratia marcescens (2.94%), Aspergillus spp. (5.88%), Cladosporium sp. (2.94%), Geomyces sp. (2.94%), Oidiodendron griseum robak (2.94%), Penicillium paneum (2.94%) and Fusarium culmorum (2.94%). The zone of inhibition for the bacteria and fungi isolates ranged from 4mm to 36 mm, with ciprofloxacin being the most effective antibiotic. This study shows that campus shuttles and ATMs, aside from their primary functions, could also serve as a means of transmitting both pathogenic and non-pathogenic microorganisms, which pose public health risks. Personal hygiene and sanitation, such as hand washing and the use of hand sanitizer to clean hands, could serve as a means of reducing the incidence of microbial transmission.

Effects of temperature, pH, and relative humidity on the growth of Penicillium paneum OM1 isolated from pears and its patulin production

Patulin is a mycotoxin produced by several species of Penicillium sp., Aspergillus sp., and Byssochlamys sp. on apples and pears. Most studies have been focused on Penicillium expansum, a common postharvest pathogen, but little is known about the characteristics of Penicillium paneum. In the present study, we evaluated the effects of temperature, pH, and relative humidity (RH) on the growth of P. paneum OM1, which was isolated from pears, and its patulin production. The fungal strain showed the highest growth rate at 25 °C and pH 4.5 on pear puree agar medium (PPAM) under 97 % RH, while it produced the highest amount of patulin at 20 °C and pH 4.5 on PPAM under 97 % RH. Moreover, RT-qPCR analysis of relative expression levels of 5 patulin biosynthetic genes (patA, patE, patK, patL, and patN) in P. paneum OM1 exhibited that the expression of the 4 patulin biosynthetic genes except patL was up-regulated in YES medium (patulin conducive), while it was not in PDB medium (patulin non-conducive). Our data demonstrated that the 3 major environmental parameters had significant impact on the growth of P. paneum OM1 and its patulin production. These results could be exploited to prevent patulin contamination by P. paneum OM1 during pear storage

FILAMENTOUS MICROMYCETES RESPONSIBLE FOR THE SPOILAGE OF SELECTED VEGETABLES IN THE FOOD RETAIL CHAIN

Vegetables represent a very important part of the diet. However, one of the problems of the vegetable market is its shelf life and related safety. A significant reason for vegetable losses in the retail network is the development of microorganisms, mainly micromycetes. They can significantly affect the quality of products, and due to the production of toxic metabolites, they also carry a toxicological risk. The aim of our study was to detect fungi that cause damage to selected types of vegetables in the food retail chains in Slovakia and are therefore directly responsible for product losses. Totally 44 samples of root, cabbage, and fruiting vegetables were mycologically analysed. Micromycetes, causing visible damage to the analysed vegetable samples, were inoculated to M137, M096, or M696 media from HiMedia and cultivated for 7 days at 25±1 °C. Important isolates were subjected to toxicological analysis by the thin-layer chromatography. The results show that the most common cause of carrot spoilage is the genus Berkeleyomyces. In the case of parsley, it was yeast Geotrichum candidum. Alternaria spp. occurred most often in the case of broccoli and cauliflower. Tomatoes were the most frequently spoiled by representatives of the genus Penicillium, or Botrytis cinerea and Cladosporium, cucumbers by Cladosporium and Alternaria species, similar to peppers, and the main spoiler of eggplants was Botrytis cinerea. Alternaria spp. showed a relatively high ability to produce altenuene, alternariol, and alternariol monomethyl ether. Penicillium expansum from carrots produced roquefortine C, patulin, and citrinin, and Penicillium paneum from tomatoes synthesized roquefortine C.

Valorization of wheat bread waste and cheese whey through cultivation of lactic acid bacteria for bio-preservation of bakery products

In this work, three lactic acid bacteria (LAB) strains, specifically, Lactiplantibacillus plantarum UMCC 2996, Furfurilactobacillus rossiae UMCC 3002, and Pediococcus pentosaceus UMCC 3010, were tested in new bread-whey media composed by wheat bread and sweet cheese whey, designed as an alternative to the conventional MRS medium. The medium resulting from hydrolysis with amylase and neutrase (AN) was considered the best for the growth of all the strains. This medium was particularly optimal for the strain F. rossiae UMCC 3002, which showed an increase in growth of 114% compared to that in MRS medium. Additionally, the bio-preservative ability of the selected LAB was assessed in pectin-based coated sliced bread inoculated with Aspergillus flavus ITEM 7828, Penicillium paneum ITEM 1381, and Aspergillus niger ITEM 7090. Different LAB strain behavior was observed towards the specific molds. A good bio-preservation activity was shown from F. rossiae UMCC 3002 against A. flavus ITEM 7828 with results compared to the protection by ethanol treatment. The results obtained in this study suggest a novel strategy for the cultivation of selected starters with a bio-protection activity by valorizing bread waste and cheese whey by-products, in a circular economy perspective.

Antifungal Synergistic Effect of Paprika and Cinnamon Oleoresins and Their Coencapsulation by Spray Chilling Technique to Produce a Carotenoid-Cinnamaldehyde-Rich Food Powder

Oleoresins are natural extracts obtained from plants and spices. Cinnamaldehyde and carotenoids are the main compounds found in cinnamon and paprika oleoresins, respectively, and exhibit pronounced antimicrobial and antioxidant potential. The coencapsulation of the two oleoresins can promote greater stability and synergism between them. Microencapsulation by spray chilling generates solid lipid microparticles when the atomized matrix crystallizes in contact with the cold chamber. This technique allows greater trapping of volatile compounds as they are more soluble in lipid materials. This work’s main objective was to evaluate the synergistic antifungal effect between cinnamon and paprika oleoresins and their coencapsulation by spray chilling. Cinnamon:paprika (1:1 and 2:1) mixture showed a synergistic effect against Penicillium paneum and Aspergillus niger. The extracts also prevented the growth of microorganisms without direct contact with the agar. The microparticles showed a spherical surface and polymorphic β′-characteristic. Particles containing paprika oleoresin presented orange color, while samples with only cinnamon were off-white. The size distribution was multimodal with (D0.5) ranging from 13.6 μm for samples containing only cinnamon to 1152.7 μm for samples containing only paprika oleoresin. The storage temperature (5 and 25 °C) affected the release of cinnamaldehyde from the microparticles. Regarding the first 14 days, samples stored at 5 °C released more cinnamaldehyde compared to that stored at 25 °C. The concentration of carotenoids in the particles remained constant throughout the 49 days of storage for both temperatures. The coencapsulation of oleoresin from paprika and cinnamon made it possible to obtain a lipid coloring powder that has antimicrobial properties.

Anti-Spoilage Activity and Exopolysaccharides Production by Selected Lactic Acid Bacteria.

In this study, eight lactic acid bacteria (LAB) strains, previously isolated from traditional and gluten-free sourdoughs, and selected for their potential in improving the sensory and rheological quality of bakery products, were screened against some common spoilage agents. The anti-mould activity was tested using strains of the species Fusarium graminearum, Aspergillus flavus, Penicillium paneum and Aspergillus niger. Regarding the antibacterial activity, it was assessed against four strains of the species Escherichia coli, Campylobacter jejuni, Salmonella typhimurium and Listeria monocytogenes. Furthermore, LAB strains were evaluated for their ability to produce exopolysaccharides, which are gaining considerable attention for their functional properties and applicability in different food industrial applications. A strain-specific behaviour against the moulds was observed. In particular, F. graminearum ITEM 5356 was completely inhibited by all the LAB strains. Regarding the antibacterial activity, the strains Leuconostoc citreum UMCC 3011, Lactiplantibacillus plantarum UMCC 2996, and Pediococcus pentosaceus UMCC 3010 showed wide activity against the tested pathogens. Moreover, all the LAB strains were able to produce exopolysaccharides, which were preliminarily characterized. The assessed features of the LAB strains allow us to consider them as promising candidates for single or multiple starter cultures for food fermentation processes.

Structure Revision of Penipacids A–E Reveals a Putative New Cryptic Natural Product, N-aminoanthranilic Acid, with Potential as a Transcriptional Regulator of Silent Secondary Metabolism

Reconsideration of the spectroscopic data for penipacids A–E, first reported in 2013 as the acyclic amidines 1–5 from the South China deep sea sediment-derived fungus Penicillium paneum SD-44, prompted a total synthesis structure revision as the hydrazones 6–10. This revision strongly supported the proposition that penipacids A–B (6–7) were artifact Schiff base adducts of the cryptic (undetected) natural product N-aminoanthranilic acid (11) with diacetone alcohol, induced by excessive exposure to acetone and methanol under acidic handling conditions. Likewise, the revised structures for penipacids C–D (8–9) and E (10) raise the possibility that they may also be artifact Schiff base adducts of 11 and the media constituents pyruvic acid and furfural, respectively. A review of the natural products literature revealed other Schiff base (hydrazone) natural products that might also be viewed as Schiff base adduct artifacts of 11. Having raised the prospect that 11 is an undetected and reactive cryptic natural product, we went on to establish that 11 is not cytotoxic to a range of bacterial, fungal or mammalian (human) cell types. Instead, when added as a supplement to microbial cultivations, 11 can act as a chemical cue/transcriptional regulator, activating and/or enhancing the yield of biosynthetic gene clusters encoding for other natural product chemical defenses. This study demonstrates the value of challenging the structure and artifact status of natural products, as a window into the hidden world of cryptic and highly reactive natural products.

Occurrence of mycotoxins and mycotoxigenic fungi in silage from the north of Portugal at feed-out

Maize and grass silages are important dietary components for ruminant livestock that influence the quality of animal products for human consumption, such as milk, in many parts of the world. Infection of plants by fungi able to produce mycotoxins, either in the field or post-harvest, can result in a decrease of silage nutritional quality and, consequently, in milk quality. In this study, 45 maize and grass silage samples were collected from 25 dairy farms located in the north of Portugal. The occurrence of fungi was evaluated in samples, the most frequently isolated species being Aspergillus fumigatus, Dipodascus geotrichum, Mucor circinelloides, Penicillium paneum, and Aspergillus flavus. The mycotoxigenic profile of the fungal species was studied using the ultra-high-performance liquid chromatography coupled to mass spectrometry–ion trap–time-of-flight (UHPLC–MS–IT–TOF) detection. In addition, a new method based on a QuEChERS extraction followed by the UHPLC- tandem mass spectrometry (UHPLC-MS/MS) detection was developed for simultaneous analysis of 39 mycotoxins in silage. A high co-occurrence of Fusarium mycotoxins was found, although at low levels of contamination. Deoxynivalenol and beauvericin were found in more than 82% of maize silage samples. It can be highlighted the low occurrence of Penicillium and Aspergillus toxins in the maize and grass silages studied despite the frequent detection of species of both genera.

Influence of environmental growth conditions on chalk yeasts causing bread spoilage

The main objective of this study was the investigation of different environmental growth conditions on the growth of chalk yeasts, Hyphopichia burtonii (HB), Wickerhamomyces anomalus (WA) and Saccharomycopsis fibuligera (SF). Through multiple methods, including radial growth, biocontrol assay, growth/no-growth modelling and a bread challenge test, the influence of pH (4.5–6.5), temperature (22–30 °C), propionic acid (0–0.3%) and presence of other spoilage fungi was assessed. This study showed that pH and temperature does not play a major role on the growth of HB, WA and SF. Only WA shows optimal growth at pH 4.5 and 30 °C on MEA. The likeliness of growth is the following: HB >SF >WA, except from WA at pH 4.5/30 °C. Biocontrol activity was observed against Aspergillus niger and Penicillium paneum in the presence of high concentrations of HB at 30 °C. Furthermore, this study showed that HB is most sensitive to propionic acid (PA), followed by SF and WA. The effectiveness of PA was also shown through bread challenge tests. The following order of sensitivity against PA was observed: HB >SF >WA. Breads inoculated with WA had a shorter shelf-life (2–3 days less).

Modeling the impact of water activity, pH, and calcium propionate on the germination of single spores of Penicillium paneum

This study aimed to assess the effect of water activity (aw) (0.93–0.95), pH (5.1–5.8), and concentration of calcium propionate (0.25 and 0.41%) on the germination time of individual spores of Penicillium paneum. The germination of single spores was examined by capturing images at every hour using the Axio Observer.Z1 inverted microscope ( × 100) connected to the camera at 25 °C for 96 h. The results indicated that P. paneum germination time was significantly affected by aw and pH (ρ < 0.05). As most of the growth curves exhibited asymmetric shapes, the asymmetric model was fitted to germination data and the maximum percentage of viable spores (Pmax; %), shape parameter (d), and germination time (τ; hour) were obtained. τ -values ranged from 26.5 to 40.7 h. After the Monte Carlo simulation, a probability distribution of time for 10% of the P. paneum population (t10%) to germinate was obtained. The mean value of t10% was 25 h, ranging from 15 to 47 h (95% confidence interval). The variability in germination and growth of P. paneum single spores highlights the challenge of predicting and preventing this critical phenomenon.

Modelling and validation of the antifungal activity of DL-3-phenyllactic acid and acetic acid on bread spoilage moulds

Most interesting antifungal compounds from sourdough fermentation are acetic acid (AA) and DL-3-phenyllactic acid (PLA). Although the role of pH on the activity of organic acids has been established long time ago, no information is available on the importance of undissociated acid (HA) expressed on the aqueous phase of bread (CHA, mmole/L). Mostly, concentrations (mmole/kg dough or bread, CTOT) and pH are given side by side. The aim of this study was to show the importance of CHA for adequate comparison of in-vitro growth data with bread shelf-life. Growth of Penicillium paneum and Aspergillus niger was recorded using a micro-dilution assay with optical density measurements. Parameters such as aw (0.94–0.98), pH (4.6–6.0), temperature (10–30 °C), time (0–8 days) and CTOT (0–300 mM) were varied. Growth/no-growth models were developed and shelf-life tests of par-baked breads of 45 days at 20 °C were conducted. The modelled inhibitory concentrations of undissociated acid were comparable with the shelf-life test of bread: (PLA) 50 versus 39–84 mmol/L; (AA) 110 versus 110–169 mmol/L. This study showed the applicability of G/NG models for bread shelf-life prediction and highlighted the importance of CHA. Moreover, it was found that naturally present PLA in sourdough bread is insufficient to increase bread shelf-life.

Editorial overview: Food mycology

In this study, the inactivation kinetics of strains of Penicillium paneum and P. roqueforti were determined during bread baking. Three strains of P. paneum (PR03, PR04, and PR05) and P. roqueforti (PR06, PR11, and PR67) were used. Baking conditions were based on those used in baking industries (160 °C, 190 °C and 220 °C). The inactivation curves did not follow first-order kinetic, and as the primary model, the Weibull model was used with the fixed p-value. The t4D value was also determined, and the secondary model was built using the log δ as a function of the baking temperature. Lower values of δ and t4D were obtained at 220 °C, and the values of this parameter were different (p < 0.05) among the three P. paneum strains at 160 °C and 220 °C. Two strains of P. roqueforti (PR06 and PR11) showed the highest values of t4D at 190 °C and 220 °C (10.2 and 8.18 min. respectively). The results of this study demonstrate that the different baking temperatures of the bread making process may result in the survival of fungi in the product, which may be vital in limiting the shelf life of these products. The quantification of fungal inactivation during bread baking is critical for the design of thermal process aiming to balance quality and microbiological stability of industrialized loaves of bread.

Validation of in-vitro antifungal activity of the fermentation quotient on bread spoilage moulds through growth/no-growth modelling and bread baking trials

The main objectives were to investigate the antifungal effect of lactic (LA) and acetic acid (AA) and the fermentation quotient (FQ, mol/L ratio of LA over AA) towards Penicillium paneum and Aspergillus niger through growth/no-growth modelling of in-vitro data and to validate its effect in chemically acidified bread by performing challenge tests. Results have shown that AA has strong antifungal activity towards both bread moulds, albeit that P. paneum is ten times more resistant compared to A. niger. Complete growth inhibition of A. niger on chemically acidified bread was observed during 35 days at 21 °C for concentrations of AA ≥ 33 mmol/kg dough or ≥165 mmol undissociated AA/L water phase in bread. Whereas for A. niger the FQ must be close to zero and the concentration of AA in bread 33 mmol/kg dough to achieve complete growth inhibition, very high concentrations of AA and LA were needed to prevent growth of P. paneum (>100 mmol/kg dough). The acids also affected yeast activity in dough resulting in lower specific volumes and harder bread crumb. To conclude, the antifungal activity of the FQ cannot be generalized because its antifungal power depends on the sensitivity of the mould species towards LA and AA.

Antifungal activity of commercial sanitizers against strains of Penicillium roqueforti, Penicillium paneum, Hyphopichia burtonii, and Aspergillus pseudoglaucus: Bakery spoilage fungi

Information on the sensitivity of spoilage fungi of bakery products to sanitizing agents is scarce in the literature. Thus, the aim of this study was to evaluate the antifungal activity of different classes of commercial sanitizers, which have permitted use in the food industry, on the main fungi involved in spoiling bakery products. The tests were carried out according to the protocol for testing the antifungal effect of chemical sanitizers of the European Committee for Standardization (CEN), with adaptations. Different strains of six isolated fungal species responsible for spoiling bakery products (Penicillium roqueforti, Penicillium paneum, Hyphopichia burtonii, and Aspergillus pseudoglaucus) were tested against five sanitizers at three concentrations: benzalkonium chloride (0.3%, 2.5%, 5%), biguanide (2%, 3.5%, 5%), peracetic acid (0.15%, 1.5%, 3%), quaternary ammonium (0.3%, 2.5%, 5%), and sodium hypochlorite (0.01%, 0.1%, 0.2%). Peracetic acid was the most effective sanitizes considering the genera, species, and concentrations evaluated, generally being capable of reductions between 2 and 4 logs of initial control tested. Biguanide should not be the compound of choice when the main goal of the bakery industry is fungal control.

Growth/no-growth models of in-vitro growth of Penicillium paneum as a function of thyme essential oil, pH, aw, temperature

The aims of this study were (i) screening of antifungal activity of thyme essential oil on Penicillium paneum; (ii) development of growth/no-growth models (G/NG); and (iii) validation of the G/NG models by performing bread baking trials. The screening method was based on the measurement of fungal growth in a semi-solid medium through optical density. The combined influence of aw (0.88–0.97), pH (4.8–7.0), temperature (22 and 30 °C), time (0–144 h) and varying concentrations of thyme oil (0–2 μL/mL YES) were assessed. Growth of P. paneum at aw 0.88 was significantly reduced compared to aw 0.93–0.97. A slight pH effect was observed at aw 0.93; growth was delayed at pH 6 compared to pH 4.8. The lowest concentration of thyme oil preventing growth during 144 h of incubation was 1 μL/mL medium. According to the results of the shelf-life test of par-baked bread, fungal growth was inhibited for more than 45 days using 0.3 mL thyme oil/100 g dough. To conclude, this study recognized the potential of using G/NG models to develop better product formulations and to facilitate product innovation.

Effect of temperature on inactivation kinetics of three strains of Penicillium paneum and P. roqueforti during bread baking

In this study, the inactivation kinetics of strains of Penicillium paneum and P. roqueforti were determined during bread baking. Three strains of P. paneum (PR03, PR04, and PR05) and P. roqueforti (PR06, PR11, and PR67) were used. Baking conditions were based on those used in baking industries (160 °C, 190 °C and 220 °C). The inactivation curves did not follow first-order kinetic, and as the primary model, the Weibull model was used with the fixed p-value. The t4D value was also determined, and the secondary model was built using the log δ as a function of the baking temperature. Lower values of δ and t4D were obtained at 220 °C, and the values of this parameter were different (p < 0.05) among the three P. paneum strains at 160 °C and 220 °C. Two strains of P. roqueforti (PR06 and PR11) showed the highest values of t4D at 190 °C and 220 °C (10.2 and 8.18 min. respectively). The results of this study demonstrate that the different baking temperatures of the bread making process may result in the survival of fungi in the product, which may be vital in limiting the shelf life of these products. The quantification of fungal inactivation during bread baking is critical for the design of thermal process aiming to balance quality and microbiological stability of industrialized loaves of bread.

Bacillus velezensis as antagonist towards Penicillium roqueforti s.l. in silage: invitro and invivo evaluation.

The present study was conducted to evaluate the antagonistic effect of BacillusvelezensisNRRL B-23189 towards Penicillium roqueforti s.s. and Penicillium paneum (designated together as P.roqueforti s.l.) in silage conditions. Corn silage conditions were simulated invitro, and the impact of B.velezensis culture supernatant or cell suspension on P.roqueforti s.l. growth and roquefortine C production was evaluated. The antagonism was promising, but growth of B.velezensis in corn silage infusion was poor. Additionally, an invivo experiment was carried out with mini-silos containing a mixture of perennial ryegrass and white clover inoculated with P.roquefortis.l. The applied B.velezensis cell suspension was unsuccessful in reducing P.roquefortis.l. numbers, but did not compromise the silage acidification. Although the antagonism observed invitro was promising, the applied B.velezensis cell suspension could not live up to the expectations invivo. To our knowledge, the present study is the first one evaluating the antagonistic properties of B.velezensis towards toxigenic moulds in silage conditions, offering a good base for further research.

Solid lipid microparticles loaded with cinnamon oleoresin: Characterization, stability and antimicrobial activity

Cinnamon bark oleoresin (CO) is a natural flavoring that has several biological properties and can act as an antimicrobial agent. However, oleoresins are susceptible to degradation by light, oxygen and temperature. Thus, the objective of this work was the production and characterization of microparticles loaded with CO obtained by the spray chilling technique. Hardfat (PH) and palm oil (PO) were used as carriers in different proportions: 100:0; 80:20; 60:40, respectively. The active concentration was 1 and 2%. Solid lipid microparticles (SLM) were stored at 25 and 45°C having their polymorphism, retention capacity of the volatile compounds and antimicrobial capacity assessed over 28 days. CO presented cinnamaldehyde (Cn), O-methoxy cinnamaldehyde (OmCn) and coumarin (Co) as the major volatile components. The minimum inhibitory concentration (MIC) of the CO against molds, yeasts and Gram-negative bacteria was of 0.1% (v/v), for every microorganism. In the SLM characterization there was a significant size variation, with a mean diameter (d 0.5) in the range of 8-72 μm. Most of the formulations showed crystals in the polymorphic form β '. The formulation containing only PH as the carrier agent and 2% CO was able to better retain the volatile compounds. During the storage period, formulations F2 and F3, containing proportions of HP and OP of 80:20 and 60:40, respectively, and 2% CO, showed the best stabilities in relation to the concentration of Cn. The antimicrobial activity of the SLM against Candida pseudointermedia and Penicillium paneum, evaluated by the diameter of inhibition zone, increased over the 28 days of storage.

The application of growth-no growth models to directly assess the stability of wholemeal multigrain bread towards Penicillium paneum LMQA-002 and Paecilomyces variotii LMQA-001

This study aimed to develop predictive models to assess the growth response of Pencillium paneum LMQA-002 and Paecilomyces variotii LMQA-001 in wholemeal multigrain bread regarding moisture, pH, calcium propionate, temperature and time of storage. A complete factorial design was performed using slices of bread with different formulation: moisture (36; 38; 40; 42%), pH (5.1; 5.3; 5.5) and calcium propionate (0.6; 0.8 and 1%). The slices were inoculated with 102-103 spores following storage at 20 °C, 25 °C and 30 °C for up to 21 days. The degree of agreement between predictions and observations was >90% for both species. According to the results, the growth of P. paneum LMQA-002 and P. variotii LMQA-001 was inhibited for up to 21 days in bread formulations presenting pH (5.1), 36% moisture and 0.6% calcium propionate. The lower temperatures (20 °C and 25 °C) contributed to the growth of P. paneum LMQA-002 and storage at 30 °C favored the growth of P. variotii LMQA-001. Validation results showed correct predictions in 80% of the cases. A significant achievement of this study comprises the extension of wholemeal multigrain bread shelf-life from 12 to 21 days (>70% increase).

Use of hop extract as antifungal ingredient for bread making and selection of autochthonous resistant starters for sourdough fermentation

Aiming at meeting the consumers' demand in terms of bio-preservation, the potential of the combination of the lactic acid bacteria fermentation and the addition of hop extract as natural preservative in breadmaking, was exploited. The antifungal properties of a hop (Humulus lupulus) extract were investigated, showing a significant inhibition of the hyphal growth of Aspergillus parasiticus, Penicillium carneum, Penicillium polonicum, Penicillium paneum, Penicillium chermesinum, Aspergillus niger, Penicillium roqueforti. Lactic acid bacteria belonging to species of Enterococcus feacium, Lactobacillus plantarum, Lactobacillus brevis, Lactobacillus helveticus, Lactobacillus curvatus, Pediococcus pentosaceus, and Pediococcus acidilactici were isolated from hop and subjected to selection based on kinetics of growth and acidification. The sourdough (hS) enriched with hop extract (hE), started with three selected strains, had phenols concentration and antioxidant activity higher than those obtained in the same condition but without the hE. Hop-sourdough used in breadmaking delayed the fungal growth (14days), giving a bread characterized by free aminoacids concentration, antioxidant and phytase activities higher than bread started only with baker's yeast, with or without the addition of hE. Specific volume and cell-total area of the bread containing hE improved, and its sensory profile was characterized by typical sourdough attributes, and a moderate bitter/herbaceous perception.