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In this study, the microbiota of ready-to-eat surströmming from three Swedish producers were studied using a combined approach. The pH values of the samples ranged between 6.67 ± 0.01 and 6.98 ± 0.01, whereas their aw values were between 0.911 ± 0.001 and 0.940 ± 0.001. The acetic acid concentration was between 0.289 ± 0.009 g/100 g and 0.556 ± 0.036 g/100 g. Very low concentrations of lactic acid were measured. Viable counting revealed the presence of mesophilic aerobes, mesophilic lactobacilli and lactococci as well as halophilic lactobacilli and lactococci, coagulase-negative staphylococci, halophilic aerobes and anaerobes. Negligible counts for Enterobacteriaceae, Pseudomonadaceae and total eumycetes were observed, whereas no sulfite-reducing anaerobes were detected. Listeria monocytogenes and Salmonella spp. were absent in all samples. Multiplex real-time PCR revealed the absence of the bont/A, bont/B, bont/E, bont/F, and 4gyrB (CP) genes, which encode botulinic toxins, in all the samples analyzed. Metagenomic sequencing revealed the presence of a core microbiota dominated by Halanaerobium praevalens, Alkalibacterium gilvum, Carnobacterium spp., Tetragenococcus halophilus, Clostridiisalibacter spp. and Porphyromonadaceae. Psychrobacter celer, Ruminococcaceae, Marinilactibacillus psychrotolerans, Streptococcus infantis and Salinivibrio costicola were detected as minor OTUs. GC-MS analysis of volatile components revealed the massive presence of trimethylamine and sulphur compounds. Moreover, 1,2,4-trithiolane, phenols, ketones, aldehydes, alcohols, esters and long chain aliphatic hydrocarbons were also detected. The data obtained allowed pro-technological bacteria, which are well-adapted to saline environments, to be discovered for the first time. Further analyses are needed to better clarify the extent of the contribution of either the microbiota or autolytic enzymes of the fish flesh in the aroma definition.
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Alimentos Fermentados , Peixes/microbiologia , Microbiota , Alimentos Marinhos , Compostos Orgânicos Voláteis/análise , Animais , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Contagem de Colônia Microbiana , Fermentação , Alimentos Fermentados/análise , Alimentos Fermentados/microbiologia , Microbiologia de Alimentos , Microbiota/genética , RNA Ribossômico 16S/genética , Alimentos Marinhos/análise , Alimentos Marinhos/microbiologia , Suécia , Compostos Orgânicos Voláteis/químicaRESUMO
Different technical cork stoppers (blend of natural cork microgranules, one-piece natural cork, agglomerated natural cork, technical cork 1+1) were compared to evaluate the effects on the phenolic, volatile profiles and dissolved oxygen in three red (Merlot, Lagrein red, St. Magdalener) and one rosé (Lagrein rosé) wines, which were stored in bottles for 12 months. Gallic acid, caffeic acid, p-coumaric acid, trans-resveratrol, glutahionyl caftaric acid and protocatechuic acid did not vary remarkably during the first three months, whereas at six months a net increase was reported, followed by a clear decrease at 12 months. The same trend was observed in Lagrein rosé, but only for gallic acid. The total anthocyanins content decreased during the storage period in the four wines. Isopentyl acetate, 1-hexanol, ethyl hexanoate, 2-phenylethyl alcohol, diethyl succinate, ethyl octanoate and ethyl decanoate were the main volatile compounds. The sum of alcohols decreased in all four of the wines. The esters decreased in Merlot; however, they increased in Lagrein rosé, Lagrein red and St. Magdalener during the storage. Univariate and multivariate statistics and a sensory discriminant triangle test displayed similar influences of the different stoppers on the phenolic and volatile compounds during the whole storage duration. The changes detected in the phenolic and volatile concentrations were presumably due to the non-oxygen-mediated reactions occurring during 12 months of storage in bottle.
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Armazenamento de Alimentos/métodos , Vinho/análise , Adulto , Antocianinas/análise , Análise por Conglomerados , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Hidroxibenzoatos/análise , Hidroxibenzoatos/isolamento & purificação , Masculino , Pessoa de Meia-Idade , Oxigênio/análise , Análise de Componente Principal , Microextração em Fase Sólida , Limiar Gustativo/fisiologia , Fatores de Tempo , Compostos Orgânicos Voláteis/análise , Compostos Orgânicos Voláteis/isolamento & purificação , Adulto JovemRESUMO
Caciofiore della Sibilla is a speciality ewes' milk cheese traditionally manufactured in a foothill area of the Marche region (Central Italy) with a crude extract of fresh young leaves of Carlina acanthifolia All. subsp. acanthifolia as a coagulating agent. The fungal dynamics and diversity of this speciality cheese were investigated throughout the manufacturing and 20-day ripening process, using a combined PCR-DGGE approach. The fungal biota of a control ewes' milk cheese, manufactured with the same batch of milk coagulated with a commercial animal rennet, was also monitored by PCR-DGGE, in order to investigate the contribution of the peculiar vegetable coagulant to the fungal diversity and dynamics of the cheese. Based on the overall results collected, the raw milk and the dairy environment represented the main sources of fungal contamination, with a marginal or null contribution of thistle rennet to the fungal diversity and dynamics of Caciofiore della Sibilla cheese. Copyright © 2016 John Wiley & Sons, Ltd.
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Asteraceae/enzimologia , Queijo/microbiologia , Quimosina/química , Microbiologia de Alimentos , Fungos/classificação , Microbiota , Leite/microbiologia , Animais , Asteraceae/microbiologia , Sobrevivência Celular , DNA Fúngico/genética , Fungos/genética , Fungos/isolamento & purificação , Concentração de Íons de Hidrogênio , Itália , Extratos Vegetais/química , Folhas de Planta/enzimologia , Folhas de Planta/microbiologia , Reação em Cadeia da Polimerase , RNA Ribossômico/genética , Ovinos , Fatores de TempoRESUMO
The quality of poultry meat offered to the consumer depends mainly on the level of hygiene during all stages of its production, storage time, and temperature. This study investigated the effect of refrigerated storage on the microbiological contamination, color, and pH of turkey thigh muscles stored at 1 °C over six days. Microbial growth, including total mesophilic aerobes, presumptive lactic acid bacteria, and Enterobacteriaceae, significantly increased, impacting the meat's sensory attributes and safety. On the 6th day of meat storage, the content of total mesophilic aerobes, presumptive lactic acid bacteria, and Enterobacteriaceae was 1.82 × 107 CFU/g, 1.00 × 104 CFU/g, and 1.87 × 105 CFU/g, respectively. The stability of color was assessed by quantifying the total heme pigments, comparing myoglobin, oxymyoglobin, and metmyoglobin concentrations, analyzing color parameters L*, a*, b*, and the sensory assessment of surface color, showing a decline in total heme pigments, three myoglobin forms, redness (a*) and lightness (L*). In contrast, yellowness (b*) increased. These changes were correlated with the growth of spoilage microorganisms that influenced the meat's pigmentation and pH, with a notable rise in pH associated with microbial metabolization. Based on the conducted research, it was found that the maximum storage time of turkey thigh muscles at a temperature of 1 °C is 4 days. On the 4th day of storage, the total mesophilic aerobe content was 3.5 × 105 CFU/g. This study underscores the critical need for maintaining controlled refrigeration conditions to mitigate spoilage, ensuring food safety, and preserving turkey meat's sensory and nutritional qualities. There is a need for further research to improve turkey meat storage techniques under specific temperature conditions by studying the impact of using varying packaging materials (with different barrier properties) or the application of natural preservatives. Additionally, future studies could focus on evaluating the effectiveness of cold chain management practices to ensure the quality and safety of turkey products during storage. By addressing these research gaps, practitioners and researchers can contribute to developing more efficient and sustainable turkey meat supply chains, which may help mitigate food wastage by safeguarding the quality and safety of the meat.
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The efficacy of plasma-activated water (PAW) as a chemical-free and environmentally friendly preservative has been documented for a variety of foods, but the onset of lipid oxidation induced by plasma-reactive species has been less extensively studied. In this work, global indices (peroxide value, UV specific absorbance) and direct analytical determinations of volatile and non-volatile oxidation products were performed on sardine lipids extracted from fish fillets immersed in PAW (treatments) and distilled water (controls) for 10-30 min. Evidence of PAW-induced lipid oxidation was provided by higher UV specific absorbances and higher levels of C5-C9 secondary volatile oxidation products in the treated samples. However, the degree of fatty acid oxidation was not sufficient to cause a significant reduction in nutritionally valuable eicosapentaenoic acid and docosahexaenoic acid. Twelve cholesterol oxidation products (COPs) were identified in the sardine lipids, but no significant differences in total COPs content were found between PAW processed and control samples.
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Ácidos Graxos , Água , Animais , Alimentos Marinhos/análise , Peixes , ColesterolRESUMO
In this study, for the very first time, aqueous extracts obtained from flowers of spontaneously grown or cultivated Onopordum platylepis (Murb.) Murb. thistles were used as coagulating agents for the pilot-scale manufacture of Caciofiore, a traditional Italian raw ewe's milk cheese. Cheese prototypes were compared to control cheeses curdled with a commercial thistle rennet obtained from flowers of Cynara cardunculus L. After 45 days of ripening under controlled conditions, both the experimental and control cheese prototypes were analyzed for: cheese yield, physico-chemical (pH, titratable acidity, aw, proximate composition), morpho-textural (color and texture), and microbiological parameters (viable cell counts and species composition assessed by Illumina sequencing), as well as volatile profile by SPME-GC-MS. Slight variations in titratable acidity, color, and texture were observed among samples. Based on the results overall collected, neither the yield nor the proximate composition was apparently affected by the type of thistle coagulant. However, the experimental cheese prototypes curdled with extracts from flowers of both spontaneous or cultivated thistles showed 10 % higher values of water-soluble nitrogen compared to the control prototypes. On the other hand, these latter showed slightly higher loads of presumptive lactococci, thermophilic cocci, coliforms, and eumycetes, but lower counts of Escherichia coli. No statistically significant differences were revealed by the metataxonomic analysis of the bacterial and fungal biota. Though most volatile organic compounds (VOCs) were consistent among the prototypes, significant variability was observed in the abundance of some key aroma compounds, such as butanoic, hexanoic, and octanoic acids, ethanol, propan-2-ol, isobutyl acetate, 2-methyl butanoic acid, and 3-methyl butanal. However, further investigations are required to attribute these differences to either the type of coagulant or the metabolic activity of the microorganisms occurring in the analyzed cheese samples. The results overall collected support the potential exploitation of O. platylepis as a novel source of thistle coagulant to produce ewe's milk cheeses.
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Queijo , Quimosina , Leite , Queijo/análise , Queijo/microbiologia , Animais , Itália , Ovinos , Leite/química , Leite/microbiologia , Flores/química , Microbiologia de Alimentos , Manipulação de Alimentos/métodos , Concentração de Íons de Hidrogênio , Compostos Orgânicos Voláteis/análise , Extratos Vegetais/químicaRESUMO
ATR-FTIR (Attenuated Total Reflectance Fourier Transform InfraRed) spectroscopy, combined with chemometric, represents a rapid and reliable approach to obtain information about the macromolecular composition of food and plant materials. With a single measurement, the chemical fingerprint of the analyzed sample is rapidly obtained. Hence, this technique was used for investigating 13 differently processed tea leaves (green, black and white) all grown and processed in European tea gardens, and their vacuum-dried tea brews, prepared using both hot and cold water, to observe how the components differ from tea leaf to the in-cup infusion. Spectra were collected in the 1800-600 cm-1 region and were submitted to Principal Component Analysis (PCA). The comparison of the spectral profiles of leaves and hot and cold infusions of tea from the same country, emphasizes how they differ in relation to the different spectral regions. Differences were also noted among the different countries. Furthermore, the changes observed (e.g., at ~1340 cm-1) due to catechin content, confirm the antioxidant properties of these teas. Overall, this experimental approach could be relevant for rapid analysis of various tea types and could pave the way for the industrial discrimination of teas and of their health properties without the need of time-consuming, lab chemical assays.
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Multiple studies demonstrated biological activities of aged black garlic, including anti-inflammatory, antioxidant, and cardioprotective effects. We aimed to investigate the protective effects of an aged black garlic water extract (ABGE) alone or in association with multivitamins consisting of combined Vitamins D, C, and B12, on mouse heart specimens exposed to E. coli lipopolysaccharide (LPS). Moreover, we studied the hydrogen sulphide (H2S) releasing properties and the membrane hyperpolarization effect of the Formulation composed by ABGE and multivitamins, using Human Aortic Smooth Muscle Cells (HASMCs). ABGE, vitamins D and C, and the Formulation suppressed LPS-induced gene expression of cyclooxygenase (COX)-2, tumor necrosis factor (TNF)-α, interleukin (IL)-6, nuclear factor-kB (NF-kB), and inducible nitric oxide synthase (iNOS) on mouse heart specimens. The beneficial effects induced by the extract could be related to the pattern of polyphenolic composition, with particular regard to gallic acid and catechin. The Formulation also increased fluorescence values compared to the vehicle, and it caused a significant membrane hyperpolarization of HASMCs compared to ABGE. To conclude, our present findings showed that ABGE, alone and in association with multivitamins, exhibited protective effects on mouse heart. Moreover, the Formulation increased intracellular H2S formation, further suggesting its potential use on cardiovascular disease.
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Cold atmospheric plasma (CAP) is a non-thermal technology that could be applied for food decontamination from both biological (microorganisms) and chemical (pesticides, food allergens, mycotoxins) contaminants, thanks to the production of reactive species (RS). However, RS could also promote the onset and the progress of food lipid oxidation, which may limit the quality and acceptability of the final products. The aim of this work was to assess the oxidation degree of pistachio kernels after treatment in a surface dielectric barrier discharge (SDBD). Two different operative conditions for CAP generation were investigated, resulting in the production of high (800 ppm) or low (300 ppm) concentrations of ozone. Limited amounts of hydroperoxides (3.00-4.22 mEq O2/kg), thiobarbituric acid reactive substances (TBARS, 0.072-0.600 mg TEP/g oil), and phytosterol oxidation products (POPs, 14.43-17.20 µg/g) were observed in lipids of both control and plasma processed pistachios. Plasma treatments did not significantly affect the total fatty acid composition and the amounts of identified unsaponifiable matter constituents (4-desmethylsterols, 4,4-dimethylsterols, 4-methylsterols), except for an unexpected significant increase of γ-tocopherol content in extracted oils. These findings contribute to gaining further knowledge for the scale-up of CAP technology to industrial processing.
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Queijo Serra da Estrela is a PDO Portuguese cheese produced through coagulation of raw ewe's milk using cardoon (Cynara cardunculus L.) flowers. The present research was aimed at depicting an up-to-date and comprehensive overview of the microbiota of Queijo Serra da Estrela cheese. To this end, viable counting and metataxonomic analysis were carried out on cheeses sampled from four Portuguese artisan producers. Physico-chemical and morpho-textural analyses were also performed, together with the analysis of volatile organic compounds (VOCs). Finally, non-starter lactic acid bacteria (NSLAB) isolated from the cheeses were characterized for their enzymatic activities using a semi-quantitative method. According to the metataxonomic analysis, Lactococcus lactis and Lactococcus piscium were the species occurring at the highest relative abundance. The isolates collected from the cheeses were assigned to Enterococcus durans, Enterococcus faecalis, Enterococcus faecium, Enterococcus lactis, Levilactobacillus brevis, Latilactobacillus graminis, Leuconostoc mesenteroides, and the Lacticaseibacillus casei group. The enzymatic characterization of these cultures highlighted esterase, aminopeptidase, acid phosphatase, beta-galactosidase, alpha-glucosidase, and beta-glucosidase among the major enzymatic activities. Fungal populations were dominated by Debaryomyces hansenii and Kurtzmaniella zeylanoides; however, species rarely found in cheese (e.g., Candida boidinii, Vishniacozyma victoriae, and Starmerella) were also detected. The volatile compounds characterizing the analyzed cheeses were carboxylic acids and esters, followed by carbonyl compounds and alcohols.
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Queijo de Nisa PDO (Protected Designation of Origin) is a semi-hard cheese obtained from raw ewe's milk clotted with cardoon (Cynara cardunculus, L.) rennet. The aim of the present study was to characterize the bacterial communities naturally occurring in Queijo de Nisa PDO cheese samples through viable counting and metataxonomic analysis. Moreover, physico-chemical and morpho-textural analyses were also performed, together with the analysis of volatile organic compounds (VOCs) through solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS). In the analyzed samples, pH values were comprised between 4.84 and 5.74. As for lactic acid, the concentration varied between 0.83 and 2.10 g 100 g-1. Water activity varied between 0.942 and 0.960. Lightness of the samples ranged from 107.82 to 119.16, whereas hardness ranged between 34.45 N and 126.05 N. As for microbiological analyses, lactococci and lactobacilli counts were up to 9.01 Log CFU g-1. Coagulase-negative cocci and enterococci counts were up to 7 Log CFU g-1. Metataxonomic analysis revealed that Lactococcus lactis and Leuconostoc mesenteroides occurred at high frequency in all the analyzed samples. Moreover, Lactiplantibacillus plantarum, Lactococcus piscium, and Lacticaseibacillus zeae were also detected. The most represented VOCs were carboxylic acids, carbonyl compounds, alcohols, and esters. In the analyzed cheese samples, significant relationships between bacteria and VOCs were also evidenced. Of note, research on the microbiological and chemical features, as well as on morpho-textural characteristics, of Queijo de Nisa PDO cheese can increase the knowledge on the interactions between raw materials, environment, and autochthonous microorganisms, thus enabling protection of biodiversity and tradition.
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Queijo , Cynara , Lactococcus lactis , Compostos Orgânicos Voláteis , Ovinos , Animais , Feminino , PortugalRESUMO
In Western and Central Mediterranean countries proteases from wild herbaceous perennial plants commonly known as "thistles" have been used as milk coagulants in cheese-making for centuries. For the first time, the technological and biochemical traits of proteases from cultivated Onopordum tauricum Willd. (Taurian thistle, bull cottonthistle) were assessed. The optimal conditions for minimizing the clotting time and the non-specific proteolytic activity were estimated at the highest (T = 43-45 °C; [Ca2+] = 11-13 mM) and the lowest (T = 35-39 °C; [Ca2+] = 5 mM) temperature and calcium ion levels in the explored range respectively, thus highlighting the difficulty to set the best operative compromise in the first step of cheesemaking. In the conditions adopted in common cheesemaking practice (T = 37 °C; pH = 6.5) 1 mL of reconstituted extract from cultivated thistles coagulated 10 mL of ewe's and goat's milk in 114-146 and 129-167 s, respectively, and 1 mL of reconstituted extract from spontaneous thistles coagulated 10 mL of ewe's and goat's milk in 232-294 and 428-621 s, respectively, while no significant differences in the non-specific proteolytic activity between cultivated and spontaneous O. tauricum extracts were observed. The purified enzyme (tauricosin) was identified as an aspartic protease made up of two sub-units with molecular weights of 32 and 9.6 kDa, respectively. Experimental data encouraged the exploitation of O. tauricum as a new and sustainable non-food crop in marginal and rainfed lands of Mediterranean countries, thus reducing the potential biodiversity losses due to wild collection.
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Queijo , Onopordum , Animais , Bovinos , Masculino , Leite/química , Peptídeo HidrolasesRESUMO
The aim of the present study was to characterize the bacterial and fungal communities naturally occurring in Queijo da Beira Baixa PDO cheese samples produced in Castelo Branco district (Beira Baixa Region, Portugal) through viable counts and metataxonomic analyses. Physico-chemical and morpho-textural analyses were also carried out, together with the analysis of volatile organic compounds (VOCs). In the analyzed samples, pH values ranged between 4.72 ± 0.15 and 5.85 ± 0.02, with values of lactic acid content comprised between 0.64 ± 0.00 and 1.95 ± 0.16 g 100 g-1. Specific volume of cheese ranged from 1.09 ± 0.08 to 1.32 ± 0.02 g mL-1. Texture profile analysis showed hardness ranging between 38.3 ± 9.6 N and 68.55 ± 7.5 N. As for lactic acid bacteria, presumptive lactococci, thermophilic cocci, and lactobacilli counts up to 9 Log cfu g-1. Coagulase-negative cocci showed counts up to 7 Log cfu g-1. Enterococci counts were up to 6 Log cfu g-1. Finally, counts of eumycetes showed values up to 4 Log cfu g-1. The results of metataxonomic analysis of bacteria showed the dominance of Lactococcus lactis in all the samples. Moreover, other taxa were detected, including Lactiplantibacillus plantarum, Loigolactobacillus coryniformis, Lactococcus piscium, Streptococcus thermophilus, and Lacticaseibacillus zeae. Mycobiota was characterized by the presence of Candida sake, Ustilago, Cladosporium variabile, Starmerella, Debaryomyces hansenii, and Pichia kluyveri. In the analyzed Queijo da Beira Baixa PDO cheese samples, carboxylic acids represented the most detected VOCs, followed by esters, carbonyl compounds, and alcohols.
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Queijo , Lactococcus lactis , Queijo/microbiologia , Microbiologia de Alimentos , Portugal , Streptococcus thermophilusRESUMO
The production of ovine or caprine milk cheeses with thistle rennet is a common practice in the Mediterranean basin. The aim of the present study was to obtain information on bacteria and yeast communities harboured by Queijo de Azeitão PDO cheese through viable counting and, for the first time, via metataxonomic analysis. Moreover, solid phase microextraction (SPME) technique was applied to characterize Queijo de Azeitão PDO cheese volatile compounds. Nine cheese samples were collected from three different artisan producers located in Portugal. The results of physico-chemical analyses showed significant differences between producers, with mean values ranging from 5.40⯱â¯0.25 (Producer 1) to 6.00⯱â¯0.22 (Producer 2). As for TTA, Producer 1 showed the highest mean value attesting at 18.04⯱â¯6.57â¯mL of 0.1â¯M NaOH used to reach pH 8.3. Regarding lactic acid concentration, Producer 1 showed the highest mean value attesting at 0.488⯱â¯0.106â¯g 100â¯g-1, whereas, for acetic acid, no significant differences were evidenced among producers with values comprised between 0.141⯱â¯0.021â¯g 100â¯g-1 and 0.245⯱â¯0.016â¯g 100â¯g-1. No significant differences were observed between overall mean values of the three producers for viable counts of presumptive lactococci, thermophilic cocci, presumptive lactobacilli, thermophilic lactobacilli and total mesophilic aerobes with values in the order of 7-8 log cfu g-1. Moreover, no significant differences were evidenced for viable counts of coagulase-negative cocci, enterococci, Enterobacteriaceae and Pseudomonadaceae. As for eumycetes, cheeses from Producer 1 showed the lowest mean value (2.78⯱â¯2.42 log cfu g-1) in respect with values detected in cheeses from Producer 2 and 3. Concerning microbiota and mycobiota of the analyzed cheeses, the alpha diversity index did not show any significant difference between the three producers in terms of composition and complexity of the microbial population. A simple composition was apparently shared by the three producers, whose cheese manufactures were dominated by the presence of Leuconostoc mesenteroides (37% of the relative frequency in average), Lactococcus lactis (29%), Lacticaseibacillus zeae (4.7%), Lentilactobacillus kefiri (4.4%), Serratia spp. (3.5%), Lactiplantibacillus plantarum (2.7%), and Latilactobacillus sakei (2.5%). The mycobiota composition showed the neat dominance of Yarrowia lipolytica (46.7% of the relative frequency in average), followed by Candida ethanolica (13.6%), Kurtzmaniella zeylanoides (9.4%), Geotrichum candidum (8.8%), Galactomyces geotrichum (8.7%), Kluyveromyces lactis (3.5%), and Geotrichum silvicola (2.7%). The volatile profile analysis allowed 24 different compounds to be identified: 7 acids, 7 esters, 4 alcohols, 3 ketones, 2 aromatic hydrocarbons, and 1 aldehyde. The most represented volatile organic compounds (VOCs) were 2-butanone, butanoic acid and hexanoic acid. A positive correlation between Len. kefiri and hexanoic acid and isopentyl isobutyrate was observed (Pâ¯<â¯0.05), whereas Y. lipolytica displayed the highest number of positive correlations with 3-methyl-butanal, 2-pentanone and 2-pentanol (Pâ¯<â¯0.05). To the authors' knowledge, this is the very first detection of Len. kefiri in a raw ewe's milk cheese coagulated with vegetable rennet.
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Queijo , Lactococcus lactis , Microbiota , Yarrowia , Animais , Queijo/análise , Geotrichum , Cabras , Kluyveromyces , Pichia , Portugal , OvinosRESUMO
The brewing value of hops is mainly affected by the content and composition of humulones (α-acids) and essential oil. Interest in hop plantations is increasing more and more in Italy, in parallel with the rising number of microbreweries and brewpubs, which are strongly oriented towards local production chains. In this context, a selection of 15 international hop varieties were grown, under the same conditions, in an experimental field in the Marche region, Central Italy, with the aim of assessing their suitability for beer production. A multivariate analysis approach to experimental data showed a high content of α- and b-acids and myrcene in the Centennial, Brewer's Gold, Sterling, Cascade, Nugget, and Columbus varieties; a consistently lower percentages of humulones and a predominance of sesquiterpene hydrocarbons in the cultivars Mount Hood, Northern Brewer, Northdown, Galena, Willamette, and Fuggle; and a desirable high α-acids content and a sesquiterpene-type aroma in cultivars Chinook, Yeoman, and Hallertau. Further studies are needed to assess the environmental adaptability and the yield performance of hop plants in the pedoclimatic conditions of the Central Italy hills.
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The consumers' opinion concerning conventional palm (Elaeis guineensis) oil is negatively affected by environmental and nutritional issues. However, oils extracted from drupes of interspecific hybrids Elaeis oleifera × E. guineensis are getting more and more interest, due to their chemical and nutritional properties. Unsaturated fatty acids (oleic and linoleic) are the most abundant constituents (60%-80% of total fatty acids) of hybrid palm oil (HPO) and are mainly acylated in position sn-2 of the glycerol backbone. Carotenes and tocotrienols are the most interesting components of the unsaponifiable matter, even if their amount in crude oils varies greatly. The Codex Committee on Fats and Oils recently provided HPO the "dignity" of codified fat substance for human consumption and defined the physical and chemical parameters for genuine crude oils. However, only few researches have been conducted to date on the functional and technological properties of HPO, thus limiting its utilization in food industry. Recent studies on the nutritional effects of HPO softened the initial enthusiasm about the "tropical equivalent of olive oil", suggesting that the overconsumption of HPO in the most-consumed processed foods should be carefully monitored.
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Plant proteases used in cheesemaking are easily available and could increase the acceptability of cheeses, otherwise hindered by ethical issues (e.g., religions, dietary habits, aversion to genetically engineered food and food ingredients). The milk clotting potential of Onopordum tauricum (Willd.) aqueous extract as an alternative to animal rennet was assessed for the first time in milk of different species (ewe, goat, cow). Among the aerial anatomical parts, i.e., receptacle, leaves, stems, and flowers, only the latter ones showed clotting properties. A response surface methodology (RSM) was used to explore the effects of three independent variables (temperature, pH, volume of coagulant) on the milk clotting activity (MCA) of the flower extract. A second-order polynomial model adequately described the experimental data and predicted a temperature value of 55 °C, a pH value of 4.9-5.7, and a volume of coagulant of 300-500 µL (added to 5 mL of milk) as optimal conditions to maximize the MCA. At a 35 °C temperature and natural milk pH of 6.7-6.8, the estimated MCA of the O. tauricum extract was 72-87, 69-86, and 75-151, in goat's, ewe's, and cow's milk, respectively. In comparison, the MCA of calf rennet was 5.4-4.9, 3.3-14.7, and 4.9-16.7 times higher than that of the plant extract in goat's, ewe's, and cow's milk, respectively.
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The quality of sourdough bread mainly depends on metabolic activities of lactic acid bacteria (LAB). The exopolysaccharides (EPS) produced by LAB affect positively the technological and nutritional properties of the bread, while phytases improve the bioavailability of the minerals by reducing its phytate content. In the present study, a pool of 152 cereal-sourced LAB were screened for production of phytases and EPS for potential use as sourdough starter cultures for the baking industry. There was large heterogeneity in the phytase activity observed among the screened isolates, with 95% showing the ability to degrade sodium phytate on plates containing Sourdough Simulation Medium (SSM). The isolates Lactobacillus brevis LD65 and Lactobacillus plantarum PB241 showed the highest enzymatic activity, while the isolates ascribed to Weissella confusa were characterized by low or no phytase activity. Only 18% of the screened LAB produced EPS, which were distinguished as ropy or mucoid phenotypes on SSM supplemented with sucrose. Almost all the EPS producers carried one or more genes (epsD/E and/or epsA) involved in the production of heteropolysaccharides (HePS), whereas the isolates ascribed to Leuconostoc citreum and W. confusa carried genes involved in the production of both HePS and homopolysaccharides (HoPS). Monosaccharide composition analysis of the EPS produced by a selected subset of isolates revealed that all the HePS included glucose, mannose, and galactose, though at different ratios. Furthermore, a few isolates ascribed to L. citreum and W. confusa and carrying the gtf gene produced ß-glucans after fermentation in an ad hoc formulated barley flour medium. Based on the overall results collected, a subset of candidate sourdough starter cultures for the baking industry was selected, including Lb. brevis LD66 and L. citreum PB220, which showed high phytase activity and positive EPS production.
Assuntos
Pão/microbiologia , Grão Comestível/microbiologia , Microbiologia de Alimentos , Indústrias , Lactobacillales/isolamento & purificação , 6-Fitase/metabolismo , Fermentação , Farinha , Genes Bacterianos , Hordeum , Lactobacillales/genética , Peso Molecular , Monossacarídeos/análise , Polissacarídeos Bacterianos/metabolismo , RNA Ribossômico 16S/genética , Especificidade da Espécie , beta-Glucanas/análiseRESUMO
The well-recognized efficiency of Tenebrio molitor larvae to convert low quality organic matter into a nutritionally valuable biomass was exploited to manage solid wastes coming from the olive oil industry, which represent a severe environmental challenge in the Mediterranean area. Three organic pomace-enriched substrates (mixtures middlings/pomace 3:1, 1:1, and 1:3) were assessed, together with 100% organic wheat flour and 100% organic middlings as control feeds. A feeding substrate made up of 25% olive pomace and 75% wheat middlings appeared to be the best compromise between growth performance (larval and pupal weights, survival rate, development time) and nutritional properties of mealworm larvae. In fact, larvae fed the 3:1 feed showed the highest dry matter (DM) yield (38.05%), protein content (47.58% DM), and essential/non-essential amino acids ratio (1.16). Fat content (32.14% DM) and fatty acid composition were not significantly different than those of larvae fed more pomace-enriched feeds.
RESUMO
Ciauscolo is a fermented sausage with the Protected Geographical Indication (PGI) status. To disclose the microbial ecology of a model Ciauscolo salami manufacture during its natural fermentation, viable counting, amplicon-based sequencing and real-time PCR were applied. The volatilome during fermentation was also characterized. The results allowed previously undetected species to be discovered. The core microbiota was composed by Lactobacillus algidus, Leuconostoc carnosum, Lactobacillus sakei, Debaryomyces hansenii, Glomus hyderabadensis, Tilletiopsis washingtonensis, and Kurtzmaniella zeylanoides. Salmonella spp. and Listeria monocytogenes were absent in all the samples; moreover, multiplex real-time PCR revealed the absence of the target genes bont/A, bont/B, bont/E, bont/F, and 4gyrB (CP), encoding botulinic toxins. Volatilome, deeply depending on microbiological metabolism, was characterized by spices-derived components. Limonene, sabinene, α- and ß-pinene, 3-carene, and α-thujene were the most represented monoterpene hydrocarbons, whereas ß- and α-copaene were the most represented sesquiterpene hydrocarbons. Allyl methyl sulphide and diallyl disulphide were the major aliphatic sulphur compounds, together with diallyl sulphide and allyl methyl disulphide.