1,721,712 research outputs found
Effect of Rosmarinus officinalis L. essential oil combined with different packaging conditions to extend the shelf life of refrigerated beef meat
No full textRosemary essential oil (REO) contains bioactives having antioxidant and antimicrobial properties. This work investigated the effect of REO combined with modified atmosphere packaging conditions (MAP), in our case, aerobic, vacuum or high O-2, to extend the shelf life of beef. Beef slices were wrapped in special three-layer sheets of packaging material, some with a coating of REO (active packaging, AP), and some without REO (non active packaging, NAP), and stored at 4 degrees C for 20 days. The use of REO proved efficacious in every storage condition, as seen in the lower counts of psychrotrophics, Brochothrix thermosphacta, Pseudomonas spp., and Enterobacteriaceae in AP meat compared to NAP meat. Sensory and colourimetric analyses showed that the best packaging conditions were high-O-2 atmosphere in combination with REO. Based on microbiological data, shelf life of beef was 5-6 days for AP samples packaged under aerobic conditions and 14-15 days for AP samples in high-O-2 conditions
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Volatile spoilage markers indicating bacterial spoilage in modified atmosphere packaged fish and fishery products
No full textBijdrage tot de risicoanalyse inzake Listeria monocytogenes door het kwantificeren van de lagfase op basis van individuele celwaarnemingen
No full textDefining novel packaging concepts for live blue mussels (Mytilus edulis)
No full textLive blue mussels (Mytilus edulis) are susceptible to mortality, due to processes such as autolysis, lipid oxidation and microbial activity that occur rapidly and affect the quality of blue mussels. The specific research objectives are as follows: 1) investigating the effect of modified atmospheres (MAs) on the quality and shelf life of blue mussels; 2) identifying dominant spoilage bacteria and characterizing their spoilage potential and spoilage activity, and 3) defining the requirements of suitable packaging for live blue mussels. To achieve this goal, current scientific knowledge on the topic was initially reviewed in Chapter 1, summarizing strategies for quality analysis methods for blue mussels. In Chapter 2 the application of high-
O2 modified atmosphere packaging was evaluated. Real-time measurements of volatile organic compounds (VOCs) were performed using selected-ion flow-tube mass spectrometry (SIFT-MS). Subsequently, specific spoilage organisms were isolated and identified in Chapter 3. Next, Chapter 4.1 evaluated the effectiveness of gamma irradiation treatment for decontaminating the blue mussel substrate used as a simulation medium for spoilage bacteria in Chapter 4.2., while Chapter 4.2 elucidated the spoilage mechanisms of the dominant bacteria identified in Chapter 3. Finally, in Chapter 5.1, packaging configurations for an equilibrium modified atmosphere packaging (EMAP) are tested. Chapter 5.2 evaluates different packaging concepts for live blue mussels. The findings highlighted the critical role of initial MAs in determining respiration through O2 consumption and CO2 production rates. Specifically, MAs containing 60 – 75% O2 in combination with 25 – 40% CO2 extended mussel viability and inhibited bacterial growth and VOC accumulation. Conversely, O2 depletion in EMAP scenarios accelerated these processes. In general, the accumulation of alcohols, aldehydes, amines, ketones, esters and sulfur compounds was associated with mortality and bacterial proliferation at > 7 log CFU.g-1. Psychrobacter arctica, Pseudoalteromonas elyakovii, and Shewanella frigidimarina emerged as dominant spoilage bacteria in specific MAs, demonstrating variability in their spoilage potential and spoilage activity. VOC accumulation was associated with unique bacterial metabolites, highlighting the potential of these bacteria as specific spoilage organisms (SSOs) in blue mussels. Ultimately, when defining packaging concepts for live blue mussels, it is suggested to consider adequate O2 and CO2 levels used in the MAs to ensure aerobic respiration of the mussels during storage and inhibit bacterial growth.Levende blauwe mosselen (Mytilus edulis) zijn vatbaar voor sterfte, als gevolg van processen zoals autolyse, oxidatie van vetten en microbiële activiteit die snel optreden en de kwaliteit van blauwe mosselen beïnvloeden. De specifieke onderzoeksdoelen zijn als volgt: 1) het onderzoeken van het effect van beschermende atmosferen (modified atmospheres, MAs) op de kwaliteit en houdbaarheid van blauwe mosselen; 2) het identificeren van dominante bederfveroorzakende bacteriën en het karakteriseren van hun bederfpotentieel en bederfactiviteit, en 3) het definiëren van de vereisten van een geschikte verpakking voor levende blauwe mosselen. Om dit doel te bereiken, werd de huidige wetenschappelijke kennis rond het onderwerp in eerste instantie opgelijst in Hoofdstuk 1, waarbij strategieën werden samengevat voor kwaliteitsanalysemethoden voor blauwe mosselen. In Hoofdstuk 2 werd de toepassing van verpakkingen met een hoge O2 gemodificeerde atmosfeer geëvalueerd. Real-time metingen van vluchtige organische stoffen (VOS) werden uitgevoerd met behulp van selected-ion flow-tube mass spectrometry (SIFT-MS). Vervolgens werden speciifieke bederforganismen geïsoleerd en geïdentificeer in Hoofdstuk 3. Vervolgens evalueerde Hoofdstuk 4.1 bestraald blauw mossel substraat als een simulatiemedium voor dode mosselen, terwijl Hoofdstuk 4.2 de bederfmechanismen van de dominante bacteriën die in Hoofdstuk 3 waren geïdentificeerd, ophelderde. Tenslotte wordt in Hoofdstuk 5.1 verpakkingconfiguraties voor een evenwichtsgemodificeerde atmosfeer (equilibrium modified atmosphere packaging, EMAP) uitgetest. Hoofdstuk 5.2 evalueert verschillende verpakkingconcepten voor levende blauwe mosselen. De bevindingen benadrukten de cruciale rol van initiële MAs bij het bepalen van de ademhaling door O2-verbruiks- en CO2-productiesnelheden. Specifiek verlengden MAs met 60-75% O2 in combinatie met 25-40% CO2 de levensvatbaarheid van mosselen en remden ze bacteriële groei en VOS-ophoping. Omgekeerd versnelden O2 depletie in EMAP-scenario's deze processen. Over het algemeen werd de accumulatie van alcoholen, aldehyden, amines, ketonen, esters en zwavelverbindingen geassocieerd met sterfte en bacteriële proliferatie bij > 7 log CFU.g-1. Psychromonas arctica, Pseudoalteromonas elyakovii, en Shewanella frigidimarina kwamen naar voren als dominante bederfveroorzakende bacteriën in specifieke MAs, waarbij variabiliteit in hun bederfpotentieel en bederfactiviteit werd aangetoond. De accumulatie van VOS werd geassocieerd met unieke metabolieten van bacteriën, waarbij het potentieel van deze bacteriën als specifieke bederforganismen (specific spoilage organisms, SSO's) in blauwe mosselen werd benadrukt. Uiteindelijk wordt bij het definiëren van verpakkingsconcepten voor levende blauwe mosselen voorgesteld om rekening te houden met adequate O2- en CO2-niveaus die in de MAs worden gebruikt om aerobe ademhaling van de mosselen gedurende de bewaring te verzekeren en bacteriële groei te remmen
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Invloed van microbiologische en fysiologische processen op de kwaliteit van verpakt fruit en minimaal behandelde groenten tijdens bewaring in consumentenverpakkingen
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