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The extraordinary organoleptic qualities of Iberian ham derive from the singular producing pig breed and from the traditional rearing conditions, both of which define its lipid content and composition. In this work 1H NM R spectro...
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The extraordinary organoleptic qualities of Iberian ham derive from the singular producing pig breed and from the traditional rearing conditions, both of which define its lipid content and composition. In this work 1H NM R spectroscopy is used for the first time to analyse the lipid profile of Iberian hams as determinant of quality. Quantification of fatty acids is readily obtained from the spectra, with the monounsaturated fat t y acids standing out, especially in the higher quality hams. Unprecedently, triacylglyceride hydrolysis products formed during the curing process can also be directly detected and quantified. Furthermore, chemometric analysis of the NMR data allows to classify Iberian hams according to the pig's crossbreed and feeding regime. Principal component analysis show s fatty acid unsaturation and triacylglyceride hydrolysis as discriminating variables. H-1 NM R spectroscopy has thus revealed as a convenient and power f u l tool for the lipid analysis and classification of Iberian hams and for detection of fraud.
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Dry-ripened foods favor the development of a superficial fungal population that may include toxigenic molds. To combat unwanted molds, an antifungal protein from Penicillium chrysogenum (PgAFP) can be useful. The aim of the presen...
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Dry-ripened foods favor the development of a superficial fungal population that may include toxigenic molds. To combat unwanted molds, an antifungal protein from Penicillium chrysogenum (PgAFP) can be useful. The aim of the present work was to study the antimicrobial activity of PgAFP against microorganisms common in dry-ripened foods, and to evaluate its sensitivity to proteolytic enzymes and heat treatments that may be applied to foods, as well as to different pH values. The inhibitory effect of the purified protein on 38 microbial strains grown in culture medium was determined. PgAFP sensitivity to various proteases, heat treatments, and preincubation at different pH values was tested by means of the residual activity on selected reference strains. Inhibitory activity of PgAFP against unwanted molds was tested in a dry-fermented sausage. This protein exhibited potent inhibitory activity against unwanted molds, including the main mycotoxin-producing species of Aspergillus and Penicillium of concern for dry-ripened foods. PgAFP withstood most proteases, intense heat and a wide range of pH values. PgAFP efficiently reduced counts of A. flavus and P. restrictum inoculated on a dry-fermented sausage. This protein can be of interest to control hazardous molds in dry-ripened foods. (C) 2015 Elsevier B.V. All rights reserved.
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Dry-cured Iberian ham is a meat product prone to be contaminated by ochratoxin A (OTA) because of colonisation by OTA-producing Penicillia on the surface of the product during its ripening. The ability of non-toxigenic moulds to c...
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Dry-cured Iberian ham is a meat product prone to be contaminated by ochratoxin A (OTA) because of colonisation by OTA-producing Penicillia on the surface of the product during its ripening. The ability of non-toxigenic moulds to control the growth of indigenous ochratoxigenic strains and OTA accumulation on this product was evaluated. Two protective cultures consisting of the antifungal protein-producing Penicillium chrysogenum RP42C and a mix of selected autochthonous non-toxigenic mould strains were spread on the surface of 45 dry-cured Iberian hams at drying stage and ripened up to 9 additional months. The results showed that the RP42C strain limited the growth of OTA-producing moulds and mainly the OTA accumulation in dry-cured Iberian ham throughout the processing in the meat industry. The use of protective cultures of non-toxigenic mould strains combined with an appropriate HACCP plan holds potential for reducing health hazard of OTA accumulation in dry-cured Iberian ham. (C) 2014 Elsevier Ltd. All rights reserved.
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This study firstly proposed the use of 3D MRI images to analyze loins in a non-destructive way. For that, interpolation and reconstruction techniques are applied on 2D MRI images of loins and the computational texture algorithms w...
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This study firstly proposed the use of 3D MRI images to analyze loins in a non-destructive way. For that, interpolation and reconstruction techniques are applied on 2D MRI images of loins and the computational texture algorithms were adapted to analyze the obtained 3D images. The influence of the i) MRI acquisition sequences (Spin Echo (SE), Gradient Echo (GE), Turbo 3D (T3D)), ii) 3D texture features algorithms (GLCM, NGLDM, GLRLM, GLCM + NGLDM + GLRLM), and iii) regression techniques (Multiple Linear Regression (MLR), Isotonic Regression (IR)) was also evaluated. Combinations of SE or GE with any texture algorithm and any regression technique gave accurate results, with correlation coefficients higher than 0.75 and mean absolute error lower than 2. However, considering not only the accuracy of the methodology but also the computational cost, the use of GE, GLCM and IR could be proposed to determine physico-chemical parameters of loins non-destructively. (C) 2017 Elsevier Ltd. All rights reserved.
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Meat and meat products are important sources of high-quality proteins, some vitamins, and minerals, but their lipid profile is sometimes put in question. Some approaches have been suggested to improve the lipid profile. This revie...
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Meat and meat products are important sources of high-quality proteins, some vitamins, and minerals, but their lipid profile is sometimes put in question. Some approaches have been suggested to improve the lipid profile. This review deals with some of the most relevant strategies aiming for the omega-3 fatty acids enrichment of meat products, given the beneficial health effects and recommended daily intakes of these bioactive compounds. Relevant information about the procedure and the achieved results are reported, with a special emphasis to the eicosapentaenoic (EPA, C20:5 omega-3) and docosahexaenoic (DHA, C22:6 omega-3) acids, the development of lipid oxidation phenomena and the changes in sensory attributes in the omega-3 enriched products. The main features of the different vehicles (animal feeding, emulsions, microcapsules) used for omega-3 addition to meat products are also reviewed in detail. The use of microcapsules seems to be the most appropriate strategy, but future researches are needed.
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In this study, data mining technique was applied on computational texture features obtained from the analysis of magnetic resonance imaging (MRI) of hams, with the main objective of determining sensory attributes of dry-cured ham ...
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In this study, data mining technique was applied on computational texture features obtained from the analysis of magnetic resonance imaging (MRI) of hams, with the main objective of determining sensory attributes of dry-cured ham non-destructively. For that, fresh and dry-cured hams were scanned and then the MRI images were analyzed by three methods of computational texture features. Data mining was applied on the computational texture features from fresh and dry-cured hams for obtaining prediction equations of the sensory attributes of dry-cured hams. The correlation coefficient (R) was used to analyze the results. Accurate prediction was found for 13 sensory attributes as a function of computational texture features of fresh ham, and three from dry-cured ham. In addition, a sensory analysis of dry-cured hams was also carried out to validate the predicted results. Similar values were found between the predicted attributes and those determined by sensory analysis. Thus, it is possible to predict sensory attributes of dry-cured hams by applying data mining on computational texture features of MRI from fresh and dry-cured hams. This supposes the chance of determining non-destructively sensory attributes of dry-cured hams, even before the curing process starts.
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Dry-cured meat products are usually contaminated with moulds during ripening. Although fungal development contributes to the desired sensory characteristics, some moulds, such as Penicillium nordicum are able to produce ochratoxin...
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Dry-cured meat products are usually contaminated with moulds during ripening. Although fungal development contributes to the desired sensory characteristics, some moulds, such as Penicillium nordicum are able to produce ochratoxin A (OTA) on meat products. Therefore, strategies to prevent OTA contamination in ripened meat products are required. Microorganisms isolated from these meat products can be adequate as biocontrol agents, given that no negative sensory impact is expected. The PgAFP antifungal protein-producer Penicillium chrysogenum (Pc) and Debaryomyces hansenii (Dh) have been shown to successfully inhibit toxigenic moulds. However, scarce information about the mechanism of action of these biocontrol agents on toxigenic mould inhibition is available. Comparative proteomic analysis is a powerful tool to investigate the physiological response of microorganisms to stimuli. Proteomic analysis was carried out on P. nordicum co-cultured with Pc, Dh, PgAFP, and their combinations on a dry-cured ham-based medium. Additionally, OTA production by P. nordicum in the different cultures was measured. The individual inoculation of Pc or Dh repressed OTA production by P. nordicum by 5 and 3.15 fold, respectively. A total of 2844 unique P. nordicum proteins were identified by proteomic analysis. The impact of the biocontrol agents on the proteome of P. nordicum was higher for Pc-containing cultures, followed by Dh-containing treatments. PgAFP alone had minimal impact on the proteome of P. nordicum. Proteomic analyses indicated Pc repressed P. nordicum OTA production through nutrient competition, potentially reducing glucose availability. Data also suggest that Dh and Pc inhibited P. nordicum through cell wall integrity impairment. Both Pc and Dh seem to hamper P. nordicum secondary metabolism (SM) as indicated by lower levels of MAP kinases and SM-associated proteins found in the co-inoculated P. nordicum. This work paves the way to use antifungal agents in the most efficient way to prevent OTA formation in meat products.
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The combined effect of temperature, water activity (a(w)) and NaCl content, usually found in dry-cured ham, on the growth and expression of the virulence and stress-related genes of Listeria monocytogenes was evaluated in a dry-cu...
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The combined effect of temperature, water activity (a(w)) and NaCl content, usually found in dry-cured ham, on the growth and expression of the virulence and stress-related genes of Listeria monocytogenes was evaluated in a dry-cured ham model system. The highest growth of this pathogen was observed at 15 degrees C and, at 0.98 and 0.96 a(w) values. At 0.94 and 0.92 a(w), values, moderate NaCl levels stimulated the L. monocytogenes growth and repressed the expression of the four tested genes. At 7 degrees C, the expression of thep/cA gene was favored while at 15 degrees C the hly and lap genes were activated. Preventive actions based on temperature, a(w) and salt content should be taken to minimise risks associated with growth and gene expression of L. monocytogenes in dry-cured ham.
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The quantification of fatty acids (FA) in meat products is frequently carried out by two-stage methylation procedures followed by long gas chromatography (GC) runs. This work aimed to simplify this methodology by means of a one-st...
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The quantification of fatty acids (FA) in meat products is frequently carried out by two-stage methylation procedures followed by long gas chromatography (GC) runs. This work aimed to simplify this methodology by means of a one-stage transmethylation method and a fast GC run, evaluating the influence of sample preparation, reagents and type of heating on the amount of FA in different meat products and optimizing a fast GC-FID (flame ionization detector) run. This allowed to establish the optimum combination of parameters (methanol + chlorotrimethylsilane, lyophilized samples and oven heating) to achieve the quantification of the highest possible amount of FA and to reduce the time of GC run from 60 to 10 min. The quality evaluation of this method obtained satisfactory results. Thus, the quantification of FA in meat products was achieved in a straightforwardly and quickly way by using a one-stage transmethylation procedure followed by a fast GC-FID run.
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To evaluate the effective implantation of a specific protective culture of Penicillium nalgiovense, a real-time quantitative PCR (qPCR) using SYBR Green methodology was developed. Two specific primers were designed on the basis of...
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To evaluate the effective implantation of a specific protective culture of Penicillium nalgiovense, a real-time quantitative PCR (qPCR) using SYBR Green methodology was developed. Two specific primers were designed on the basis of the published partial sequences of the Internal Transcribe Spacer (ITS)1-5.8S-ITS2 region of various strains of P. nalgiovense. Using the developed method, a PCR product of 51 bp with a T (m) value 81.34 A degrees C was detected. T (m) values of the amplified product allowed specific differentiation between P. nalgiovense and the remaining mould species tested. The developed qPCR method was tested on inoculated slices of dry-cured sausage ('salchichn') showing an efficiency of 97.24 %, a R (2) value of 0.99 and a detection limit of P. nalgiovense of 1 log colony-forming units (cfu)/cm(2). The qPCR method demonstrated that the protective strain of P. nalgiovense grew and competed against an ochratoxin A (OTA)-producing Penicillium verrucosum strain on commercial dry-cured sausage. This qPCR method provides a specific, accurate and sensitive detection and quantification of P. nalgiovense on dry-cured sausage salchichn in order to estimate its colonization during their processing. This assay will improve strategies to prevent and control unwanted mould colonization and OTA risk in dry-cured meat commodities.
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