RESUMO
Despite the increasing efforts in improving bone health assessments, current diagnostics suffer from critical shortcomings. The present article therefore describes a multiplex label-free immunosensor designed and validated for the assessment of two bone turnover markers (BTMs), namely beta isomerized C-terminal telopeptide of type I collagen (CTx) and Procollagen I Intact N-Terminal (PINP), the combination of which is needed to illustrate an accurate overview of bone health. The immunosensor was then tested outside and inside of a microsystem, with the aim of becoming compatible with a point of care system fabricated for automated assessment of these biomarkers later-on at patient side. Custom-made monoclonal antibodies were specifically designed for this purpose in order to guarantee the selectivity of the immunosensor. In the final platform, a finger prick blood sample is introduced into the microfluidic manifolds without any need for sample preparation step, making the tool suitable for near patient and outside of the central laboratory applications. The platform was exploited in 30 real blood samples with the results validated using electrochemiluminescence immunoassay. The results revealed the platform was capable of measuring the target analyte with high sensitivity and beyond the recommended clinical reference range for each biomarker (CTx: 104-1028 ng L-1 and PINP: 16-96 µg L-1, correspondingly). They also showed the platform to have a limit of detection of 15 (ng L-1) and 0.66 (µg L-1), a limit of quantification of 49 (ng L-1) and 2.21 (µg L-1), and an inter- and intra-assay coefficient of variance of 5.39-6.97% and 6.81-5.37%, for CTx and PINP respectively, which is comparable with the gold standard. The main advantage of the platform over the state-of-the art was the capability of providing the results for two markers recommended for assessing bone health within 15 minutes and without the need for skilled personnel or costly infrastructure.
Assuntos
Biomarcadores , Remodelação Óssea , Colágeno Tipo I , Fragmentos de Peptídeos , Pró-Colágeno , Humanos , Biomarcadores/sangue , Biomarcadores/análise , Pró-Colágeno/sangue , Colágeno Tipo I/sangue , Remodelação Óssea/fisiologia , Fragmentos de Peptídeos/sangue , Imunoensaio/métodos , Peptídeos/sangue , Técnicas Biossensoriais/métodos , Sistemas Automatizados de Assistência Junto ao LeitoRESUMO
Currently, there is considerable interest in seeking an environmentally friendly technique that is neither thermally nor organic solvent-dependent for producing advanced polymer films for food-packaging applications. Among different approaches, plasma polymerization is a promising method that can deposit biodegradable coatings on top of polymer films. In this study, an atmospheric-pressure aerosol-assisted plasma deposition method was employed to develop a poly(ethylene glycol) (PEG)-like coating, which can act as a potential matrix for antimicrobial agents, by envisioning controlled-release food-packaging applications. Different plasma operating parameters, including the input power, monomer flow rate, and gap between the edge of the plasma head and substrate, were optimized to produce a PEG-like coating with a desirable water stability level and that can be biodegradable. The findings revealed that increased distance between the plasma head and substrate intensified gas-phase nucleation and diluted the active plasma species, which in turn led to the formation of a non-conformal rough coating. Conversely, at short plasma-substrate distances, smooth conformal coatings were obtained. Furthermore, at low input powers (<250 W), the chemical structure of the precursor was mostly preserved with a high retention of C-O functional groups due to limited monomer fragmentation. At the same time, these coatings exhibit low stability in water, which could be attributed to their low cross-linking degree. Increasing the power to 350 W resulted in the loss of the PEG-like chemical structure, which is due to the enhanced monomer fragmentation at high power. Nevertheless, owing to the enhanced cross-linking degree, these coatings were more stable in water. Finally, it could be concluded that a moderate input power (250-300 W) should be applied to obtain an acceptable tradeoff between the coating stability and PEG resemblance.
RESUMO
Biobased plastics have the potential to be sustainable, but to explore their circularity further, current end-of-life options need to be broadened. Mechanical recycling is one of the most accepted methods to bring back plastics into the loop. Polyhydroxybutyrates (PHBs) are biobased and biodegradable in nature with promising properties and varied applications in the market. This study focuses on their potential for mechanical recycling by multiple extrusion cycles (E1-E5) and multi-faceted characterization of the virgin (V) and reprocessed materials from E1 to E5. The behavior is compared to polypropylene (PP) as a reference with a similar property profile, which has also been reprocessed five times. The thermal properties of both series showed a stable melting point and thermal decomposition temperature from thermal analyses (differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)). However, a steady increase in the degree of crystallinity was observed which could counterbalance the decrease in molecular weight due to repeated extrusion measured by gel permeation chromatography and resulted in similar values of tensile strength across the cycles. The strain at break was impacted after the first extrusion, but no significant change was observed thereafter; the same was observed for impact strength. Even in scanning electron microscopy (SEM) images, virgin and E5 samples appeared similar, showing the stability of morphological characteristics. Fourier transform infrared spectroscopy (FTIR) results revealed that no new groups are being formed even on repeated processing. The deviation between the PHB and PP series was more predominant in the melt mass flow rate (MFR) and rheology studies. There was a drastic drop in the MFR values in PHB from virgin to E5, whereas not much difference was observed for PP throughout the cycles. This observation was corroborated by frequency sweeps conducted with the parallel plate method. The viscosity dropped from virgin to E1 and E2, but from E3 to E5 it presented similar values. This was in contrast to PP, where all the samples from virgin to E5 had the same values of viscosity. This paper highlights the possibilities of mechanical recycling of PHB and explains why future work with the addition of virgin material and other additives is an area to be explored.
RESUMO
This manuscript provides an overview of the legislative requirements for the use of mechanical recycled plastics in articles placed on the EU market, as seen from the perspective of a plastics recycler. The first part reviews the main principles included in the overarching legislation on Registration, Evaluation, Authorisation and Restrictions of Chemicals (REACH) and to what extent these are applicable for mechanical recyclers of plastics. The interactions between REACH and the Waste Framework Directive (WFD) is discussed, as well as the difficulties for recyclers to comply with certain REACH requirements. In a second part, the focus is moved to the use of recycled plastics as Food Contact Material (FCM). The scope of the different applicable EU FCM regulations is inventorised as well as the key legislative principles involved. A final section is dedicated to the discussion on the authorisation of recycling processes under the FCM regulation and the practical challenges involved for the effective introduction of FCMs containing recycled plastics. Altogether it could be concluded that the complexity of the different legal perspectives, a lack of communication and transparency within the plastic value chain together with technical challenges related to recycling processes have been hindering the effective uptake of recycled plastic FCM (with the exception for bottle PET). The development of targeted solutions across the entire value-chain, taking into account different perspectives in terms of legislation and health protection, economic growth and technical innovations, will be crucial in achieving a circular economy for plastics, including recycled plastics for FCM.
Assuntos
Plásticos , ReciclagemRESUMO
The current research describes an alternative test method to evaluate the impact of food properties and compound characteristics on migration from paperboard to food. Tightly sealed bottles containing paperboard spiked with surrogate components as a donor, together with modified polyphenylene oxide (MPPO or Tenax®) or one of the nine considered foods as a receptor, were stored at 22°C. Instead of analysing the receptor, migration from donor to receptor was followed up by evaluating the recovery of surrogates from the donor over time, thus avoiding challenges in the analysis of the foods as such. Free fat content affected the migration more than the specific surface area of the food, reaching a plateau at fat contents >8.1%. The highest migration was observed to fatty foods such as biscuits (8% to 25% fat) and chocolate (40% fat). Intermediate migration occurred to starchy and particulate foods such as egg-based wheat pasta (2.6% fat), wheat flour (1% fat) and rice flour (0.5% fat). Low migration occurred in the case of paperboard in contact with wheat pasta (0.4% fat). Native starch was found to be more sensitive to migration than gelatinised starch. Volatility was identified as the most important characteristic of the migrating compounds. MPPO was considered as a suitable surrogate for dry foods as it did not underestimate migration in any case. However, for low-fat foods such as wheat pasta, clear overestimations could occur, but only for volatile surrogates with vapour pressure over 1.45 mTorr.
Assuntos
Análise de Alimentos , Contaminação de Alimentos/análise , Embalagem de Alimentos , Fenóis/análise , Polímeros/análise , PressãoRESUMO
Minimally processed vegetables (MPV) are any fresh vegetables that have been physically altered from their original form, but remains in a fresh state. Microorganisms present in MPV can cause foodborne illnesses or spoilage; hence, decontamination of MPV can produce more stable products. The present review examines the difficulties to decontaminate and prolong the shelf-life of MPV, evaluating the current way of data analysis and interpretation. It addresses the different aspects of the problem of the accessibility of sanitizers to microorganisms (irregularities of produce surface, injuries, internalization, attachment, and biofilms). It also includes a critical exposition of the methodological problems to estimate the prolongation of shelf-life due to a decontamination method, namely: the variability among samples, the reproducibility of the results, and the interpolation when lacking some crucial data. Furthermore, it revises the difficulties to control the microbial loads of decontaminated MPV during storage (the enhanced growth rate of microorganisms in decontaminated MPV, the patterns of microbial growth in non decontaminated and decontaminated MPV, and the role of temperature in keeping the decontamination effect).
Assuntos
Descontaminação/métodos , Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Verduras/microbiologia , Fatores de TempoRESUMO
Gaseous ClO2 was evaluated for effectiveness in prolonging the shelf-life of minimally processed (MP) lettuce and MP cabbage, previously immersed in a cysteine solution in order to inhibit browning occurring during ClO2 treatment. Each vegetable was shredded, washed, and separated in two portions, one to be treated with ClO2 gas and the other to remain untreated as reference sample. The batch to be treated with ClO2 gas was immersed for 1 min in a 0.5% solution of HCl.L-cysteine monohydrate. Then both batches were spun dried. MP vegetables were decontaminated in a cabinet at 90-91% relative humidity and 22-25 degrees C up to 10 min, including 30 s of ClO2 injection into the cabinet. The ClO2 concentration rose to 1.74 mg/L (MP lettuce) and 1.29 mg/L (MP cabbage). Then samples were stored under modified atmosphere at 7 degrees C for shelf-life studies. Changes in O2 and CO2 headspace concentrations, microbiological quality (aerobic plate count (APC), psychrotrophs, lactic acid bacteria, and yeasts), sensory quality, and pH were followed during storage. The respiration rate of the minimally processed vegetables was significantly increased by the ClO2 gas treatment only in the case of MP cabbage (P<0.05). The gas treatment reduced initially APC and psychrotroph count of MP lettuce and APC, psychrotroph counts, yeast counts and pH of MP cabbage (P<0.05). ClO2 treatment did not cause initially any significant (P<0.05) sensorial alteration, except for a weak off-odour in MP lettuce. Interestingly, no browning was observed after treating, which can be accounted to the use of L-cysteine. Although an initial microbiological reduction was observed due to ClO2 gas treatment, APC and psychrotroph counts reached in the samples treated with ClO2 higher levels than in those non-treated with ClO2 before the third day of the shelf-life study. Untreated and treated samples of MP lettuce were sensorial unacceptable due to bad overall visual quality after 4 days, while treated and untreated MP cabbage remained sensorial acceptable during the 9 days of the study. L-cysteine reduced (P<0.05) the decontamination efficacy of ClO2 when applied to MP cabbage but not in the case of MP lettuce. Gaseous ClO2 failed to prolong the shelf-life of MP lettuce and MP cabbage, the reason for the enhanced growth of microorganisms in decontaminated samples should be investigated. Nonetheless, our results prove that it is possible to inhibit browning caused by ClO2.
Assuntos
Brassica/microbiologia , Compostos Clorados/farmacologia , Cisteína/farmacologia , Desinfetantes/farmacologia , Embalagem de Alimentos/métodos , Conservação de Alimentos/métodos , Lactuca/microbiologia , Óxidos/farmacologia , Bactérias/crescimento & desenvolvimento , Brassica/normas , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , Contaminação de Alimentos/prevenção & controle , Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Humanos , Concentração de Íons de Hidrogênio , Lactuca/normas , Oxirredução , Paladar , Fatores de TempoRESUMO
Fresh cut iceberg lettuce spoilage was studied considering the microbial and biochemical activity, the formation of volatile organic compounds (VOC) and consumer acceptability. Lettuce was packaged under three different packaging conditions and stored at 4⯰C for 10â¯days: anaerobic packaging (ANAER), equilibrium modified atmosphere packaging with 3% O2 (EMAP) and perforated packages (AIR). Results indicated a clear distinction between packaging conditions. EMAP and AIR resulted in a short shelf life (≤5.6â¯days) which was limited due to browning, leading to consumer rejection as assessed via the Weibull hazard analysis method, while no off-odors were detected. Culture- independent 16â¯s rRNA gene amplicon sequencing revealed Pseudomonas spp. as the dominating species. In contrast, under ANAER conditions, lactic acid bacteria dominated with genera of Leuconostoc spp. and Lactococcus spp. proliferating, while also oligotypes of Pseudomonas spp. were found. Spoilage under ANAER occurred after 6.6â¯days and it was related to strong fermentative-like off-odors that were present by the end of storage. As revealed by selective ion flow tube mass spectrometry (SIFT-MS), these odors were associated with several VOCs such as: ethanol, 3-methyl-1-butanol, 2,3-butanediol, (Z)-3-hexen-1-ol, hexanal, acetic acid, ethyl acetate and dimethyl sulfide. Panelists rejected the iceberg lettuce due to the formation of off-odors while the overall appearance remained good throughout the study. Hence a sensor based technology incorporated in the packaging, detecting VOCs and in particular ethanol as dominant compound, could serve as a spoilage indicator for ANAER packed lettuce, which proved to have the longest shelf life.
Assuntos
Microbiologia de Alimentos/métodos , Embalagem de Alimentos/métodos , Conservação de Alimentos/métodos , Lactuca/microbiologia , Compostos Orgânicos Voláteis/análise , Anaerobiose/fisiologia , Contagem de Colônia Microbiana , Lactococcus/classificação , Lactococcus/genética , Lactococcus/isolamento & purificação , Leuconostoc/classificação , Leuconostoc/genética , Leuconostoc/isolamento & purificação , Odorantes/análise , Oxigênio , Pseudomonas/classificação , Pseudomonas/genética , Pseudomonas/isolamento & purificaçãoRESUMO
Minimally processed vegetables (MPV) have a short shelf-life. Neutral electrolysed oxidising water (NEW) is a novel decontamination method. The objective of this study was to test the potential of NEW to extend the shelf-life of a MPV, namely shredded cabbage. Samples of shredded cabbage were immersed in NEW containing 40 mg/L of free chlorine or tap water (control) up to 5 min, and then stored under equilibrium modified atmosphere at 4 degrees C and 7 degrees C. Proliferation of aerobic mesophilic bacteria, psychrotrophic bacteria, lactic acid bacteria and yeasts were studied during the shelf-life. Also pH and sensorial quality of the samples as well as O(2) and CO(2) composition of the headspace of the bags was evaluated. From the microbial groups, only psychrotrophic counts decreased significantly (P<0.05) due to the effect of NEW, but the counts in treated samples and controls were similar after 3 days of storage at 4 degrees C and 7 degrees C. Packaging configurations kept O(2) concentration around 5% and prevented CO(2) accumulation. pH increased from 6.1-6.2 to 6.4 during the shelf-life. No microbial parameter reached unacceptable counts after 14 days at 4 degrees C and 8 days of storage at 7 degrees C. The shelf-life of controls stored at 4 degrees C was limited to 9 days by overall visual quality (OVQ), while samples treated with NEW remained acceptable during the 14 days of the experiment. The shelf-life of controls stored at 7 degrees C was limited to 6 days by OVQ and browning, while that of samples treated with NEW were limited to 9 days by OVQ, browning and dryness. According to these results, a shelf-life extension of at least 5 days and 3 days in samples stored respectively at 4 degrees C and 7 degrees C can be achieved by treating shredded cabbage with NEW. NEW seems to be a promising method to prolong the shelf-life of MPV.
Assuntos
Bactérias/crescimento & desenvolvimento , Brassica/microbiologia , Manipulação de Alimentos/métodos , Embalagem de Alimentos/métodos , Conservação de Alimentos/métodos , Água/química , Dióxido de Carbono/metabolismo , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , Microbiologia de Alimentos , Humanos , Concentração de Íons de Hidrogênio , Oxigênio/metabolismo , Temperatura , Fatores de Tempo , VácuoRESUMO
Rosemary 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 O2, 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°C for 20days. 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-O2 atmosphere in combination with REO. Based on microbiological data, shelf life of beef was 5-6days for AP samples packaged under aerobic conditions and 14-15days for AP samples in high-O2 conditions.
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Embalagem de Alimentos/métodos , Conservação de Alimentos/métodos , Óleos Voláteis/administração & dosagem , Carne Vermelha/análise , Refrigeração/métodos , Rosmarinus , Animais , Atmosfera/análise , Brochothrix/efeitos dos fármacos , Brochothrix/fisiologia , Bovinos , Contagem de Colônia Microbiana/métodos , Microbiologia de Alimentos/métodos , Óleos Voláteis/isolamento & purificação , Componentes Aéreos da Planta , Carne Vermelha/microbiologia , VácuoAssuntos
Antibacterianos/farmacologia , Compostos Clorados/farmacologia , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Leuconostoc/efeitos dos fármacos , Óxidos/farmacologia , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , Relação Dose-Resposta a Droga , Humanos , Fatores de TempoRESUMO
Quantitative risk assessment studies performed elsewhere showed the importance of reducing counts of Campylobacter jejuni on chicken carcasses for decrease of incidence of human campylobacteriosis. The current study indicated that 1.8 log CFU/g reduction of inoculated C. jejuni (6 log CFU/g) can be achieved by decontamination with lactic acid buffered with sodium lacatate (LA/NaLA, 10% w/v, pH 3.0). Subsequent packaging under modified atmosphere of 80% O(2)/20%N(2) resulted in additional reduction of approximately 1.2 log CFU/g. These results were confirmed in naturally contaminated samples (2-3 log CFU/g) resulting in immediate reduction of present C. jejuni under the limit of enumeration (1 log CFU/g). However, enrichment showed presence of C. jejuni in 10g of sample. Under 80% O(2) LA/NaLA treated C. jejuni remained detectable per 10g until day 7, after which no positive samples were found until the end of the two-weeks storage. Under 80% CO(2) LA/NaLA treated C. jejuni remained fluctuating at 10 CFU/g until the end of two-weeks storage. Control cells were reduced by approx. 1.5 log CFU/g during storage under 80% O(2)/20% N(2), whereas no reduction was observed under 80% CO(2)/20% N(2). The present study showed the potential of buffered lactic acid and high-O(2) MAP to reduce C. jejuni both on inoculated and naturally contaminated samples. The immediate effect of decontamination was further extended by additive, not synergistic, effect of 80% O(2), suggesting the practical value of the tested concept in combating C. jejuni on chicken carcasses.
Assuntos
Campylobacter jejuni/crescimento & desenvolvimento , Descontaminação/métodos , Desinfetantes/farmacologia , Embalagem de Alimentos/métodos , Carne/microbiologia , Viabilidade Microbiana/efeitos dos fármacos , Animais , Campylobacter jejuni/efeitos dos fármacos , Dióxido de Carbono/farmacologia , Galinhas , Contaminação de Alimentos/análise , Contaminação de Alimentos/prevenção & controle , Embalagem de Alimentos/instrumentação , Ácido Láctico/farmacologia , Oxigênio/farmacologia , Lactato de Sódio/farmacologiaRESUMO
The total volatile basic nitrogen fraction (TVB-N) is often used as a quality parameter in the fish industry to assess spoilage. This parameter often leads to discussions between producers and retailers when it comes to defining clear limits of acceptability for modified atmosphere (MA) packed fish and fishery products. Suggested product limits (mg N/100 g fish) do not always correlate with the presence of off-odors. Gray shrimp are an economic valuable, very perishable niche product, where the TVB-N fraction plays an important role considering its shelf life. This research focuses on the effect of a shrimp matrix and its pH on the volatilization of these formed bases, revealing the relationship between concentrations in the fishery product and the concentrations of these bases present in the headspace of the packed product. Especially, the pH of the product, which is lowered when fishery products are packed under a carbon dioxide enriched atmosphere, appeared to have an immense effect on the volatilization of these bases. The effect of the fish matrix itself is established by means of calculated equilibration constants (dimensionless) being 2.13×10(-4)±0.38×10(-4) for trimethylamine, 6.34×10(-5)±1.71×10(-5) for dimethylamine, and 2.58×10(-5)±0.49×10(-5) for ammonia. Comparison of these constants with the equilibration constants of an aqueous solution indicated the retention of these bases in the product. This article provides not only the important insights for the interpretation of TVB-N values in modified atmosphere packaged gray shrimp but also the methodology to extend these findings to other fish and fishery products.
Assuntos
Crangonidae/química , Embalagem de Alimentos/métodos , Nitrogênio/análise , Frutos do Mar/análise , Compostos Orgânicos Voláteis/análise , Animais , Qualidade de Produtos para o Consumidor , Manipulação de Alimentos , Concentração de Íons de Hidrogênio , Controle de QualidadeRESUMO
Selective ion flow tube mass spectrometry (SIFT-MS) is a direct mass spectrometric technique that allows qualitative and quantitative analysis of a large number of volatile organic compounds. Because of its speed and ease of use, this nondestructive technique could be considered as a practical tool for quality control. This research focuses on the possibilities of direct headspace sampling by SIFT-MS for the quantification of the volatile basic nitrogen content (TVB-N) of fish fillets. These volatile bases [trimethylamine (TMA), dimethylamine (DMA), and ammonia] give additional information in conjunction with the sensory scoring and microbiological analysis about the quality of the fish fillets. This research validates in a first part the SIFT-MS method for the quantification of the volatile bases in mixed cod samples. With regard to the investigated linearity, repeatability, reproducibility, recovery, limit of detection, and limit of quantification, SIFT-MS appeared to be an adequate technique for measuring volatile bases spiked on cod. In the second part of this research, the technique was validated for the analysis of volatile bases on cod fillets during a storage experiment under ice. A good correlation was obtained between the proposed direct headspace sampling and traditional methods. The sensitivity of the SIFT-MS method can be improved when cod fillets are made more alkaline (pH >11) during sampling.
Assuntos
Peixes , Espectrometria de Massas/métodos , Nitrogênio/análise , Animais , VolatilizaçãoAssuntos
Fragaria , Odorantes , Acetatos/análise , Etanol/análise , Manipulação de Alimentos , Fragaria/microbiologia , Humanos , VolatilizaçãoRESUMO
Besides the traditionally used sodium hypochlorite (20 and 200 mg L(-1)), alternative sanitizers such as peroxyacetic acid (80 and 250 mg L(-1)) and neutral electrolyzed oxidizing water (4.5 and 30 mg L(-1) free chlorine) as well as chlorine dioxide gas (1.54 mg L(-1)) were evaluated for their efficiency in reducing the microbial load of fresh-cut iceberg lettuce. An additional rinsing step with tap water and cooling of the sanitizing solutions, which are obvious for the fresh-cut industry, were not performed within the current study. The high doses of sodium hypochlorite and peroxyacetic acid tested within this study do not conform to the normally used concentrations within the fresh-cut industry. Neutral electrolyzed oxidizing water (30 mg L(-1)), peroxyacetic acid (250 mg L(-1)), and gaseous chlorine dioxide significantly reduced the total aerobic plate count of cut lettuce in comparison with water wash treatments alone. None of the treatments significantly affected the sensory quality of the lettuce, although small color changes were observed after colorimetric measurements. From a nutritional point of view water rinsing significantly decreased the vitamin C (maximum 35%) and phenol (maximum 17%) contents, but did not affect the carotenoid and α-tocopherol contents. Additional effects caused by adding a sanitizer to the wash water were not observed for vitamin C and phenols. Conversely, washing with 250 mg L(-1) peroxyacetic acid reduced the ß-carotene content by about 30%, whereas using 200 mg L(-1) sodium hypochlorite reduced both the lactucaxanthin and the lutein contents by about 60%. Use of gaseous chlorine dioxide also had an impact on the lutein content (-18%). Furthermore, the α-tocopherol content was reduced by 19.7 and 15.4% when the two concentrations of neutral electrolyzed oxidizing water were used, respectively. These data represent the situation on day 0. In a next phase, shelf-life studies considering microbial and sensory quality and nutrient content should be conducted.
Assuntos
Compostos Clorados/administração & dosagem , Lactuca , Valor Nutritivo , Óxidos/administração & dosagem , Ácido Peracético/administração & dosagem , Sensação , Hipoclorito de Sódio/administração & dosagem , Carotenoides/análise , Descontaminação/métodos , Desinfetantes/administração & dosagem , Manipulação de Alimentos/métodos , Humanos , Lactuca/química , Lactuca/microbiologia , Oxirredução , Água/administração & dosagem , Água/químicaRESUMO
Several decontamination agents including water, sodium hypochlorite, peroxyacetic acid, neutral electrolyzed oxidizing water, and chlorine dioxide gas were tested for their effectiveness to reduce the natural microflora on grated carrots. Microbial reductions of the total aerobic count obtained after the different treatments varied between 0.11 and 3.29 log colony-forming units (cfu)/g. Whether or not a decontamination step induced significant changes in the sensory attributes of grated carrots is highly dependent on the type and concentration of disinfectant. To maintain the nutritional value, the influence of the decontamination agents on carotenoid content, alpha-tocopherol content, total phenols, and antioxidant capacity was studied. Besides the part of the nutrients that was leached away from the cutting areas by water, the nutrient losses caused by adding sanitizers were rather limited. Compared with the untreated carrots alpha-tocopherol content was, however, significantly reduced when 250 ppm of peroxyacetic acid (-80%) or 200 ppm of sodium hypochlorite (-59%) was used. Additional losses in carotenoid content were caused by contact with chlorine dioxide gas (-9%). On the condition of an optimized decontamination process toward time and concentration, the microbial quality of fresh-cut carrots could be improved without negatively influencing their sensory quality and nutrient content.