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1.
Nutrients ; 13(4)2021 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-33800596

RESUMO

BACKGROUND: Since 1979, the World Health Organization (WHO) and the United Nations Children's Fund (UNICEF) have recommended the use of pasteurized human milk from a human milk bank (HMB) to feed low birthweight (LBW) and preterm newborns as the 'first alternative' when mothers are unable to provide their own milk. However, they have not issued any guidelines for the safe establishment and operation of an HMB. This gap contributes to the demand for gathering experiences from HMB networks, especially those from lower-middle income countries. To fill this knowledge gap, this study examines the characteristics of donors, donation, pasteurization, and recipients during the first four years of operation in the first HMB in Vietnam. METHODS: Data about the donors, donation, pasteurization, and recipients were extracted from the web-based electronic monitoring system of the HMB from 1 February 2017 to 31 January 2021. RESULTS: In the first four years of operation there were 433 donors who donated 7642 L of milk (66% from the community) with an increased trend in the amount of donated milk, donation duration, and average amount of milk donated by a donor. Approximately 98% of the donated milk was pasteurized, and 82% passed both pre- and post-pasteurization tests. Although the pass rate tended to increase with time, a few dips occurred. Of 16,235 newborns who received pasteurized donor milk, two thirds were in the postnatal wards. The main reason for the prescription of pasteurized donor milk was insufficient mothers' own milk in the first few days after birth. There was a decreased trend in the amount and duration of using pasteurized donor milk in both postnatal wards and the neonatal unit. CONCLUSIONS: The HMB has operated efficiently in the previous four years, even during the COVID-19 pandemic, to serve vulnerable newborns. Ongoing evidence-based adjustments helped to improve the operation to recruit suitable donors, to increase the access to and quality of raw donor milk, to improve the pasteurization process, and to meet the need of more newborns.


Assuntos
Bancos de Leite , Adulto , Feminino , Humanos , Recém-Nascido , Bancos de Leite/organização & administração , Bancos de Leite/estatística & dados numéricos , Leite Humano , Pasteurização , Doadores de Tecidos/estatística & dados numéricos , Vietnã
2.
Int J Mol Sci ; 22(7)2021 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-33810380

RESUMO

The mechanism underlying the allergy-protective effects of raw cow's milk is still unknown, but the modulation of the gut microbiome may play a role. The effects of consuming raw cow's milk or processed milk on fecal microbial communities were therefore characterized in an experimental murine model. C3H/HeOuJ mice were treated with raw milk, pasteurized milk, skimmed raw milk, pasteurized milk supplemented with alkaline phosphatase (ALP), or phosphate-buffered saline (PBS) for eight days prior to sensitization and challenge with ovalbumin (OVA). Fecal samples were collected after milk exposure and after OVA sensitization, and microbiomes were characterized using 16S ribosomal RNA gene amplicon sequencing. Treatment with raw milk prior to OVA sensitization increased the relative abundance of putative butyrate-producing bacteria from the taxa Lachnospiraceae UCG-001, Lachnospiraceae UCG-008, and Ruminiclostridium 5 (Clostridial clusters XIVa and IV), while it decreased the relative abundance of Proteobacterial genera such as Parasutterella, a putative pro-inflammatory bacterial genus. This effect was observed after eight days of raw milk exposure and became more pronounced five weeks later, after allergic sensitization in the absence of milk. Similar trends were observed after treatment with skimmed raw milk. Conversely, the feeding of pasteurized milk led to a loss of allergy protection and a putative dysbiotic microbiome. The addition of ALP to pasteurized milk restored the protective effect observed with raw milk and mitigated some of the microbial community alterations associated with milk pasteurization. Raw milk-induced protection against food allergic symptoms in mice is accompanied by an increased relative abundance of putative butyrate-producing Clostridiales and a decreased relative abundance of putative pro-inflammatory Proteobacteria. Given the safety concerns regarding raw milk consumption, this knowledge is key for the development of new, microbiologically safe, preventive strategies to reduce the incidence of allergic diseases.


Assuntos
Hipersensibilidade Alimentar/prevenção & controle , Microbioma Gastrointestinal , Leite/imunologia , Animais , Hipersensibilidade Alimentar/imunologia , Hipersensibilidade Alimentar/microbiologia , Camundongos , Leite/microbiologia , Pasteurização
3.
Molecules ; 26(6)2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33801934

RESUMO

Yogurt is a nutritious food that is regularly consumed in many countries around the world and is widely appreciated for its organoleptic properties. Despite its contribution to human dietary requirements, yogurt in its traditional recipe is a poor source of fat-soluble vitamins. To respond to consumer demands and further increase the nutritional value of this product, this work aimed to fortify yogurt with vitamin E by using emulsification as the method of encapsulation. The effects of thermal processing and chilled storage on the physicochemical stability of the yogurt-based beverage was investigated. Vitamin E was only minorly affected by bulk pasteurization at 63 °C for 30 min and remained stable during storage at 4 °C for 28 days. Fortified samples showed increased in vitro antioxidant activity compared with non-fortified samples. Lactic acid bacterial counts were above the minimum recommended levels (>106 cfu/g) after processing and storage. In conclusion, this work has demonstrated that emulsification can be an effective strategy for developing yogurt-based products fortified with fat soluble vitamins.


Assuntos
Encapsulamento de Células/métodos , Vitamina E/análise , Iogurte/análise , Animais , Técnicas de Cultura Celular por Lotes/métodos , Bebidas , Emulsões/química , Emulsões/farmacologia , Fermentação , Manipulação de Alimentos , Alimentos Fortificados/análise , Leite/química , Pasteurização/métodos , Vitamina E/química
4.
J Dairy Sci ; 104(5): 5229-5238, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33685676

RESUMO

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a major etiologic agent that causes bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). Shiga toxin (Stx) is the main virulence factor of EHEC responsible for the progression to HUS. Although many laboratories have made efforts to develop an effective treatment for Stx-mediated HUS, a specific therapy has not been found yet. Human consumption of bovine colostrum is known to have therapeutic effects against several gastrointestinal infections because of the peptide and proteins (including antibodies) with direct antimicrobial and endotoxin-neutralizing effects contained in this fluid. We have previously demonstrated that colostrum from Stx type 2 (Stx2)-immunized pregnant cows effectively prevents Stx2 cytotoxicity and EHEC O157:H7 pathogenicity. In this study we evaluated the preservation of the protective properties of hyperimmune colostrum against Stx2 (HIC-Stx2) after pasteurization and spray-drying processes by performing in vitro and in vivo assays. Our results showed that reconstituted HIC-Stx2 colostrum after pasteurization at 60°C for 60 min and spray-dried under optimized conditions preserved specific IgG that successfully neutralized Stx2 cytotoxicity on Vero cells. Furthermore, this pasteurized/dehydrated and reconstituted HIC-Stx2 preserved the protective capacity against EHEC infection in a weaned mice model. The consumption of hyperimmune HIC-Stx2 bovine colostrum could be effective for HUS prevention in humans as well as in EHEC control in calves. However, further studies need to be done to consider its use for controlling EHEC infections.


Assuntos
Doenças dos Bovinos , Escherichia coli Êntero-Hemorrágica , Infecções por Escherichia coli , Animais , Bovinos , Doenças dos Bovinos/prevenção & controle , Chlorocebus aethiops , Colostro , Infecções por Escherichia coli/prevenção & controle , Infecções por Escherichia coli/veterinária , Feminino , Pasteurização , Gravidez , Células Vero , Virulência
5.
Artigo em Inglês | MEDLINE | ID: mdl-33671763

RESUMO

BACKGROUND: Human milk banks have a pivotal role in provide optimal food for those infants who are not fully breastfeed, by allowing human milk from donors to be collected, processed and appropriately distributed. Donor human milk (DHM) is usually preserved by Holder pasteurization, considered to be the gold standard to ensure the microbiology safety and nutritional value of milk. However, as stated by the European Milk Banking Association (EMBA) there is a need to implement the improvement of the operating procedure of human milk banks including preserving and storing techniques. AIM: The purpose of this study was to assess the effectiveness and safety of the selected new combination of methods for preserving donor human milk in comparison with thermal treatment (Holder pasteurization). METHODS: We assessed (1) the concentration of bioactive components (insulin, adiponectin, leptin, activity of pancreatic lipase, and hepatocyte growth factor) and (2) microbiological safety in raw and pasteurized, high-pressure processed and lyophilization human breast milk. RESULTS: The combination of two techniques, high-pressure processing and freeze-drying, showed the best potential for preserving the nutritional value of human milk and were evaluated for microbiological safety. Microbiological safety assessment excluded the possibility of using freeze-drying alone for human milk sample preservation. However, it can be used as a method for long-term storage of milk samples, which have previously been preserved via other processes. CONCLUSION: The results show that high-pressure treatment is the best method for preservation that ensures microbiological safety and biological activity but subsequent freeze-drying allowed long-term storage without loss of properties.


Assuntos
Bancos de Leite , Animais , Aleitamento Materno , Feminino , Liofilização , Humanos , Lactente , Leite Humano , Pasteurização
6.
Int J Food Microbiol ; 344: 109114, 2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33652336

RESUMO

Thermal inactivation kinetics of Salmonella in low moisture foods are necessary for developing proper thermal processing parameters for pasteurization. The effect of water activity on thermal inactivation kinetics of Salmonella and Enterococcus faecium NRRL B-2354 in ground black pepper has not been studied previously. Identification of a suitable surrogate assists in conducting in-plant process validations. Ground black pepper was inoculated with a 5-serotype Salmonella cocktail or E. faecium NRRL B-2354, equilibrated to water activities of 0.25, 0.45 or 0.65 in a humidity-controlled chamber, and isothermally treated at different temperatures. The survivor data were used for fitting the log-linear models to obtain the D and z-values of Salmonella and E. faecium in ground black pepper. Modified Bigelow models were developed to evaluate the effects of temperature and water activity on the thermal inactivation kinetics of Salmonella and E. faecium. Water activity and temperature showed significant negative effects on the thermal resistance of Salmonella and E. faecium in ground black pepper. For example, significantly higher D values of Salmonella were observed at water activity of 0.45 (D70°C = 20.5 min and D75°C = 7.8 min) compared to water activity of 0.65 (D70°C = 3.9 min and D75°C = 2.0 min). D-values of E. faecium were significantly higher than those of Salmonella at all three water activities, indicating that E. faecium is a suitable surrogate for Salmonella in thermal processing validation.


Assuntos
Enterococcus faecium/crescimento & desenvolvimento , Pasteurização/métodos , Piper nigrum/microbiologia , Salmonella/crescimento & desenvolvimento , Contagem de Colônia Microbiana , Enterococcus faecium/classificação , Enterococcus faecium/fisiologia , Microbiologia de Alimentos , Temperatura Alta , Salmonella/fisiologia , Água/análise
7.
Food Chem ; 351: 129361, 2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-33662905

RESUMO

This study evaluated the chemical changes in five types of whole-milk powders (WMP) with different heating loads during storage. The WMP was preheated using low-heat [low-temperature long-time (LTLT), high-temperature short-time pasteurization (HTST)] and high-heat process [ultra-pasteurization (ESL), ultra-high-temperature (UHT) treatments, and in-bottle sterilization (BS)]. Furosine increased by 2.5-3.0 times in high-heat WMP and 5.7-8.4 times in low-heat WMP during storage. 5-(hydroxymethyl)furfural (HMF) content in high-heat WMP was on average 1.4- to 2.4-fold higher than in low-heat WMP during storage. The increases in the amount of Nε-(carboxymethyl)lysine (CML) and Nε-(carboxyethyl)lysine (CEL) in high-heat WMP were more than that in low-heat WMP (CML, 3.4-4.9 vs 3.1-3.4 times; CEL, 3.4-4.2 vs 2.7-3.0 times). Pyrraline in high-heat WMP increased by 1.8- to 2.1-fold. 2-Furaldehyde, CML, and CEL increased slowly with 12 months of storage and then accelerated. Storage time significantly contributed to more furosine, HMF, CML, and CEL contents in high-heat WMP.


Assuntos
Armazenamento de Alimentos , Temperatura Alta , Reação de Maillard , Leite/química , Animais , Produtos Finais de Glicação Avançada/química , Pasteurização , Pós
8.
Food Chem ; 351: 129273, 2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-33662907

RESUMO

Heat processing of ready-to-drink beverages is required to ensure a microbiologically safe product, however, this can result in the loss of bioactive compounds responsible for functionality. The objective of this study was to establish the thermal stability of a novel dihydrochalcone, 3',5'-di-ß-d-glucopyranosyl-3-hydroxyphloretin (2), 3',5'-di-ß-d-glucopyranosylphloretin (3) and other Cyclopia subternata phenolic compounds, in model solutions with or without citric acid and ascorbic acid. The solutions were heated at 93, 121 and 135 °C, relevant to pasteurisation, commercial sterilisation and ultra-high temperature (UHT) pasteurisation, respectively. For most compounds, the acids decreased the second order reaction rate constants, up to 27 times. Compound 2 (46.29 ± 0.53 (g/100 g)-1 h-1), and to a lesser extent compound 3 (5.94 ± 0.01 (g/100 g)-1 h-1) were the most thermo-unstable compounds when treated at 135 °C without added acids. Even though differential effects were observed for compounds at different temperatures and formulations, overall, the phenolic compounds were most stable under UHT pasteurisation conditions.


Assuntos
Bebidas/análise , Chalconas/química , Fabaceae/química , Extratos Vegetais/química , Polifenóis/química , Temperatura , Glicosilação , Pasteurização , Fenóis/análise , Soluções
9.
Food Chem ; 347: 129058, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33486367

RESUMO

In the present work, a comprehensive phenolic analysis of fresh sugarcane juice from three different harvest seasons was performed and the effect of ohmic heating and ultrasound treatments on the phenolic content and color of the juice was evaluated. Among the 32 phenolic compounds identified, a total of 17 were quantified, comprising, in decreasing order of abundance, flavones (38-49 mg/L), dilignols (22-29 mg/L), and phenolic acid derivatives (17-30 mg/L). The main phenolic groups affected by the crop season (year and season) were flavones and phenolic acid derivatives. Juice treated by ohmic heating and ultrasound showed a total phenolic content similar to fresh juice, indicating the absence of additional non-thermal effects. Regarding color, both treatments promoted only a slight difference by visual perception. Considering these two quality parameters, ultrasound and ohmic heating seem to be a good alternative for sugarcane juice pasteurization.


Assuntos
Sucos de Frutas e Vegetais/análise , Espectrometria de Massas/métodos , Fenóis/análise , Saccharum/química , Cromatografia Líquida de Alta Pressão , Cor , Flavonas/análise , Manipulação de Alimentos , Oxirredução , Pasteurização , Saccharum/metabolismo , Estações do Ano , Sonicação
10.
J Med Microbiol ; 70(3)2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33475480

RESUMO

Introduction. In May-June 2018, an outbreak of campylobacteriosis involved students and school staff from kindergartens and primary schools in Pescara, southern Italy.Aim. We present details of the epidemiological and microbiological investigation, and the findings of the analytical study, as well as the implemented control measures.Methodology. To identify possible risk factors associated with the observed outbreak, a case control study was conducted using a questionnaire to collect information on the date of symptoms onset, type and duration of symptoms, type of healthcare contact, school attendance, and food items consumed at school lunches during the presumed days of exposure. Attack rates were calculated for each date and school. Logistic regression models were used to estimate the odds ratios of being a case and the odds of illness by food items consumed, respectively. Moreover, we carried out a comparative genomic analysis using whole genome multilocus sequence typing (wgMLST) of Campylobacter jejuni strains isolated during the outbreak investigation to identify the source of the outbreak.Results. Overall, 222 probable cases from 21 schools were identified, and C. jejuni was successfully isolated from 60 patients. The meals in the schools involved were provided by two cooking centres managed by a joint venture between two food companies. Environmental and food sampling, epidemiological and microbiological analyses, as well as a case control study with 176 cases and 62 controls from the same schools were performed to identify the source of the outbreak. The highest attack rate was recorded among those having lunch at school on 29 May (7.8 %), and the most likely exposure was 'caciotta' cheese (odds ratio 2.40, 95 % confidence interval 1.10-5.26, P=0.028). C. jejuni was isolated from the cheese, and wgMLST showed that the human and cheese isolates belonged to the same genomic cluster, confirming that the cheese was the vehicle of the infection.Conclusion. It is plausible that a failure of the pasteurization process contributed to the contamination of the cheese batches. Timely suspension of the catering service and summer closure of the schools prevented further spread.


Assuntos
Infecções por Campylobacter , Campylobacter jejuni/isolamento & purificação , Queijo/microbiologia , Surtos de Doenças , Microbiologia de Alimentos , Doenças Transmitidas por Alimentos/microbiologia , Adulto , Infecções por Campylobacter/epidemiologia , Infecções por Campylobacter/microbiologia , Estudos de Casos e Controles , Criança , Pré-Escolar , Feminino , Doenças Transmitidas por Alimentos/epidemiologia , Humanos , Itália , Masculino , Pasteurização , Instituições Acadêmicas , Inquéritos e Questionários
11.
Food Chem ; 345: 128786, 2021 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-33310559

RESUMO

The effects of single and twofold continuous pressure change technology (PCT) applications on the volatiles and sensory characteristics of pineapple juice were studied. Fresh and thermally pasteurised juices were additionally characterised. 128 volatiles were tentatively assigned in the four juices. Thermal pasteurisation and a single PCT treatment caused substantial losses in total volatiles of 6 and 20%, respectively. A second PCT passage further reduced the volatiles (36%) and is thus not recommended. PCT-treated samples were clearly distinguished from the remaining juices by principal component analysis. The descriptive sensory profiles, assessed by trained panellists, were not substantially affected by thermal pasteurisation and non-thermal PCT. The fresh juice exhibited a significant fishy off-flavour. In the consumer acceptance test, the thermally pasteurised juice was highly rated compared to both PCT-treated and the fresh juice. This study highlights the potential of PCT to avoid the genesis of off-flavours in fresh-like pineapple juice.


Assuntos
Ananas/química , Comportamento do Consumidor , Manipulação de Alimentos/métodos , Sucos de Frutas e Vegetais/análise , Pressão , Paladar , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Pasteurização , Microextração em Fase Sólida
12.
J Food Sci ; 86(1): 112-119, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33368317

RESUMO

The dielectric properties and specifically the complex relative permittivity of foods are key elements for the design of pasteurization processes with high frequency electromagnetic waves. Mexican sauces are recognized worldwide for their flavor and nutritional properties. In this work, the complex permittivity of four of the most representative sauces of Mexican cuisine (chipotle chili, habanero chili, red and green sauce) is presented. The permittivity was measured with the open coaxial probe method at temperatures of 25, 40, 55, 70, 85 °C and in the frequency range of 500 MHz to 6 GHz. Additionally, moisture content, specific heat, viscosity, water activity, density and electrical conductivity are reported, these last three at 25 °C. Dielectric properties were affected by the sauce formulation. The loss factor of each sauce sample at any temperature presents significant changes in relation to the frequency. At 915 and 2,450 MHz, d ε ' ' d T > 0 , which would cause a thermal runaway effect or the uncontrolled rise in temperature in the sauces during the microwave pasteurization. At 5,800 MHz, d ε ' ' d T < 0 , which would give better control for microwave heating than at 915 and 2,450 MHz. At 915 MHz, the loss factor of all sauces is higher than at 2,450 and 5,800 MHz, therefore, more rapid heating can be produced. Moreover, at 915 MHz, microwaves exhibit higher penetration depth than at 2,450 and 5,800 MHz; therefore, at 915 MHz, the greatest uniform microwave dielectric heating would be achieved. Thus, 915 MHz is the frequency recommended for the studied sauces pasteurization. PRACTICAL APPLICATION: This work provides the dielectric properties of Mexican sauces at different temperatures and their penetration depths in the microwave range, which are key information for further microwave-assisted pasteurization process and for getting safer sauces for consumers. Moreover, this research supplies suggestions about what frequency for ISM (Industrial, Scientific and Medical) applications is the best for microwave-assisted pasteurization according to the penetration depth of the electromagnetic wave in the sauces and microwave dielectric heating speed of the sauces.


Assuntos
Condimentos/análise , Análise de Alimentos/métodos , Calefação , Micro-Ondas , Pasteurização/métodos , Temperatura
13.
Food Chem ; 337: 127751, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32777575

RESUMO

The type of container (airtight and pouches with different O2 permeability) and packing conditions (cover brine, air or N2 atmosphere) has been studied to preserve black ripe olives in acid medium for a year. Unlike the traditional sterilized product, these acidified olives only needed pasteurization to assure its microbial safety, the absence of acrylamide being an additional advantage. Surprisingly, an increase in the oxygen diffusion through the films (i) faded the black color of the olives, (ii) softened the fruit that lost around 33% of its initial firmness in only 6 months, and (iii) produced the lipid́s oxidation forming volatile compounds that transmitted an abnormal flavor which tasters identified as rancid. Therefore, ripe olives in acid medium must be packed in airtight containers such as glass jars, cans o metallic pouches with cover brine or N2 atmosphere. The addition of calcium is recommended to avoid olive softening.


Assuntos
Embalagem de Alimentos/métodos , Olea/química , Acrilamida/análise , Cor , Frutas/química , Concentração de Íons de Hidrogênio , Fenômenos Mecânicos , Oxirredução , Pasteurização , Paladar
14.
Food Chem ; 337: 127690, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32795853

RESUMO

Climate and feeding influence the composition of bovine milk, which is further affected by thermal treatment inducing oxidation and Maillard reactions. This study aimed to evaluate season- and processing-related changes in the modified proteome of milk from two different feeding systems. Therefore, tryptic digests of regular and hay milk were analyzed by targeting 26 non-enzymatic modifications using LC-MS. Forty-five glycated, 48 advanced glycation endproduct (AGE-) modified, and 20 oxidized/carbonylated peptides representing 44 proteins were identified with lactosylation, formyllysine, and carboxymethyllysine being most common. The numbers and quantities of glycation- and oxidation-related modifications were similar between regular and hay milk and among seasons. The effects of pasteurization and ultra-high temperature (UHT) treatment were comparable for both milk types. In particular UHT treatment increased the numbers of identified modifications and the relative quantities of lactosylated peptides. The number of identified AGE-modified and oxidized residues increased slightly after UHT-treatment, but the contents were stable.


Assuntos
Proteínas do Leite/química , Pasteurização , Estações do Ano , Animais , Bovinos , Produtos Finais de Glicação Avançada/química , Glicosilação , Temperatura Alta , Lisina/análogos & derivados , Lisina/química , Reação de Maillard , Oxirredução
15.
Waste Manag ; 119: 11-21, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33032154

RESUMO

This study investigated the possibility to use thermophilic anaerobic high solid digestion of dewatered digested sewage sludge (DDS) at a wastewater treatment plant (WWTP) as a measure to increase total methane yield, achieve pasteurization and reduce risk for methane emissions during storage of the digestate. A pilot-scale plug-flow reactor was used to mimic thermophilic post-treatment of DDS from a WWTP in Linköping, Sweden. Process operation was evaluated with respect to biogas process performance, using both chemical and microbiological parameters. Initially, the process showed disturbance, with low methane yields and high volatile fatty acid (VFA) accumulation. However, after initiation of digestate recirculation performance improved and the specific methane production reached 46 mL CH4/g VS. Plug flow conditions were assessed with lithium chloride and the hydraulic retention time (HRT) was determined to be 19-29 days, sufficient to reach successful pasteurization. Degradation rate of raw protein was high and resulted in ammonia-nitrogen levels of up to 2.0 g/L and a 30% lower protein content in the digestate as compared to DDS. Microbial analysis suggested a shift in the methane producing pathway, with dominance of syntrophic acetate oxidation and the candidate methanogen family WSA2 by the end of the experiment. Energy balance calculations based on annual DDS production of 10000 ton/year showed that introduction of high-solid digestion as a post-treatment and pasteurization method would result in a positive energy output of 340 MWh/year. Post-digestion of DDS also decreased residual methane potential (RMP) by>96% compared with fresh DDS.


Assuntos
Reatores Biológicos , Esgotos , Anaerobiose , Digestão , Metano/análise , Pasteurização , Suécia
16.
Food Chem ; 340: 127911, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-32896778

RESUMO

Emerging technologies, such as focused microwave heating of liquid foods, have been studied to reduce quality losses due to the high temperatures of conventional processing. Besides faster heating, microwaves can also have non-thermal effects on inactivation; however, this is a controversial issue. The objective of this study was to compare conventional and focused microwave heating under similar conditions for the inactivation of two polyphenol oxidases (PPOs): mushroom tyrosinase in buffer and the PPO present in coconut water. Small samples under stirring were treated at temperatures between 50 and 90 °C and three kinetic models were adjusted considering the whole time-temperature history. The Weibull model could best describe inactivation in both heating processes, which was more effective with microwave heating for temperatures over 70 °C. Validation runs show that the model can satisfactorily describe the PPO inactivation. This study contributes for the design of liquid food pasteurization by focused microwave technology.


Assuntos
Catecol Oxidase/química , Pasteurização/métodos , Agaricales/enzimologia , Tampões (Química) , Catecol Oxidase/metabolismo , Cocos/enzimologia , Ativação Enzimática , Indústria de Processamento de Alimentos/métodos , Calefação , Cinética , Micro-Ondas , Modelos Teóricos , Monofenol Mono-Oxigenase/química , Monofenol Mono-Oxigenase/metabolismo , Temperatura
17.
Int J Food Microbiol ; 338: 108993, 2021 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-33310209

RESUMO

Fungal spoilage in fruit juices is a currently relevant issue considering that recent reports have found unacceptable fungal levels even after traditional pasteurization processes. Ohmic heating demonstrated to be a good alternative process to conventional pasteurization, as it can promote higher heating rates and additional cell damage in some scenarios (nonthermal effects). However, the application of ohmic processing for fungi inactivation has not been properly investigated. The objective of this study was to analyze the inactivation of Aspergillus fumigatus, a highly distributed fungi species, in apple juice by ohmic and conventional heating at 75, 80, 85, 90 and 94 °C. Predictive primary and secondary models were fitted and the Weibull-Mafart models were the most accurate to describe the experimental behavior considering the statistical indices applied. Statistical differences between both thermal processes were found in the three lower analyzed temperatures (75, 80 and 85 °C), which is possibly related to nonthermal effects. When ohmic heating was applied, processing time was up to 23% shorter. The resulted model was successfully validated in two distinct temperatures (83 and 92 °C) and could be applied to obtain adequate processing times for apple juice pasteurization. This study contributes to deepen the knowledge concerning the use of ohmic heating for fungi inactivation.


Assuntos
Aspergillus fumigatus/fisiologia , Eletricidade , Microbiologia de Alimentos/métodos , Sucos de Frutas e Vegetais/microbiologia , Malus/microbiologia , Pasteurização , Temperatura
18.
Int J Food Microbiol ; 337: 108948, 2021 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-33197682

RESUMO

Novel processing methods such as cold atmospheric plasma (CAP) and natural antimicrobials like nisin, are of interest to replace traditional food decontamination approaches as, due to their mild nature, they can maintain desirable food characteristics, i.e., taste, texture, and nutritional content. However, the microbial growth characteristics (planktonic growth/surface colonies) and/or the food structure itself (liquid/solid surface) can impact the inactivation efficacy of these novel processing methods. More specifically, cells grown as colonies on a solid(like) surface experience a completely different growth environment to cells grown planktonically in liquid, and thus could display a different response to novel processing treatments through stress adaptation and/or cross protection mechanisms. The order in which combined treatments are applied could also impact their efficacy, especially if the mechanisms of action are complementary. This work presents a fundamental study on the efficacy of CAP and nisin, alone and combined, as affected by food system structure. More specifically, Listeria innocua was grown planktonically (liquid broth) or on a viscoelastic Xanthan gum gel system (1.5% w/v) and treated with CAP, nisin, or a combination of the two. Both the inactivation system, i.e., liquid versus solid(like) surface and the growth characteristics, i.e., planktonic versus colony growth, were shown to impact the treatment efficacy. The combination of nisin and CAP was more effective than individual treatments, but only when nisin was applied before the CAP treatment. This study provides insight into the environmental stress response/adaptation of L. innocua grown on structured systems in response to natural antimicrobials and novel processing technologies, and is a step towards the faster delivery of these food decontamination methods from the bench to the food industry.


Assuntos
Antibacterianos/farmacologia , Manipulação de Alimentos/métodos , Listeria/efeitos dos fármacos , Nisina/farmacologia , Gases em Plasma/farmacologia , Contagem de Colônia Microbiana , Microbiologia de Alimentos , Listeria/crescimento & desenvolvimento , Modelos Biológicos , Pasteurização/métodos
19.
Food Chem ; 340: 127938, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-32871356

RESUMO

We evaluated the effects of processing - pasteurization and yoghurt manufacturing - on some health-promoting lipidome components in milk from two feeding treatments - brushland grazing or hay-feeding in confinement - in dairy goats. The contents of fat and protein were higher, and of urea, lower, in grazing goats. Fatty acid composition - at the exception of saturated fatty acids - was affected by dietary management and milk processing. Phospholipid contents was lower in confined goats, with little effect for processing. The phospholipid-to-triglyceride ratio was decreased by pasteurization. Sensitivity to pasteurization of phospholipid composition differed between feeding treatments. The percentage of sphingomyelin increased following pasteurization, with no response for fermentation to yoghurt. These results can be exploited to modulate health-promoting fats in dairy products.


Assuntos
Ração Animal/análise , Cabras , Lipidômica , Leite/metabolismo , Fosfolipídeos/metabolismo , Animais , Dieta/veterinária , Feminino , Fermentação , Pasteurização
20.
Food Chem ; 338: 127747, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32858434

RESUMO

In this study, we evaluated the influence of the ultrasound application on five levels of energy density (1000; 3000; 5000 and 7000 J g-1) compared to two pasteurization techniques (70 °C/5 min and 94 °C/0.5 min) on color parameters, polyphenoloxidase activity, chemical composition, and antioxidant properties of araçá-boi pulp. Ultrasound caused changes in the parameters brightness/darkness, hue angle, and total color difference, but did not change chroma, yellowness/blueness, color index, and yellow index. Moreover, this technique was efficient for inactivating polyphenoloxidase. Ultrasound at 7000 J g-1 was responsible for an increase in soluble solids (16%), vitamin C (46.5%), phenolics (15.65%), flavonoids (50%) and antioxidant capacity in relation to untreated pulp, while ultrasound at 5000 J g-1 increased the relative intensity of compounds of biological interest. Thus, ultrasound can be considered as a promising technique to maintain the shelf life, without drastically affecting the nutritional and functional qualities of this fruit.


Assuntos
Antioxidantes/química , Cor , Eugenia/química , Extratos Vegetais/química , Sonicação , Ácido Ascórbico/análise , Catecol Oxidase/metabolismo , Colorimetria , Eugenia/metabolismo , Flavonoides/análise , Frutas/química , Frutas/metabolismo , Pasteurização , Fenóis/análise
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