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1.
J Agric Food Chem ; 67(38): 10624-10636, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31483633

RESUMO

The freshness and color quality of postharvest tea leaves can be markedly prolonged and retained by proper preservation measures. Here, we investigated the dynamic changes of chlorophyll and its derivatives in postharvest tea leaves under different low-temperature treatments using natural withering as a control. Chlorophyll decomposition was found closely related with chlorophyllide, pheophorbide, and pheophytin. Low-temperature withering could slow chlorophyll degradation in postharvest tea leaves via significant inhibition on the enzyme activity and gene expression of Mg-dechelatase, chlorophyllase, and pheophorbide a oxygenase. At the initial stage of withering, a significant increase was observed in the chlorophyll content, expression of chlorophyll-synthesis-related enzymes (such as glutamyl-tRNA synthetase, etc.), and chlorophyll synthase activity in newly picked tea leaves. Moreover, an obvious decrease was found in the content of l-glutamate as the foremost precursor substance of chlorophyll synthesis. Hence, our findings revealed that the chlorophyll synthesis reaction was induced by the light-dehydration-stress in the initial withering of tea leaves. This study provides a theoretical basis for exploring preservation technology in actual green tea production.


Assuntos
Camellia sinensis/genética , Camellia sinensis/metabolismo , Clorofila/metabolismo , Manipulação de Alimentos/métodos , Regulação da Expressão Gênica de Plantas , Camellia sinensis/química , Camellia sinensis/crescimento & desenvolvimento , Hidrolases de Éster Carboxílico/genética , Hidrolases de Éster Carboxílico/metabolismo , Clorofila/química , Cor , Enzimas/genética , Enzimas/metabolismo , Oxigenases/genética , Oxigenases/metabolismo , Folhas de Planta/química , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Temperatura Ambiente
2.
Rev Bras Epidemiol ; 22: e190046, 2019 Aug 26.
Artigo em Português, Inglês | MEDLINE | ID: mdl-31460625

RESUMO

OBJECTIVE: To investigate the food consumption according to the degree of processing and associations with sociodemographic characteristics. METHODS: A cross-sectional study of the Estudo Pró-Saúde (Pro-Health Study), with 520 civil servants of university campuses, Rio de Janeiro, 2012-13. A food frequency questionnaire was used to classify food consumption: 1) in natura, minimally processed, food preparations based on these foods; 2) processed foods; 3) ultra-processed foods. The relative energy contribution of each group was determined, and a seemingly unrelated equations regression (SUR) regression model was used to estimate associations with sociodemographic characteristics. RESULTS: The in natura food group (1) contributed with 59% of the energy consumption and was directly associated with age [45-49 years (ß = 1.8 confidence interval of 95% - 95%CI -1.2; 4.8); 50-54 (ß = 1.5 95%CI -1.5; 4.5); 55-59 (ß = 2.9 95%CI -0.4; 6.3) and ≥ 60 (ß = 4.6 95%CI 1.1; 8.2)], compared to age ≤ 44. In contrast, the group of ultra-processed foods contributed 27% and were inversely associated with age [45-49 (ß = -1.7 95%CI -4.3; 0.9); 50-54 (ß = -1.8 95%CI -4.3; 0.9); 55-59 (ß = -4.9 95%CI -8.0; -2.0); ≥ 60 (ß = -4.5 95%CI -7.6; -1.5)]. Gender, income and schooling were not associated with food consumption. CONCLUSION: Younger adults had higher consumption of ultra-processed foods, indicating the need for interventions mainly in this age group. The absence of association with other sociodemographic characteristics may be due to the influence of contextual factors.


Assuntos
Inquéritos sobre Dietas/estatística & dados numéricos , Ingestão de Energia , Comportamento Alimentar , Manipulação de Alimentos/estatística & dados numéricos , Adulto , Brasil , Estudos Transversais , Escolaridade , Feminino , Humanos , Renda , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Valores de Referência
3.
J Agric Food Chem ; 67(33): 9295-9306, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31365237

RESUMO

As a result of an innovative olive fruit processing method involving stone removal and dehydration, a new kind of olive oil and olive flour are generated. The main objective of this work was to accomplish the comprehensive characterization of the minor compounds of both products and to evaluate the effect of the dehydration temperature on their composition. To this end, olive oil and flour samples obtained through the novel processing method were analyzed and compared with "conventional" virgin olive oils (VOO). The applied LC-MS methodology allowed the determination of 57 metabolites belonging to different chemical classes (phenolic compounds, pentacyclic trirterpenes, and tocopherols). Both the new oils and flours presented considerable amounts of olive fruit metabolites that are usually absent from VOO. Quantitative differences were found among VOOs and the new oils, probably due to the inhibition of some enzymes caused by the temperature increase or the absence of water during the processing.


Assuntos
Manipulação de Alimentos/métodos , Olea/química , Extratos Vegetais/química , Resíduos/análise , Cromatografia Líquida , Farinha/análise , Frutas/química , Azeite de Oliva/análise , Fenóis/química , Fenóis/isolamento & purificação , Extratos Vegetais/isolamento & purificação , Espectrometria de Massas em Tandem , Tocoferóis/química , Tocoferóis/isolamento & purificação
4.
Food Chem ; 299: 125039, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31288166

RESUMO

An integrated targeted-untargeted 1H and 13C Nuclear Magnetic Resonance (NMR) analysis was applied to determine the impact of roasting on coffee lipids. For targeted analysis, both an internal standard (IS) method, as well as the ERETIC2 tool based on PULCON (Pulse Length-based Concentration determination), were used for quantitation. PULCON allows for quantitative analysis without sample contamination with an IS and was found to be in very good agreement with the traditional IS approach as indicated by a systematic Bland-Altman comparison study. For the untargeted analysis, NMR was coupled with multivariate statistical analysis (MVSA), namely Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA), and Orthogonal Projection to Latent Structures Discriminant Analysis (OPLS-DA). 13C NMR spectra were acquired using a z-stored spin-echo sequence to achieve higher spectral quality, which is important for both targeted and untargeted analysis. Results showed that roasting has a clear effect on coffee lipids, with diterpenes, oxidation/hydrolysis products and unsaturated fatty acid chains being the most significant markers. In addition, the application of MRI indicated important morphological alterations in bean structure and lipid migration from the endosperm to the surface of the coffee bean.


Assuntos
Café/química , Análise de Alimentos/métodos , Manipulação de Alimentos , Lipídeos/análise , Imagem por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Análise de Alimentos/normas , Temperatura Alta , Análise Multivariada , Padrões de Referência
5.
New Microbiol ; 42(3): 156-160, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31305934

RESUMO

In October 2017, two outbreaks of gastroenteritis (GE) occurred among patrons of a cafeteria in Italy in one week. Virological and bacteria investigations on stool samples, environment and food were conducted to identify the infectious agents and the possible source of infection. Forty-five cases occurred in the two outbreaks, including 13 laboratory-confirmed cases of norovirus GI. Nine staff members were interviewed, six were confirmed positive for NoV GI and 3 experienced GE symptoms. Bacteria faecal indicators and other bacteria pathogens were not detected in either environmental swab samples or food. A low level of NoV GII was detected in two environmental swab samples. The same GI.6 strain was identified in cases related to both outbreaks, suggesting a common source of infection. Since the two outbreaks occurred in one week, the NoV contamination could have persisted in the cafeteria. Furthermore, virological investigation revealed confirmed cases among food handlers who had worked at the cafeteria between and during the two outbreaks. Several studies highlighted the importance of excluding symptomatic food handlers to prevent contamination of foods and environment.


Assuntos
Infecções por Caliciviridae , Surtos de Doenças , Manipulação de Alimentos , Gastroenterite , Norovirus , Infecções por Caliciviridae/epidemiologia , Microbiologia Ambiental , Contaminação de Alimentos/prevenção & controle , Manipulação de Alimentos/normas , Gastroenterite/epidemiologia , Gastroenterite/virologia , Humanos , Itália/epidemiologia , Norovirus/fisiologia
6.
Sci Total Environ ; 691: 252-262, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31323571

RESUMO

Various antimicrobial interventions are applied sequentially in the beef processing industry to reduce microbial load on beef products by using intensive inputs (e.g., chemicals, energy), high strength wastewater, and potentially result in meat discoloration. This study serves as the first analysis to jointly evaluate environmental and economic assessment with its microbial load reduction of proposed antimicrobial systems in the U.S. beef processing industry to identify relatively sustainable systems that minimize environmental and economic impacts while providing microbial safe meat. Specifically, forty potential sequential antimicrobial systems were proposed and evaluated from three perspectives: microbial load reduction, environmental, and economic impacts, by meta-analysis, life cycle assessment, and operational cost analysis orderly. The results show that the antimicrobial systems applying steam pasteurization during the main intervention offer high microbial load reduction (>4.2 log CFU/cm2 reduction from a hypothetical initial contamination at 5.0 log CFU/cm2). Human health impact (31.0 to 65.6%) and ecosystem toxicity (3.6 to 12.5%), eutrophication (11.9 to 15.5%) and global warming (6.4 to 22.2%) are the main contributors to the overall environmental single score among the forty antimicrobial systems. Antimicrobial chemicals (up to 82.8%), wastewater treatment (up to 12.7%), and natural gas (up to 10.7%) are the three major drivers of operational cost for sanitizing 1000 kg hot standard carcass weight (HSCW). Devalued (discolored) meat due to contact with heat from steam pasteurization or hot water wash has a considerable increase in economic ($4.5/1000 HSCW) and environmental (especially at farm stage) impacts. Certain antimicrobial systems (e.g., water wash followed by steam pasteurization) were found to be more promising with satisfactory effectiveness, better environmental and cost performance under uncertainty (1000 Monte Carlo simulations). Results from this study can guide the U.S. beef processing industry to advance sustainability while protecting human health from foodborne illness.


Assuntos
Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Carne Vermelha , Matadouros , Animais , Anti-Infecciosos , Bovinos , Qualidade de Produtos para o Consumidor , Manipulação de Alimentos/estatística & dados numéricos , Doenças Transmitidas por Alimentos , Humanos
7.
Toxicol Lett ; 314: 75-81, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31284020

RESUMO

Aflatoxin is a fungal secondary metabolite with high toxicity that is capable of contaminating various types of food crops. It has been identified as a Group 1 human carcinogen by the International Agency for Research on Cancer. Chronic aflatoxin exposure has caused worldwide concern as a matter of public food safety. Peanuts and peanut products are the major sources of aflatoxin exposure. Therefore, some reduction interventions have been developed to minimize contamination throughout the peanut production chain. The purpose of this study is to estimate the efficacy of interventions in reducing the health impact of hepatocellular carcinoma caused by aflatoxin contamination in peanuts. The estimated total Disability-Adjusted Life Years (DALYs) were calculated using FDA-iRISK software. Six aflatoxin reduction strategies were evaluated, including good agricultural practice (GAP), biocontrol, Purdue Improved Crop Storage packaging, basic processing, ozonolysis, and ultraviolet irradiation. The results indicated that basic processing could prevent huge public health loss of 4,079.7-21,833 total DALYs per year. In addition, GAP and biocontrol were both found to be effective strategies in the farm field. Meanwhile, the other three interventions had limited effectiveness in reducing total DALYs. In conclusion, this study could help farmers, processing plants, and government policy makers to alleviate aflatoxin contamination issues in the peanut production chain.


Assuntos
Aflatoxinas/efeitos adversos , Arachis/microbiologia , Carcinoma Hepatocelular/prevenção & controle , Produtos Agrícolas/microbiologia , Exposição Dietética/efeitos adversos , Exposição Dietética/prevenção & controle , Microbiologia de Alimentos/métodos , Doenças Transmitidas por Alimentos/prevenção & controle , Neoplasias Hepáticas/prevenção & controle , Anos de Vida Ajustados por Qualidade de Vida , Agentes de Controle Biológico , Carcinoma Hepatocelular/diagnóstico , Carcinoma Hepatocelular/epidemiologia , Efeitos Psicossociais da Doença , Avaliação da Deficiência , Manipulação de Alimentos/métodos , Armazenamento de Alimentos , Doenças Transmitidas por Alimentos/diagnóstico , Doenças Transmitidas por Alimentos/epidemiologia , Humanos , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/epidemiologia , Ozônio/química , Fatores de Proteção , Medição de Risco , Fatores de Risco , Fatores de Tempo , Raios Ultravioleta
8.
J Agric Food Chem ; 67(32): 8725-8734, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31295997

RESUMO

Texture perception is conceptualized as an emergent cognitive response to food characteristics that comprise several physical and chemical properties. Contemporary oral processing research focuses on revealing the relationship between the sensory perceptions and food properties, with the goal of enabling rational product design. One major challenge is associated with revealing the complex molecular and biocolloidal interactions underpinning even simple texture percepts. Here, we introduce in vitro oral processing, which considers oral processing in terms of discrete units of operation (first bite, comminution, granulation, bolus formation, and tribology). Within this framework, we systematically investigate the material properties that govern each specific oral processing unit operation without being impacted by the biological complexity of the oral environment. We describe how this framework was used to rationally design a low-fat potato chip with improved sensory properties by investigating the impact from adding back, to a low-fat potato chip, a small amount of oil mixed with the surface-active agent polyglycerol polyricinoleate (PGPR). The relevance of instrumental measures is validated by sensory assessment, whereby panelists ranked the perceived oiliness of three different types of potato chips. The sensory results indicate that perceived oiliness was higher when a low-fat potato chip was supplemented with an additional 0.5% (w/w) topical coating (the coating comprised 15%, w/w, PGPR in oil) compared to the unaltered low-fat potato chip. The perceived difference in oiliness is hypothesized to correspond to the dynamic friction measured in vitro with a saliva-coated substrate in the presence and absence of PGPR. The study illustrates how dividing oral processing into distinct units provides a rational approach to food product design focused on controlling key sensory attributes.


Assuntos
Gorduras/análise , Boca/metabolismo , Solanum tuberosum/metabolismo , Gorduras/metabolismo , Manipulação de Alimentos , Humanos , Modelos Biológicos , Reologia , Saliva/metabolismo , Lanches , Solanum tuberosum/química
9.
Environ Monit Assess ; 191(8): 477, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31264019

RESUMO

The present study evaluated the concentration of six trace elements in processed meat products and in meat cuts. We also assessed the risk associated with the consumption of these foods based on the estimated daily intake (EDI) of these elements. Fifty-eight processed meat and 148 meat cuts samples were analyzed using ICP-OES. As and Cd were not detected in any sample of processed meat. The highest mean level of lead was observed in frankfurters (0.056 µg g-1), which is half the maximum permissible level. For Cr, the highest mean concentrations were detected in chicken nuggets and beef hamburger (0.121 and 0.105 µg g-1, respectively), which are above the allowed limit. The comparison between the impact of a diet restricted to processed meats with a diet restricted to meats cuts showed that the individuals following the latter are exposed to higher amounts of the trace elements analyzed.


Assuntos
Monitoramento Ambiental , Poluentes Ambientais/análise , Carne , Oligoelementos/análise , Animais , Brasil , Bovinos , Galinhas , Manipulação de Alimentos , Análise de Perigos e Pontos Críticos de Controle , Humanos , Chumbo/análise , Medição de Risco
10.
J Agric Food Chem ; 67(28): 8061-8069, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31264412

RESUMO

Food processing of infant formula alters chemical structures, including the formation of Maillard reaction products between proteins and sugars. We detected early Maillard reaction products, so-called Amadori products, in stool samples of formula-fed infants. In total, four Amadori products (N-deoxylactulosyllysine, N-deoxyfructosyllysine, N-deoxylactulosylleucylisoleucine, N-deoxyfructosylleucylisoleucine) were identified by a combination of complementary nontargeted and targeted metabolomics approaches. Chemical structures were confirmed by preparation and isolation of reference compounds, LC-MS/MS, and NMR. The leucylisoleucine Amadori compounds, which most likely originate from ß-lactoglobulin, were excreted throughout the first year of life in feces of formula-fed infants but were absent in feces of breastfed infants. Despite high inter- and intraindividual differences of Amadori products in the infants' stool, solid food introduction resulted in a continuous decrease, proving infant formula as the major source of the excreted Amadori products.


Assuntos
Alimentação Artificial/estatística & dados numéricos , Fezes/química , Produtos Finais de Glicação Avançada/química , Fórmulas Infantis/análise , Cromatografia Líquida , Feminino , Manipulação de Alimentos , Humanos , Lactente , Fórmulas Infantis/efeitos adversos , Espectroscopia de Ressonância Magnética , Reação de Maillard , Masculino , Espectrometria de Massas em Tandem
11.
J Agric Food Chem ; 67(31): 8559-8572, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31298518

RESUMO

Avenin-like b protein is rich in cysteine residues, providing the possibility to form intermolecular disulfide bonds and then participate in glutenin polymerization. Site-directed mutagenesis was adopted to produce mutant avenin-like b gene encoding mutant avenin-like b protein, in which one tyrosine codon at the C-terminal is substituted by a cysteine codon. Compared with the control lines, both transgenic lines with wild-type and mutant avenin-like b genes demonstrated superior dough properties. While compared within the transgenic lines, the mutant lines showed relative weaker dough strength and decreased sodium-dodecyl-sulfate sedimentation volumes (from 69.7 mL in line WT alb-1 to 41.0 mL in line Mut alb-4). These inferior dough properties were accompanied by the lower contents of large-sized glutenin polymers, the decreased particle diameters of glutenin macropolymer (GMP), due to the lower content of intermolecular ß-sheets (from 39.48% for line WT alb-2 to 30.21% for line Mut alb-3) and the varied contents of disulfide bonds (from 137.37 µmol/g for line WT alb-1 to 105.49 µmol/g for line Mut alb-4) in wheat dough. The extra cysteine might alter the original disulfide bond structure, allowing cysteine residue usually involved in an intermolecular disulfide bond to become available for an intrachain disulfide bond. Avenin-like b proteins were detected in glutenin macropolymers, providing further evidence for this protein to participate in the polymerization of glutenin. This is the first time to investigate the effect of a specific cysteine residue in the avenin-like b protein on flour quality.


Assuntos
Cisteína/genética , Farinha/análise , Plantas Geneticamente Modificadas/genética , Prolaminas/genética , Triticum/genética , Pão/análise , Cisteína/metabolismo , Dissulfetos/química , Manipulação de Alimentos , Mutagênese Sítio-Dirigida , Plantas Geneticamente Modificadas/química , Plantas Geneticamente Modificadas/metabolismo , Prolaminas/metabolismo , Triticum/química , Triticum/metabolismo
12.
J Agric Food Chem ; 67(29): 8074-8084, 2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31299152

RESUMO

Consumers often malign conventional curing agents while concomitantly accepting the natural forms of the same constituents in numerous food products. This paradox ostensibly exceeds all other food-related controversies to date and likely contributes to the rapid expansion of meat products that utilize natural nitrate derivatives. While there is high demand for these products, a fundamental lack of understanding regarding the safety and chemical implications of curing agents, whether derived from synthetic or natural sources, continues to persist. This manuscript elucidates the variations among curing preparations with particular emphasis pertaining to the associated safety, chemical, and regulatory ramifications encompassing these product categories.


Assuntos
Rotulagem de Alimentos/legislação & jurisprudência , Produtos da Carne/análise , Nitratos/análise , Nitritos/análise , Extratos Vegetais/análise , Plantas/química , Animais , Aditivos Alimentares/efeitos adversos , Aditivos Alimentares/análise , Manipulação de Alimentos , Rotulagem de Alimentos/normas , Inocuidade dos Alimentos , Humanos , Nitratos/efeitos adversos , Nitritos/efeitos adversos , Extratos Vegetais/efeitos adversos
13.
J Agric Food Chem ; 67(30): 8402-8410, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31276623

RESUMO

Wines aged in oak wood barrels with various uniform tannin contents (which were classified according to their total ellagitannins contents as predicted by Near Infrared Spectroscopy on the untoasted wood) and different toasting levels (high precision toasting by radiation) were distinguished according to their overall abilities to resist against oxidation. Wine trials were carried out on two different vintages (2015, 2016) and three grape varieties (Sauvignon blanc, Sémillon, Chardonnay). Regardless of the vintage and the wine matrix, a relationship was established between wine oxidative stability (based on EPR spin trapping methodology) and oak barrel tannin potential. The extraction kinetic of ellagitannins by wines appeared linear during barrel aging and achieved its maximum at six or eight months, in a grape variety dependent manner. Oak wood barrel tannin potentials and toastings had no effect on wine glutathione and polyphenols contents. However, wines aged in new barrels with both low and medium tannin potentials, preserved at the end of aging and important number of S-N containing compounds, which was in addition to the known ellagitanins, revealed wines better antioxidant stability.


Assuntos
Antioxidantes/química , Manipulação de Alimentos/instrumentação , Quercus/química , Taninos/análise , Vinho/análise , Madeira/química , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas , Fenóis/química , Vitis/química
14.
J Food Sci ; 84(7): 1799-1805, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31218694

RESUMO

Defatting of seabass skins using pulsed electric field (PEF)-assisted process at different electric field strengths (16 and 24 kV/cm) and times (36, 72, and 108 ms) in combination with porcine pancreas lipase (PPL) at 25 U/g dry matter was investigated. PEF-treated skin at 24 kV/cm for 72 ms followed by PPL treatment removed 86.93% lipids. PEF-treated skin was further optimized for lipid reduction by response surface methodology. Central composite design was adopted to establish treatments based on two independent variables, involving PPL concentration (30 to 55 U/g dry matter) and hydrolysis time (60 to 180 min). Second-order polynomial model was used for predicting the response. The highest lipid removal (91.96 ± 1.70%) was attained when the optimal condition (42.36 PPL units/g dry skin matter for 139.78 min) was used. The experiment value was in accordance with the predicted value. PEF-PPL-treated skin had lower monounsaturated and polyunsaturated fatty acids than the solvent-extracted skin (P < 0.05). When PEF-PPL-treated skin was hydrolyzed using papain at 0.30 U/g dry matter, lower fishy odor/flavor of resulting hydrolyzed collagen (PEF-PPL-HC) was found than other samples (P < 0.05). Lower total volatile compounds were also obtained in PEF-PPL-HC sample. Thus, the use of PEF pretreatment along with PPL before papain hydrolysis effectively prevented the formation of fishy odor/flavor in hydrolyzed collagen from seabass skin. PRACTICAL APPLICATION: Fishy odor/flavor caused by lipid oxidation of fish skin hydrolysates limits their applications in foods. Defatting process is the significant step for skin pretreatment. Although several methods could remove lipids from fish skins, either by lipase or solvent extraction, fishy odor/flavor is still detected in hydrolysate. Pulsed electric field-assisted process in combination with porcine lipase is another approach that can be used to enhance efficiency via electroporation, causing the loosened skin matrix and facilitating the migration of lipase into the skin. Consequently, the resulting hydrolysate might have the lowered fishy odor/flavor and could be used in foods, especially for fortification.


Assuntos
Manipulação de Alimentos/métodos , Lipase/química , Lipídeos/química , Pele/química , Animais , Bass , Biocatálise , Colágeno/química , Ácidos Graxos Insaturados/química , Proteínas de Peixes/química , Manipulação de Alimentos/instrumentação , Humanos , Odorantes/análise , Oxirredução , Suínos , Paladar
15.
J Sci Food Agric ; 99(13): 5792-5798, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31162672

RESUMO

BACKGROUND: Recently, a producer of fermented ciders observed 'vinyl' off-odors formed during fermentation of pear juice previously depectinized at ≥ 49 °C but not if depectinized at lower temperatures. The objective of this study was to investigate the source of this spoilage and evaluate factors that affect formation. RESULTS: Analysis of untainted and tainted samples obtained from the producer determined the causative agent to be indole, a compound sometimes produced by yeast (Saccharomyces cerevisiae) during fermentation. To mimic commercial depectinization conditions, pectinases were added to pear juices held at 35 °C for 45 min (Treatment A), 49 °C for 45 min (Treatment B), or 49 °C for 90 min (Treatment C). Juice processing conditions did not affect yeast growth nor progress of alcoholic fermentation. Although neither yeast strain (DV10 or MERIT) synthesized indole during fermentation of Treatment A juices, the compound was produced by MERIT in Treatments B (27.05 µg L-1 ) and C (469.9 µg L-1 ). Supplementation of Treatment C juice with pyridoxine (vitamin B6 ) prior to fermentation resulted in no detectable indole formed. However, juices from Treatments A, B, or C contained similar concentrations of pyridoxine and non-detectable amounts of tryptophan, a potential precursor to indole. Furthermore, indole was not detected during fermentations of a synthetic pear juice medium without pyridoxine. CONCLUSION: Supplementation of cider musts with pyridoxine prior to fermentation and choice of yeast strain can lower the risk of formation of off-odors caused by indole. However, other unidentified factors are present which affect its formation in perry. © 2019 Society of Chemical Industry.


Assuntos
Bebidas Alcoólicas/análise , Etanol/metabolismo , Manipulação de Alimentos/métodos , Indóis/metabolismo , Pectinas/metabolismo , Pyrus/química , Saccharomyces cerevisiae/metabolismo , Bebidas Alcoólicas/microbiologia , Etanol/análise , Fermentação , Sucos de Frutas e Vegetais/análise , Sucos de Frutas e Vegetais/microbiologia , Indóis/análise , Malus/química , Malus/microbiologia , Odorantes/análise , Poligalacturonase/química , Pyrus/microbiologia
16.
J Sci Food Agric ; 99(13): 5808-5818, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31177542

RESUMO

BACKGROUND: Rice bran oil and soy protein nanoparticles (SPNs) may be considered as novel functional food ingredients for soy yogurt production. Formulation of soy yogurt with SPNs and rice bran oil, which has significant physiological functions, will convert them into functional food products. This study was conducted to develop rice bran oil-based soy protein nanoparticles emulsion (SPNE) and to evaluate physical properties, antioxidant activities, oxidative stability and microbiological load as well as textural attributes of SPNs incorporated yogurt (SPNY) during storage at 4 °C for 45 days. RESULTS: SPNs were prepared from soy protein isolate of defatted soy flour. Solubilization, crystallization and ultrasonication was carried out six times. After the sixth cycle of repeated solubilizing, crystallization and ultrasonication, the size of nano protein was reduced to 72.42 ± 0.22 nm from 586.72 ± 0.75 nm (after first cycle). Viscosity, penetration values and water-holding capacity of SPNs added to yogurt were decreased with increase in reduction size of SPNs. SPNs added to yogurt exhibited greater antiradical scavenging ability and ferric reducing antioxidant property than control yogurt. Fortified soy yogurt had significant higher oxidative stability and proteolytic activity. CONCLUSION: Fortification of non-dairy food products with SPNs, which has significant physiological functions, convert conventional soy yogurt into functional food products. © 2019 Society of Chemical Industry.


Assuntos
Nanopartículas/química , Proteínas de Soja/química , Iogurte/análise , Emulsões/química , Manipulação de Alimentos , Armazenamento de Alimentos , Humanos , Oryza/química , Oxirredução , Paladar , Viscosidade
17.
J Sci Food Agric ; 99(13): 5852-5857, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31206178

RESUMO

BACKGROUND: During the industrial production of ß-glucan, a protein-rich fraction remains as a by-product. Recovery of this protein as oat protein concentrate (OPC) results in a source of cereal protein for food and improves the overall economy of the process. In this study, a yoghurt-type product is developed by lactic acid fermentation of an OPC suspension after subjection to heat treatment to assure starch gelatinization. RESULTS: In detail, the process of yoghurt production involved an initial heating step to 90 °C, followed by 24 h fermentation with a starter culture consisting of Lactobacillus delbrueckii subsp. bulgaricus und Streptococcus thermophilus. The resulting yoghurt-type product was mildly sour (pH 4.2) with a certain amount of lactic acid (3.3 ± 0.2 g kg-1 ) and contained 4.9 × 106 cfu g-1 lactobacillus after 24 h fermentation. Scanning electron microscopy revealed a porous network presumably built up from the gelatinized starch fraction containing aggregated structures, between which were assumed to be aggregated oat proteins. Moreover, to a limited extent, proteolysis occurred during fermentation. Thus some of the proteolytic enzymes present in the yoghurt culture cleaved oat protein and released peptides. However, the effect on essential amino acids was small. CONCLUSION: The results of this study provide a deeper knowledge into the role of starch and protein in fermented OPC yoghurts. The structure of fermented OPC verifies the applicability of oat protein as an alternative source for yoghurt-type products. © 2019 Society of Chemical Industry.


Assuntos
Avena/metabolismo , Aditivos Alimentares/análise , Manipulação de Alimentos/métodos , Lactobacillus delbrueckii/metabolismo , Proteínas de Plantas/análise , Streptococcus thermophilus/metabolismo , Iogurte/análise , Aminoácidos Essenciais/análise , Aminoácidos Essenciais/metabolismo , Avena/química , Avena/microbiologia , Fermentação , Aditivos Alimentares/metabolismo , Ácido Láctico/análise , Ácido Láctico/metabolismo , Proteínas de Plantas/metabolismo , Iogurte/microbiologia
18.
J Sci Food Agric ; 99(13): 5834-5841, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31206711

RESUMO

BACKGROUND: Many studies have described cocoa polyphenols as being bioactive compounds with a potential positive effect on human health. Although dark chocolate is a most powerful source of antioxidants, their content is lower in milk chocolate; conversely, in white chocolate the fat-free cocoa solids are omitted. The aim of this study was to increase polyphenol content and antioxidant capacity of white chocolate by adding encapsulated green tea extract (GTE) in amounts of 60, 80 and 100 g kg-1 . RESULTS: GTE influenced the particle size parameters, increasing the volume weighted mean from 15.43 µm in white chocolate to 19.34 µm in chocolate with 100 g kg-1 GTE. At the same time, the viscosity of enriched chocolate also increased owing to the addition of new solid particles. The surface color of enriched chocolates changed in accordance with the amount of encapsulate, where all enriched chocolates had a slightly lighter color after 12 months of storage. Total polyphenol content (mg gallic acid equivalents (GAE) kg-1 ) increased from 0.41 in white chocolate to 2.73 in chocolate enriched with maximal GTE. This amount of GTE increased antioxidant capacity (mmol Trolox equivalents kg-1 ) from 1.22 in white chocolate to 16.12. After 12 months of storage, degradation of polyphenols was found to be a maximum of 37.27%, while antioxidant capacity decreased up to 44.14%. CONCLUSION: In addition to the impact on chocolate viscosity, GTE added value through the polyphenol content and sensorial profile of the new product with an unusual green tea flavor and a shelf life of at least 12 months. © 2019 Society of Chemical Industry.


Assuntos
Cacau/química , Camellia sinensis/química , Chocolate/análise , Aditivos Alimentares/análise , Extratos Vegetais/análise , Antioxidantes/análise , Manipulação de Alimentos , Humanos , Polifenóis/análise , Paladar , Viscosidade
19.
J Sci Food Agric ; 99(13): 5994-6000, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31215047

RESUMO

BACKGROUND: Dynamic high-pressure microfluidization (DHPM) is an emerging and promising technique for continuous production of fluid foods. This study aimed to investigate the influence of DHPM and conventional homogenization (CH) on the quality of peach juice. Processing was performed by passing peach juice through CH at 20 MPa and DHPM at 20-160 MPa for one or three passes. The effect of DHPM pressure and passing number were also assessed. RESULTS: The results indicate that DHPM could maintain the antioxidant activity of peach juice much better than CH processing. Total phenolic compounds were decreased by 11.7% and 7.9%-15.8% through CH and DHPM processing in different conditions. Moreover, particle size, non-enzymatic browning index and turbidity decreased significantly under DHPM and CH processing, and decreased more and more with the increasing of DHPM pressure and treatment times. However, vitamin C content and zeta-potential did not reveal remarkable variation before and after these two types of processing. CONCLUSION: Taken together, DHPM is able to maintain the quality and stability of peach juice, which can be a reliable technological alternative to CH to produce fresh-like peach juices. © 2019 Society of Chemical Industry.


Assuntos
Manipulação de Alimentos/métodos , Sucos de Frutas e Vegetais/análise , Preparações de Plantas/química , Prunus persica/química , Manipulação de Alimentos/instrumentação , Fenóis/química , Pressão
20.
Food Chem ; 295: 432-440, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174779

RESUMO

This study examined the effects of vacuum, ethanol pretreatment, and infrared-hot air drying methods on the characteristics and quality of scallion slices. The pretreatment of scallion includes four conditions: 1) Control: soaking in distilled water under normal pressure, 2) Ethanol: soaking in 75% ethanol under normal pressure, 3) Water + VC: soaking in distilled water under a vacuum of 0.6 bar, 4) Ethanol + VC: soaking in 75% ethanol under a vacuum of 0.6 bar. The pretreatment times were 5, 10, 20 and 30 min. The drying process was done in an infrared hot air drying oven at 60 °C. The ethanol pretreated samples exhibited better rehydration, odor, vitamin C retention, bactericidal effect and significantly reduced drying time. Water + VC samples showed better scallion morphology and color. Ethanol + VC samples showed the combined advantages of ethanol and Water + VC pretreatments. Therefore, Ethanol + VC pretreatment can significantly improve the drying rate and quality of scallion.


Assuntos
Allium/química , Manipulação de Alimentos/métodos , Ácido Ascórbico/química , Cor , Dessecação/métodos , Etanol/química , Qualidade dos Alimentos , Temperatura Alta , Raios Infravermelhos , Pressão , Vácuo , Água/química
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