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1.
Food Chem ; 298: 125080, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260985

RESUMO

Propolis extract was investigated as potential substitute for sorbate in orangeade. Extract was prepared by using aqueous solution of hydroxypropyl-beta-cyclodextrins. Propolis extract was incorporated in non-carbonated orange soft drinks and its antioxidant activity, microbiological stability and color changes were estimated and compared to those of orangeade containing potassium sorbate. l-Ascorbic acid (AsA) degradation at concentrations 0.13 and 1.3% w/w was investigated in the presence of propolis during storage using High Performance Liquid Chromatography-Ion Exclusion Column (HPLC-IEC). The results indicate that the rate of degradation decreased with an increase in ascorbic acid concentration, while addition of propolis affected the degradation rate of samples containing a high AsA concentration. The antifungal effect of propolis extract, potassium sorbate and their combination was assayed. Results showed the inhibition of Aspergillus spp. and B. bruxellensis inhibited in low combined concentrations antimicrobials, while Aspergillus spp. and T. macrosporus were inhibited at 450 mg/g propolis extract.


Assuntos
Bebidas , Conservação de Alimentos/métodos , Conservantes de Alimentos/química , Própole/química , Anti-Infecciosos , Antifúngicos/farmacologia , Antioxidantes/química , Ácido Ascórbico/análise , Ácido Ascórbico/química , Aspergillus/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão/métodos , Cor , Microbiologia de Alimentos , Extratos Vegetais/química , Própole/farmacologia , Ácido Sórbico/farmacologia
2.
Food Chem ; 296: 29-39, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31202303

RESUMO

Eggs are staple food in the human diet and are consumed globally. They represent a complete food required for well-being and are recognized by consumers as versatile and wholesome with a balance of essential nutrients. However, eggs are perishable and susceptible to contamination with certain microorganisms. Past studies concluded that edible coatings have been successful to maintain the interior quality and reduce the microbial load on the eggshell surface. This paper provides an overview of the egg quality and safety and discusses the application of various types of lipid-, polysaccharide-, and protein-based edible coating systems on eggs. Edible coatings could be a viable alternative to existing techniques for maintaining the internal quality and safety of fresh eggs during long-term storage.


Assuntos
Ovos/análise , Conservação de Alimentos/métodos , Animais , Casca de Ovo/química , Casca de Ovo/microbiologia , Contaminação de Alimentos/prevenção & controle , Microbiologia de Alimentos , Humanos , Óleo Mineral/química
3.
J Sci Food Agric ; 99(13): 6032-6041, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31226218

RESUMO

BACKGROUND: In order to inhibit microorganisms and improve storage quality of fresh-cut cucumber, fresh-cut cucumber was treated by carbon dots (CDs) from kelp/chitosan (CH) coating solution with CD concentrations of 0%, 1.5%, 3% and 4.5% and then packaged as well as stored at 4 °C for 15 days. The effect of CDs/CH coating on microorganisms and the quality of modified-atmosphere-packaged fresh-cut cucumber during storage were investigated. RESULTS: The CDs was monodispersed spherical morphology with size distribution of 0.54-0.83 nm. Interaction of CDs and CH had the generation of strong hydrogen bond. Inhibition zone diameters of CDs/CH coating against Staphylococcus aureus and Escherichia coli were enhanced with the increase of CD concentrations. Moreover, CDs/CH coating inhibited the growth of total number of colonies, mold, and yeast in modified-atmosphere-packaged fresh-cut cucumber during storage. A coating of 4.5% CDs/CH effectively reduced the losses of weight, firmness, and total soluble solids, the degradation of ascorbic acid content and flavor, and inhibited peroxidases activity, as well as decreased water mobility in fresh-cut cucumber during storage. CONCLUSION: The results indicated that a CDs/CH coating was helpful for inhibiting microorganisms and improving storage quality, and could be an effective method to prolong shelf life of fresh-cut cucumber. © 2019 Society of Chemical Industry.


Assuntos
Carbono/farmacologia , Quitosana/farmacologia , Cucumis sativus/efeitos dos fármacos , Conservação de Alimentos/métodos , Conservantes de Alimentos/farmacologia , Carbono/química , Quitosana/química , Cucumis sativus/microbiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Embalagem de Alimentos , Conservação de Alimentos/instrumentação , Conservantes de Alimentos/química , Armazenamento de Alimentos , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Humanos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Paladar
4.
J Sci Food Agric ; 99(13): 6060-6065, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31226223

RESUMO

BACKGROUND: Chestnuts are gluten-free, low-fat, cholesterol-free products. Postharvest decay reduces chestnut shelf life and can cause severe economic losses. In this study we investigated the effect of ozone (O3 ) gaseous treatment on chestnut rot caused by Gnomoniopsis castanea and the quality parameters of chestnuts. RESULTS: The results showed that ozone treatment (150 ppb during the day, and 300 ppb during the night) reduced the decay of chestnuts and had a fungistatic effect on isolates of G. castanea. The exposure of chestnuts to ozone did not alter weight losses, sugar content and titratable acidity. The concentration of total phenolics decreased during the storage period, both for treated and untreated nuts. However, after 150 days of treatment the polyphenol content of the chestnuts exposed to ozone was significantly higher than in control nuts. CONCLUSIONS: Our results suggested that ozone is an appropriate and economical tool to maximize the quality of chestnut shelf life, enabling it to be stored for long periods. © 2019 Society of Chemical Industry.


Assuntos
Fagaceae/química , Conservação de Alimentos/métodos , Conservantes de Alimentos/farmacologia , Nozes/química , Ozônio/farmacologia , Ascomicetos/efeitos dos fármacos , Ascomicetos/fisiologia , Carboidratos/química , Fagaceae/microbiologia , Conservação de Alimentos/instrumentação , Conservantes de Alimentos/química , Armazenamento de Alimentos , Nozes/microbiologia , Ozônio/química , Fenóis/química , Controle de Qualidade
5.
Food Chem ; 295: 16-25, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174745

RESUMO

The instability of Laurel essential oil (LEO) and easy leakage of silver nanoparticle (AgNP) restricts their application in food field. To control their release, liposomes were used to encapsulate LEO and AgNPs (Lip-LEO-AgNPs), and mixed with chitosan to coat polyethylene (PE) films (PC-Lip/LEO/AgNPs) to package pork. The results show that only about 29.30% of LEO and 11.79% of AgNPs were released from the liposome after 7 days at 25 °C. Nevertheless, Lip-LEO-AgNPs showed good antioxidant properties. Moreover, PC-Lip/LEO/AgNPs films had good antimicrobial activity. Evaluation tests on pork indicate that PC-Lip/LEO/AgNPs films could keep the quality of pork at 4 °C for 15 days while pure PE film only kept it for 9 days, and that the coating films had no cytotoxicity. PC-Lip/LEO/AgNPs films exhibited significant combined action in functional packaging to extend storage period, and provided a new idea for the application of LEO and AgNPs in food.


Assuntos
Conservação de Alimentos/métodos , Lipossomos/química , Óleos Voláteis/química , Carne Vermelha , Sesquiterpenos/química , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Quitosana/química , Qualidade dos Alimentos , Armazenamento de Alimentos/métodos , Humanos , Lipossomos/farmacologia , Nanopartículas Metálicas/química , Óleos Voláteis/farmacologia , Tamanho da Partícula , Sesquiterpenos/farmacologia , Prata/química , Suínos , Temperatura Ambiente
6.
Food Chem ; 295: 26-35, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174758

RESUMO

Bell peppers are susceptible to chilling injury (CI). To uncover the metabolism of membrane lipid fatty acids (FAs) accompanying CI, a gas chromatography-mass spectrometry (GC-MS)-based approach was used to quantitatively profile major membrane lipid FAs in bell peppers. RT-qPCR was performed to investigate the expression of the key genes that regulate the synthesis of unsaturated FAs. Additionally, we used microstructural, organoleptic, and physicochemical investigations to monitor the primary physiological metabolism of bell peppers. The study revealed that CI symptoms mostly resulted from the destabilization of the cytomembrane, which was induced by decreasing FA desaturation. Moreover, three times lower level of the double bond index in chilled fruits, than the control, further proved that membrane FA unsaturation can be considered a key factor during CI. In conclusion, this study revealed that the metabolism of membrane lipid FAs is involved in responses to CI.


Assuntos
Capsicum/metabolismo , Ácidos Graxos/metabolismo , Conservação de Alimentos/métodos , Lipídeos de Membrana/metabolismo , Capsicum/química , Capsicum/genética , Ácidos Graxos/análise , Ácidos Graxos Insaturados/genética , Ácidos Graxos Insaturados/metabolismo , Frutas/química , Frutas/genética , Frutas/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Regulação da Expressão Gênica de Plantas , Lipoxigenase/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Temperatura Ambiente
7.
J Sci Food Agric ; 99(11): 5219-5228, 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31049967

RESUMO

BACKGROUND: The globe artichoke [Cynara cardunculus var. scolymus (L.) Fiori] is a natural source of minerals, fiber, inulin, and polyphenols. A ready-to-cook (RTC) version of this product could improve its commercialization and consumption. In this study, the effects of (i) anti-browning treatments (citric acid 0.5% + ascorbic acid 2%, or cysteine 0.5%, w/v) and (ii) dipping in locust bean gum (LBG) edible coating with or without Foeniculum vulgare essential oil (EO) were evaluated on RTC globe artichoke slices cv. 'Spinoso sardo' during storage (11 days at 4 °C). Fresh weight loss, color, texture, polyphenol oxidase (PPO), microbiological and chemical parameters, antioxidant capacity, and sensory descriptors were determined. RESULTS: The results showed that, despite the antioxidant treatment used, when EO was added to LBG, all microbiological groups underwent an average reduction of 0.50 log CFU g-1 . Cysteine preserved the antioxidant capacity, color, and texture of samples better than citric acid and ascorbic acid, and inhibited PPO; the addition of EO to LBG enhanced these effects. At the end of the storage period, the overall highest sensory attribute score was attained by the coated globe artichoke samples with EO. CONCLUSION: The marked efficacy of the LBG edible coating with added F. vulgare EO in maintaining microbiological, physical, chemical, and sensory qualities makes it a promising processing tool for the preservation of ready-to-cook Spinoso sardo globe artichoke slices during storage for 11 days at 4 °C. © 2019 Society of Chemical Industry.


Assuntos
Cynara scolymus/química , Fast Foods/análise , Foeniculum/química , Aditivos Alimentares/análise , Conservação de Alimentos/métodos , Óleos Voláteis/análise , Óleos Vegetais/análise , Cor , Culinária , Conservação de Alimentos/instrumentação , Humanos , Polifenóis/análise , Paladar
8.
Int J Food Microbiol ; 301: 9-18, 2019 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-31055161

RESUMO

A large amount of GRAS (generally recognized as safe) salts and concentrations were evaluated in in vitro tests (inhibition of mycelial growth on PDA dishes) against Lasiodiplodia theobromae, the causal agent of citrus Diplodia stem-end rot. Ammonium carbonate (AC, 0.2%), potassium sorbate (PS, 2.0%), potassium carbonate (PC, 0.2%), sodium methylparaben (SMP, 0.1%), sodium ethylparaben (SEP, 0.1%), sodium benzoate (SB, 2.0%), and potassium silicate (PSi, 2.0%) were selected as the most effective. Disease control ability of edible composite coatings formulated with hydroxypropyl methylcellulose (HPMC), beeswax (BW), and these selected antifungal GRAS salts was assessed in in vivo experiments with 'Ortanique' mandarins and 'Barnfield' oranges artificially inoculated with L. theobromae. Coatings containing 2% PS, 0.1% SEP, or 2% SB were the most effective reducing disease severity (up to 50% reduction) and were also applied to non-inoculated and cold-stored 'Barnfield' oranges to determine their effect on postharvest fruit quality. After periods of 21 and 42 d at 5 °C followed by 7 d of shelf life at 20 °C, coatings containing SEP and SB significantly reduced weight loss and did not adversely affect the physicochemical quality attributes (firmness, soluble solid content, titratable acidity, and ethanol and acetaldehyde content) and sensory flavor with respect to uncoated control fruit. Although the internal gas concentration (CO2 level) of coated fruit increased, the coatings did not induce off-flavors.


Assuntos
Ascomicetos/efeitos dos fármacos , Citrus/microbiologia , Microbiologia de Alimentos/métodos , Conservação de Alimentos/métodos , Derivados da Hipromelose/farmacologia , Sais/farmacologia , Antifúngicos/farmacologia , Frutas/microbiologia , Lipídeos/química , Lipídeos/farmacologia
9.
J Food Sci ; 84(6): 1547-1553, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31107547

RESUMO

Frozen storage of lobster meat (Homarus americanus) can result in undesirable quality changes that decrease consumer acceptability of these products. Current seafood industry methods use cryoprotective agents that contain phosphates including sodium tripolyphosphates (STPP). However, recent evidence suggests that cryoprotective mixtures that combine different carbohydrates and STPP can have equal or even greater cryoprotective properties compared to using STPP alone. The objective of this study was to compare the overall consumer acceptability of lobster meat stored for 6 months in different blends of these cryoprotective solutions. One hundred and seven panelists were recruited to score the acceptability of the lobster samples using nine-point hedonic scales. A check-all-that-apply (CATA) question containing 27 literature-informed, sensory descriptors was also used to identify terms frequently used to describe lobster meat. Analysis of variance analysis, indicated a significant increase for overall liking (22.1%, P < 0.0001), liking of flavor (23.6%, P < 0.0001) and texture (15.6%, P = 0.000) scores for samples stored in a novel carbohydrate blend plus sodium chloride (NaCl) and STPP compared to the water control. Subsequent penalty analysis revealed that overall liking scores were most positively associated with the attributes tender, sweet, moist and soft. Moreover, the attributes with the highest positive mean impact were more frequently used to describe lobster samples stored in solutions containing NaCl and the novel carbohydrate blend, as well as NaCl and STPP (Lobster-3 and Lobster-5 samples, respectively). PRACTICAL APPLICATION: The positive impact on the sensory quality of this novel blend of cryoprotective compounds (carbohydrates and NaCl) is proof of concept that this mixture is comparable, if not better than preservatives currently used by the seafood industry. Given the necessary regulatory approval and industry acceptance, lobster processors may consider this novel blend as a suitable alternative to freeze lobster products for up to 6 months.


Assuntos
Crioprotetores/farmacologia , Conservação de Alimentos/métodos , Conservantes de Alimentos/farmacologia , Nephropidae/química , Frutos do Mar/análise , Animais , Aromatizantes/química , Conservação de Alimentos/instrumentação , Congelamento , Humanos , Carne/análise , Nephropidae/efeitos dos fármacos , Polifosfatos/farmacologia , Cloreto de Sódio/farmacologia , Paladar
10.
J Food Sci ; 84(6): 1288-1296, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31120570

RESUMO

The preservation effects of tartary buckwheat extract (T) and chitosan (C) coatings on the physicochemical (pH value, thiobarbituric acid value, Peroxide value (PV), total volatile basic nitrogen (TVB-N), K value, surface color and the texture profiles), bacteriological (total viable counts (TVC) and psychrotrophic bacteria counts (PBC)), and sensory characteristics of tilapia (Oreochromis niloticus) fillets storage at 0 °C for 18 days were evaluated. The fillets coated with 0.5% T + 1.0% C, 1.0% T + 1.0% C and 1.5% T + 1.0% C maintained better quality and had longer shelf life with respect to samples coated with chitosan alone and the control. Base on the limit values of TVB-N, K value, TVC and sensory preference scores, the shelf life of control fillets was 6 days. By contrast, shelf life of 9 days for 0.5% T + 1.0% C-coated fillets, 12 days for 1.0% T + 1.0% C treated-fillets, and 15 days for 1.5% T + 1.0% C-treated fillets were obtained. Therefore, TBE combined with chitosan coatings have the potential to extend the shelf life of tilapia fillets during storage at 0 °C. PRACTICAL APPLICATION: This study provides basic theory regarding the application of TBE to fish preservation. The edible coating of TBE combined with chitosan has potential use in developing activity food preservation coating.


Assuntos
Quitosana/química , Fagopyrum/química , Produtos Pesqueiros/análise , Conservação de Alimentos/métodos , Conservantes de Alimentos/química , Extratos Vegetais/química , Animais , Ciclídeos , Cor , Conservação de Alimentos/instrumentação , Armazenamento de Alimentos , Humanos , Paladar
11.
J Sci Food Agric ; 99(12): 5417-5423, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31077387

RESUMO

BACKGROUND: Smoked fish is a major source of animal protein in developing countries. It is largely produced by hot-smoking on traditional kilns using fuelwood. This practice is associated with high polycyclic aromatic hydrocarbon (PAH) contamination in products, with consequences for public health. An improved kiln, comprising the FAO-Thiaroye Technique (FTT), has been introduced by the Food and Agriculture Organization of the United Nations to address such a concern. The present study investigated the efficacy of the FTT in Ghana through comparative fish smoking experiments with traditional kilns followed by determination of PAH levels [benzo(a)pyrene (BaP) and PAH4] in the products by gas chromatography-mass spectrometry. For each kiln, the effect of smoking fuel type on PAH contamination was determined. The impact of the design characteristics of the FTT on the levels of the compounds was also determined. RESULTS: Mean BaP and PAH4 levels in the FTT products were up to 1.8 and 7.6 µg kg-1 , respectively, whereas the corresponding levels in traditional kiln products were up to 70 and 395 µg kg-1 . PAH levels in FTT products were below European Union regulatory limits, whereas levels in traditional kiln products exceed such limits by up to 33-fold. Across kiln types, the use of wood fuels caused higher PAH contamination compared to the use of fully-lit charcoal as an alternative fuel. CONCLUSION: The improved kiln (FTT) is efficacious in yielding smoked fish with a PAH content lower than the levels in traditional kiln products and also below current regulatory limits. Kiln design and type of processing fuel have significant impacts on PAH contamination during fish smoking. © 2019 Society of Chemical Industry.


Assuntos
Produtos Pesqueiros/análise , Contaminação de Alimentos/análise , Conservação de Alimentos/métodos , Hidrocarbonetos Policíclicos Aromáticos/análise , Animais , Benzo(a)pireno/análise , Carvão Vegetal/efeitos adversos , Carvão Vegetal/análise , Contaminação de Alimentos/prevenção & controle , Conservação de Alimentos/instrumentação , Cromatografia Gasosa-Espectrometria de Massas , Gana , Madeira/efeitos adversos , Madeira/química
12.
Carbohydr Polym ; 217: 126-134, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31079668

RESUMO

Longan pulp is an excellent source of polysaccharides and other nutrients that have many health benefits. However, longans is susceptible to pulp breakdown after harvest and loses its nutrition values. To solve this problem, this study aimed to study the effects of a novel chitosan, Kadozan, on pulp breakdown index, contents of pectin, cellulose and hemicelluloses, and activities of enzymes in longan pulp relating to disassembly of polysaccharides (XET, PE, PG, ß-Gal, and cellulase). The data illustrated that, compared to the control longans, chitosan-treated longans contained higher amounts of CWM, CSP, ISP, cellulose and hemicelluloses, but exhibited lower pulp breakdown index, lower activities of cell wall-disassembling enzymes, and contained lower WSP amount. These results suggested that Kadozan with a dilution of 1:500 (VKadozan: VKadozan + Water) could significantly decrease activities of disassembling-enzymes and depolymerization of polysaccharides in cell wall, and subsequently alleviate pulp breakdown and prolong storage-life of postharvest longans.


Assuntos
Parede Celular/efeitos dos fármacos , Quitosana/farmacologia , Inibidores Enzimáticos/farmacologia , Frutas/metabolismo , Polissacarídeos/metabolismo , Sapindaceae/metabolismo , Parede Celular/metabolismo , Celulose/metabolismo , Conservação de Alimentos/métodos , Qualidade dos Alimentos , Glicosídeo Hidrolases/antagonistas & inibidores , Hidrólise/efeitos dos fármacos , Pectinas/metabolismo
13.
Molecules ; 24(9)2019 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-31052263

RESUMO

Edible coatings and films (ECF) are employed as matrixes for incorporating antimicrobial nanoparticles (NPs), and then they are applied on the fruits and vegetables to prolong shelf life and enhance storage quality. This paper provides a comprehensive review on the preparation, antimicrobial properties and mechanisms, surface and physical qualities of ECF containing antimicrobial NPs, and its efficient application to vegetables and fruits as well. Following an introduction on the properties of the main edible coating materials, the preparation technologies of ECF with NPs are summarized. The antimicrobial activity of ECF with NPs against the tested microorganism was observed by many researchers. This might be mainly due to the electrostatic interaction between the cationic polymer or free metal ions and the charged cell membrane, the photocatalytic reaction of NPs, the detachment of free metal ion, and partly due to the antimicrobial activity of edible materials. Moreover, their physical, mechanical and releasing properties are discussed in detail, which might be influenced by the concentration of NPs. The preservation potential on the quality of fruits and vegetables indicates that various ECF with NPs might be used as the ideal materials for food application. Following the introduction on these characteristics, an attempt is made to predict future trends in this field.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologia , Conservação de Alimentos , Frutas , Nanopartículas/química , Verduras , Fenômenos Químicos , Quitosana , Embalagem de Alimentos , Conservação de Alimentos/métodos , Conservantes de Alimentos , Fenômenos Mecânicos , Estrutura Molecular
14.
Meat Sci ; 155: 16-19, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31055229

RESUMO

The combined effect of temperature, water activity (aw) and NaCl content, usually found in dry-cured ham, on the growth and expression of the virulence and stress-related genes of Listeria monocytogenes was evaluated in a dry-cured ham model system. The highest growth of this pathogen was observed at 15 °C and, at 0.98 and 0.96 aw values. At 0.94 and 0.92 aw values, moderate NaCl levels stimulated the L. monocytogenes growth and repressed the expression of the four tested genes. At 7 °C, the expression of the plcA gene was favored while at 15 °C the hly and iap genes were activated. Preventive actions based on temperature, aw and salt content should be taken to minimise risks associated with growth and gene expression of L. monocytogenes in dry-cured ham.


Assuntos
Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Listeria monocytogenes/efeitos dos fármacos , Listeria monocytogenes/crescimento & desenvolvimento , Listeria monocytogenes/metabolismo , Produtos da Carne/microbiologia , Cloreto de Sódio/farmacologia , Animais , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Listeria monocytogenes/genética , Suínos , Temperatura Ambiente , Virulência/genética , Água
15.
J Food Sci ; 84(6): 1400-1410, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31132154

RESUMO

Retrogradation affects acceptability of starchy foods; however, it is preferred in some products such as rice noodles. Amylose content, gelatinization temperature, and storage condition were reported to affect retrogradation but with disputed data. The joint effects of these parameters were interested in this study. Rice starch was gelatinized using different temperatures (77, 81, 95, and 121 °C) and stored isothermally with temperature cycles for 10 days. Results showed that the most important parameter that affected retrogradation was storage time followed by storage condition and gelatinization temperature. The recrystallization rate constant (k) and Avrami exponent (n) of retrograded starches stored under temperature cycle were higher than isothermal storage. All samples showed similar polymorphs of a mixture of B and V types. High-temperature gelatinized starch gel stored under temperature cycle condition produced higher yield of resistant starch. The study provided useful information on how to apply these parameters to control the retrogradation of starchy foods, especially rice noodle. PRACTICAL APPLICATION: Retrogradation is found to be more prominent at higher gelatinization temperature and longer storage time. Resistant starch produced from retrograded starch depended largely on storage time than storage condition. This finding can be applied to improve rice noodle qualities (by increasing retrogradation) with lower digestibility (by producing higher resistant starch).


Assuntos
Conservação de Alimentos/métodos , Armazenamento de Alimentos , Temperatura Alta , Oryza/química , Amido/química , Amilose/química , Cristalização , Digestão , Gelatina , Géis/química , Humanos , Temperatura Ambiente
16.
Ultrason Sonochem ; 55: 369-382, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31027999

RESUMO

High intensity ultrasound (HIU) offers an alternative to traditional methods of food preservation, and is regarded as a green and promising emerging technology. Ultrasound generates acoustic cavitation in a liquid medium, developing physical forces that are considered the main mechanism responsible for changes in exposed materials. In meat, ultrasound has been successfully used to improve processes such as mass transfer and marination, tenderization of meat and inactivation of microorganisms. It is also an alternative to traditional meat ageing methods for improving the quality properties of meat. Moreover, the combination of ultrasonic energy with a sanitizing agent can improve the effect of microbial reduction in foods. This review describes recent potential applications of ultrasound in meat systems, as well as physical and chemical effects of ultrasound treatment on the conservation and modification of processed meat foods. Finally, the ultrasound application parameters must be deep explored and established before the method can be scaled to industrial levels.


Assuntos
Conservação de Alimentos/métodos , Qualidade dos Alimentos , Carne , Ondas Ultrassônicas , Animais , Humanos
17.
J Food Sci ; 84(4): 798-806, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30977919

RESUMO

The effect of dipping and vacuum impregnation (VI) pretreatments with lemon juice solution on the quality and stability of organic and conventional frozen apples was investigated. Fresh apples were characterized; organic apples showed, at equal starch and ripeness index, a lower sugar content, and higher acidity than conventional ones. The polyphenol content was slightly higher in organic apples than in conventional ones while polyphenoloxidase activity was similar. No differences in color and firmness were evidenced. Dipping affected organic and conventional apples' color by determining an increase of lightness (ΔL* ≈ 4) and h° (Δh° ≈ 6) parameters. VI reduced the lightness of apples (ΔL* ≈ -3) but the addition of lemon juice counterbalanced the lightness reduction by increasing ΔL* from 3 to 1.5 ca. Pretreatments did not affect the firmness of organic fruits while impaired that of the conventional ones ( 26% on average), likely due to different fruit matrix porosity and cell wall composition. Freezing (-40 °C) and frozen storage (up to 300 days) dramatically reduced the firmness of organic (42%) and conventional products (58%). At equal pretreatment and storage time (that is, 15, 30, 300 days), higher firmness retention was evidenced in organic apples than in conventional ones. All through frozen storage, VI was shown to better preserve the mechanical properties of organic apples than that of conventional ones. Both freezing and frozen storage reduced the hue of frozen apple products by up to 8% due to browning reactions. Lemon juice addition increased the hue of both frozen samples and thawed samples by about 2% all through storage time.


Assuntos
Conservação de Alimentos , Alimentos Orgânicos/análise , Frutas , Malus/química , Conservação de Alimentos/métodos , Conservação de Alimentos/normas , Frutas/química , Frutas/normas , Vácuo
18.
Molecules ; 24(7)2019 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-30974792

RESUMO

In this study, we fabricated polyvinyl alcohol (PVA)/chitosan (CS) bilayer films by casting and investigated the effects of preparation conditions and CS content (2, 2.5, or 3 wt.%) on the ability of these films to preserve packaged strawberries. The best performance was achieved at a CS loading of 2.5 wt.% (ultrasound time, 25 min); the strain and stress values were 143.15 ± 6.43% and 70.67 ± 0.85 MPa, respectively, oxygen permeability was 0.16 ± 0.08 cm²·m²·day-1·MPa-1, water vapor permeability was 14.93 ± 4.09 g·cm-1·s-1·Pa-1, and the shelf life of fresh strawberries packaged in the PVA/CS 2.5 wt.% bilayer film was determined to be 21 days at 5 ± 2 °C and a relative humidity of 60 ± 5%. Treatment with PVA/CS bilayer films prevented the decrease in the firmness of strawberries during storage (21 days). The evaluated physicochemical parameters (weight loss, decay, firmness, titratable acidity, soluble solid content, ascorbic acid content, and color) indicated that treatment with PVA/CS bilayer films led to better maintenance of the fruit quality. We believe that our study makes a significant contribution to literature because it paves the way to the fabrication of smart packaging materials and facilitates the commercialization of fresh strawberries as an important health food.


Assuntos
Quitosana/química , Conservação de Alimentos/métodos , Frutas , Membranas Artificiais , Álcool de Polivinil/química , Ondas Ultrassônicas , Fragaria
19.
Food Chem ; 290: 144-151, 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31000030

RESUMO

Guavas are tropical climacteric fruit with a short postharvest shelf life at room temperature. This study aims to extend the shelf life of red guavas 'Pedro Sato' using edible coatings of hydroxypropyl methylcellulose (HPMC) and beeswax (BW) at concentrations of 10%, 20%, and 40% (dry basis). Coated and uncoated guavas were stored for 8 days at 21 °C and assessed every 2 days. The HPMC + BW produced a modified atmosphere around the fruit, delaying ripening process. The coatings reduced loss of mass, maintained green color, and increased firmness compared to the control fruit. The uncoated fruit had 6 days of shelf life. The treatment with HPMC + 20% BW provided the best maintenance of fruit quality. On the eighth day, fruit with this coating showed the same physicochemical characteristics of control fruit in the second day of storage, which represents a gain of 6 days in the shelf life of guavas 'Pedro Sato'.


Assuntos
Conservação de Alimentos/métodos , Derivados da Hipromelose/química , Derivados da Hipromelose/farmacologia , Psidium/efeitos dos fármacos , Ceras/química , Cor , Relação Dose-Resposta a Droga , Qualidade dos Alimentos , Frutas/efeitos dos fármacos , Frutas/metabolismo , Psidium/metabolismo
20.
J Food Sci ; 84(5): 971-979, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30990890

RESUMO

To enhance the oxidative stability of organogels made from canola oil, 40 ppm sesamol was added to beeswax-based organogels stored under ultraviolet (UV) light irradiation and 60 or 100 °C thermal oxidation conditions. To study the practical application of organogels as animal fat substitutes, beef tallow was mixed with organogels and their oxidative stability was determined under oxidative stress conditions. Without sesamol addition, the organogels and beef tallow with organogel oxidized rapidly under UV irradiation and thermal oxidation. The addition of 40-ppm sesamol decreased the consumption of headspace oxygen and the formation of primary and secondary oxidation products significantly (P < 0.05) compared with those in samples without the addition of sesamol, irrespective of oxidative stress. Sesamol improved the oxidative stability of organogels and beef tallow with organogel, which could be used in the meat industry. PRACTICAL APPLICATION: Organogels may replace trans-fat or highly saturated lipids in food products. The high degree of unsaturation and processing temperature mean that antioxidants are needed to extend the shelf life of organogels or organogel-containing products. The addition of sesamol significantly enhanced the oxidative stability of organogels and of beef tallow-containing organogels under UV irradiation and thermal oxidation conditions. Therefore, sesamol-supplemented organogels could replace saturated fats in beef tallow and prolong the shelf-life of meat products.


Assuntos
Benzodioxóis , Gorduras/metabolismo , Conservação de Alimentos/métodos , Produtos da Carne/análise , Estresse Oxidativo , Fenóis , Óleo de Brassica napus/metabolismo , Ceras , Animais , Antioxidantes , Bovinos , Substitutos da Gordura/metabolismo , Substitutos da Gordura/efeitos da radiação , Gorduras/efeitos da radiação , Ácidos Graxos/metabolismo , Ácidos Graxos/efeitos da radiação , Manipulação de Alimentos/métodos , Armazenamento de Alimentos , Géis , Temperatura Alta , Humanos , Carne/análise , Produtos da Carne/efeitos da radiação , Oxirredução , Óleo de Brassica napus/efeitos da radiação , Raios Ultravioleta
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