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1.
Foods ; 10(11)2021 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-34828886

RESUMO

The paper presents water diffusion coefficients as providing a significant contribution to the creation of a comprehensive database and knowledge of weight variation during the drying process of raw plant materials that is used for modelling the technological process and designing innovative products. Dehydration is one of the most widely used methods for improving the stability and durability of fruit and vegetables because it reduces water activity and microbial activity, and minimises the physical and chemical changes during storage. The considerable impact of pressure on heat exchange and weight during the convection drying process of osmotically pretreated apples is demonstrated. The course of the drying curves and the drying rate is determined by the use of pressures of 0.02 and 500 MPa. Varied pressure applied during osmotic impregnation significantly influences the value of the diffusion coefficient: the average determined for the entire course of the drying curve and the average determined in the intervals of the reduced water content. The lowest values of the average water diffusion coefficient are obtained for apples preboiled under overpressure conditions and, at the same time, the determined diffusion coefficients in the water content are characterised on the drying curve by a clearly decreasing course until the reduced water content reaches approximately 0.2.

2.
Molecules ; 25(23)2020 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-33276446

RESUMO

The visible trend in the development of the snack market focuses on the use of innovative technologies such as low-temperature or hybrid processes that allow the preservation of native ingredients of raw plant materials. In addition, the high antioxidant potential of, for example, chokeberry fruit can be used to support technological processes and create new products. The aim of the study was to evaluate the possibility of using chokeberry juice concentrate as a component of an osmotic solution to enrich apple samples with natural bio-ingredients and obtain dried apples with increased content of ingredients with antioxidant properties; pro-healthy apple chips. The research material consisted of apples that underwent osmotic dehydration in solutions of sucrose or sucrose and chokeberry juice concentrate and then were dried by the freeze-drying or the hybrid method. The freeze-drying was more beneficial for maintaining the vitamin C content, while the use of the hybrid method resulted in the preservation of more polyphenolic compounds. The sensory evaluation indicated the need to modify the composition of the osmoactive solution. Due to the use of chokeberry juice concentrate, the content of vitamin C, polyphenols, and the antioxidant activity of dried apples was increased.


Assuntos
Antioxidantes/análise , Manipulação de Alimentos/métodos , Sucos de Frutas e Vegetais/análise , Malus/química , Photinia/química , Extratos Vegetais/química , Ácido Ascórbico/análise , Convecção , Dessecação , Liofilização , Frutas/química , Micro-Ondas , Osmose , Polifenóis/análise , Vácuo
3.
Molecules ; 25(23)2020 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-33255419

RESUMO

Japanese quince has high health value, but due to its taste and texture, it is difficult to eat raw. The use of innovative drying methods to produce dried snack foods from these fruits may be of interest to producers and consumers. The physicochemical and sensory properties of 3 mm slices of Japanese quince fruit (with skin, without seeds) obtained by osmotic pre-treatment in chokeberry and apple juice concentrates, and with the use of convection (convective drying, C-D), freeze-drying (F-D), and convection-microwave-vacuum drying (hybrid) are assessed. The methods of drying osmo-dehydrated slices do not affect the dry matter content. In most dried quince, the water activity is 0.40 or lower. Pre-osmotic dehydration and drying have a significant impact on the mechanical and acoustic properties of quince chips. Sensory attractive chips emit loud acoustic emission (AE) during the breaking test. Chips that are osmo-dehydrated in a mixture of chokeberry juice concentrate and sucrose and dried by a hybrid method are attractive. They have a dark red color given by chokeberry concentrate and a slight sweet (with a slight sour-bitter) taste. The sensory evaluation was useful for determining the quality of the chips in terms of their texture (crispness) tested by mechanical methods. Their sensory ratings (overall desirability as weight of color, taste, crispness, and flavor) are high and similar (from 3.8 to 4.1). The use of innovative drying methods with pre-osmotic treatment allows obtaining dried material with properties comparable to those obtained by the F-D method, but in a much shorter time, i.e., with lower energy and using a simple method.


Assuntos
Fenômenos Químicos , Análise de Alimentos , Manipulação de Alimentos/métodos , Sucos de Frutas e Vegetais , Rosaceae/química , Lanches , Paladar , Análise de Alimentos/métodos , Sucos de Frutas e Vegetais/análise
4.
Molecules ; 25(21)2020 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-33167405

RESUMO

In this study, the impacts of two different pear cultivars, "Conference" and "Alexander Lucas", on the kinetics and the final quality of samples dried by convection (CD) and microwave-convection (MCD) methods, were investigated. The quality of dried material was evaluated by the analysis of water activity, porosity, color, acoustic emission (AE) and mechanical and sensory properties. The required drying time to obtain 0.2 kg H2O/kg dry solid (d.s.) was longer for "Conference" than "Alexander Lucas" and was 20 min by CD and 5 min by MCD. The pear cultivar, in conjunction with the drying method (CD or MCD), affected the number of AE events and the work of breaking. The CD pear of the "Conference" cultivar was characterized by higher force, higher breaking work and stronger AE relative to the CD pear of the "Alexander Lucas" cultivar. There were no differences in taste or overall quality, but the hardness was higher for the CD "Conference" pear. A principal component analysis showed that panelists preferred dried fruit with good taste and overall quality but lower hardness. A positive correlation was found between the number of acoustic events and sensory hardness; thus, an acoustic method can be useful for effectively evaluating the texture of dried pears. These results show that the dried pear slices that generated fewer AE events upon breaking were perceived as better by the panelists.


Assuntos
Análise de Alimentos/métodos , Manipulação de Alimentos/métodos , Conservação de Alimentos/métodos , Liofilização , Frutas/química , Pyrus/química , Acústica , Cor , Dessecação , Dureza , Cinética , Micro-Ondas , Fenóis/análise , Porosidade , Análise de Componente Principal , Estresse Mecânico , Paladar , Água/química
5.
J Food Sci Technol ; 57(1): 350-363, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31975738

RESUMO

Volatile aromatic substances are the main factors contributing to the acceptability of cocoa products. The beneficial effect of fat-free ingredients of cocoa beans on human health has been scientifically proven. This encourages the consumption of cocoa products as well as further research on improving their processing technology. The aim of this study was to analyse changes in the composition of volatile compounds and their impact on the sensory characteristics of an agglomerated cocoa powder mixture with modified composition for the raw material. The basic mixture was composed of 20% cocoa and 80% sucrose. Changes in mixture composition involved partial or total replacement of sucrose with maltodextrin or a mixture of glucose and fructose. Mixing and agglomeration were carried out in a fluid bed agglomerator. The analysis of volatile compounds was carried out using a gas chromatograph coupled with mass spectrometer, and 1,2-dichlorobenzene was used as an internal standard. The analysis showed the presence of over 70 various chemical compounds. Such volatile compounds as acetic acid, 2,3-butanediol, nonanal, and pentanoic acid, were found in almost all tested products. The highest content of acetic acid was determined in cocoa powder. In the case of the investigated cocoa beverages, the raw material composition and agglomeration affected their volatile compounds content. The analyses demonstrated a reduction in the content of volatile compounds caused by agglomeration.

6.
Int J Mol Sci ; 20(9)2019 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-31064114

RESUMO

In order to extend the shelf life of the fruit, improve appearance, and to keep all nutrition properties of the plum from diminishing, edible coatings comprised of wheat starch and wheat starch-whey protein isolate (in ratio 80/20) were created. Stand-alone films were produced to assess properties which helped to understand the phenomena occurring on the surface level of coated plums. The properties of coatings based on starch are similar to starch coatings containing oil because the natural epicuticular wax layer of plums merges with coating materials. Adding oil doubled the contact angle value and the dispersive component of the surface tension. The workings of adhesion and cohesion, spreading coefficient, water absorption, water content, and solubility in water of the films decreased. Similar processes were observed on the fruits' surface. In appearance, the coating process is similar to polishing the plum surface for removing crystalline wax. The color parameters of coated fruits did not significantly change. Newly formed bonds or interactions established between starch, whey proteins, water, glycerol, and oil are displayed by Fourier transform infrared (FTIR) analysis. This work revealed how the interactions between the epicuticular wax on the fruit's surface and the hydrocolloid-based coatings affect the efficiency of the coatings.


Assuntos
Conservantes de Alimentos/química , Frutas/efeitos dos fármacos , Prunus domestica/efeitos dos fármacos , Conservantes de Alimentos/farmacologia , Frutas/química , Glicerol/química , Espectroscopia de Infravermelho com Transformada de Fourier , Amido/química , Tensão Superficial , Ceras/química , Molhabilidade , Proteínas do Soro do Leite/química
7.
J Food Sci Technol ; 56(4): 1927-1938, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30996428

RESUMO

Osmotic dehydration (OD) of apples caused a reduction of normalized water content (NWC) and an increase of normalized solids gain (NSG), independently of the kind of osmotic solution. The use of 22°Brix osmotic solutions with the addition of fruit concentrates or bilberry extract resulted in only slight reduction in the NWC in the samples, i.e. by about 15 and 20%, respectively after 6 and 24 h, against a value up to 80% in case of 65°Brix use. Similarly, larger NSG was achieved at higher solution concentrations, but the differences were smaller. In the case of the use of 80% bilberry press cake extract the NSG was very low but NWC was relatively high. Such a low concentration of slightly concentrated fruit juices is not effective for dehydration of apples, but it may be sufficient to enrich the fruit with the desired colorants. This higher concentration of osmotic solution and a larger addition, especially of the concentrate of chokeberry juice, significantly affected the color changes of dehydrated apples. The apple dehydrated in mixture of 65°Brix sucrose and 15% chokeberry juice concentrate solution exhibited the highest sensory parameters. The addition of berry fruit juices and extract was able to improve the apple sensory quality after 24 h OD in comparison with sucrose solution. Ethanol extract was a good osmotic agent, but not accepted due to taste and overall quality. However, the addition of the extract can be successfully used in conjunction with a sugar solution.

8.
Food Sci Biotechnol ; 27(3): 799-807, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29937683

RESUMO

The purpose of this study was to determine the possibility of using a chokeberry juice concentrate as a component of osmotic solution and convection-microwave-vacuum drying applying to obtain dried pro-health-promoting strawberries. The research material was Honeoye strawberries, which were dehydrated in sucrose and sucrose with chokeberry juice concentrate addition, and then subjected to microwave-convection-vacuum or freeze-drying. Analyses were conducted to determine the influence of the applied processes on vitamin C content, total polyphenols, antioxidant activity, and sensory properties in dried fruit. Study results confirmed the possibility of using a chokeberry juice concentrate as a component of the osmotic solution, especially with regard to polyphenolics content and antioxidant activity. In addition, convection-microwave-vacuum drying was shown to be a promising technology for the production of dried strawberries, with high pro-health potential and acceptable sensory qualities.

9.
Polymers (Basel) ; 10(4)2018 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-30966447

RESUMO

As starch is an inexpensive, filmogenic, easily processable and a widely available material, it is a material that can be utilized in the creation of biodegradable films and containers, presenting as a viable alternative to polymers derived from petrol. Moreover, starch could also be used to create edible coatings for fresh foods in order to extend shelf life. As such, wheat starch films with two glycerol contents were formulated to mimic the effects of compounds currently used to coat fruit. Their structural and functional properties were characterized. This study found that the transfer properties of starch films containing 33% of plasticizer was less effective than film comprised of 50% glycerol. Water diffusivity, oxygen permeability, and water vapor permeability at two different humidity gradients, surface tension, works of surface adhesion and cohesion, and moisture sorption were tested. Glycerol content does not play a significant role on the color or mechanical properties. This work shows that glycerol can strongly affect the functional properties of starch-based coatings and films.

10.
J Texture Stud ; 48(2): 131-142, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28370113

RESUMO

The influence of the structure formed by the type of hydrocolloids (low-methoxyl pectin, the mixture of xanthan gum, and locust bean gum, and mixture of xanthan gum, and guar gum) and the aeration time (3, 5, 7, and 9 min) on textural properties of freeze-dried gels were investigated. The hardest texture generating the strongest acoustic emission was obtained by freeze-dried pectin gel, characterised by the lowest porosity and the largest pore diameter. Aeration time significantly affected mechanical and acoustic properties of the pectin gel lyophilisate. No effect of gel aeration time on tested characteristics of samples with mixture of hydrocolloids was observed. Strong positive correlations between acoustic energy as well as the maximum force and work and negative ones between porosity and pore diameter indicate that greater resilience and stronger acoustic emission of freeze-dried gels was caused by the reduction of porosity and the increase in the pore size of the material. PRACTICAL APPLICATIONS: The research is expected to show the phenomenon of structure formation when preparing and freeze-drying gels and explain the influence of the process parameters (time of aeration, the type of hydrocolloids) on the formation of the internal structure and physical properties of a dried product, especially mechanical and acoustic properties. This achievement will contribute to the development of the science of food and human nutrition, especially within the context of the popular research on aerated diet products. The expected result will be the ability to develop a new technology for producing food with a delicate texture, using the phenomenon of sublimation. As a result, designing changes in the structure of freeze-dried fruit gels with a delicate structure will be possible due to the choice of ingredients and aeration parameters in order to develop innovative food characterised by favorable nutritional, health and functional properties, which will be attractive for the consumers.


Assuntos
Acústica , Coloides/química , Liofilização , Géis/química , Fenômenos Mecânicos , Aditivos Alimentares/química , Dureza , Tamanho da Partícula , Gomas Vegetais/química , Porosidade
11.
Int J Biol Macromol ; 98: 348-356, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28137462

RESUMO

Food preservation is mostly related to packaging in oil-based plastics, inducing environmental problems, but this drawback could be limited by using edible/biodegradable films and coatings. Physical and chemical properties were assessed and reflect the role of the starch type (wheat, corn or potato) and thus that of the amylose/amylopectin ratio, which influences thickness, colour, moisture, wettability, thermal, surface and mechanical properties. Higher amylose content in films induces higher moisture sensitivity, and thus affects the mechanical and barrier properties. Films made from potato starch constitute a greater barrier for oxygen and water vapour though they have weaker mechanical properties than wheat and corn starch films. Starch species with higher amylose content have lower wettability properties, and better mechanical resistance, which strongly depends on the water content due to the hydrophilic nature of starch films, so they could be used for products with higher water activity, such as cheese, fruits and vegetables. It especially concerns wheat starch systems, and the contact angle indicates less hydrophilic surfaces (above 90°) than those of corn and potato starch films (below 90°). The starch origin influences optical properties and thickness: with more amylose, films are opalescent and thicker; with less, they are transparent and thinner.


Assuntos
Fenômenos Químicos , Conservação de Alimentos/métodos , Amido/química , Amilopectina/análise , Amilose/análise , Fenômenos Mecânicos , Fenômenos Ópticos , Oxigênio/química , Permeabilidade , Vapor , Temperatura , Molhabilidade
12.
J Sci Food Agric ; 97(3): 858-867, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27197704

RESUMO

BACKGROUND: Starch and whey protein isolate and their mixtures were used for making edible films. Moisture sorption isotherms, water vapour permeability, sorption of aroma compounds, microstructure, water contact angle and surface properties were investigated. RESULTS: With increasing protein content, the microstructure changes became more homogeneous. The water vapour permeability increases with both the humidity gradient and the starch content. For all films, the hygroscopicity increases with starch content. Surface properties change according to the starch/whey protein ratio and are mainly related to the polar component of the surface tension. Films composed of 80% starch and 20% whey proteins have more hydrophobic surfaces than the other films due to specific interactions. CONCLUSIONS: The effect of carbohydrate/protein ratio significantly influences the microstructure, the surface wettability and the barrier properties of wheat starch-whey protein blend films. © 2016 Society of Chemical Industry.


Assuntos
Carboidratos da Dieta/análise , Proteínas na Dieta/química , Embalagem de Alimentos , Sementes/química , Amido/química , Triticum/química , Proteínas do Soro do Leite/química , Acetatos/análise , Acetatos/química , Adsorção , Butiratos/análise , Butiratos/química , Caproatos/análise , Caproatos/química , Caprilatos/análise , Caprilatos/química , Carboidratos da Dieta/metabolismo , Proteínas na Dieta/análise , Proteínas na Dieta/metabolismo , Digestão , Géis , Humanos , Interações Hidrofóbicas e Hidrofílicas , Microscopia Eletrônica de Varredura , Valor Nutritivo , Odorantes/análise , Permeabilidade , Amido/metabolismo , Propriedades de Superfície , Água/análise , Proteínas do Soro do Leite/metabolismo
13.
Food Chem ; 195: 56-63, 2016 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-26575712

RESUMO

To reduce the hygroscopic character of biodegradable starch-based films, rapeseed oil was incorporated by lamination (starch-oil-starch 3-layers technique). The lipid lamination followed by starch solution casting step induced an emulsion type structure of dried films. Composite films are more opalescent and glossier than fatty free starch films. For all the films, structure is heterogeneous in the cross-section only. Adding fat induced a twice decrease of the tensile strength. Thermal gravimetry analysis did not show differences between films with and without oil. Lipid reduced the moisture absorption particularly at higher RH as well as the surface swelling index, when water droplet contact occurred. Addition of lipids always decreases the contact angle for all liquid tested, except for water. Surface affinity of films for liquids less polar that water increased with rapeseed oil addition. The addition of rapeseed oil significantly reduces water vapour and oxygen permeability.


Assuntos
Óleos Vegetais/química , Plastificantes/química , Amido/química , Ácidos Graxos Monoinsaturados , Permeabilidade , Óleo de Brassica napus , Propriedades de Superfície , Água/química
14.
J Food Sci ; 75(5): E276-84, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20629874

RESUMO

The aim of this study was to investigate the influence of the wet agglomeration in a fluidized bed on flowability of agglomerated products, such as baby food powders. The agglomeration process was performed in the fluidized bed. The wetting liquid used to the process was: water, 2% lecithin solution, and 50% sugar solution. Food powders flowability was expressed as: Hausner Ratio, pouring time, angles of sliding and of repose and flow function. The composition of materials, used to prepare mixtures, has a significant influence on tested properties. The higher milk powder of the mixtures caused decreasing of their flowability. Wet agglomeration of baby food powders caused an increase in the mean diameter of particles, which made it possible to receive agglomerates with good flowability and decreased bulk density. The increase of milk powder content from 0 to 73% in the mixture before the agglomeration contributed to improve its flowability. Wet agglomeration with 2% lecithin solution and 50% sugar solution reduced particle size and bulk density, improved flowability of received agglomerates in relation to agglomerates received with water as a wetting liquid.


Assuntos
Manipulação de Alimentos/métodos , Alimentos Infantis , Pós/química , Agentes Molhantes/química , Fenômenos Químicos , Físico-Química/métodos , Fragaria , Humanos , Lactente , Lecitinas , Oryza , Tamanho da Partícula , Sacarose , Propriedades de Superfície , Água
15.
J Sci Food Agric ; 90(10): 1673-80, 2010 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-20564446

RESUMO

BACKGROUND: Edible films and coatings based on protein/lipid combinations are among the new products being developed in order to reduce the use of plastic packaging polymers for food applications. This study was conducted to determine the effect of rapeseed oil on selected physicochemical properties of cast whey protein films. RESULTS: Films were cast from heated (80 degrees C for 30 min) aqueous solutions of whey protein isolate (WPI, 100 g kg(-1) of water) containing glycerol (50 g kg(-1) of WPI) as a plasticiser and different levels of added rapeseed oil (0, 1, 2, 3 and 4% w/w of WPI). Measurements of film microstructure, laser light-scattering granulometry, differential scanning calorimetry, wetting properties and water vapour permeability (WVP) were made. The emulsion structure in the film suspension changed significantly during drying, with oil creaming and coalescence occurring. Increasing oil concentration led to a 2.5-fold increase in surface hydrophobicity and decreases in WVP and denaturation temperature (T(max)). CONCLUSION: Film structure and surface properties explain the moisture absorption and film swelling as a function of moisture level and time and consequently the WVP behaviour. Small amounts of rapeseed oil favourably affect the WVP of WPI films, particularly at higher humidities.


Assuntos
Emulsões/química , Embalagem de Alimentos/métodos , Proteínas do Leite , Óleos Vegetais/química , Vapor , Água/química , Dessecação , Ácidos Graxos Monoinsaturados , Glicerol , Interações Hidrofóbicas e Hidrofílicas , Permeabilidade , Óleo de Brassica napus , Propriedades de Superfície , Temperatura , Proteínas do Soro do Leite
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