Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Compr Rev Food Sci Food Saf ; 20(5): 5097-5144, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34402592

RESUMO

In recent years, traditional high-temperature food processing is continuously being replaced by nonthermal processes. Nonthermal processes have a positive effect on food quality, including color and maintaining natural food pigments. Thus, this article describes the influence of nonthermal, new, and traditional treatments on natural food pigments and color changes in plant materials. Characteristics of natural pigments, such as anthocyanins, betalains, carotenoids, chlorophylls, and so forth available in the plant tissue, are shortly presented. Also, the characteristics and mechanism of nonthermal processes such as pulsed electric field, ultrasound, high hydrostatic pressure, pulsed light, cold plasma, supercritical fluid extraction, and lactic acid fermentation are described. Furthermore, the disadvantages of these processes are mentioned. Each treatment is evaluated in terms of its effects on all types of natural food pigments, and the possible applications are discussed. Analysis of the latest literature showed that the use of nonthermal technologies resulted in better preservation of pigments contained in the plant tissue and improved yield of extraction. However, it is important to select the appropriate processing parameters and to optimize this process in relation to a specific type of raw material.


Assuntos
Antocianinas , Manipulação de Alimentos , Carotenoides/análise , Qualidade dos Alimentos , Pressão Hidrostática
2.
Foods ; 10(8)2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34441719

RESUMO

The aim of this work was to compare selected physicochemical properties of air dried 'Golden Delicious' apples, pretreated either by high-pressure processing (HPP), ultrasound (US) or pulsed electric field (PEF). Following parameters of pretreatment were used: HPP-400 MPa for 15 min, US-21 kHz, 180 W for 45 min, PEF-1 kV/cm, 3.5 kJ/kg. The quality of materials was evaluated by their rehydration properties, hygroscopicity, color and total phenolic content. To compare the effectiveness of the utilized methods, determined properties were expressed as relative comparison values against the reference sample obtained without any pretreatment in the same conditions. The performed research demonstrated that properties can be shaped by the application of proper pretreatment methods. For instance, PEF was shown to be the best method for improving water uptake during rehydration, whereas HPP was the most effective in decreasing hygroscopic properties in comparison with untreated dried apples. Among the investigated methods, HPP resulted in the deepest browning and thus total color difference, while the effects of US and PEF were comparable. For all pretreated dried apples, the total phenolic content was lower when compared with reference material, though the smallest drop was found in sonicated samples.

3.
Molecules ; 26(7)2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33916010

RESUMO

Most agricultural products are harvested with a moisture content that is not suitable for storage. Therefore, the products are subjected to a drying process to prevent spoilage. This study evaluates an infrared rotary dryer (IRRD) with three levels of infrared power (250, 500, and 750 W) and three levels of rotation speed (5, 10, and 15 rpm) to dry terebinth. Response surface methodology (RSM) was used to illustrate and optimize the interaction between the independent variables (infrared power and rotation speed) and the response variables (drying time, moisture diffusivity, shrinkage, color change, rehydration rate, total phenolic content, and antioxidant activity). As infrared power and rotation speed increased, drying time, rehydration rate, antioxidant activity, and total phenolic content decreased, while the other parameters were increased. According to the results, the optimum drying conditions of terebinth were determined in the IRRD at an infrared power of 250 W and drum rotation speed of 5 rpm. The optimum values of the response variables were 49.5 min for drying time, 8.27 × 10-9 m2/s for effective moisture diffusivity, 2.26 for lightness, 21.60 for total color changes, 34.75% for shrinkage, 2.4 for rehydration rate, 124.76 mg GAE/g d.m. for total phenolic content and 81% for antioxidant activity.


Assuntos
Análise de Alimentos/métodos , Conservação de Alimentos/métodos , Qualidade dos Alimentos , Raios Infravermelhos , Pistacia/química , Antioxidantes/química , Antioxidantes/farmacologia , Ingredientes de Alimentos/análise , Fenômenos Físicos , Compostos Fitoquímicos/análise , Compostos Fitoquímicos/química
4.
Foods ; 10(2)2021 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33499383

RESUMO

It has been demonstrated previously in the literature that utilization of PEF or a combination of a pulsed electric field (PEF) and ultrasounds (US) can facilitate dehydration processes and improve the quality of dried products even better than the application of thermal methods such as blanching. The aim of the study was to evaluate the quality of red bell pepper subjected to freeze-drying preceded by blanching or PEF or US treatment applied in a single and combined mode. Furthermore, the freeze-drying was preceded by shock freezing or vacuum freezing performed inside the freeze-dryer as a result of pressure drop during the first stage of freeze-drying. All of the analyzed technological variants enhanced the drying kinetics when compared to the intact material. Freeze-dried bell pepper subjected to non-thermal pretreatment exhibited higher vitamin C, total phenolic and carotenoids content than blanched material despite the fact that blanching reduced drying time the most compared to all other analyzed methods.

5.
Polymers (Basel) ; 14(1)2021 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-35012177

RESUMO

Due to the content of lignocellulosic particles, wood plastic composites (WPC) composites can be attacked by both domestic and mold fungi. Household fungi reduce the mechanical properties of composites, while mold fungi reduce the aesthetics of products by changing their color and surface decomposition of the wood substance. As part of this study, the impact of lignocellulosic fillers in the form of sawdust and bark in poly (lactic acid) (PLA)-based biocomposites on their susceptibility to mold growth was determined. The evaluation of the samples fouled with mold fungi was performed by computer analysis of the image. For comparison, tests were carried out on analogous high-density polyethylene (HDPE) composites. Three levels of composites' filling were used with two degrees of comminution of lignocellulosic fillers and the addition of bonding aids to selected variants. The composites were produced in two stages employing extrusion and flat pressing. The research revealed that PLA composites were characterized by a higher fouling rate by Aspergillus niger Tiegh fungi compared to HDPE composites. In the case of HDPE composites. The type of filler (bark, sawdust) affected this process much more in the case of HDPE composites than for PLA composites. In addition, the use of filler with smaller particles enhanced the fouling process.

6.
Molecules ; 25(18)2020 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-32962060

RESUMO

The aim of the study was an investigation of the effect of traditional and non-thermal treatment on the bioactive compounds of red bell pepper. As a thermal process, blanching in water and in steam was studied, while for non-thermal the sonication, pulsed electric field treatment and their combination were used in this experiment. The red bell peppers were evaluated based on quality attributes such as: total carotenoids content; polyphenols; vitamin C; antioxidant activity and sugars content. Vitamin C and sugar content were analyzed using liquid chromatography and other measurements were determined based on the spectrophotometric method. Results showed that the blanching in water or in steam reduced bioactive compounds concentration; whereas non-thermal treatments as pulsed electric field (PEF) applied separately or in combination with ultrasound (US + PEF) let to obtain similar or slightly lower content of bioactive compounds in comparison to untreated peppers. When sonication (US) and combined treatment as PEF + US were applied; in most cases reduction of bioactive compounds concentration occurred. This effect was probably related to the effect of relatively long (30 min) ultrasound treatment. The application of appropriate parameters of non-thermal processing is crucial for the high quality of processed material.


Assuntos
Capsicum/metabolismo , Carotenoides/análise , Manipulação de Alimentos/métodos , Açúcares/análise , Antioxidantes/química , Ácido Ascórbico/análise , Capsicum/química , Análise por Conglomerados , Eletricidade , Polifenóis/análise , Análise de Componente Principal , Sonicação
7.
Molecules ; 25(14)2020 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-32708245

RESUMO

Kiwifruit is an excellent source of vitamin C and other bioactive compounds, which contribute to its high antioxidant activity. However, the fruits with small size and low weight are considered waste and are unprofitable; therefore, the production of healthy kiwifruit-based dried snacks, which contain a lot of health-beneficial ingredients, could be a viable alternative for their use. The aim of this study was to develop formulations and methods to produce attractive and nutritionally valuable dried snacks based on yellow kiwifruit. Three different puree formulations (kiwifruit; fennel; and strawberry, lemon, or spinach) with or without addition of sugar were subjected to two drying methods: freeze-drying (fruit bars) and conventional hot air drying (fruit leathers). The obtained products were analysed for their content of total polyphenols (TPs), flavonoids, and vitamin C, as well as their antioxidant activity. The results showed that snacks prepared by freeze-drying (fruit bars) presented higher TP, vitamin C, and flavonoids content than those prepared by convective drying; however, the antioxidant activity did not always follow this trend. The amount of bioactive compounds depended on the formulation used for the preparation of snacks. The effect of the sugar addition seems to be strictly related to the mix used and specific bioactive compound investigated.


Assuntos
Actinidia/química , Antioxidantes/química , Frutas/química , Extratos Vegetais/química , Lanches , Ácido Ascórbico/química , Flavonoides/química , Foeniculum/química , Tecnologia de Alimentos , Fragaria/química , Liofilização , Humanos , Valor Nutritivo , Polifenóis/química , Spinacia oleracea/química
8.
Foods ; 8(11)2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31766141

RESUMO

Nowadays, one of the main objectives of the fruit and vegetable industry is to develop innovative novel products with high quality, safety, and optimal nutritional characteristics in order to respond with efficiency to the increasing consumer expectations. Various emerging, unconventional technologies (e.g., pulsed electric field, pulsed light, ultrasound, high pressure, and microwave drying) enable the processing of fruits and vegetables, increasing their stability while preserving their thermolabile nutrients, flavour, texture, and overall quality. Some of these technologies can also be used for waste and by-product valorisation. The application of fast noninvasive methods for process control is of great importance for the fruit and vegetable industry. The following Special Issue "Safety, Quality, and Processing of Fruits and Vegetables" consists of 11 papers, which provide a high-value contribution to the existing knowledge on safety aspects, quality evaluation, and emerging processing technologies for fruits and vegetables.

9.
Foods ; 8(8)2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31344943

RESUMO

The aim of this study was to investigate the effect of a pretreatment, performed by a combined method based on blanching, ultrasound, and vacuum application, on the kinetics of osmotic dehydration and selected quality properties such as water activity, color, and bioactive compound (polyphenols, flavonoids, and anthocyanins) content. The pretreatment was carried out using blanching, reduced pressure, and ultrasound (20 min, 21 kHz) in various combinations: Blanching at reduced pressure treatment conducted three times for 10 min in osmotic solution; blanching with reduced pressure for 10 min and sonicated for 20 min in osmotic solution; and blanching with 20 min of sonication and 10 min of reduced pressure. The osmotic dehydration was performed in different solutions (61.5% sucrose and 30% sucrose with the addition of 0.1% of steviol glycosides) to ensure the acceptable taste of the final product. The changes caused by the pretreatment affected the osmotic dehydration process by improving the efficiency of the process. The use of combined pretreatment led to an increase of dry matter from 9.3% to 28.4%, and soluble solids content from 21.2% to 41.5%, lightness around 17.3% to 56.9%, as well as to the reduction of bioactive compounds concentration until even 39.2% in comparison to the blanched sample not subjected to combined treatment. The osmotic dehydration caused further changes in all investigated properties.

10.
Foods ; 8(7)2019 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-31284456

RESUMO

Beetroot is a root vegetable rich in different bioactive components, such as vitamins, minerals, phenolics, carotenoids, nitrate, ascorbic acids, and betalains, that can have a positive effect on human health. The aim of this work was to study the influence of the pulsed electric field (PEF) at different electric field strengths (4.38 and 6.25 kV/cm), pulse number 10-30, and energy input 0-12.5 kJ/kg as a pretreatment method on the extraction of betalains from beetroot. The obtained results showed that the application of PEF pre-treatment significantly (p < 0.05) influenced the efficiency of extraction of bioactive compounds from beetroot. The highest increase in the content of betalain compounds in the red beet's extract (betanin by 329%, vulgaxanthin by 244%, compared to the control sample), was noted for 20 pulses of electric field at 4.38 kV/cm of strength. Treatment of the plant material with a PEF also resulted in an increase in the electrical conductivity compared to the non-treated sample due to the increase in cell membrane permeability, which was associated with leakage of substances able to conduct electricity, including mineral salts, into the intercellular space.

11.
Food Chem ; 299: 125122, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31288165

RESUMO

To ease the mass exchange in fruit tissues, cutting and blanching are traditionally performed. However, recently, unconventional methods such as sonication are becoming more popular, which cause several alterations of physical and chemical properties as well as microstructure changes. The aim of this work was to evaluate the distribution of water inside the cranberry fruits, microstructural changes and sugars content, following traditional and sonication pre-treatments in osmotic solutions. TD-NMR spectroscopy was used to measure the transverse relaxation time (T2) and intensity of proton pools in different cellular compartments. The microstructure of the samples was evaluated by SEM microscopy, sugars content by HPLC and sucrose melting temperature and enthalpy by DSC. Different pre-treatments appeared to promote microstructure alterations and loss of water from vacuole and cytoplasm/extracellular space, more pronounced in cut and blanched samples. Cutting and blanching followed by osmotic dehydration with assisted sonication eased sucrose penetration into the tissue.


Assuntos
Conservação de Alimentos/métodos , Frutas/química , Açúcares/análise , Vaccinium macrocarpon/química , Água/metabolismo , Varredura Diferencial de Calorimetria , Dessecação , Frutas/ultraestrutura , Espectroscopia de Ressonância Magnética , Microscopia Eletrônica de Varredura , Osmose , Sonicação , Sacarose/análise , Temperatura , Vaccinium macrocarpon/ultraestrutura
12.
Ultrason Sonochem ; 56: 1-13, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31101243

RESUMO

A lot of effort is put to decrease the energy consumption of drying. This effect might be achieved by shift of a drying technology e.g. from a hot-air to a microwave-vacuum method. Moreover, an unconventional pre-treatment such as ultrasound or pulsed electric field may modify a cellular tissue, what influences drying kinetics of plant tissue. The aim of the study was to analyse the quality of microwave-vacuum dried, osmodehydrated (OD) cranberries processed by the means of blanching and ultrasound (US) or blanching followed by pulsed electric field and sonication (PEF + US) in comparison to traditionally treated material. Physical, chemical and sensorial properties of cranberry fruits were assessed. What is more, the impact of aforementioned unconventional treatments on the kinetics of microwave-vacuum dried cranberries was studied. Microwave-vacuum drying process was very short (25-38 min) in comparison to convective drying, which lasted several hours (13.2 h). Most of the samples subjected to US and PEF + US treatments before OD and drying were characterized by similar or a higher amount of bioactive compounds such as polyphenols, anthocyanins and flavonoids, and better colour and taste, as compared to cut osmodehydrated cranberry fruits subjected to convective drying (reference samples).

13.
Sensors (Basel) ; 18(4)2018 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-29617343

RESUMO

The dynamic laser speckle (biospeckle) method was tested as a potential tool for the assessment and monitoring of the maturity stage of tomatoes. Two tomato cultivars—Admiro and Starbuck—were tested. The process of climacteric maturation of tomatoes was monitored during a shelf life storage experiment. The biospeckle phenomena were captured using 640 nm and 830 nm laser light wavelength, and analysed using two activity descriptors based on biospeckle pattern decorrelation—C4 and ε. The well-established optical parameters of tomatoes skin were used as a reference method (luminosity, a*/b*, chroma). Both methods were tested with respect to their prediction capabilities of the maturity and destructive indicators of tomatoes—firmness, chlorophyll and carotenoids content. The statistical significance of the tested relationships were investigated by means of linear regression models. The climacteric maturation of tomato fruit was associated with an increase in biospckle activity. Compared to the 830 nm laser wavelength the biospeckle activity measured at 640 nm enabled more accurate predictions of firmness, chlorophyll and carotenoids content. At 640 nm laser wavelength both activity descriptors (C4 and ε) provided similar results, while at 830 nm the ε showed slightly better performance. The linear regression models showed that biospeckle activity descriptors had a higher correlation with chlorophyll and carotenoids content than the a*/b* ratio and luminosity. The results for chroma were comparable with the results for both biospeckle activity indicators. The biospeckle method showed very good results in terms of maturation monitoring and the prediction of the maturity indices of tomatoes, proving the possibility of practical implementation of this method for the determination of the maturity stage of tomatoes.


Assuntos
Lycopersicon esculentum , Carotenoides , Lasers , Luz
14.
Food Chem ; 239: 242-251, 2018 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-28873566

RESUMO

Parsley leaves contain a high amount of bioactive components (especially lutein), therefore it is crucial to select the most appropriate pre-treatment and drying conditions, in order to obtain high quality of dried leaves, which was the aim of this study. The optimization was done using response surface methodology (RSM) for the following factors: microwave power (100, 200, 300W), air temperature (20, 30, 40°C) and pre-treatment variant (ultrasound, steaming and dipping as a control). Total phenolic content (TPC), antioxidant activity, chlorophyll and lutein contents (using UPLC-PDA) were determined in dried leaves. The analysed responses were dependent on the applied drying parameters and the pre-treatment type. The possibility of ultrasound and steam treatment application was proven and the optimal processing conditions were selected.


Assuntos
Petroselinum , Micro-Ondas , Fenóis , Folhas de Planta , Vapor , Ultrassom
15.
Ultrasonics ; 83: 33-41, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28778552

RESUMO

The aim of the study was to investigate the effect of ultrasound treatment in two osmotic solutions, carried out at different time, on some physical properties, antioxidant activity and cell survival of cranberries. Ultrasound treatment was conducted at 21kHz for 30 and 60min in liquid medium: 61.5% sucrose solution and 30% sucrose solution with 0.1% steviol glycosides addition. Some samples before the ultrasound treatment were subjected to cutting or blanching. The results showed that dry matter content and concentration of the dissolved substances increased during ultrasound treatment in osmotic solution, however higher value was observed for treatment in 61.5% sucrose solution and for longer time. Water activity and volume of cranberries did not change after the ultrasonic treatment. Combined treatment led to colour and antioxidant activity alterations as well. A cell viability of whole and cut samples decreased after 60min of osmotic treatment and completely lost in the blanched samples.


Assuntos
Sobrevivência Celular/efeitos da radiação , Dessecação/métodos , Conservação de Alimentos/métodos , Qualidade dos Alimentos , Ondas de Choque de Alta Energia , Osmose/efeitos da radiação , Vaccinium macrocarpon/efeitos da radiação , Sobrevivência Celular/fisiologia , Diterpenos do Tipo Caurano/química , Relação Dose-Resposta à Radiação , Análise de Alimentos , Glucosídeos/química , Doses de Radiação , Sacarose/química
16.
Ultrasonics ; 83: 18-25, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28693863

RESUMO

The aim of the study was to investigate the influence of ultrasound treatment applied in osmotic solution on bioactive compounds, such as vitamin C, polyphenols, anthocyanins and flavonoids content as well as antioxidant activity in cranberries (Vaccinium oxycoccus). Ultrasound treatment was performed at the frequency of 21kHz for 30 and 60min in two osmotic solutions - 61.5% sucrose and 30% sucrose with an addition of 0.1% of steviol glycosides. Before the ultrasound treatment the material was subjected to cutting or blanching. The obtained results indicated that the influence of ultrasound waves on cranberries depends on a type of bioactive component. The ultrasound treated cranberries as well as the ones subjected to cutting or blanching enhanced by ultrasound were characterized mainly by a lower content of bioactive compounds.


Assuntos
Biopolímeros/química , Biopolímeros/efeitos da radiação , Dessecação/métodos , Osmose/efeitos da radiação , Ondas Ultrassônicas , Vaccinium macrocarpon/química , Vaccinium macrocarpon/efeitos da radiação , Relação Dose-Resposta à Radiação , Conservação de Alimentos/métodos , Doses de Radiação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...