RESUMO
The yacon roots are rich in fructooligosaccharides (FOS) and highly perishable. Drying is crucial for food quality and extending shelf life. However, preserving thermosensitive compounds, such as FOS, poses a challenge in conventional drying methods. In this regard, microwave drying and ethanol pretreatment (ET) have emerged as promising solutions for maintaining nutrients and reducing drying time (DT). The objective of this study was to assess how ET and sample temperature affect quality and process parameters during intermittent microwave drying of yacon. Drying at 52°C treated with ethanol was the one that stood out for presenting the highest fructan retention (64.1%), low DT, lower energy consumption (EC) (364.00 ± 5.03 kWh kg water-1), higher retention of antioxidant capacity (73.9%) and total phenolic content (77.5%), and slight variation in color parameters. Therefore, microwave drying with a controlled temperature of yacon pretreated with ethanol effectively reduces DT and EC by maintaining quality parameters.
Assuntos
Antioxidantes , Dessecação , Etanol , Micro-Ondas , Etanol/química , Dessecação/métodos , Antioxidantes/química , Fenóis/análise , Raízes de Plantas/química , Oligossacarídeos/química , Temperatura , Frutanos/química , Frutanos/análise , Manipulação de Alimentos/métodos , Conservação de Alimentos/métodosRESUMO
This study aimed to evaluate coconut sugar (CS) as an alternative osmotic agent to sucrose for the osmotic dehydration (OD) of strawberries. OD was performed by immersing strawberries cut into 13.6 ± 0.4 mm edge cubes in osmotic solutions of CS or sucrose, at two different concentrations (40% and 60%, w/w), with and without application of vacuum (AV) in the first 20 min of the process. The total OD time was 300 min. Evaluations of the kinetics of solid gain (SG), water loss (WL), and weight reduction (WR) were performed at 30, 60, 120, 180, 240, and 300 min. SG, WL, and WR increased over the OD time and showed values of up to 7.94%, 63.40%, and 55.94%, respectively. AV increased WL, WR, shrinkage, pH, and total color difference and decreased anthocyanin, ascorbic acid (AA), phenolic, and antioxidant contents. The higher concentration led to higher SG, WL, WR, shrinkage, hardness, and lower moisture content, water activity, anthocyanin, AA, phenolic, and antioxidant contents. The use of CS instead of sucrose had little influence on strawberry properties, except pH and color responses. The optimal treatment was using a 60% CS solution without AV, showing a very distinct color change, hardness increased by approximately 4.5 times and maintenance of acidity, anthocyanins, AA, total phenolics, and antioxidants of 38.0%, 39.6%, 11.8%, 30.0%, 31.1%, and 30.3%, respectively, compared to fresh strawberries. PRACTICAL APPLICATION: Osmotic dehydration of fruit is a process traditionally carried out using sucrose. However, increasing health concerns have made consumers seek alternative sugars to sucrose. The use of coconut sugar made it possible to produce osmo-dehydrated strawberries different from the traditional one, maintaining product quality and process efficiency.
Assuntos
Antioxidantes , Fragaria , Antioxidantes/química , Fragaria/química , Antocianinas/análise , Açúcares/análise , Cocos , Desidratação , Dessecação , Ácido Ascórbico/análise , Frutas/química , Sacarose/análise , Água/análiseRESUMO
Spent coffee grounds (SCG) are a coproduct that causes environmental impacts worldwide. Thus, consciously reusing the SCG is an eminent need. This work aimed to encapsulate phenolic compounds and antioxidants obtained from SCG extracts through spray- and freeze-drying techniques using different isolated and combined wall materials. The dried powders produced were evaluated for moisture content, water activity, bulk density, hygroscopicity, color, content of phenolic compounds and antioxidants, and the results were compared. The results showed that all evaluated treatments resulted in a powdered product with low values of bulk density, moisture and water activity, especially for freeze-drying. The freeze-dried product also showed higher hygroscopicity. Regarding the content of phenolic compounds and antioxidants, both drying methods showed high levels of these compounds in the dried product and good encapsulation efficiency, reaching 83.43%. In most cases, spray-drying and freeze-drying did not differ statistically (p > 0.05) in relation to bioactive compound content and encapsulation efficiency. In relation to wall materials, albumin showed the worst performance in the retention of bioactive compounds. On the other hand, pure gum arabic combined with maltodextrin led to better preservation of these compounds. PRACTICAL APPLICATION: Spent coffee grounds are a coproduct generated in large quantities in the world. The encapsulation of phenolic and antioxidant compounds protects and enables their application in different food matrices. Therefore, the evaluation of different encapsulation methods and wall materials is important to define good process conditions.
Assuntos
Antioxidantes , Café , Albuminas , Antioxidantes/análise , Goma Arábica , Fenóis/análise , Pós , ÁguaRESUMO
Coffee silverskin is a coproduct that has a rich composition in bioactive compounds. However, most of these compounds are susceptible to the conditions used during food processing and storage. Encapsulation is a process of great interest to increase the stability of these bioactive compounds, and different methods can influence the final characteristics of the product. Therefore, this study aimed to evaluate the encapsulation methods by foam mat drying, spray drying and freeze-drying for producing powder from coffee silverskin extracts. Density, porosity, overrun, and stability foam were evaluated and the physicochemical properties of powders, such as water activity, moisture, wettability, hygroscopicity, solubility, color, antioxidant activity, and total phenolic were determined. The optimal condition required for the feed mixture for foam formation was 7.6% gum arabic, 2% maltodextrin, and 10.4% egg albumin. All methods presented powders with desirable values of water activity, moisture content, and hygroscopicity, being considered stable for storage, and high content of bioactive compounds. Higher temperatures for foam mat drying produced powders with higher encapsulation efficiency (>77%) and longer wettability than lower temperatures (50 and 60°C). Therefore, this study verified that foam mat drying can be considered an efficient and promising method for encapsulating bioactive compounds from coffee silverskin extract. PRACTICAL APPLICATION: Foam mat drying can be considered an alternative method to conventional encapsulation by spray drying and freeze-drying. This method is simple, inexpensive, and generates high-quality products. Optimization of foam properties is necessary to ensure successful drying.
Assuntos
Café , Secagem por Atomização , Liofilização , Extratos Vegetais/química , Pós/química , ÁguaRESUMO
Dragon fruit shows good sensory and nutritional attributes, but it is also highly perishable. Drying is a unitary operation that promotes the reduction of moisture content, extending the useful life of the product. In this study, the elaboration of white and red dragon fruit powder by foam mat drying was studied with optimization of the proportion of foaming agent and stirring time. The use of ethanol and air temperature were evaluated on drying kinetics, effective moisture diffusivity (Deff ), and drying rate (DR). The study was divided into two steps. In the first, density, stability, porosity and overrun foam were evaluated and the optimal condition was determined. For the white and red pulp foams, the optimal conditions were, respectively, 26.88 min and 4.12 kg 100 kg-1 and 23.5 min and 3.44 kg 100 kg-1 . In the second step, the foam was subjected to ethanol pretreatment and convective drying (50 or 70 °C). The best condition involved pretreatment and the highest tested temperature, with the shortest drying time and the highest Deff and DR. PRACTICAL APPLICATION: Foam mat drying is a suitable method for drying perishable fruits, such as dragon fruit. The foam properties need to be optimized to ensure the success of the drying process. The ethanol pretreatment and the drying air temperature influence the drying kinetics. Therefore, determining the optimal process conditions is very important.
Assuntos
Cactaceae , Dessecação/métodos , Etanol , Manipulação de Alimentos/métodos , Frutas , Alimentos em Conserva , Temperatura Alta , TemperaturaRESUMO
BACKGROUND: Coffee is a raw material of global interest. Due to its relevance, this work evaluated the performance of calibration models constructed from spectral data obtained using near-infrared spectroscopy (FT-NIR) to determine the pH values and acidity in coffee beans in a practical and non-destructive way. Partial least squares regression was used during the calibration and the cross-validation to optimize the number of latent variables. The predictive capacity of the spectral pre-processing methods was also accessed. RESULTS: The results obtained showed that the best methods of pre-processing were the first derivative for the pH variable and the standard normal variate for the acidity, which produced models with correlations of 0.78 and 0.92, ratios of prediction to deviation of 2.061 and 2.966 and biases of -0.00011 and -0.152 to test set validation, respectively. The average errors between predicted and experimental values were lower than 7%. CONCLUSIONS: FT-NIR was successfully applied to predict properties related to the quality of coffee. The method was demonstrated to be a fast and non-destructive tool which allows the rapid inline evaluation of samples facilitating industrial and commercial processing. © 2020 Society of Chemical Industry.
Assuntos
Coffea/química , Concentração de Íons de Hidrogênio , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Calibragem , Análise dos Mínimos Quadrados , Sementes/químicaRESUMO
The Atlantic Forest biome is recognized for its biodiversity and is one of the most threatened biomes on the planet, with forest fragmentation increasing due to uncontrolled land use, land occupation, and population growth. The most serious aspect of the forest fragmentation process is the edge effect and the loss of biodiversity. In this context, the aim of this study was to evaluate the dynamics of forest fragmentation and select potential forest fragments with a higher degree of conservation for seed harvesting in the Itapemirim river basin, Espírito Santo State, Brazil. Image classification techniques, forest landscape ecology, and multi-criteria analysis were used to evaluate the evolution of forest fragmentation to develop the landscape metric indexes, and to select potential forest fragments for seed harvesting for the years 1985 and 2013. According to the results, there was a reduction of 2.55% of the occupancy of the fragments in the basin between the years 1985 and 2013. For the years 1985 and 2013, forest fragment units 2 and 3 were spatialized with a high potential for seed harvesting, representing 6.99% and 16.01% of the total fragments, respectively. The methodology used in this study has the potential to be used to support decisions for the selection of potential fragments for seed harvesting because selecting fragments in different environments by their spatial attributes provides a greater degree of conservation, contributing to the protection and conscious management of the forests. The proposed methodology can be adapted to other areas and different biomes of the world.