Physicochemical and Quality Properties of Dried Courgette Slices: Impact of Vacuum Impregnation and Drying Methods

The aim of this study was to determine the effects that the type of impregnating solution and drying method (freeze drying (FD) and vacuum drying (VD) at 45 °C and convective drying (CD) at 50, 60, and 70 °C) had on the physicochemical and quality properties of courgettes. Courgette slices were vacuum-impregnated (6 kPa) in freshly squeezed onion, kale, and onion and kale (50:50) juices with 3% NaCl solution (N). The application of vacuum impregnation (VI) with impregnating solutions from freshly squeezed onions and kale had a beneficial effect on the bioactive values of courgette. The highest contents of quercetin (41.84 μg/g d.m.) and carotenoids (276.04 μg/g d.m.) were found in courgette impregnated with onion juice after freeze drying. The highest values of lutein and zeaxanthin (216.42 μg/g d.m.) were recorded for courgette impregnated with kale juice and convective dried. By analysing the kinetics of convective drying, the best matching of the logistic model was found. Increasing the drying process temperature from 50 to 70 °C reduced the drying time from 15% to 36%, depending on the type of impregnating solution used. Water activity <0.6 was recorded for courgette dried by freezing, vacuum, and convection at 60 and 70 °C. Conclusions: The vacuum impregnation process and the impregnation solutions from freshly squeezed vegetables can be used to develop new snacks with high levels of bioactive compounds. The FD method is the most appropriate considering both the bioactive compounds content and the obtained colour and water activity.

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Design of Healthy Snack Based on Kiwifruit

Molecules ◽

10.3390/molecules25143309 ◽

2020 ◽

Vol 25 (14) ◽

pp. 3309 ◽

Cited By ~ 2

Author(s):

Urszula Tylewicz ◽

Malgorzata Nowacka ◽

Katarzyna Rybak ◽

Kinga Drozdzal ◽

Marco Dalla Rosa ◽

...

Keyword(s):

Antioxidant Activity ◽

Vitamin C ◽

Bioactive Compounds ◽

Freeze Drying ◽

Bioactive Compound ◽

Convective Drying ◽

Drying Methods ◽

Hot Air ◽

Sugar Addition ◽

High Antioxidant Activity

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.

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The Influence of Selected Drying Methods on the Physical Properties of Dried Apples cv. Jonagold Grown in Different Locations in Europe

International Journal of Food Engineering ◽

10.1515/ijfe-2016-0312 ◽

2017 ◽

Vol 13 (6) ◽

Cited By ~ 3

Author(s):

Anna Michalska ◽

Krzysztof Lech ◽

Adam Figiel ◽

Grzegorz P. Łysiak

Keyword(s):

Physical Properties ◽

Freeze Drying ◽

Geographical Origin ◽

Raw Material ◽

Convective Drying ◽

Vacuum Drying ◽

Drying Methods ◽

Drying Time ◽

Microwave Vacuum Drying ◽

Apple Slices

Abstract The aim of the study was to determine the influence of four different growing locations of apples cv. ‘Jonagold’ in Europe on the drying kinetics and the physical properties of dried apple slices. The drying methods applied in the study (freeze-drying, convective drying, microwave-vacuum drying and combined drying) significantly affected the drying time, which was the shortest in the case of microwave vacuum drying. The geographical origin of the apples affected the chemical and physical properties of the raw material used for drying, and, consequently, the drying time. Water activity of dried samples was connected with the final dry matter, regardless of the geographical origin of the apples. Freeze-drying resulted in the lightest in colour products (L*), whereas microwave-vacuum dried products had the highest levels of yellow pigments (b*). The highest chroma and browning index values were noted for microwave-vacuum dried samples and were strongly influenced by the drying temperature. The mechanical properties of the apple slices were more dependent on the drying method and temperature of the process than on the geographical origin when the temperature exceeded 83 °C.

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Mathematical modeling of pequi pulp drying and effective diffusivity determination

Revista Brasileira de Engenharia Agrícola e Ambiental ◽

10.1590/1807-1929/agriambi.v21n7p493-498 ◽

2017 ◽

Vol 21 (7) ◽

pp. 493-498 ◽

Cited By ~ 3

Author(s):

Elisabete P. de Sousa ◽

Rossana M. F. de Figueirêdo ◽

Josivanda P. Gomes ◽

Alexandre J. de M. Queiroz ◽

Deise S. de Castro ◽

...

Keyword(s):

Experimental Data ◽

Effective Diffusivity ◽

Drying Kinetics ◽

Convective Drying ◽

Drying Time ◽

Air Speed ◽

Drying Curves ◽

Increasing Temperature ◽

Kinetics Of ◽

Best Fit

ABSTRACT The aim of this work was to study the drying kinetics of pequi pulp by convective drying at different conditions of temperature (50, 60, 70 and 80 °C) and thickness (0.5, 1.0 and 1.5 cm) at the air speed of 1.0 m s-1, with no addition of adjuvant. The experimental data of pequi pulp drying kinetics were used to plot drying curves and fitted to the models: Midilli, Page, Henderson & Pabis and Newton. Effective diffusivity was calculated using the Fick’s diffusion model for a flat plate. It was found that, with increasing thickness, the drying time increased and, with increasing temperature, the drying time was reduced. The Midilli model showed the best fit to the experimental data of pequi pulp drying at all temperatures and thicknesses, presenting higher coefficients of determination (R2), indicating that this model satisfactorily represents the pequi pulp drying phenomenon. There was a trend of increase in the effective diffusivity with the increase in pulp layer thickness and temperature.

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Thin-layer mathematical modeling of apple slices drying, using open sun and cabinet solar drying methods

International Journal of Innovative Research and Scientific Studies ◽

10.53894/ijirss.v4i2.55 ◽

2021 ◽

Vol 4 (2) ◽

pp. 43-52

Author(s):

Abdul Wasim Noori ◽

Mohammad Jafar Royen ◽

Juma Haydary

Keyword(s):

Thin Layer ◽

Mathematical Models ◽

Water Activity ◽

Model Fitting ◽

Coefficient Of Determination ◽

Drying Methods ◽

Solar Drying ◽

Drying Time ◽

Climate Conditions ◽

Thin Layer Drying

This paper aims to investigate the effect of climate conditions such as ambient temperature, humidity, pressure, sun radiation and pollution on sliced apples quality and drying time which are dried in an indirect forced cabinet solar drying (IFCSD) and open sun drying (OSD) systems. Both experiments were implemented at same place (Kabul, Afghanistan) and time. The IFCSD yield for saving time is 42.8 % which is more effective than drying in the OSD system. Simultaneously with the decreasing of sliced apple weight from 512.9 g down to 73.9 g, the water activity decreased from 0.955 down to 0.355 in the IFCSD system. For OSD system, the sample weight decreased from 512.6 g down to 78.4 g and its water activity from 0.955 down to 0.411. On the experiment day the average sun radiation was 571 w/m2 . The pressure drop between inlet and outlet of the dryer was 0.1 kPa. Different thin-layer mathematical models were investigated to identify the best model fitting the experimental data. The mathematical models’ performances were investigated by comparing the coefficient of determination (R 2 ), reduced chi-square (X2 ) and root mean square error (RMSE) coefficients. From all 11 applied thin-layer drying models the Page, Approximation diffusion, Verma et al and Midilli and Kacuk models are more fitted to our data.

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Effect of Drying on the Bioactive Compounds and Antioxidant Activity of Rubus lambertianus

International Journal of Food Engineering ◽

10.1515/ijfe-2016-0412 ◽

2018 ◽

Vol 14 (2) ◽

Author(s):

Jun Yu ◽

Zijian Shangguan ◽

Xingju Yang ◽

Dan Sun ◽

Baoqing Zhu ◽

...

Keyword(s):

Bioactive Compounds ◽

Freeze Drying ◽

Antioxidant Activities ◽

Drying Methods ◽

Protective Effects ◽

Red Raspberry ◽

Hot Air Drying ◽

Hot Air ◽

Freeze Dried ◽

Total Anthocyanins

AbstractDifferent drying methods, including hot air drying (HAD), freeze drying (FD), spray drying and vacuum drying (VD), were investigated to determine their influence on the chromatic coordinates, phenolics, anthocyanins and antioxidant activities of dried red raspberry (Rubus lambertianus). Pelargonidin-3-O-glucoside and catechin were found to be the main anthocyanin and non-anthocyanin phenolics, respectively, in fresh red raspberry. The most effective method for controlling browning was FD. The highest protective effects against bioactive compounds were observed in freeze-dried powders, when measuring the total anthocyanins, the scavenging of DPPH (1,1-diphenyl-2-picrylhydrazyl) and hydroxyl radicals and the inhibition effects on lard oxidation. HAD was effective for the preservation of total phenolics, while VD was useful for protecting catechin and procyanidin B1.

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Physicochemical Properties of Dried Apple Slices: Impact of Osmo-Dehydration, Sonication, and Drying Methods

Molecules ◽

10.3390/molecules25051078 ◽

2020 ◽

Vol 25 (5) ◽

pp. 1078

Author(s):

Joanna Cichowska-Bogusz ◽

Adam Figiel ◽

Angel Antonio Carbonell-Barrachina ◽

Marta Pasławska ◽

Dorota Witrowa-Rajchert

Keyword(s):

Physicochemical Properties ◽

Osmotic Dehydration ◽

Convective Drying ◽

Drying Methods ◽

Drying Method ◽

Drying Time ◽

Hygroscopic Properties ◽

Fruit Samples ◽

Apple Slices ◽

Pre Treatment

Apple slices of the Elise variety were previously osmo-dehydrated in erythritol, xylitol, and sucrose for 2 h. In some parts of the experiment, 30 min of ultrasound pre-treatment (US) were applied. Afterwards, fruit samples were dried by convective (CD), microwave-vacuum (VM), and a combined method (CD/VM, mix two of them). The main aim of the research was to characterize an impact of osmotic dehydration, sonication pre-treatment, and drying method on the physicochemical properties of the dried apples. The use of sugar alcohols (xylitol, erythritol) in the production of dried apples did not badly affect the taste of the obtained dried products; it enabled a noticeable cooling/refreshing effect felt in the mouth when consuming a snack, and enabled the production of dried snacks with lower calorific value. Polyol residues in the product were at a level that was safe for consumers. The most popular convective drying was long lasting, whereas the VM drying method allowed for the shortest drying time, amounting to 76 min; moreover, additional application of ultrasounds reduced this time to 36 min. The combined drying method allowed the total duration of the process to be reduced 2–4.5 times. Ultrasound applied during osmotic dehydration did not significantly affect attributes of the descriptive sensory analysis for the obtained dried apples. The best hygroscopic properties, ensuring the storage stability of the dried product, showed dried apples previously osmo-dehydrated in erythritol and sucrose solutions.

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Effect of drying methods on properties of green curry powder

MATEC Web of Conferences ◽

10.1051/matecconf/201819203023 ◽

2018 ◽

Vol 192 ◽

pp. 03023

Author(s):

Natthacha Chaloeichitratham ◽

Pornkanya Mawilai ◽

Thadchapong Pongsuttiyakorn ◽

Pimpen Pornchalermpong

Keyword(s):

Moisture Content ◽

Bulk Density ◽

Water Activity ◽

Freeze Drying ◽

Total Phenolic ◽

Drying Methods ◽

Hot Air Drying ◽

Air Drying ◽

Drying Temperature ◽

Hot Air

In this study, the effects of two drying methods: hot-air and freeze drying for Thai green curry paste in a terms of drying time and qualities have been investigated. The hot-air drying was carried out in tray dryer at temperature of 50, 60 and 70 °C. The freeze drying was carried out in freeze dryer at freezing temperature of -20°C, primary drying temperature of -10°C and secondary drying temperature of 50°C. Moisture content, water activity, colour, bulk density, and total phenolic content (TPC) were determined in samples. Freeze dried sample had significantly (p<0.05) lower moisture content, water activity, bulk density, total colour difference and browning index than hot air dried samples. For antioxidant activity, the results showed hot-air drying at 70°C effected highest TPC similar to freeze drying.

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Effects of Different Drying Methods on the Characterization, Dissolution Rate and Antioxidant Activity of Ursolic Acid-Loaded Chitosan Nanoparticles

Foods ◽

10.3390/foods10102470 ◽

2021 ◽

Vol 10 (10) ◽

pp. 2470

Author(s):

Lujie Zhao ◽

Xu Duan ◽

Weiwei Cao ◽

Xing Ren ◽

Guangyue Ren ◽

...

Keyword(s):

Antioxidant Activity ◽

Particle Size ◽

Ursolic Acid ◽

Freeze Drying ◽

Water Solubility ◽

Drug Loading ◽

Chitosan Nanoparticles ◽

Simulated Gastric Fluid ◽

Drying Methods ◽

Drying Time

To improve the water solubility of ursolic acid (UA), UA-loaded chitosan nanoparticles were firstly prepared by the ionotropic gelation method and dried by freeze drying (FD), microwave freeze drying (MFD) and spray drying (SD). The characterization of UA-loaded chitosan nanoparticles was performed with particle size, drug loading (DL), scanning electron microscope (SEM), fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), dissolution studies and antioxidant activity. The results demonstrated that UA was successfully encapsulated into chitosan nanoparticles using sodium tripolyphosphate (TPP) as a cross-linker, with a 79% encapsulation efficiency. The spray-dried, UA-loaded chitosan nanoparticles had the lowest drug loading (11.8%) and the highest particle size (496.9 ± 11.20 nm). The particle size of UA-loaded chitosan nanoparticles dried by MFD and FD was lower, at 240.8 ± 12.10 nm and 184.4 ± 10.62 nm, respectively, and their antioxidant activity was higher than those nanoparticles dried by SD. Moreover, the drying time and energy consumption of UA-loaded chitosan nanoparticles dried by MFD and SD were lower than that of FD. The dissolution rates of UA-loaded chitosan nanoparticles prepared by FD and MFD were 60.6% and 57.1%, respectively, in a simulated gastric fluid, which was a greater value than SD (55.9%). Therefore, the UA-loaded chitosan nanoparticles encapsulation method, combined with MFD technology, showed a promising potential to improve the water solubility of UA.

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Influence of the temperature and ultrasound application in drying kinetics of apple skin

Proceedings of 21th International Drying Symposium ◽

10.4995/ids2018.2018.7889 ◽

2018 ◽

Author(s):

Juan A. Cárcel ◽

Matheus P. Martins ◽

Edgar J. Cortés ◽

Carmen Rosselló ◽

Ramón Peña

Keyword(s):

Physical Structure ◽

Drying Kinetics ◽

Convective Drying ◽

Drying Time ◽

Different Temperatures ◽

Ultrasound Application ◽

Quality Of Products ◽

Drying Conditions ◽

Kinetics Of ◽

By Products

The great amount of waste produced by food industry contains interesting bioactive compounds. The extraction of these compounds requires the by-products previous stabilization being the convective drying one of most used techniques to this end. Drying conditions can affect both drying kinetics and final quality of products. The apple skin, byproduct of apple juice or cider industries, is rich in functional compounds such as polyphenols or vitamin C. The main goal of this contribution was to quantify the influence of temperature and ultrasound application in drying kinetics of apple skin. For this purpose, drying experiments at different temperatures (-10, 30, 50 and 70 ºC) and with (20.5 kW/m3) and without application of ultrasound were carried out. Drying kinetics were modelled by using a diffusion based model. As can be expected, the higher the temperature the faster the drying. Ultrasound application accelerated the process at every temperature tested being the influence slightly lower than found from the literature for other products. This can be attributed at the physical structure of the apple skin, less porous than the pulp. In any case, the application of ultrasound significantly reduced the drying time. Keywords: by-products; dehydration;diffusivity; mass transfer

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Study of vacuum and freeze drying of bee honey

Thermal Science ◽

10.2298/tsci200317194n ◽

2020 ◽

Vol 24 (6 Part B) ◽

pp. 4241-4251

Author(s):

Nebojsa Nedic ◽

Milan Gojak ◽

Ivan Zlatanovic ◽

Nedzad Rudonja ◽

Kristina Lazarevic ◽

...

Keyword(s):

Water Activity ◽

High Performance ◽

Freeze Drying ◽

Soluble Solids ◽

Diffusivity Coefficient ◽

Chromatography Method ◽

Drying Time ◽

Freeze Dried ◽

Acacia Honey ◽

The Impact

The aim of this research is to study the drying kinetics of vacuum-dried and freeze-dried bee honey produced from two different varieties: Sunflower honey (Helianthus Annuus L.) and Acacia honey (Robinia pseudo acacia L.). Vacuum drying treatments were carried out with the honey samples? initial temperatures of +25?C, ?20?C, and ?40?C. Water content, total soluble solids, as well as the water activity of fresh and dried honey samples were determined. Freeze-drying of bee honey with initial sample temperature of ?40?C has resulted in shorter drying time (7-9 hours), moisture content (10%-12%), water activity (0.405-0.427 aW) and effective moisture diffusivity coefficient (8.26?10?7-9.51?10-7 m2/s). The high-performance liquid chromatography method was used when analyzing the impact that drying pre-treatments had on honey quality. The application of pre-treatments has led to an increase in hydroxy-methyl-furfural by 39-71%, and a decrease in diastase activity by 17-36%, all compared to fresh honey samples. The solutions of Verma model proved to be the best fit with the experimental results.

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