Convective drying of spine gourd ( Momordica dioica ): Effect of ultrasound pre‐treatment on drying characteristics, color, and texture attributes

Author(s):  
Yogesh Kumar ◽  
Vijay Singh Sharanagat ◽  
Lochan Singh ◽  
Prabhat K. Nema
2018 ◽  
Vol 36 (No. 2) ◽  
pp. 187-193 ◽  
Author(s):  
Süfer Özge ◽  
Demir Hande ◽  
Sezer Seda

The textural characteristics of onion slices (Allium cepa L.) of 3- and 7-mm thicknesses undergoing convective drying (50, 60, and 70°C) and microwave drying (68, 204, and 340 W real effective power levels) techniques with or without pre-treatment were evaluated. Pre-treatment consisted of dipping into brine solution (8% NaCl). Texture profile analysis at 25% compression was applied and hardness, chewiness, springiness and gumminess values of onions were recorded. As the temperature (convective) or real effective power level (microwave) increased, the hardness and chewiness levels of dried onion slices were enhanced. The values of these parameters were higher in response to microwave application compared to convective drying. Pre-treatment had an additive effect on hardness and chewiness in convectively dried samples. Maximum springiness was observed in response to convective drying. Dipping in brine solution generally caused no significant changes among slices of the same thickness (P < 0.05). With respect to gumminess, the results were quite similar to those for hardness and chewiness, i.e., markedly higher in microwave-dried onions.


Author(s):  
Ionut Dumitru Velescu ◽  
Ioan Tenu ◽  
Petru Carlescu ◽  
Vasile Dobre

Introduction: Carrot is one of the most commonly used vegetables for human nutrition due to high vitamin and fibre content. Drying is one of the oldest methods of food preservation, and it represents a very important aspect of food processing. Sun drying is the most common method used to preserve agricultural products in most tropical countries; this technique is extremely weather dependent, and has the problems of contamination with dust, soil, sand particles and insects. Also, the required drying time can be quite long. Therefore, using solar and hot-air dryers, which are far more rapid, providing uniformity and hygiene are inevitable for industrial food drying processes. Aim: This paper presents a kinetic study of convective drying without pre-treatment of carrot. The effects of the temperature of the drying agent, the speed of the drying agent and the thickness of the kinetics of drying the sample of carrots were investigated. Materials and methods: The experiments were carried out with the aid of an installation for drying food products, that is capable of ensuring the temperature of the drying agent (air) in the range of +25 ... +125 °C. The drying process was conducted at temperature of 45 °C in first hour of process, 2 hours at 55 °C, and 3 hours at 60 °C. The air velocity was setup  at 1.0 - 2.5 m/s. Carrots were divided into segments of a thickness of 0.4 cm. Two mathematical models available in the literature were fitted to the experimental data. Results: The drying rate increases with temperature and decreases with the sample diameter. The Page model is given better prediction than the Henderson and Pabis model and satisfactorily described drying characteristics of carrot slices. Conclusions: The most important characteristics of carrot required for simulation and optimization of the drying were studied. The values of calculated effective diffusivity for drying at 45, 55 and 60oC of air temperature and 1.0, 1.5, 2.0 and 2.5 m/s of air flow velocity. The effective diffusivity increases as air-flow rate and temperature increases. Page’s empirical model showed a good fit curves than the Henderson and Pabis model.


2002 ◽  
Vol 54 (2) ◽  
pp. 141-146 ◽  
Author(s):  
Piotr P Lewicki ◽  
Hoa Vu Le ◽  
Wanda Pomarańska-Łazuka

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1078
Author(s):  
Joanna Cichowska-Bogusz ◽  
Adam Figiel ◽  
Angel Antonio Carbonell-Barrachina ◽  
Marta Pasławska ◽  
Dorota Witrowa-Rajchert

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.


2018 ◽  
Vol 40 (4) ◽  
Author(s):  
Eliana Janet Sanjinez-Argandoña ◽  
Luciane Yukari Yahagi ◽  
Tais Boveda Costa ◽  
Aline Janaina Giunco

Abstract Mango (Mangifera indica L.) can be characterized as a greatly accepted fruit due to its sensory attributes of flavor and aroma. However, it has a large production during the harvest season and requires preservation through processing. Osmotic pretreatment, followed by drying, provides products with higher quality and stability. The present study explored the effects of osmotic pretreatment with and without addition of calcium chloride in the nutritional characteristics and sensorial acceptance of dehydrated mango. Four different osmotic treatments were applied in mango slices followed by drying. Drying without osmotic treatment was considered control. Dried samples pre-treated with calcium had lower sugar content and higher retention of acids in the fruit. The increase of sucrose and glucose content during osmotic treatment contributed to maintaining nutritional quality and color of the product when compared with control treatment. Products dehydrated with osmotic pre-treatment were the most preferred, presenting higher purchase intention. The combination of osmotic pretreatment with convective drying provided higher acceptance of dehydrated mango due to its higher quality.


2012 ◽  
Vol 45 (2) ◽  
pp. 5-14 ◽  
Author(s):  
R. Chayjan ◽  
H. Agha-Alizade ◽  
H. Barikloo ◽  
B. Soleymani

Modeling Some Drying Characteristics of Cantaloupe Slices This study investigated thin layer drying of cantaloupe slices under different drying conditions with initial moisture content about 18.53 (d.b.). Air temperature levels of 40, 50, 60 and 70°C were applied in drying of samples. Fick's second law in diffusion was applied to compute the effective moisture diffusivity (Deff) of cantaloupe slices. Minimum and maximum values of Deff were 4.05x10-10 and 1.61x10-9 m2/s, respectively. Deff values increased as the input air temperature was increased. Activation energy values of cantaloupe slices were found between 30.43 and 36.23 kJ/mol for 40°C to 70°C, respectively. The specific energy consumption for drying cantaloupe slices was calculated at the boundary of 1.01x105 and 9.55x105 kJ/kg. Increasing in drying air temperature in different air velocities led to increase in specific energy value. Results showed that applying the temperature of 70°C is more effective for convective drying of cantaloupe slices. The aforesaid drying parameters are important to select the best operational point of a dryer and to precise design of the system.


2020 ◽  
Vol 193 ◽  
pp. 01067
Author(s):  
Mirolim Aripov ◽  
Sherzod Mamatov ◽  
Sadriddin Turobjonov

In this paper, we studied the characteristics of drying red beets that were pretreated using microwaves before convective drying. The results of shortening the drying period using microwave pre-treatment during drying are analyzed. Experimental data were also obtained and the rehydration process of the dried sample was compared.


2018 ◽  
Vol 192 ◽  
pp. 03041
Author(s):  
Setthawat Thanimkarn ◽  
Ekkapong Cheevitsopon ◽  
Jiraporn Sripinyowanich Jongyingcharoen

This study aimed to investigate the effect of drying temperature (40, 60, 80, and 100°C) on drying characteristics of Cissus quadrangularis Linn. (CQ) undergoing convective drying. Physical properties and phytochemicals of the dried CQ were also evaluated. CQ with the thickness of 5 mm was dried from about 10 to 0.1 g water/g dry matter. The results showed that increasing drying temperature increased drying rate (DR) and effective moisture diffusivity (Deff) and consequently decreased drying time. The drying time, maximum DR, and Deff were in the ranges of 85-1920 min, 0.0059-0.0248 g water/g dry matter·min, and 0.7302-9.1281×10-9 m2/s, respectively. Lower drying temperature could preserve quality of the dried CQ. Decreasing drying temperature resulted in greener and lower bulk density and shrinkage. The greatest total phenolic content (TPC) and quercetin content were obtained by drying the CQ at 60°C.


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