scholarly journals Effect of air drying on quality characteristics and mass transfer kinetics of osmotically dehydrated sea buckthorn by stevia

Food Research ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 1140-1150
Author(s):  
G. Lentzou ◽  
Ch. Templalexis ◽  
G. Xanthopoulos

Sea buckthorn is ranked among the most significant super foods worldwide. Its fruits and leaves are used as fresh or dried in food, pharmaceutical and cosmetic industry. As super food any pre-treatment should sustain this property and hence this research was focused on osmotic dehydration of sea buckthorn by stevia also a super food. Therefore, water loss, sugar gain, acidity, ascorbic acid and water diffusivity were evaluated during osmotic dehydration of sea buckthorn by two stevia solutions, 15ο and 30οBrix and following were air-dried at 50οC by comparing the effect of steam blanching per case. Steam blanched samples exhibited increased water loss at the end of the process, 55% at 30οBrix and 48% at 15οBrix, compared to untreated samples where losses were 43% (30οBrix) and 28% (15οBrix) respectively. Ascorbic acid was significantly reduced, exceeding 50% in steam blanched samples and 23% in untreated samples. Steam blanched samples dehydrated at 15oBrix exhibited 82% dry matter increase and only 39% the untreated samples. Similarly, samples dehydrated at 30oBrix exhibited 84% dry matter increase and 53% when no steam blanching was applied. Solid gain was seven times less compared to water loss which is attributed to high molecular weight of steviol glycoside. The osmotic dehydration and airdrying curves were described effectively by Peleg and Fick models, and Logarithmic and Fick models respectively, having in all cases R2 adj>99% and SEE<0.2. The water diffusivity of steam blanched samples was 3.2-5.57×10-11 m 2 /s for water loss and 1.27- 2.03×10-11 m 2 /s for solid gain at 30oBrix and 2.12-4.27×10-11 m 2 /s and 0.91-1.98×10-11 m 2 /s at 15oBrix. Finally, the water diffusivity of steam blanched samples during air-drying was 2.11-2.29×10-11 m 2 /s and 1.56-1.66×10-11 m 2 /s in the case of untreated samples.

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1846
Author(s):  
Varvara Andreou ◽  
Ioanna Thanou ◽  
Marianna Giannoglou ◽  
Maria C. Giannakourou ◽  
George Katsaros

This study concerns the implementation of osmotic dehydration (OD) as a pre-treatment of air-drying in fig halves, aiming at drying acceleration, energy savings and product quality improvement. The effect of solid/liquid mass ratio, process temperature (25–45 °C) and duration (up to 300 min) on water activity (aw) and transport phenomena during OD, was modelled. The effective diffusion coefficients, drying time and energy consumption, were also calculated during air-drying at 50–70 °C. At optimum OD conditions (90 min, 45 °C), the highest water loss and solid gain ratio were achieved, while the aw (equal to an initial value 0.986) was decreased to 0.929. Air-drying time of OD- and control samples was estimated at 12 and 21 h, at 60 °C, respectively, decreasing the required energy by up to 31.1%. Quality of dried figs was systematically monitored during storage. OD-assisted air-drying led to a product of improved quality and extended shelf-life.


2003 ◽  
Vol 9 (6) ◽  
pp. 427-433 ◽  
Author(s):  
P. M. Azoubel ◽  
F. E.X. Murr

Osmotic dehydration of cashew apple in sucrose and corn syrup solids solutions as influenced by temperature (30-50 C), sugar syrup concentration (40-60% w/w) and immersion time (90-240 min) was studied through response surface methodology. Responses of water loss (%) and solid gain (%) were fitted to polynomials, with multiple correlation coefficients ranging from 0.92 to 0.99. The fitted functions were optimised for maximum water loss and minimised incorporation of solids in order to obtain a product resembling non-processed fruit. Three optimum sets were selected for each solute and the ascorbic acid content was determined. The ascorbic acid losses were similar to those reported for osmotic dehydration processes.


2016 ◽  
Vol 12 (6) ◽  
pp. 515-525 ◽  
Author(s):  
N. Ghanem Romdhane ◽  
N. Djendoubi ◽  
C. Bonazzi ◽  
N. Kechaou ◽  
N. Boudhrioua Mihoubi

Abstract Combined osmotic dehydration (sucrose solution: 50–70 % w/w, 30–50 °C for 2 h followed by air drying at 40 and 60 °C) is an appropriate process for preservation of oil retention capacity, lightness and yellowness of lemon peels (Citrus limon. v. lunari). Incorporation of sugars to lemon cuboids pieces increased drying rate during the first falling rate phase of the air dehydration step and improved their color stability. Osmotic dehydration process allows protective effect against further total phenol loss during air drying: significant loss of total phenol content (70–80 %) was recorded during osmotic dehydration and then it remains constant during air drying at 40 and 60 °C. For the investigated temperature of osmotic pre-treatment (30–50 °C), water retention capacities were reduced by up to 70 % and were maintained constant during air drying.


Author(s):  
Fernanda Rezende Abrahão ◽  
Jefferson Luiz Gomes Corrêa

Foods ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 308
Author(s):  
S. M. Atiqure Rahman ◽  
Ahmed M. Nassef ◽  
Mujahed Al-Dhaifallah ◽  
Mohammad Ali Abdelkareem ◽  
Hegazy Rezk

A study on mass transfer using new coating materials (namely alginic acid and polygalacturonic acid) during osmotic dehydration—and hence in a laboratory-scale convective dryer to evaluate drying performance—was carried out. Potato and apple samples were examined as model heat-sensitive products in this study. Results indicate that the coating material containing both alginic acid and polygalacturonic acid causes higher water loss of about 17% and 7.5% and lower solid gain of about 4% and 8%, respectively, compared to uncoated potato sample after a typical 90 min osmotic dehydration process. Investigation of drying performance using both coating materials showed a higher reduction in the moisture content of about 22% and 18%, respectively, compared with uncoated samples after the 3 h drying period. Comparisons between the two proposed coating materials were also carried out. Samples (potato) coated with alginic acid demonstrated better performance in terms of higher water loss (WL), lower solid gain (SG), and notable enhancement of drying performance of about 7.5%, 8%, and 8%, respectively, compared to polygalacturonic acid. Similar outcomes were observed using apple samples. Additionally, an accurate model of the drying process based on the experimental dataset was created using an artificial neural network (ANN). The obtained mean square errors (MSEs) for the predicted water loss and solid gain outputs of the potato model were 4.0948e−5 and 3.924e−6, respectively. However, these values for the same parameters were 3.164e−5 and 4.4915e−6 for the apple model. The coefficient of determination (r2) values for the two outputs of the potato model were found to be 0.99969 and 0.99895, respectively, while they were 0.99982 and 0.99913 for the apple model, which reinforces the modeling phase.


2003 ◽  
Vol 9 (5) ◽  
pp. 321-328 ◽  
Author(s):  
M. Chafer ◽  
C. Gonzalez-Martinez ◽  
B. Fernandez ◽  
L. Perez ◽  
A. Chiralt

Osmotic dehydration of pear cylinders (var. blanquilla) was studied by analysing the effect of blanching pre-treatment and the application of a vacuum pulse on the kinetics and yield of the process and on product quality (colour and mechanical behaviour). Fresh and stem-blanched samples were treated with 65 Brix sucrose at atmospheric pressure and by applying a vacuum pulse (50 mbar for 5 min). The influence of the sugar gain and water loss fluxes, and the tissue structural response to the vacuum pulse, on the total mass and volume losses of the samples has been discussed. Blanching implied an increase in the mass transfer rate in pear tissue. Vacuum pulse in blanched samples resulted in more volume compression than sample impregnation with the external solution due to the sample softening by thermal effect and to the partial gas release during its thermal expansion. This provoked the greatest volume losses and a reductionof the ratio of sugar gain to water loss, where the highest values reached were for non-blanched samples submitted to vacuum pulse. Mechanical changes induced by treatments were similar inall cases, but colour hue and chrome were better preserved in samples treated by PVOD. Nevertheless, this treatment implied a transparency gain due to the sample gas release and so, samples become darker.


Author(s):  
Fabiano An. Fernandes ◽  
Sueli Rodrigues

Abstract Genipap (Genipa americana L.) is an exotic tropical fruit that can be used in production of sweets, liqueurs, and several other foodstuffs. In this work the effect of ultrasonic pre-treatment prior to air-drying on dehydration of genipap was investigated. The study allowed estimating the water diffusivity in the air-drying process for genipaps submitted to ultrasound. Results showed that the water diffusivity increased after application of ultrasound and that the overall drying time was reduced by 28.2%. During the ultrasonic treatment, genipaps lost sugar showing that the ultrasonic pre-treatment can be a valuable process to produce dried fruits with lower sugar content.


Author(s):  
Manivannan Petchi ◽  
Rajasimman Manivasagan

Response surface methodology was used to determine the optimum processing conditions that yield maximum water loss and weight reduction and minimum solid gain during osmotic dehydration of radish in salt solution. The experiments were conducted according to Central Composite Design (CCD). The independent process variables for osmotic dehydration process were temperature (25 – 45°C), processing time (30 -150 minutes), salt concentrations (5 - 25% w/w) and solution to sample ratio (5:1 – 25:1). The osmotic dehydration process was optimized for water loss, solid gain, and weight reduction. The optimum conditions were found to be: temperature – 36°C, immersion time - 95 min, salt concentration – 25% and solution to sample ratio 15:1. At this optimum point, water loss, solid gain and weight reduction were found to be 34.5 (g/100 g initial sample), 2.2 (g/100 g initial sample) and 32.1 (g/100 g initial sample), respectively.


Author(s):  
S. N. Patil ◽  
S. M. Shingade ◽  
R. C. Ranveer ◽  
A. K. Sahoo

The orange is 5th most important tropical fruit in the world production. The juice or pulp is extracted from the oranges and preserved for further use. Whereas for fruits and vegetables, osmotic dehydration is considered as one of best method for preservation. Hence in the present research focus on optimize process conditions for osmotic dehydration of orange segments. Fresh orange fruits were peeled and segments were separated. These segments were osmotically dehydrated at different sugar syrup concentrations 40 to 700B, time 60 - 300 min. and fruit solution ratio 1:3 to 1:5. The observation recorded with respect to water loss (WL), solid gain (SG) and weight reduction (WR). The results showed 500 B sugar syrup concentration, 300 min. time, and 1:4 fruit to solution ratio were optimum conditions to obtain water loss of 44.49 %, solid gain 6.91 % and weight reduction of 51.40%. Osmotic dehydration can be one of the alternative methods for the orange preservation than the traditional methods of food preservations. Also, it will be helpful to preserve orange segments for the longer time, which will be beneficial to small scale entrepreneur to improve their socio- economical status.


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