The Temperature Influence on Drying Kinetics and Physico-Chemical Properties of Pomegranate Peels and Seeds (original) (raw)
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Drying Kinetics of Pomegranate (Punica Granatum) Peels
The main product of pomegranate is the juice extracted from the shells. The peels, a by-product after pomegranate juice processing, can be used as animals feed or submitted to extraction of bioactive compounds. The effects of drying parameters before extraction are important in the quality attributes of final products. Thus, the aim of this work was study the drying process of pomegranate peels in order to obtain the best operational condition to preserve the bioactive compounds in the dried raw material. The shells were then dried in a lab cabinet dryer at 40, 50 and 60ºC, air velocity of 1 ms -1 , in triplicate assay. Drying curves obtained from the experimental data are fitted from Fick's second law of diffusion for evaluating a suitable thin layer drying model. Statistica (v.7.0) was used to estimate the effective diffusivity (D ef) that reached the maximum value of 1.57 x 10 -10 m 2 s -1 at 60°C.
Drying kinetics of pomegranate fruit peel (cv. Wonderful)
Scientific African, 2019
Pomegranate juice processing produces large amount of peel as by-product or waste which is a potential source of raw material for food and other bioprocessing industries. Drying the peel offers opportunities for value addition into novel products, thus reducing waste from the fruit processing operations. This study presents the mathematical models of thin layer drying behaviour of pomegranate peels (initial thickness 5.00 ± 0.05 mm and moisture content 70.30% wet basis) using three air temperatures (40 °C, 50 °C and 60 °C) at a constant air velocity of 1.0 m/s. The results obtained showed that drying time decreased as the oven drying temperature increased. The drying process took place mainly in the falling rate period. Ten thin layer drying models were evaluated based on coefficient of determination (r 2) and standard error (e s). Among the tested drying models, Midilli et al. mathematical model was found to be the best fit for establishing the drying kinetics of pomegranate peel. Furthermore, the effective moisture diffusivity of pomegranate peel ranged from 4.05 × 10 −10 to 8.10 × 10 −10 m 2 /s over the temperature range investigated, with mean activation energy (Ea) of 22.25 kJ/mol.
2014
Samples of pomegranate peels and seeds were dried in laboratory dryer at different temperatures (70, 80, 90 and 100°C) and (50, 60, 70 and 80°C) respectively. The results indicated that drying took place in the falling rate period at all temperatures studied for all samples. Moisture transfer from pomegranate peels and seeds was described by applying the Fick's diffusion model, and the effective diffusivity was calculated. Effective diffusivity increased with increasing temperature. An Arrhenius relation with an activation energy value of 7189.282 kJ/mol. for pomegranate seeds and 11223.9for pomegranate peels. The effect of temperature on vitamin C,minerals and antioxidant was investigated
Journal of Agricultural Science and Technology, 2017
For years, sun and hot air drying have been considered as traditional drying methods. Today, using microwave is one the newest methods of drying. Iran is one of the main producers of pomegranate fruit in the world. To manufacture better product, drying needs to be handled in controlled and optimized process, therefore investigation of process condition kinetic is an obligation. In this study, thin layer drying behavior of pomegranate arils using microwave drier at 4 power levels (180, 360, 540 and 720W), oven drier at 4 temperature levels (45, 55, 65 and 75°C) and sun drying was studied. Page, Henderson and Pabis, Midilli et al., Newton, Logarithmic and Two-Term models were compared according to their Root Mean Square error (RMSE), Chi-square (χ), Mean Bias Error (MBE) and correlation coefficient (R). The results of the studied models indicated that Midilli et al., model exhibited the best fit to the data obtained for oven, microwave and sun drying. Increasing the oven drier tempera...
Processes
The effect of blanching conditions on the hot-air drying kinetics of three pomegranates (cvs. “Acco”, “Herskawitz” and “Wonderful”) were assessed. Water blanching conditions considered were 90 °C for 30 s, 90 °C for 60 s, 100 °C for 30 s and 100 °C for 60 s. The drying experiments were carried out at 60 °C, 19.6% relative humidity and at a constant air velocity of 1.0 m s−1. The experimental curves were fitted to seven different drying models. For the Acco cultivar, the drying behaviour was best predicted by the Logarithmic and Page model for blanched (R2 ranging between 0.9966 and 0.9989) and unblanched (R2 = 0.9918) samples, respectively. Furthermore, for the Herskawitz cultivar, Logarithm, Page and Midili models were most suitable for predicting drying behaviour of both blanched and unblanched samples. Also, for the Wonderful cultivar, Logarithm and Midili models were most accurate for predicting the drying behaviour for both blanched and unblanched samples amongst other models. ...
Quality of pomegranate pomace as affected by drying method
Journal of Food Science and Technology, 2018
During the industrial manufacturing of pomegranate juice, large amounts of pomace are produced. The aim of this work was to find the effective method to dry pomegranate pomace to open new commercial applications for this co-product. The effects of three drying methods: (i) convective drying (CD) at 50, 60, and 70°C; (ii) vacuum microwave drying (VMD) at 240, 360, and 480 W, and (iii) a combined method (CPD-VMFD); convective pre-drying (60°C) followed by vacuum microwave finish drying (360 W), on drying kinetics and quality of PomP (pomegranate pomace obtained after preparing pomegranate juice by squeezing only arils) were evaluated. The shortest treatments were VMD at 240 and 360 W (52 and 33 min, respectively); besides, these treatments led to interesting values of the green-red coordinate, a*, (12.2 and 4.1, respectively), total phenolic content (4.0 and 4.1 mg eq gallic acid g-1 dry weight, respectively), and antioxidant activity (30.8 and 29.0 lmol g-1 dry weight, respectively). On the other hand, this study demonstrated that this co-product is a rich source of punicic acid (average value = 66.4%), being a good opportunity for the pharmaceutical and nutraceutical industries. Moreover, no significant changes in the fatty acid profile was observed as affected by the drying treatments, and no off-flavors were generated by any of the drying methods.
Effect of drum drying temperature on drying kinetic and polyphenol contents in pomegranate peel
Journal of Food Engineering, 2017
The pomegranate peel, an agro-industrial waste, has a high content of antioxidant polyphenolic compounds with proven health-benefiting and technological properties. Polyphenol stability might be affected by heat treatments that are required during drying. Thus, the aim of this study was to analyze the drying kinetics of pomegranate peel dried by double drum drying and to evaluate its effect on polyphenolic compounds. Pomegranate peel was dried at 100, 110 and 120°C using a constant clearance (2 mm); the processes were modeled and the physiochemical and antioxidant properties were analyzed. Drum drying at 100, 110 and 120°C were very fast processes that required short drying times (422 s, 400 s and 257 s, respectively) to reach low moisture contents (5.0, 1.6 and 2.6 g water/ 100 g peel, respectively). At these short drying times, the total polyphenolic content and antioxidant activity were not significantly decreased at any temperature, and the hydrolysable tannins content was maintained by drum drying at 100 and 110°C. Thus, the drum drying results demonstrate an efficient alternative to obtain a high quality product from pomegranate peel and thereby reuse and add value to this agro-industrial waste.
Standardization of Drying Method and Organoleptic Evaluation of Wild Pomegranate (Anardana) Seeds
2013
Drying of wild pomegranate seeds was carried out by using various drying methods to evaluate the best and feasible method of drying and to produce a value added product "anardana". The various drying methods used were vacuum drying, oven drying, sun drying, poly-tent house drying and room drying. The experimental results showed that out of all the drying methods, sun drying method for anardana preparation is the best one method as it resulted in 73.62% reduction in moisture content with a dehydration ratio of 3.81. Moreover, overall acceptance score of 23.4 was obtained which was significantly higher as compared to other treatments under study. Wild pomegranate (Punica protopunica L.) belongs hymenoletidosis, dyspepsia, bronchitis and cardiac to the plant family Punicaceae. It is a hardy and can problem. It is also used in tanning and colouring in survive in arid as well as in semi-arid climatic industries (3). Besides, therauptic use includes condiment conditions. As a cr...
Food and Bioprocess Technology
The drying of pomegranate seeds was investigated at 40 °C, 50 °C and 60 °C with air velocity of 2 m/s. Prior to drying, seeds were osmodehydrated in 55 °Brix sucrose solution for 20 min at 50 °C. The drying kinetics and the effects of osmotic dehydration (OD) and air-drying temperature on antioxidant capacity, total phenolics, colour and texture were determined. Analysis of variance revealed that OD and air-drying temperature have a significant influence on the quality of seeds. Both anthocyanin and total phenolic contents decreased when air-drying temperature increased. The radical diphenylpicril-hydrazyl activity showed the lowest antioxidant activity at 60 °C. Both chromatic parameters (L*, C* and h°) and browning index were affected by drying temperatures, which contributed to the discolouring of seeds. The final product has 22%, 20% and 16% of moisture; 0.630, 0.478 and 0.414 of a w; 151, 141 and 134 mg gallic acid equivalent/100 g fresh matter (FM) of total phenolics; 40, 24, 20 mg/100 g FM of anthocyanins and 46%, 39% and 31% of antioxidant activity, for drying temperatures of 40 °C, 50 °C and 60 °C, respectively. In view of these results, the temperature of 40 °C is recommended as it has the lowest impact on the quality parameters of the seeds. Differential scanning calorimetry data provided complementary information on the mobility changes of water during drying. Glass transition temperature (Tg′) depends on moisture content and as consequence, on drying conditions. In fact, Tg′ of seeds dried at 60 °C (Tg′ = −21 °C) was higher than those dried at 50 °C (Tg′ = −28 °C) or 40 °C (Tg′ = −31 °C) and osmodehydrated seeds (Tg′ = −34 °C). During OD and drying process, the texture of seeds changed. The thickness of seeds shrank by 55% at 60 °C.