Convective and microwave drying influence on the chemical composition, functional properties and sensory quality of pomegranate arils and rind (original) (raw)
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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.
Foods
Pomegranate is a fruit desirable for its nutritional and medicinal properties which has a great industrial potential that is yet under-explored. Notable for its integral use, the peels are used in medicinal infusions and the seeds consumed without restrictions. In this sense, the objective of this work is to determine the drying kinetics of pomegranate peels and seeds in a hot air circulation oven, at temperatures of 50, 60, and 70 °C, adjust mathematical models to experimental data, determine the effective diffusivities and thermodynamic properties of the process and the physicochemical characteristics of peels and seeds of fresh pomegranates and in their flours. Twelve models were used to adjust the drying kinetics, obtaining better results with the Diffusion Approximation model, Verma, and modified Henderson and Pabis. The effective diffusivities were well represented by an Arrhenius equation, with activation energies of 31.39 kJ/mol for seeds and 10.60 kJ/mol for peels. In the d...
Scientia Horticulturae, 2020
Drying of different parts of wild pomegranate fruits such as arils, flavedo (peel), albedo (inner membrane) and pomace (residue remains after juice extraction from arils) were carried out with four different methods viz. natural sun drying (D 1), solar tunnel drier (D 2), mechanical cabinet (D 3) and oven (D 4) drying. Different attributes such as yield, drying time, moisture, total phenols (TP), total flavonoids (TF) and antioxidant properties of dried samples (arils, flavedo, albedo and pomace) were evaluated separately during the study. Out of which, one drying method (D 3) with one fruit part (flavedo) was selected for comparison on the basis of highest TP, TF, DPPH antioxidant activity (AA), metal chelating activity (MA) and ferric reducing antioxidant power (FRAP). The functional groups of mechanical cabinet dried arils and flavedo were analyzed by FTIR, which indicates the presence of significant amount of phytochemicals in flavedo than arils. Further, effect of drying temperature shows that lyophilized flavedo had comparatively higher L* (33.40), a* (3.68), b* (13.78) values, TP (61.87 mg GAE/g), TF (8.48 mg QuE/g), AA (91 %), MA (63.86 %) and FRAP (3.40 μM Fe 2+ /g) as compared to mechanical cabinet dried flavedo. The study concluded that lyophilized wild pomegranate fruit flavedo could be utilized in pharmaceutical and nutraceutical industries to make various functional/nutraceutical foods.
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.
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
Open Agriculture, 2021
In this study, the drying kinetics, effective moisture diffusivity (D eff), specific energy consumption (SEC), colour, and shrinkage (S b) of pomegranate arils were compared when dried by convective (CV) drying and microwave (MW) drying. The experiments were performed at air temperature of 50, 60, and 70°C and air velocity of 1 m/s for CV drying and 270, 450, and 630 W for MW drying. The results showed that increasing air temperature and MW power increased the D eff. The calculations demonstrated that the maximum D eff for pomegranate arils was obtained for MW drying (630 W). Maximum SEC for pomegranate arils in the CV dryer was 145.12 kWh/kg, whereas in the MW dryer was 35.42 kWh/kg. In MW dryer, the lowest values of colour change and shrinkage were 6.77 and 50.5%, respectively. Comprehensive comparison of the different drying methods (MW and CV) revealed that MW drying had best drying performance for pomegranate arils, considering the drying time, effective moisture diffusion, SEC...
Effective moisture diffusivity of pomegranate arils under going microwave-vacuum drying
Journal of Food Engineering, 2014
Drying of pomegranate arils was done using microwave-vacuum technique, using microwave power of 25 to 95 W, vacuum pressure of 25 to 195 mm Hg and sample mass of 65 to 235 g. The effective moisture diffusivity varied from 5.18 Â 10 À11 to 6.58 Â 10 À10 m 2 /s. Effective moisture diffusivity (D eff) values were found to increase as microwave power increases or sample mass decreases for constant values of remaining variables while vacuum pressure had negligible effect. A third order polynomial relationship was found to correlate the effective moisture diffusivity (D eff) with moisture content. Multivariate polynomial models were also developed for estimating the effective moisture diffusivity as a function of the microwave-vacuum drying process parameters.
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.