Effective moisture diffusivity, colour and consumer acceptability of marula (Sclerocarya birrea) fruit leather as affected by drying hot air temperature and added sugar

2020 ◽  
pp. 111-120
Author(s):  
P.F. Ndlovu ◽  
O.C. Wokadala ◽  
S.Z. Tesfay ◽  
S.P. Lepule ◽  
M.E.K. Ngcobo ◽  
...  
Keyword(s):  
Air Temperature ◽  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Consumer Acceptability ◽  
Added Sugar ◽  
Sclerocarya Birrea ◽  
Hot Air ◽  
Effective Moisture

Modelling Effective Moisture Diffusivity of Pumpkin (Cucurbita moschata) Slices under Convective Hot Air Drying Condition

2016 ◽  
Vol 12 (5) ◽  
pp. 481-489 ◽  
Author(s):  
Daniel I. Onwude ◽  
Norhashila Hashim ◽  
Rimfiel B. Janius ◽  
Nazmi Nawi ◽  
Khalina Abdan
Keyword(s):  
Activation Energy ◽  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Slice Thickness ◽  
Cucurbita Moschata ◽  
Drying Time ◽  
Hot Air ◽  
Effective Moisture ◽  
Shrinkage Effect ◽  
Increasing Temperature

Abstract This study seeks to investigate the effects of temperature (50, 60, 70 and 80 °C) and material thickness (3, 5 and 7 mm), on the drying characteristics of pumpkin (Cucurbita moschata). Experimental data were used to estimate the effective moisture diffusivities and activation energy of pumpkin by using solutions of Fick’s second law of diffusion or its simplified form. The calculated value of moisture diffusivity with and without shrinkage effect varied from a minimum of 1.942 × 10–8 m2/s to a maximum of 9.196 × 10–8 m2/s, while that of activation energy varied from 5.02158 to 32.14542 kJ/mol with temperature ranging from 50 to 80 °C and slice thickness of 3 to 7 mm at constant air velocity of 1.16 m/s, respectively. The results indicated that with increasing temperature, and reduction of slice thickness, the drying time was reduced by more than 30 %. The effective moisture diffusivity increased with an increase in drying temperature with or without shrinkage effect. An increase in the activation energy was observed due to an increase in the slice thickness of the pumpkin samples.

Microwave Drying of Pitaya (Hylocereus) Peel and the Effects Compared with Hot-Air and Freeze-drying

2019 ◽  
Vol 62 (4) ◽  
pp. 919-928 ◽  
Author(s):  
Ying Ming Chew ◽  
V. An-Erl King
Keyword(s):  
Freeze Drying ◽  
Arrhenius Equation ◽  
Moisture Diffusivity ◽  
Microwave Drying ◽  
Effective Moisture Diffusivity ◽  
Fick’S Law ◽  
Fick's Law ◽  
Hot Air ◽  
Effective Moisture ◽  
Dpph Scavenging

Abstract. Microwave drying (MD) of pitaya peel was performed at 75, 225, 375, 525, and 750 W. The drying effects on the effective moisture diffusivity (De), total polyphenol content (TPC), betalain content, DPPH scavenging ability, and rehydration abilities of pitaya peel were examined. The data were compared with hot-air drying (HD) at 100°C for 4 h and freeze-drying (FD) for 24 h. The results showed that the MD kinetics of pitaya peel fit Fick’s law and the Arrhenius equation with an activation energy (Ea) of 34.08 W g-1. The De values of MD, which ranged from 2.35E-07 m2 s-1 (at 75 W) to 5.56E-06 m2 s-1 (at 750 W), indicated that the effectiveness of MD was appreciably higher than that of HD (2.44E-08 m2 s-1) and FD (4.43E-09 m2 s-1). Although MD resulted in decreased betacyanin (9.31 mg L-1 extract) and betaxanthin (6.58 mg L-1 extract) contents, the DPPH inhibition of pitaya peel remained at 75% due to an increase in TPC (115 mg GAE per 100 FW). MD of pitaya peel can also provide higher rehydration ability than HD and was comparable to FD. This study concludes that MD of pitaya peel was highly effective while maintaining high levels of TPC and DPPH inhibition. Keywords: Arrhenius equation, Effective moisture diffusivity, Fick’s law, Microwave drying, Pitaya peel.

Comparative Study on Drying of Selected Marine Products: Bombay Duck (Herpodon nehereus) and Prawn (Penaeus indicus)

2011 ◽  
Vol 7 (4) ◽  
Author(s):  
Ganesh Lotanrao Visavale ◽  
Parag P Sutar ◽  
Bhaskar Narayan Thorat
Keyword(s):  
Freeze Drying ◽  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Hot Air ◽  
Effective Moisture ◽  
Page Model ◽  
Drying Behavior ◽  
Marine Products ◽  
Drying Rates ◽  
Bombay Duck

A study on drying of two types of fish, viz., Bombay duck and Prawn, using the open sun, a solar cabinet, hot air and freeze drying was carried out. The fish were dried to 5–6% moisture content. The drying rates were calculated and drying data were fitted to the Page model, and on the basis of R2 and RMSE values it was found that the Page model describes satisfactorily the drying behavior of Bombay duck and Prawn. Also, effective moisture diffusivity values were calculated during fish drying by different methods. The values of the average effective moisture diffusivity of Bombay duck and Prawn were in the range of 1.01 × 10-9 to 1.51 × 10-9 m2 s-1and 0.21 × 10-9 to 0.31 × 10-9 m2 s-1, respectively. Freeze drying was found to provide the best quality of dehydrated product, which was as expected. Solar cabinet drying was found to be a low-energy intensive process compared to freeze and hot air drying, resulting in a dehydrated product with acceptable quality.

scholarly journals Modelling the Drying Characteristics and Kinetics of Hot Air-Drying of Unblanched Whole Red Pepper and Blanched Bitter Leaf Slices

2017 ◽  
Vol 5 (1) ◽  
pp. 24
Author(s):  
Samuel Enahoro Agarry
Keyword(s):  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Red Pepper ◽  
Coefficient Of Determination ◽  
Drying Time ◽  
Drying Characteristics ◽  
Hot Air ◽  
Effective Moisture ◽  
Drying Curves ◽  
Kinetics Of

The objective of this study was to investigate the drying characteristics and kinetics of red pepper and bitter leaf under the influence of different drying temperatures. The drying experiments were carried out at dry bulb temperature of 35, 45, 55 and 75oC, respectively in an oven dryer. The results showed that as drying temperature increased, drying rate also increased and the drying time decreased. It was observed that un-sliced red pepper and sliced bitter leaf would dry within 2.5-12 h and 1.67-7 h, respectively at temperature ranging from 75 to 35oC. The drying of red pepper and bitter leaf was both in the constant and falling rate period. Four semi-empirical mathematical drying models (Newton, Page, Henderson and Pabis, and Logarithmic models) were fitted to the experimental drying curves. The models were compared using the coefficient of determination (R^2) and the root mean square error (RMSE). The Page model has shown a better fit to the experimental drying data of red pepper and bitter leaf, respectively as relatively compared to other tested models. Moisture transport during drying was described by the application of Fick’s diffusion model and the effective moisture diffusivity was estimated. The value ranges from 15.69 to 84.79 × 10-9 m2/s and 0.294 to 1.263 × 10-9 m2/s for red pepper and bitter leaf, respectively. The Arrhenius-type relationship describes the temperature dependence of effective moisture diffusivity and was determined to be 37.11 kJ/mol and 32.86 kJ/mol for red pepper and bitter leaf, respectively. A correlation between the drying time and the heat transfer area was also developed.

Effective moisture diffusivity and drying simulation of walnuts under hot air

2020 ◽  
Vol 150 ◽  
pp. 119283 ◽  
Author(s):  
Chang Chen ◽  
Chandrasekar Venkitasamy ◽  
Weipeng Zhang ◽  
Ragab Khir ◽  
Shrinivasa Upadhyaya ◽  
...  
Keyword(s):  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Hot Air ◽  
Effective Moisture

scholarly journals Effective moisture diffusivity during hot air solar drying of tomato slices

2016 ◽  
Vol 62 (No. 1) ◽  
pp. 15-23 ◽  
Author(s):  
H. Samimi Akhijani ◽  
A. Arabhosseini ◽  
M.H. Kianmehr
Keyword(s):  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Slice Thickness ◽  
Solar Drying ◽  
Air Velocity ◽  
Hot Air Drying ◽  
Chi Square ◽  
Air Drying ◽  
Hot Air ◽  
Effective Moisture

Mathematical modelling and effective moisture diffusivity of tomato (Lycopersicon esculentum) was studied during hot air solar drying. An experimental solar dryer with a swivel collector was used for experiments. The collector followed the solar radiation using a precious sensor. Drying experiments were performed in a thin layer hot air drying at slice thicknesses of 3, 5 and 7 mm and air velocities of 0.5, 1 and 2 m/s. The experimental data were fitted to different mathematical moisture ratio models and the Page model was selected as the best model according to correlation coefficient R<sup>2</sup>, chi-square &chi;<sup>2</sup> and root mean square error (RMSE) parameters. The maximum values of moisture diffusivity was&nbsp;6.98 &times; 10<sup>&ndash;9</sup> m<sup>2</sup>/s at air velocity of 2 m/s and slice thickness of 7 mm while the minimum value of the moisture diffusivity was 1.58 &times; 10<sup>&ndash;9</sup> m<sup>2</sup>/s at air velocity of 0.5 m/s and slice thickness of 3 mm.

scholarly journals EFFECT OF DIFFERENT TEMPERATURE ON REHYDRATION KINETICS OF CHICKEN BREAST MEAT CUBES

2021 ◽  
Vol 51 (3) ◽  
pp. 211-216
Author(s):  
Orhan Ozunlu ◽  
Haluk Ergezer ◽  
Engin Demiray ◽  
Ramazan Gokce
Keyword(s):  
Moisture Diffusivity ◽  
Chicken Meat ◽  
Effective Moisture Diffusivity ◽  
Chicken Breast ◽  
Breast Meat ◽  
First Order ◽  
Hot Air ◽  
Effective Moisture ◽  
Kinetics Of ◽  
Chicken Breast Meat

In the present research, it was aimed to understand the effect of different rehydration temperatures (80, 90 and 100°C) on rehydration kinetics of hot air dried chicken breast meat cubes. The rehydration rate increased with the increasing of temperature of rehydration water. ΔE and chroma values of the rehydrated samples at 90°C and 100°C samples were found statistically similar. To describe the rehydration kinetics, four different models, Peleg’s, Weibull, first order and exponential association, were considered. Between these four models proposed Peleg’s model gave a better fit for all rehydration conditions applied. The effective moisture diffusivity values of chicken meat increased as water rehydration temperature increased.

Microwave Assisted Convective Air Drying of Sugarloaf Pineapples (Ananas Comosus)

2021 ◽  
Vol 37 (5) ◽  
pp. 763-774
Author(s):  
Ernest Ekow Abano
Keyword(s):  
Air Temperature ◽  
Microwave Power ◽  
Moisture Diffusivity ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Microwave Assisted ◽  
Hot Air ◽  
Effective Moisture ◽  
Drying Conditions

HighlightsMicrowave pretreatment before drying reduced drying time significantly.Microwave-assisted drying increased the effective moisture diffusivity coefficient.Microwave pretreatment before convective hot-air drying improved quality parameters.The Middili et al. (2002) model best fitted the microwave-assisted drying of sugarloaf pineapples.Abstract. This study’s objective was to provide the optimum drying conditions to produce quality dried sugarloaf pineapples using microwave pretreatments before the conventional hot air drying. For this, the effect of microwave power (385 to 697 W), microwave time (2 to 4 min), and air temperature (50°C to 70°C) on the drying kinetics and quality of sugarloaf pineapple were evaluated using the Box Behnken response surface methodology. To reach a 17.44±0.09% kg/kg dry matter moisture content, we found the optimum drying conditions for sugarloaf pineapples to be 697 W microwave power for 2.26 min before convective hot air drying at a temperature of 64.75°C. The predicted drying time, ascorbic acid content, and browning index were 13.68 h, 20.89 mg/100 g, and 0.099 Abs unit at this optimum condition, respectively. The pineapple slices’ effective moisture removal rate pretreated with microwave before drying was higher than the control and was between 6.42 × 10-10 m2/s and 11.82 × 10-10 m2/s while ones without a microwave were between 3.54 × 10-10 m2/s and 8.78 × 10-10 m2/s for drying at air temperature between 50°C and 70°C. It was discovered that the Midilli et al. (2002) model was the most appropriate thin layer model for microwave-assisted drying of sugarloaf pineapples. The pineapple slices’ drying rate potential generally increased with microwave power and pretreatments time but not the corresponding increase in the air temperature. Drying time for microwave-assisted drying was in the range of 11 to 20 h, while the ones without microwaves were between 18 and 24 h. Therefore, microwaves should be considered a pretreatment step to the industrial production of sugarloaf pineapple to reduce drying time and produce better quality products. Keywords: Drying, Hot air, Microwave, Moisture diffusivity, Sugarloaf pineapple.

Experimental Investigation to Evaluate the Effective Moisture Diffusivity and Activation Energy of Cassava (Manihot Esculenta) under Convective Drying

2021 ◽  
Author(s):  
Pathiwat Waramit ◽  
Bundit Krittakom ◽  
Ratinun Luampon
Keyword(s):  
Activation Energy ◽  
Type Equation ◽  
Moisture Diffusivity ◽  
Experimental Results ◽  
Effective Moisture Diffusivity ◽  
Convective Drying ◽  
Air Velocity ◽  
Drying Time ◽  
Hot Air ◽  
Effective Moisture

Investigation of effective moisture diffusivity (Deff) and activation energy (Ea) of cassava were conducted under convective drying at temperature and velocity of 60, 70 and 80 °C, and 1.0, 1.5 and 2.0 m/s, respectively. In the experiment, cassava was sliced into 3 mm-thickness and dried under given conditions until mass was saturated. Deff and Ea were described by Fick’s second law and Arrhenius-type equation, respectively. The experimental results indicated that the increase in Deff was significantly affected by increasing the hot air temperature and velocity. The slope method was used to calculate average Deff, and results were found to range from 3.83 × 10–9 – 9.86 × 10–9 m2/s. The Ea was found to decrease with an increase in hot air velocity, ranging from 21.23– 24.92 kJ/mol. Additionally, Moisture content (Mw) and Drying rate (DR) were also used to describe the drying kinetics. From the experimental results, Mw and DR decreased with an increase in drying time. DR increased with an increase in temperature and velocity causing Mw to rapidly decrease and drying time to reduce. The highest DR was found to be 0.55 gwater/min at temperature of 80 °C and velocity of 2.0 m/s.

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