Drying Kinetics of Microwave-Dried Vegetable Amaranth (Amaranthus dubius) Leaves

Mujaffar, Saheeda; Loy, Alex Lee

doi:10.5539/jfr.v5n6p33

Cited by 11 publications

(6 citation statements)

References 26 publications

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“…From Table 1, it can also be observed that the retention of chlorophyll was higher when the microwave drying was performed at power level of 720 W in comparison with other power levels (540 W & 900 W). Similar finding was reported by Alibas Ozkan, Akbudak, and Akbudak (2007) when the drying of spinach carried out at different power levels, less changes was observed at the power level of 750 W. In the research study of Mujaffar, Loy, and Augustine (2016), it was mentioned that the intensification of green color was perceived when microwave drying of amaranth leaves was accomplished at higher power levels.…”

Section: Resultssupporting

confidence: 83%

Influence of pre‐treatments on the degradation kinetics of chlorophylls in morisa xak (Amaranthus caudatus) leaves after microwave drying

Nayak

Chandrasekar

Haque

et al. 2021

J Food Process Engineering

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Drying is one of the complex processes, comprising parallel heat and mass transfer reactions. It extends the shelf life of perishable agricultural produces (like green leafy vegetables) by decreasing the level of water activity. In the present work, hot water and ultrasound pretreatments were conducted, prior to the dehydration of fresh morisa xak (Amaranthus caudatus) leaves by microwave drying for improving color stability. In order to assess the color degradation kinetics of chlorophyll, the impact of drying techniques on hunter color parameters (L*, a*, b*) and total color difference (TCD) has been evaluated. Thermal degradation of chlorophyll of the green leaves followed the first order kinetics and Arrhenius equation was employed to describe the temperature dependence of the reaction rate constant. From the study, the protective effect of ultra sound pretreatment on the color stability of morisa xak leaves prior to microwave drying can be observed. Practical Applications Morisa xak is popular and an important green leaves consumed by North Eastern Part of India. As it has high moisture content, morisa xak leaves has been prone to deterioration during post‐harvest storage. Microwave drying has been preferred over traditional hot air drying method due to its high drying rates and better drying quality. As chlorophyll is the main coloring pigment in green leaves, its deterioration is very common during drying. In the current investigation, different pre‐treatments (hot water and ultra sound) were applied to morisa xak leaves before microwave drying to improve the chlorophyll content. The results of the study indicated that the application of ultra sound pretreatment before microwave drying could be a promising technique in comparison with hot air drying method for drying of green leaves with minimum degradation in chlorophyll.

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Section: Resultssupporting

confidence: 83%

Influence of pre‐treatments on the degradation kinetics of chlorophylls in morisa xak (Amaranthus caudatus) leaves after microwave drying

Nayak

Chandrasekar

Haque

et al. 2021

J Food Process Engineering

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“…Pumpkin slices, dried with microwave (160 W and 350 W) had close a* values to fresh samples. Similarly, Mujaffar and Loy (2016) dried vegetable amaranth leaves with microwave at different powers (200, 500, 700, and 1000 W), but they reported that a* values of samples dried at low powers (200 and 500 W) were similar to fresh samples. The final color value to be discussed is b* value, which indicates yellow color when positive.…”

Section: Resultsmentioning

confidence: 98%

Phenolic content and some physical properties of dried broccoli as affected by drying method

Yılmaz

Şakıyan

Mazı

et al. 2018

Food sci. technol. int.

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Broccoli samples ( Brassica oleracea) with an initial moisture content of 82.87% (wb) were dried using microwave technology (18, 36, and 54 W/g). Convective drying was used as a control group. The dependent variables investigated in the study were phenolic content, color, rehydration capacity, and microstructure of broccoli samples. Moreover, the best fitting thin layer model to the experimental moisture ratio was determined. The phenolic contents were found as 892.4, 740.6, and 759.8 mg gallic acid/100 g dry matter for fresh, convective dried, and microwave (MW) dried at 54 W/g broccoli samples, respectively. The total phenolic content of samples dried at 54 W/g was closest to fresh samples compared to other MW power intensities and convective drying. A similar result was obtained for color values too. L*, a*, and b* of microwave-dried samples at 54 W/g were comparable to fresh broccoli. Another important result obtained from the study was the insignificant effect of drying conditions on rehydration capacity. In addition, it was found that microwave power had a positive effect on drying time; as the microwave powers applied were compared, the shortest drying time was reached at 54 W/g. When the process durations of microwave drying and convective drying were compared, it can be reported that a much lower process time for microwave drying was obtained with respect to convective drying. Drying in microwave oven has reduced the drying time by 49-52%. In the light of the results obtained, it may be declared that it is possible to produce high-quality dried broccoli samples in a very short time by using microwave drying at 54 W/g.

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“…Surface color of the powders was measured using a CR-410 Choma Meter (Konica Minolta Sensing Americas, Inc., Ramsey, NJ, USA). Hunter values ( L *, a *, b *) were recorded and Hue angle (°) and Chroma calculated [20]. Fat (%) was measured using the AOAC 920.39 Randall Method for Fat Analysis [21], using petroleum ether.…”

Section: Methodsmentioning

confidence: 99%

Fluidized Bed Drying of Pumpkin (Cucurbita sp.) Seeds

Mujaffar

Ramsumair

2019

Foods

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Pumpkin seeds are a major agricultural waste from the fresh-cut produce industry. The objective of this study was to investigate the drying behavior of untreated, whole pumpkin seeds in a fluidized bed dryer at 50–80 °C (2.87 m/s), with a view to producing a high-quality pumpkin powder from dried seeds. Seeds were dried at 50–80 °C to an average equilibrium moisture value of 0.035 to 0.006 g H2O/g DM (3.4 to 0.6% wb). Drying occurred in the falling rate period only and drying rate constants ranged from 0.0226 to 0.0900 1/min with corresponding diffusivity values for the first falling-rate period ranging from 4.68 to 18.63 × 10−10 m2/s. The activation energy (Ea)—for the first falling rate period was determined to be 43.9 kJ/mol. Of the nineteen thin layer models tested, the Alibas model could be successfully used as a general model to predict the Moisture Ratio (MR) data for all temperatures investigated. After drying, seeds were blended to produce powders, which were found to be high in fat, crude protein and fiber.

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Drying Kinetics of Microwave-Dried Vegetable Amaranth (Amaranthus dubius) Leaves

Cited by 11 publications

References 26 publications

Influence of pre‐treatments on the degradation kinetics of chlorophylls in morisa xak (Amaranthus caudatus) leaves after microwave drying

Influence of pre‐treatments on the degradation kinetics of chlorophylls in morisa xak (Amaranthus caudatus) leaves after microwave drying

Phenolic content and some physical properties of dried broccoli as affected by drying method

Fluidized Bed Drying of Pumpkin (Cucurbita sp.) Seeds

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