Effects of drying methods on color retention and chlorophyll of celery (ApiumgraveolensL.), spinach (Spinacia oleraceaL.), Malabar spinach (Basella albaL.)

2020 ◽  
pp. 53-61
Author(s):  
Dat Q Tran
Keyword(s):  
Microwave Drying ◽  
Drying Methods ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Color Retention ◽  
Hot Air ◽  
Drying Techniques ◽  
Dried Vegetables

Dried vegetables are considered convenient for storage, transportation and preservation. The different drying techniques could influence the quality of resulting products. This study aimed to evaluate the effects of three distinguish drying methods as hot-air drying, foam-mat drying and microwave drying on the color retention and chlorophyll of green vegetables powder. Fresh spinach(Spinacia oleraceaL.), celery (Apium graveolensL.), Malabar spinach (Basella albaL.) were dried by different methods: hot air at 60oC, foam-mat at 60oC and microwave at 270 W until the samples reached approximately 9% of moisture content (wb). The drying time of the dried samples by microwave, foam-mat and hot-air method were 60, 210 and 240 min, respectively. Foam-mat dried vegetables were found to have the best quality in terms of color and the residual chlorophyll content. The findings suggest that foam-mat drying is promising in dried vegetable processing

scholarly journals STUDY OF PHYSICOCHEMICAL PROPERTIES OF CAPSICUM POWDER BY DIFFERENT DRYING TECHNIQUES

2021 ◽  
Vol 10 (4) ◽  
pp. 3110-3114
Author(s):  
Madhumita Saha
Keyword(s):  
Bulk Density ◽  
Freeze Drying ◽  
Microwave Drying ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Hot Air ◽  
Drying Techniques ◽  
Peroxidase Enzyme ◽  
Density Values

The objective of this study was to analyse the effects of phytochemical parameter, physical parameter, color, and sensory analysis in green capsicum by different drying processes (microwave, freeze, and hot air drying). Results showed an increase in microwave output power (600W), decreased drying time, moisture content, Chroma, and bulk density values. The Freeze drying process significantly improved the lightness of dried capsicum. Due to take less time for the Microwave drying technique, phytochemical parameters are intact in capsicum; on the other side, color degradation has been occurred due to the Maillard reaction (L*=29.34±0.08, a*=6.98±0.09,b*=15.36±0.10). Bulk density (0.335±0.01) and dispersibility (40±2.00%) were highest in Microwave drying powder. The capsaicin content of dried capsicum was higher than the fresh capsicum sample, but compared to the different drying techniques, the Microwave drying sample has higher capsaicin content than the Hot air drying and Freeze-drying samples. The lower capsaicin content in fresh capsicum may occur due to the catalytic activity of the peroxidase enzyme. The capsaicin content of all dried capsicum varied between 1.91±0.05 and 3.31±0.16 mg/100 g. In this research, the Microwave drying powder of capsicum was the best product for its highest antioxidant content and other physical properties.

A Comparative Study of Combined Microwave Techniques for Longan (Dimocarpus longan Lour.) Drying with Hot Air or Vacuum

2017 ◽  
Vol 13 (7) ◽  
Author(s):  
Krit Apinyavisit ◽  
Adisak Nathakaranakule ◽  
Somchart Soponronnarit ◽  
Gauri S. Mittal
Keyword(s):  
Energy Efficient ◽  
Preference Score ◽  
Drying Method ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Microwave Vacuum Drying ◽  
Hot Air ◽  
Drying Techniques ◽  
Microwave Techniques

AbstractThe aim of this study is to find a better drying method to replace conventional hot air drying (HAD) in terms of faster, energy efficient and better product quality. Two alternative drying techniques, microwave combined with hot air drying (MHD) and microwave vacuum drying (MVD), are compared in this study to dry peeled and destoned longan fruit. Both MHD and MVD reduced the drying time up to 48 % and energy consumption as compared to HAD. These techniques provided lower product redness, yellowness and shrinkage but higher lightness and porous structure as compared to HAD. MVD reduced hardness and toughness of the dried product. MHD provided the highest preference score in terms of colour and shape and was as acceptable as the commercial product dried by HAD. MHD is the most suitable method for longan drying.

scholarly journals Impact of Different Drying Techniques on Quality Traits of Ginger (Zingiber officinale Rosc.) Rhizomes

2021 ◽  
pp. 30-37
Author(s):  
Annu Kumari ◽  
Yeluru Mohan Babu ◽  
Eggadi Ramesh ◽  
Tshering Ongchu Lepcha ◽  
Suman Tamang ◽  
...  
Keyword(s):  
Essential Oil ◽  
Fiber Content ◽  
Microwave Drying ◽  
Crude Fiber ◽  
Drying Methods ◽  
Hot Air Drying ◽  
Air Drying ◽  
Sun Drying ◽  
Crude Fiber Content ◽  
Hot Air

Under the present investigation, ginger was produced at the instruction cum research plots of the Department of Plantation Crops and Processing, Faculty of Horticulture, Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar, West Bengal. The experiment was laid out in a factorial CRD. The study was undertaken with four ginger varieties namely Gorubathan, Suprabha, Suruchi and Suravi to evaluate the effect of different drying methods (sun drying, hot air drying at 50OC, 60oC and 70oC and microwave drying on time required for drying to a moisture content of 8 – 10% and to chemical composition (essential oil, oleoresin content and crude fiber content) of the end product. Results shown that Gorubathan variety has the highest essential oil (2.243%) and oleoresin content (14.840%) among the four varieties in this study, highest crude fiber content (5.253%) was observed in Suprabha and highest dry recovery (25.77%) was obtained from Suravi variety. In hot air drying, with increase in temperature essential oil, oleoresin and crude fiber content in dry ginger as well as dry recovery reduced. With high dry recovery (25.77%), essential oil (2.037%) and oleoresin content (13.510%) and moderately low crude fiber content (4.637%), it can be concluded that Suravi variety is best suitable for producing dry ginger. Apart from microwave drying, sun drying can be recommended as better practice, when hygienically conducted, based on essential oil and oleoresin content.

Drying Behaviour and Change in Colour and Textural Properties of Mushroom During Drying

2012 ◽  
Vol 8 (1) ◽  
Author(s):  
Tarsem Chand Mittal ◽  
Sajeev Rattan Sharma ◽  
Jarnail Singh Muker ◽  
Satish Kumar Gupta
Keyword(s):  
Textural Properties ◽  
Microwave Drying ◽  
Drying Methods ◽  
Button Mushroom ◽  
Hot Air Drying ◽  
Air Drying ◽  
Hot Air ◽  
Drying Behavior ◽  
L Value ◽  
Drying Behaviour

Button mushroom in the form of whole and slices were dried using convective hot air drying and microwave drying methods. Main objectives were to study the drying behavior and change in colour and textural properties. To get moisture content of 0.08 g/g, hot air drying at 600C took 463 minutes and 350 minutes for whole and sliced mushroom respectively whereas these times were just 9 minutes and 8.5 minutes when the microwave oven was run at 60% of its maximum power (1350 W). The convective hot air drying process can be put into two falling rate periods. The decrease in brightness (indicated by L-value) in dried samples was about 44% as compared to the fresh ones. The variation within the differently dried samples was not much. Hardness was lowest (<2>N) in fresh samples and was highest (>5.5 N) in microwave dried samples with hot air dried samples in between. For most of the samples, the springiness were between 0.4 and 0.6 except for hot air dried sliced samples where it was 0.9. Except in hot air dried samples, the change in cohesiveness was not much. Adhesiveness was found in fresh mushroom only..

scholarly journals Effect of freeze drying and hot air drying methods on quality of cordycepin production

2018 ◽  
Vol 192 ◽  
pp. 03001
Author(s):  
Thitiphan Chimsook
Keyword(s):  
Freeze Drying ◽  
Low Cost ◽  
Bioactive Compound ◽  
Raw Material ◽  
Total Phenolic ◽  
Drying Methods ◽  
Hot Air Drying ◽  
Air Drying ◽  
Hot Air

This study determined the effect of drying methods including hot air drying and freeze drying on the quality of cordycepin production from Cordyceps militaris. The fruiting bodies and mycelium of C. militaris were used as the raw material. For hot air drying was performed at 55 °C for 24 hrs. Whereas the freeze drying was carried out under vacuum at 140 L min-1 for 48 hours. The bioactive compound extracted from dried powder of C. militaris from two drying methods was investigated. The results showed that both cordycepin and adenosine extracted from freezed drying sample had higher value than those of extracted from hot air dried sample. The bioactivities of C. militaris extract were investigated. The results revealed that the antioxidant activity and also total phenolic contents of C. militaris extract prepared from freeze drying had higher value than that of extracted from hot air drying. However, most of C. militaris production performed using hot air drying to dry sample because of its low cost technique.

Assessment of Quality Attributes of Banana Slices Dried by Different Drying Methods

2014 ◽  
Vol 10 (2) ◽  
pp. 251-260 ◽  
Author(s):  
Kianoosh Pirnazari ◽  
Ali Esehaghbeygi ◽  
Morteza Sadeghi
Keyword(s):  
Moisture Transfer ◽  
Color Change ◽  
Drying Methods ◽  
Drying Method ◽  
Hot Air Drying ◽  
Drying Time ◽  
Moisture Movement ◽  
Air Drying ◽  
Hot Air ◽  
Significant Difference

Abstract In the present study, banana slices were dried and compared using electrohydrodynamic (EHD) drying method at 4.5, 6.5, and 8.5 kV/cm; oven at 50, 60, and 70°C; and hot-air drying at 50, 60, and 70°C at a constant air velocity of 1.5 m/s. ANOVA showed that drying method had a significant effect on drying time, rehydration capacity, shrinkage, color features (L*, a*, b*, and ∆E), and consumed energy. The values of consuming energy for EHD at 8.5 kV/cm, oven, and hot-air drying at 70°C were 2.99, 20.9, and 81.7 kJ/g run on full capacity of each dryer, respectively. Oven drying led to a greater color change than did hot-air. No significant difference was observed between the color change feature ∆E for EHD and hot-air dried samples in the orthogonal contrast analysis. The falling rate period for EHD moisture movement showed that diffusion was describing the moisture gradients and the internal moisture transfer was dominant. EHD is not fast; however, its advantages like less energy needed, lower shrinkage, and great rehydration capacity make it a good choice for combining with other convection drying methods.

scholarly journals Comparative Evaluation of Drying Kinetics of Carrot Slices in Hot air and Microwave Drying

2021 ◽  
Vol 10 (4) ◽  
pp. 242-248
Author(s):  
Gitanjali Behera ◽  
◽  
Mitali Madhumita ◽  
J. Aishwarya Aishwarya ◽  
V. Gayathri ◽  
...  
Keyword(s):  
Microwave Drying ◽  
Quality Analysis ◽  
Rehydration Ratio ◽  
Hot Air Drying ◽  
Drying Time ◽  
Air Drying ◽  
Hot Air ◽  
Sensory Score ◽  
Kinetics Of ◽  
Different Thickness

Carrot is most the important vegetable grown throughout the World. It is also a very good source of βcarotene, α-carotene and zeaxanthin. The post-harvest losses because of having high moisture content limit the utilization of carrot. In the present investigation, the comparative analysis was done between hot air drying and microwave drying for different thickness of carrot slices. The quality analysis for both the dried products was performed and compared. The drying time was varied between 3.5 h to 10 h for try drying whereas for microwave drying it was 240 sec to 681.6 sec. The drying time reduces drastically in case of microwave drying in comparison to hot air drying. The moisture ratio for both dried techniques was found to decreasing with an increase in drying time. The microwave dried samples showed a better rehydration ratio than the hot air dried sample. Also, the dehydration ratio of dried carrot sample using microwave drying was found to be lowest compared to the hot air dried sample. The microwave dried carrot slices showed a better sensory score in terms of colour and shape than hot air dried sample. Therefore, microwave drying may be recommended to dry carrot slices to have better energy efficiencies

Effect of Drying Methods on Yield and Quality of the Avocado Oil

2017 ◽  
Vol 735 ◽  
pp. 127-131 ◽  
Author(s):  
Thitiphan Chimsook ◽  
Rittichai Assawarachan
Keyword(s):  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Raw Material ◽  
Drying Methods ◽  
Hot Air Drying ◽  
Air Drying ◽  
Hot Air ◽  
Avocado Oil

This experimental study was carried out to verify the quality enhancement of avocado oil production by different drying methods. During this study, samples of green avocado cake were obtained from Tak Province, Thailand. The small size of fresh green avocados was the raw material to prepare the high quality of avocado oil. The drying methods composed of air drying, hot air drying and vacuum drying, respectively. The dried avocado pulp was evaluated the moisture contents and then pressed avocado oil using the extraction machine. All avocado oil were determined the physical and chemical properties. The current study revealed that hot air drying and air drying had the highest and lowest yield, respectively. The unsaturated fatty acids in avocado oil were higher than the saturated fatty acids in all avocado oils from the three drying methods. The costs of drying methods were considered and the present study revealed that the best method for drying green avocado cake was hot air drying with the desired oven.

Thermal-Oxidation Degradation of Microwave Drying Nature Rubber

2011 ◽  
Vol 399-401 ◽  
pp. 1600-1603
Author(s):  
Fu Quan Zhang ◽  
Mao Fang Huang ◽  
Mei Chen ◽  
Yong Zhou Wang ◽  
Jian He Liao
Keyword(s):  
Thermal Oxidation ◽  
Oxidation Stability ◽  
Attenuated Total Reflection ◽  
Microwave Drying ◽  
Drying Methods ◽  
Hot Air Drying ◽  
Air Drying ◽  
Degradation Temperature ◽  
Hot Air ◽  
Oxidation Degradation

The effects of drying methods on thermal-oxidation degradation and ageing behavior of nature rubber (NR) was investigated using Fourier transform infrared/Attenuated total reflection (FTIR-ATR) and thermogravimetric analysis. Examining the samples of thermal-oxidation ageing for 24h by FTIR-ATR spectroscopy allowed appearance of obvious carboxyl absorption of hot-air drying NR at 1723cm-1, decay of methylene stretch and C=C plane stretch during thermal-oxidation ageing process, to be monitored. TG and DTG were used to determine thermal-oxidation degradation temperature in air atmosphere and active energy using Coats-Redfern equation. Showed from the results, the degradation temperature and active energy of microwave drying NR was higher than hot-air drying, thermal-oxidation resistance was more excellent by FTIR analysis, indicating a higher thermal-oxidation stability of microwave drying NR.

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