Showing papers by "Arun S. Mujumdar published in 2019"
TL;DR: Pretreatment is widely used before drying of agro-products to inactivate enzymes, enhance drying process and improve quality of dried products, and non-thermal technologies can be a better alternative to thermal blanching to overcome these drawbacks.
Abstract: Pretreatment is widely used before drying of agro-products to inactivate enzymes, enhance drying process and improve quality of dried products. In current work, the influence of various pretreatments on drying characteristics and quality attributes of fruits and vegetables is summarized. They include chemical solution (hyperosmotic, alkali, sulfite and acid, etc.) and gas (sulfur dioxide, carbon dioxide and ozone) treatments, thermal blanching (hot water, steam, super heated steam impingement, ohmic and microwave heating, etc), and non-thermal process (ultrasound, freezing, pulsed electric field, and high hydrostatic pressure, etc). Chemical pretreatments effectively enhance drying kinetics, meanwhile, it causes soluble nutrients losing, trigger food safety issues by chemical residual. Conventional hot water blanching has significant effect on inactivating various undesirable enzymatic reactions, destroying microorganisms, and softening the texture, as well as facilitating drying rate. However, it induces undesirable quality of products, e.g., loss of texture, soluble nutrients, pigment and aroma. Novel blanching treatments, such as high-humidity hot air impingement blanching, microwave and ohmic heat blanching can reduce the nutrition loss and are more efficient. Non-thermal technologies can be a better alternative to thermal blanching to overcome these drawbacks, and more fundamental researches are needed for better design and scale up.
242 citations
TL;DR: The AI application of modeling, predicting, and optimization of heat and mass transfer, thermodynamic performance parameters, and quality indicators as well as physiochemical properties of dried products in artificial biomimetic technology (electronic nose, computer vision) and different conventional drying technologies are summarized.
Abstract: Intellectualization is an important direction of drying development and artificial intelligence (AI) technologies have been widely used to solve problems of nonlinear function approximation, pattern detection, data interpretation, optimization, simulation, diagnosis, control, data sorting, clustering, and noise reduction in different food drying technologies due to the advantages of self-learning ability, adaptive ability, strong fault tolerance and high degree robustness to map the nonlinear structures of arbitrarily complex and dynamic phenomena. This article presents a comprehensive review on intelligent drying technologies and their applications. The paper starts with the introduction of basic theoretical knowledge of ANN, fuzzy logic and expert system. Then, we summarize the AI application of modeling, predicting, and optimization of heat and mass transfer, thermodynamic performance parameters, and quality indicators as well as physiochemical properties of dried products in artificial biomimetic technology (electronic nose, computer vision) and different conventional drying technologies. Furthermore, opportunities and limitations of AI technique in drying are also outlined to provide more ideas for researchers in this area.
127 citations
TL;DR: In this paper, the feasibility of cold plasma as a non-thermal pretreatment technology for chili pepper drying is explored and the effects of different cold plasma pretreatment time (15, 30, 45, 60) on hot air drying kinetics and quality attributes of chili pepper, such as colour, red pigment retention, antioxidant activity, and microstructure were investigated.
103 citations
TL;DR: A survey of recent developments in the modeling and experimental results on microwave-assisted freeze-drying (MFD) over the past decade and the needs and opportunities for future research and developments are outlined.
Abstract: Microwave heating has been applied in the drying of high-value solids as it affords a number of advantages, including shorter drying time and better product quality. Freeze-drying at cryogenic temperature and extremely low pressure provides the advantage of high product quality, but at very high capital and operating costs due partly to very long drying time. Freeze-drying coupled with a microwave heat source speeds up the drying rate and yields good quality products provided the operating unit is designed and operated to achieve the potential for an absence of hot spot developments. This review is a survey of recent developments in the modeling and experimental results on microwave-assisted freeze-drying (MFD) over the past decade. Owing to the high costs involved, so far all applications are limited to small-scale operations for the drying of high-value foods such as fruits and vegetables. In order to promote industrial-scale applications for a broader range of products further research and development efforts are needed to offset the current limitations of the process. The needs and opportunities for future research and developments are outlined.
86 citations
TL;DR: In this article, the authors proposed a novel dryer for the food industry, which requires different levels of energy to produce commercially high-quality-dried food products and is one of the most vital preservation techniques used in food industry.
Abstract: Drying is one of the most vital preservation techniques used in the food industry. It demands different levels of energy to produce commercially high-quality-dried food products. Novel dryi...
69 citations
TL;DR: In this article, an intelligent technology of combined low field NMR (LF-NMR) and back propagation artificial neural network (BP-ANN) was used to monitor moisture content in carrot during microwave vacuum drying.
Abstract: In this paper, intelligent technology of combined low field NMR (LF-NMR) and back propagation artificial neural network (BP-ANN) was used to monitor moisture content in carrot during microwave vacuum drying. The relationship between different drying powers (200, 300, and 400 W) and NMR signals (A21, A22, A23, and Atotal) was investigated. Results show that as the drying time elapsed, the NMR signals of Atotal and A23 decrease all drying conditions, A21 and A22 tend to increase at high moisture content and then decrease, which is consistent with the state of water while changes during drying. NMR signals can be used as indicators for online monitoring of moisture and control of the drying process. With NMR signals as input variables, a BP-ANN model was built optimized by transfer function, training function, and the number of neurons to model the moisture content (output). Compared with a linear regression model and multiple linear regression model, the BP-ANN model with the topology of 4-25-1, transfer function of tansig and purelin, and training function of trainlm outperformed the fitting performance and accuracy. This shows that the combined approach of utilizing LF-NMR and BP-ANN has great potential in intelligent online monitoring and control applications for carrot drying.
58 citations
TL;DR: In this article, the effect of four drying techniques namely hot air drying (AD), infrared drying (IRD), hot air-assisted radio frequency drying (RFD), and microwave-assisted hot-air drying (HEAD) was investigated.
Abstract: In this article, the effect of four drying techniques namely hot air drying (AD), infrared drying (IRD), hot air-assisted radio frequency drying (RFD), and microwave-assisted hot air drying...
50 citations
TL;DR: In this article, the authors reviewed the recent literature on applications of RF heating in fresh food processing, including cooking, microorganism reduction, disinfestation, thawing, and blanching.
Abstract: Fresh foods, such as vegetables, fruits, and aquatic products, have high water activity and are highly heat-sensitive. Thermal processing of fresh foods is often employed to extend shelf-life without chemical treatment in order to avoid any chemical residues in the preserved food. Radio frequency (RF) heating is one of the most promising heating methods applicable to fresh foods due to rapid heating, low cost, deep thermal penetration, and possibility of better quality control. This paper reviews the recent literature on applications of RF heating in fresh food processing, including cooking, microorganism reduction, disinfestation, thawing, and blanching. The heating efficiency and product quality of aforementioned applications were further discussed. Moreover, recommendations were made for future research on RF to effectively achieve enhanced thermal processing and reliable scale-up. The present study provides some useful information for the use of RF heating in industry and the future study of RF application in fresh food processing.
48 citations
TL;DR: In this paper, the authors summarized the research progress of berry drying technology by the perspectives of traditional drying technology and innovative drying concepts and explored the research situation of convective drying, freeze drying, vacuum drying, microwave drying, and interesting drying techniques.
Abstract: Fresh berries containing in bioactive compounds are perishable under natural conditions. Drying is one of the most effective processing techniques to extending the shelf life of berry products, and the nutrients and active components of berries can be retained to a great extent. However, the flavor and texture of the final product considerably correlate with drying techniques. Therefore, the present reviewed work summarizes the research progress of berry drying technology by the perspectives of traditional drying technology and innovative drying concepts and explores the research situation of convective drying, freeze drying, vacuum drying, microwave drying and innovative drying technology for berry drying. The dehydration mechanism, pretreatment methods, and drying technology of various berries were summarized. And the effects of different drying treatments on nutritional components of berry drying were presented; application status of mathematical modeling employed in berry drying was also discussed. Moreover, the research direction and development trend of berry drying techniques in the future were pointed out, which are aimed at improving the drying efficiency of berries, preserving the active components of berries to the greatest extent, and promoting the processing utilization of berries and economic benefits in the future to provide a reference for further research and utilization of drying technology.
41 citations
TL;DR: In this article, the application of physical field technologies mainly include microwave, radio frequency, infrared radiation, ultrasound, pulsed electric field, and so on, and nowadays, the application is very broad.
Abstract: Modern physical field technologies mainly include microwave, radio frequency, infrared radiation, ultrasound, pulsed electric field, and so on. Nowadays, the application of physical field t...
40 citations
TL;DR: Sustained-release micro-/nanospheres of the ketorolac tromethamine (KTC) were prepared using four different techniques viz., single emulsion solvent evaporation, high pressure homogenization, spray...
Abstract: Sustained-release micro-/nanospheres of the ketorolac tromethamine (KTC) were prepared using four different techniques viz., single emulsion solvent evaporation, high pressure homogenization, spray...
TL;DR: In this article, a Miglitol-loaded poly (d, l-lactide-co-glycolide) (PLGA) microparticles were prepared using high pressure homogenization-solvent evaporation method.
Abstract: Sustained release Miglitol-loaded poly (d, l-lactide-co-glycolide) (PLGA) microparticles were prepared using high pressure homogenization-solvent evaporation method. 23 full factorial desig...
TL;DR: In this article, a laboratory scale spray dryer was used to encapsulate vildagliptin (VLG), an antihyperglycemic drug, into different polymers such as poly(dl-lactide) (PDLA), poly-dlactide-glycolide)-50:50 (PLGA 50:50), and poly-(dl- lactide)-75:25(PLGA 75:25) Response surface methodology (RSM) was employed to evaluate the effects of process and formulation factors on the encapsulation efficiency.
Abstract: A laboratory scale spray dryer was used to encapsulate vildagliptin (VLG), an antihyperglycemic drug, into different polymers such as poly(dl-lactide) (PDLA), poly(dl-lactide-glycolide)-50:50 (PLGA 50:50), and poly(dl-lactide-glycolide)-75:25 (PLGA 75:25) Response surface methodology (RSM) was employed to evaluate the effects of process and formulation factors on the encapsulation efficiency (EE) The physicochemical properties of the drug-loaded micro-/nanoparticles, mainly the drug loading (DL), particle size distribution, surface morphology, drug–polymer compatibility, and release rate were investigated % EE of drug-loaded micro-/nanoparticles were in the range of 5710% to 7644% PLGA50:50 micro-/nanoparticles showed highest EE as compared to PDLA and PLGA75:25 micro-/nanoparticles The mean particle size of the micro-/nanoparticles containing PLGA 50:50, PLGA 75:25, and PDLA polymers were 428 nm, 640 nm, and 122 µm, respectively Surface morphology study revealed smooth, spherical and non
TL;DR: In this article, the microwave power density (PD) was varied from 1.03 to 2.67 Wg−1 at 1.5 and 2.0 pulsation ratios (PRs).
Abstract: Microwave rotary drum drying of whole garlic bulbs was investigated for the Aspergillus niger inactivation and moisture removal. The Weibull and Bigelow models were applied to microbial inactivation data. Garlic bulbs with initial moisture content in the range 1.95–2.14 g water g−1 dry matter were dried up to 0.06 g water g−1 dry matter. The microwave power density (PD) was varied from 1.03 to 2.67 Wg−1 at 1.5 and 2.0 pulsation ratios (PRs). Effect of PD and PR on A. niger inactivation, product temperature, moisture diffusivity, moisture ratio, drying rate, color, and sensory parameters was studied. Page model was found to be a better fit for microwave rotary drying characteristics of whole garlic bulbs. Microwave rotary drum drying resulted in the average log reduction of A. niger between 1.12 and 1.60. Weibull model predicted A. niger inactivation better than the Bigelow model as it considered the nonlinearity associated with a microbial population in the sterilization process. Garlic powder pre...
TL;DR: Radiofrequency pasteurization retained better antioxidant substances, lightness, green color, and odors in barley grass powder, compared with hot-air sterilization, and led to an improvement in sourness, bitterness and umami tastes.
Abstract: Background Young barley grass powder contains abundant nutrition and its antioxidant substances are severely impaired by radiation (60 Co) sterilization. To overcome product quality degradation, radiofrequency pasteurization was conducted using pilot-scale radiofrequency equipment (27 MHz, 6 kW) with electrode gaps of 12, 14 and 16 cm, while hot-air (80 °C) pasteurization was used for comparison. Results Assessment suggested that uneven radiofrequency heating was improved for the 14 cm electrode gap. With an increase of electrode gap, microbial inactivation needs more energy consumption. A minimum energy consumption of 970 J g-1 was required for 1 log-reduction of colonies. Radiofrequency pasteurization retained better antioxidant substances, lightness (L*), green color (a*) and odors in barley grass powder, compared with hot-air sterilization. Contents of flavonoid and chlorophyll were 5.82 and 4.87 g kg-1 respectively, using the 14 cm electrode gap. Additionally, radiofrequency pasteurization led to an improvement in sourness, bitterness and umami tastes. Conclusions Radiofrequency pasteurization would be a superior alternative for the pasteurization of barley grass powder. © 2019 Society of Chemical Industry.
TL;DR: To decrease microbial quantity and conserve antioxidant substances of Ashitaba leaves, microwave freeze-drying was conducted at 1, 1.5, and 2 W/g in pilot scale as discussed by the authors.
Abstract: To decrease microbial quantity and conserve antioxidant substances of Ashitaba leaves, microwave freeze-drying was conducted at 1, 1.5, and 2 W/g in pilot scale. After drying, microbial inactivation and quality parameters of color, chlorophylls, flavonoids, moisture content, and flavor of dried Ashitaba leaves were evaluated. After drying, the highest contents of chlorophylls and flavonoids maintained 14.62 g/kg and 15.75 mg/g, respectively; microbial colonies decreased by about 2-log; various tastes of dried sample were improved. It could be a suitable dehydration in processing of Ashitaba leaves.
TL;DR: In this paper, a mathematical model was presented to characterise heat transfer in high-humidity hot air impingement blanching (HHAIB) of cuboid carrots.
TL;DR: In this article, a microwave hot air-assisted pulse-spouted vacuum drying (MHAPSVD) has been designed using microwave vacu... to resolve the issue of high fat content to impair people healthy.
Abstract: Fried carrot slices feature high fat content to impair people healthy. To resolve this issue, microwave hot air-assisted pulse-spouted vacuum drying (MHAPSVD) has been designed using microwave vacu...
TL;DR: In this article, the coherent structures of pulsed opposing jets by large eddy simulation (LES) model and proper orthogonal decomposition (POD) snapshot method were investigated and the results of the simulation in different time steps (snapshots) are stored and POD is applied on the snapshots.
Abstract: The purpose of this study is to investigate the coherent structures of pulsed opposing jets by large eddy simulation (LES) model and proper orthogonal decomposition (POD) snapshot method. Flow pulsation as an active flow control method is considered for the enhancement of transport phenomena in impinging jets. The effect of flow pulsation parameters such as pulsation signal shape and frequency on the vortical coherent structures, the energy content of primary modes and their variation are studied numerically.,In this study, flow field of turbulent pulsating opposing jets has been simulated using LES. The result of the simulation in different time steps (snapshots) are stored and POD is applied on the snapshots. In this study, the POD method and calculation of spatial modes has been done using OpenFOAM, and time coefficients have been calculated using a MATLAB code.,The results of this study show that the flow excitation has a great effect on the coherent structure formation and the energy containment of fundamental modes of the flow. When the flow was excited by a harmonic sinusoidal or step function, the turbulent kinetic energy accumulated in the set of primary modes. On the other hand, the pulsed opposing jets had more regularity compared to the steady jets. The shapes, patterns and energy values of dominant modes depended on the inlet pulsation signal. An increase in pulsation frequency leads to an augmentation in energy content of the primary modes.,The predictions may be extended to include various pulsation conditions such as: various amplitudes, Reynolds number and aspect ratio.,The results of this study are a valuable source of information for active control of transport phenomena in opposing jet configurations which is used in different industrial applications such as cooling, combustion, reactors, heating and drying processes.,In this study, the coherent structures and energy content of primary modes was studied for the first time by LES model and POD snapshot method and a comprehensive discussion on numerical results is provided.
TL;DR: The RPG and DIL-loaded chitosan nanoparticles produced in this study were evaluated for drug-polymer interaction, surface morphology, encapsulation efficiency, drug loading, particle size and invitro drug release and FTIR analysis confirmed compatibility of the drug with excipients.
Abstract: The oral-sustained release dosage form containing Repaglinide (RPG, antidiabetic) and Diltiazem HCL (DIL, antihypertensive) loaded chitosan nanoparticles were prepared by the ionotropic gel...