Sabah Mounir

Three-Stage Spray Drying: New Process Involving Instant Controlled Pressure Drop

The goal of this article is to define a new industrial operation called three-stage spray drying that can increase the specific surface area of powder while reducing the amount of fine dust. Because of their compact structure, spray-dried granules have an exchange surface limited to their surface area. We performed experiments inserting the instant controlled pressure drop (DIC®) treatment between the atomization (first stage of spray drying) and the final drying stage. As a high-temperature, short time (HTST) process, DIC treatment expanded granule texture at a rate depending on pore distribution, mesopore volume, and the mean porosity thus generated; the cumulative specific surface area thus induced evolved as a function of the DIC treatment conditions: the higher the DIC steam pressure, the higher the expansion rate. Both specific surface area and mean particle diameter may then simultaneously increase. Technological properties were investigated in order to compare DIC textured powders and conventional spray-dried powders and optimize the treatment; such an optimization can include the rate of decontamination thus generated.

Study of Instant Controlled Pressure Drop DIC Treatment in Manufacturing Snack and Expanded Granule Powder of Apple and Onion

While the use of “puffing” process is mainly limited to products like cereals or carrot, the instant controlled pressure drop (DIC) can treat and expand the large domain of heat sensitive food products. In the present article, this operation is applied on partially dried apple and onion, to produce snack or, by shadow grinding, expanded granule powder. DIC is a high-steam pressure treatment (up to 0.6 MPa in this article), where steam is applied constantly during a short treatment time t (5–55 s) and instantaneously dropping the pressure toward vacuum 5 kPa with a rate higher than 0.5 MPa s−1. The expanded structure allows the product to achieve better functional properties linked with a greater specific surface area. Thus, the time of final hot air drying (with air flow at 40°C, 1 m s−1, and 267 Pa partially pressure humidity) is reduced by about 55% through greater effective diffusivity and initial starting accessibility. The products nutritional value is partially preserved (vitamins) or even improved through more available flavonoids. DIC can perfectly decontaminate the products, and end quality attributes are higher than normally dried or as good as freeze-dried fruits.

Fruits & Vegetables Drying Combining Hot Air, DIC Technology and Microwaves

Dehydration of fruits and vegetables is one of the most ancient and efficient preservation methods. The quality of the product and its cost depend mainly on the final stage of drying. In the present paper we analyze physical mechanisms occurring during drying throughout heat and mass transfer for defining an efficient and economic three stage drying process of hot air drying combined to a texturing stage by DIC (Instant Controlled Pressure Drop) and finally using microwave assisted by ambient temperature air dehydration.

Swell Drying: Coupling Instant Controlled Pressure Drop DIC to Standard Convection Drying Processes to Intensify Transfer Phenomena and Improve Quality—An Overview

Increasing globalization is driving agricultural production in developing countries toward better recovery levels and high additional value. A great opportunity is thus offered to emerging economies. By adopting appropriate and improved methods that allow better preservation, transport, and storage and that conform to the rigorous requirements and standards of organoleptic and nutritional quality as well as stringent hygienic criteria, emerging economies can derive significant benefits. Drying of biological materials usually results in shrinkage. The impact of shrinkage is often highly prejudicial for both the function and use of these materials. On the one hand, shrinkage results in a sharp decrease in water diffusivity through the porous structure (for dehydration and rehydration processes). On the other hand, the compact structure of dried biological material is usually unsuitable in terms of organoleptic quality and is inadequate for grinding. Thus, it is becoming very important to include retexturing and structure-expanding processes in standard drying processes. To this end, the instant controlled pressure drop (DIC) technology has been proposed and successfully tested as a texturing process for partially dried materials, which should normally intensify the whole operation. The quality of the final product as well as the performance of the drying process can also be dramatically improved. Finally, for a large category of dried fruits and vegetables, and even freeze-dried materials, microbiological contamination and the presence of insects and larvae are serious problems. DIC technology can be used as an ultra-high-temperature treatment for a controlled decontamination. Such dried, expanded, and completely decontaminated products can be used as highly nutritional snacks. They can easily be ground to produce expanded granulated powders with excellent sensory, nutritional, functional, and textural properties.

Texturing of Chicken Breast Meat as an Innovative Way to Intensify Drying: Use of a Coupled Washing/Diffusion CWD Phenomenological Model to Enhance Kinetics and Functional Properties

In the present study, instant controlled pressure drop (DIC) was used as a novel texturing pretreatment of fresh chicken breast meat, before hot airflow drying, in order to modify the texture of the meat and obtain a controlled expansion. Three different drying techniques were compared: conventional hot airflow drying, freeze drying, and swell drying (a combination of DIC and hot airflow drying). DIC was carried out under various conditions in order to achieve multi-criteria optimization. A two-parameter, five-level response surface methodology was used to optimize the operating parameters of saturated steam pressure and thermal holding time, starting with the meats initial water content. Saturated steam pressure had a significant impact on the expansion ratio. The higher the expansion ratio, the better the different functional qualities. Microstructural changes reduced drying time, and increased rehydration kinetics and water holding capacity (WHC). The starting accessibility δWs and the internal effective water diffusivity Deff were studied for both drying and rehydration processes in accordance with the coupled washing/diffusion (CWD) phenomenological model.

Instant Controlled Pressure Drop (DIC) Texturing of Heat-Sensitive Spray-Dried Powders: Phenomenological Modeling and Optimization

Powders of expanded granules generally get high functional characteristics due to porous structure of such granules. The present study aimed at comparing the two ways of high-pressure air or steam alternatively used in détente instantanée contrôlée (DIC; French for instant controlled pressure drop) to achieve the modified three-stage spray-drying operation. Both operations were studied in terms of the process performance and functional/structural powder quality in the case of skim milk. The initial water content, the temperature levels, and the initial and final pressures contribute together to define the amount of expanding air or vapor thus generated. This is an important texturing parameter strictly combined with rheological and glass transition to define the texturing phenomenon. Response surface methodology—design of experiments (RSM-DoE) was achieved with DIC pressure, treatment time, and water content as independent variables for both operation ways. The analyses of the technological, physical, and structural properties of untreated and DIC textured powders were carried out and considered as response dependent variables. The results illustrated that whatever the type of DIC, the optimized DIC treatment implied a controlled increase in porosity, interstitial air volume, and compressibility, as well as specific surface area and reconstitution aptitude.

Effect of instant controlled pressure drop (DIC) treatment on milk protein's immunoreactivity

In this work, we tried to investigate the impact of treatment with instant controlled pressure drop technology (DIC) on the allergenicity of milk proteins. In DIC treatment, milk proteins are exposed to a high-pressure saturated steam (0.4 MPa, 144 °C) during 25 s and ended with an abrupt pressure drop towards a vacuum (5 kPa, 32 °C). Immunoglobulin E (IgE)-binding ability is determined with indirect enzyme linked immuno spectrophotometric analysis and western blot test. Results indicate significant changes in the IgE binding of treated proteins with DIC. Treated caseins showed increase in the IgE-binding ability; this indicates that DIC enhance the antigenicity of treated caseins. In the opposite, treated whey proteins (ß-lactoglobulin and α-lactalbumin) showed decrease in the IgE binding of these proteins. DIC treatment at 0.4 MPa during 25 s causes a greater reduction of the allergenicity of whey proteins than treatment with 0.6 MPa for 25 s.

DIC Decontamination of Solid and Powder Foodstuffs

Instant controlled pressure drop (DIC) technology is used as a highly appropriate ultrahigh temperature (UHT)-type treatment to decontaminate biological powders and solid dry materials. It combines different effects such as high temperature, thermal stress during both heating and instant cooling, and micromechanical impacts. The latter is due to the vapor constraints acting on cell walls when the high pressure instantaneously drops. The cell walls of both vegetative and spore forms may possibly explode. Some other gases can produce a similar micromechanical effect.

Response surface methodology (RSM) as relevant way to study and optimize texturing by instant controlled pressure drop DIC in innovative manufacturing of egg white and yolk powders

ABSTRACT This study aimed to use the Instant Controlled Pressure Drop as a texturing pretreatment prior to air flow drying as a new way for the manufacturing of egg white and yolk powders evaluating the impact of DIC operating parameters; the saturated steam pressure and processing time, on the physical and functional properties of the end products. The obtained results showed that the DIC-textured egg white and yolk powders had high quality attributes compared to those obtained from classical air flow drying. Moreover, it was better than freeze dried powders in terms of water absorption capacity, emulsifying capacity, and foaming capacity and stability.

Effect of feed concentration and inlet air temperature on the properties of soymilk powder obtained by spray drying

ABSTRACT In this study, soymilk powder was produced by spray drying. The inlet air temperature of spray dryer was varied from 200 to 280°C and the feed concentration was varied from 15 to 25% (w/v). Response surface methodology was used to examine the effects of these independent variables on the detailed characteristics in terms of physical, structural, functional properties of powder. Overall, results show that rising the inlet air temperature caused a decrease in tapped and loose bulk density, true density, filling rate, water holding capacity, and water content of powder; and an increase in compressibility, Hausner ratio, porosity, interstitial air volume, and wettability index. An increase in feed concentration led to an increase in true density, compressibility, Hausner ratio, porosity, interstitial air volume, and wettability index; and a decrease in tapped and loose bulk density, filling rate, water holding capacity, and water content; whereas oil holding capacity might be increased or decreased and it depended almost solely on the feed concentration.