Extruder Operating Conditions Research Articles

Karakteristik Fisik Beras Analog dari Jagung Berkadar Amilosa Sedang dengan Menggunakan Ulir Ekstruder Kecepatan Menengah

Indonesia has the highest rice consumption rate in the world, averaging 130 kg per capita per year. Despite government efforts to reduce this through food diversification programs, there has been little success. One approach to reducing rice consumption is to process non-rice ingredients into rice analogues that have similar characteristics to traditional rice. The amylose content of the ingredients plays a significant role in determining the physical properties of these rice analogues. Additionally, the screw speed of the extruder used in the production process also influences these physical characteristics. This study aimed to explore the impact of extruder screw speed and material amylose content on the physical properties of rice analogues. Local corn flour was mixed with high-amylose corn starch to create mixtures with amylose contents of 16.99, 19.35, 21.72% and 24.08%. The tested screw speeds were 100, 125, and 150 rpm. The evaluated physical characteristics included the hardness of the rice analogues, bulk density, cooked rice hardness, gumminess, and sensory properties of the cooked rice. The results showed that as amylose levels increased, the hardness of the rice analogues, cooked rice hardness, and gumminess also increased. Similarly, increasing the screw speed of the extruder led to higher cooked rice hardness, gumminess, and rice analogue hardness, but it decreased bulk density. The optimal extruder operating conditions were found to be an amylose content of 21.72% and a screw speed of 100 rpm, producing rice analogues with a hardness of 3610 gf, a bulk density of 0.63 g/mL, a cooked rice hardness of 3200 gf, and gumminess of 1200 gf.

Optimization of Extrusion Parameters and Feed Composition for Enhanced Quality of Millet Extrudates

Extrudates prepared from cereal grains, such as corn, wheat, rice, and other starch-rich grains, are the second largest contributors to the global ready-to-eat snack market. These cereals contain optimal characteristics, like amount, type and particle size of starch/protein which are important for starch gelatinisation, viscosity and flow characteristics. These factors contribute to the rheology and organoleptic characteristics of the extrudates. In recent years, there has been a significant push in the utilization of the millets for development of extrusion products as they are ready-to-eat and considered as healthier. Major issues with 100% millet incorporation are dark colour, lower expansion, harder and denser extrudates and lower shelf life. In case of millets feed moisture (9-12%), barrel temperature (120-150°C) and screw (123-460 rpm) speed have favorable impact on expansion ratio and bulk density. Addition of starch containing cereals, legumes and hydrocolloids like sodium alginate and carboxymethylcellulose enhances expansion, lighten color and increases nutritional and health benefits. The aim of this review is to highlight the potential of extrusion technology for development of millet products, role of extrusion operating conditions and their effect on product parameters. The review also provides detailed insights about application of extrusion based 3-D printing, hot melt extrusion, hydrogel forming extrusion, centrifugal co-extrusion and extrusion-based encapsulation for the development of innovative millet based novel product development.

Effect of Blending Ratio and Extrusion Operating Conditions on Nutritional Quality and Functional and Sensory Acceptability of Teff‐Bulla‐Based Complementary Food: A Response Surface Methodology Approach

The purpose of this study was to identify possible locally accessible cereals, tubers, and legumes for use in the extrusion of teff, bulla, and haricot beans to prepare inexpensive supplemental foods. This study used central composite rotatable design (CCRD) to assess the effects of specific processing parameters on response variables such as proximate composition and physical, functional, and sensory qualities of produced complementary food. The processing parameters included haricot bean blending ratios (BR) (10–30%), feed moisture content (FMC) (15–21%), and barrel temperature (BT) (120–160°C). The proximate composition of the complementary food ranged from 9.25 to 12.36% moisture content, 7.82 to 14.04% protein, 2.1 to 3.28% ash, 1.13 to 3.93% fiber, 1.17 to 3.12% fat, 65.40 to 78.25% carbohydrate, and 338.42 to 354.86 kcal/100 g energy. The predominant minerals and antinutritional factors ranged from 2.40 to 10.37 mg/100 g, 58.70 to 146.26 mg/100 g, 0.8 to 4.74 mg/100 g, 113.21 to 325.00 mg/100 g, and 16.54 to 44.62 mg/100 g for Fe, Ca, Zn, phytate, and tannin, respectively. The blending ratio and extrusion parameters demonstrated significant (p < 0.05) linear, quadratic, and interaction impacts on the physical and functional responses, according to analysis of variance (ANOVA). Mothers and caregivers largely approved all the trial porridges. The best blending and extrusion parameters, according to numerical optimization, were a BR of 28.2837%, FMC of 15.0007%, and BT of 120.001°C. The predicted responses for optimization were water solubility index (WSI) (32.4462 g/g), water absorption index (WAI) (3.69849%), viscosity (2016.47cP), protein (14.046%), and energy (348.034 kcal/100 g) with a desirability value of 0.856. This research leads us to believe that producing complementary meals with excellent nutritional value for developing nations may be achieved by evidence‐based selection of locally accessible plant‐based components.

Optimization of Single Screw Extrusion Processing Variables and Soy and Rice Flour Blend Formulations based on Physical Properties of Extrudates

Background: Extruded cereals and snacks are mainly carbohydrates. Most adults require more protein above RDA by restricting carbohydrates for many health benefits. A wide variety of soy protein-rich extrudates can be produced by blending with rice flour. However, optimum extrusion processing variables (i.e., screw speed, die temperature, and product formulations) are required for maximum retention of nutrients with desired product characteristics. Objective: The objective of this study was to optimize the extrusion operating conditions and soy flour and rice flour blend formulations for developing protein-rich cereal-like extrudates. Methods: Twenty formulations using CCRD with the combinations of soy flour content (43-77%), die temperature (123-157°C), and screw speed (250-350 rpm) were extruded using a single screw extruder. The physical properties (expansion ratio, density, porosity, hardness, crispness, color, and water solubility index) of extrudates were determined. The regression models and 3-dimensional response surface models were developed for each property of extrudates using RSM. Numerical and graphical optimizations were conducted based on the desirability to determine an optimum condition. Results: The regression models were able to predict the physical properties of extrudates with an accuracy of 75-90%, depending on their properties. The 3-dimensional response surface models indicated that the soy flour content, die temperature, and screw speed affected the physical properties of extrudates significantly (p < 0.05). Soy flour content (50-55%), die temperature (140-145°C), and screw speed (290-320 rpm) were very effective for the desired quality of soy flour and rice flour blend extrudates. Conclusion: The optimum condition is expected to be very useful for soy protein and rice flour blend extruded cereal-like product development commercially within the experimental range.

Extrusion Simulation for the Design of Cereal and Legume Foods.

A 1D global twin-screw extrusion model, implemented in numerical software, Ludovic®, was applied to predict extrusion variables and, therefore, to design various starchy products with targeted structure and properties. An experimental database was built with seven starchy food formulations for manufacturing dense and expanded foods made from starches, starch blends, breakfast cereals, pulse crop ingredients such as pea flour, fava bean flour, and fava bean starch concentrated, and wheat flour enriched with wheat bran. This database includes the thermal and physical properties of the formulations at solid and molten states, melt viscosity model, extruder configurations and operating parameters, and extruded foods properties. Using extrusion and viscosity models, melt temperature (T) and specific mechanical energy (SME) were satisfactorily predicted. A sensitivity analysis of variables at die exit was performed on formulation, extruder configuration, and operating parameters, generating the extruder operating charts. Results allowed the establishment of relationships between predicted variables (T, SME, melt viscosity) and product features such as starch and protein structural change, density and cellular structure, and functional properties. The extrusion operating conditions leading to targeted food properties can be assessed from these relationships and also the relationship between extrusion operating parameters and variables provided by simulation.

Effects of extrusion operating conditions and blend proportion on the physicochemical and sensory properties of teff-rice blend extruded products

The effects of extrusion conditions, teff-to-rice blend ratio (25-100%), feed moisture content (21-25%) and barrel temperature (130- 150°C) on the physico-chemical properties and the sensory attributes of extruded product from teff-rice blend was investigated. The physico-chemical properties (specific length, bulk density, expansion, water absorption index (WAI), water solubility index (WSI) and hardness), and sensory acceptability (flavor, color, texture and overall acceptability) were significantly (p<0.05) influenced by the extrusion conditions. Increasing barrel temperature resulted in higher expansion, lower density, reduced hardness and higher WAI, and WSI. Increase in the proportion of teff resulted in increased density, hardness, and WSI whereas increase in teff proportion brought about a decrease in expansion and WAI. Increasing feed moisture content resulted in higher density, lower expansion, higher WAI, lower WSI, higher hardness and lower crispness. The sensory scores reduced with increase in the proportion teff. The numerical optimization revealed that the optimal extrusion conditions for the best result were extrusion temperature of 150°C, feed moisture content of 21.2% and blending ratio of 40% teff with a desirability value of 0.901. The graphical optimization revealed that the best results were found between 140 to 150°C, 21 to 22% feed moisture and 25 to 46% of teff proportion.

Effect of extrusion operating conditions on the functional and sensory properties of instant multigrain porridge

Effect of extrusion operating conditions on the functional and sensory properties of instant multigrain porridge

Optimization of extrusion process parameters for preparing fiber‐rich oat flour

AbstractIn this study, the effect of extrusion temperature and screw speed on the nutritional properties of the extrudates was evaluated by using a response surface methodology. The total, soluble, insoluble dietary fiber, beta‐glucan, resistant starch, and total starch contents were evaluated through enzymatic assays. The processing parameters affected the content of all constituents of the flour mixture, except for beta‐glucan. The total starch content, insoluble dietary fiber, and resistant starch were significantly decreased with increasing temperature and screw speed (until 13, 12, and 97%, respectively). The extrusion parameters had a positive effect on total dietary fiber content (increased this parameter up to 29%) when compared with the raw material, that is, oat and rice blend, causing changes from the insoluble to soluble dietary fibers. In the electron microscopic analysis, the structure of all extrudates showed to be homogeneous and compact with irregular surfaces.Practical applicationsThe processing of oats by using extrusion‐cooking technique is challenging due to the high lipid and fiber content. For this reason, expansion agents such as rice or corn flours are commonly mixed to the oats before processing. In addition to changing rheological, physical and chemical properties of the raw materials, the extrusion operating conditions may lead to loss of food nutritional properties. In this study, we used the response surface methodology to understand which processing conditions maximize the food nutritional value. The selection of an optimum operating condition in terms of energy efficiency and thermal quality represent a relevant requirement for the current food industry. The content of β‐glucan was preserved regardless of the processing condition while the insoluble and soluble fiber ratio was significantly affected by screw speed. Once low temperatures could be used for preparing fiber‐rich oat flour, a reduction in energy consumption from the process is expected.

Influence of the extrusion operating conditions on the antioxidant, hardness and color properties of extruded mango

The effects of extrusion temperature (50–100 °C) and formulation (glycerin 0–3%, dried fruit moisture 8–14%, glucose 5–15% and xanthan gum 0–3%) on technological (hardness and color) and nutritional (antioxidant activity-AA and total polyphenol content-PC) quality parameters for extruded mango bars were analyzed using response surface methodology (RSM) and principal component analysis (PCA).The PC increased, first, when the extrusion temperature was at lower values and the dried ingredient content was higher, and second, with higher temperatures and xanthan gum content. The AA showed similar behavior but decreased when the liquid ingredients were at their lowest values.Extrudate hardness remained fairly constant, except for an increase at low barrel temperature and high non-fruit ingredients content. The bars measured color parameters were affected the most by fruit moisture.Two principal components explained 73.00% of the total variability by PCA. The results for the relationships of PC and AA with barrel temperature and xanthan gum content were similar to those obtained by RSM.Based on previous findings, some responses were set as optimization objectives that suggested two sets of conditions for optimum extrusion.

Healthy Ready-to-Eat Expanded Snack with High Nutritional and Antioxidant Value Produced from Whole Amarantin Transgenic Maize and Black Common Bean.

The snack foods market is currently demanding healthier products. A ready-to-eat expanded snack with high nutritional and antioxidant value was developed from a mixture (70:30) of whole amarantin transgenic maize (Zea mays L.) and black common bean (Phaseolus vulgaris L.) by optimizing the extrusion process. Extruder operation conditions were: feed moisture content (FMC, 15-25%, wet basis), barrel temperature (BT, 120-170°C), and screw speed (SS, 50-240). The desirability numeric method of the response surface methodology (RSM) was applied as the optimization technique over four response variables [expansion ratio (ER), bulk density (BD), hardness (H), antioxidant activity (AoxA)] to obtain maximum ER and AoxA, and minimum BD, and H values. The best combination of extrusion process variables for producing an optimized expanded snack (OES, healthy snack) were: FMC=15%/BT=157°C/SS=238rpm. The OES had ER=2.86, BD=0.119g/cm (3) , H=1.818N, and AoxA=13,681μmol Trolox equivalent (TE)/100g, dry weight. The extrusion conditions used to produce the OES increased the AoxA (ORAC: +18%, ABTS:+20%) respect to the unprocessed whole grains mixture. A 50g portion of OES had higher protein content (7.23 vs 2.32g), total dietary fiber (7.50 vs 1.97g), total phenolic content (122 vs 47mg GAE), and AoxA (6626 vs 763μmol TE), and lower energy (169 vs 264kcal) than an expanded commercial snack (ECS=Cheetos™). Because of its high content of quality protein, dietary fiber and phenolics, as well as high AoxA and low energy density, the OES could be used for health promotion and chronic disease prevention and as an alternative to the widely available commercial snacks with high caloric content and low nutritional/nutraceutical value.

Improving bioactivities of Jatropha curcas protein hydrolysates by optimizing with response surface methodology the extrusion cooking process

Bioactive peptides, as product of hydrolysis of diverse food proteins, exert various biological roles of great interest in health care. Several pre-hydrolysis treatments of food proteins are commonly used to improve specific bioactivities of protein hydrolysates. In this study, we employed an optimized extrusion cooking process before applying an enzymatic hydrolysis in order to increase bioactivities of Jatropha protein hydrolysates (JPH). Response surface methodology (RSM) was used to study the influence of two main independent variables of the single-screw extruder operation conditions: extrusion temperature (ET) and screw speed (SS). Bioactivities such as antioxidant capacity (AOXC) and antihypertensive activity (ACEI-activity) were selected as response variables. The model was statistically appropriate to describe both responses. Results revealed that both ET and SS significantly influence on AOXC, while only the ET showed influence on ACEI-activity. According to the numerical method used of RSM, the optimum operation conditions were ET=160°C and SS=200rpm. Optimized JPH exhibited a significant increase in both responses AOXC and ACEI-activity. Along with this increase, optimized JPH presented greater protein degree of hydrolysis indicating the presence of short biologically active peptides. Additionally, extrusion cooking process decreased the levels of the major antinutritional factors commonly present in raw Jatropha cake. Overall, this study might contribute to appraise Jatropha as a suitable source of bioactive compounds for the development of nutraceutical products highlighting the economic importance of this crop, and shows extrusion cooking process as appropriate method to improve food quality and increase protein digestibility.

Effect of Extrusion Pretreatment on Enzymatic Hydrolysis of Miscanthus for the Purpose of Ethanol Production

Lignocellulosic biomass can be converted to energy via several routes. One of them is hydrolysis to sugars with subsequent transformation to fuels and chemicals. Due to the crystalline structure of lignocellulose, pretreatment is a prerequisite to achieving increased enzymatic hydrolysis’ rates. The objective of this study was to determine the optimum extrusion operating conditions for glucose and xylose production from Miscanthus. Extrusion was conducted in a high shear extruder (single screw type) with compression ratio 3:1. Barrel temperature and screw speed, along with sample moisture content and particle size were the parameters evaluated using Response surface methodology (RSM). Conversion rate to glucose and xylose was monitored after enzymatic hydrolysis with low enzyme loadings (5 FPU g-1 of cellulase complex and 18 CBU g-1 of B-glucosidase). The optimum conditions for the glucose production (3.63 g L-1) were: barrel temperature 150 °C, screw speed 2.5 Hz, moisture content 20% and particle size 2 mm; the optimum conditions for the xylose production (0.78 g L-1) were: barrel temperature 150 °C, screw speed 1.67 Hz, moisture content 15% and particle size 2 mm. Hence, under controlled conditions, extrusion resulted in better digestibility of Miscanthus and as such it can be utilized as a source of glucose and xylose in ethanol production.

Expanded Gluten-Free Extrudates Made from Rice Grits and Bandinha (Bean) Flour Mixes: Main Quality Properties

The effect of extrusion operating conditions on main quality properties of gluten-free expanded snack-type products, developed from rice grits and bandinha flour formulations, was studied. The protein content in the extrudate varied from 9.44 to 14.74 g/100 g for formulations containing 13 and 47% bandinha flour, respectively, processed at 85C and 15% feed moisture. Apparent density and the radial expansion index of the extrudate were significantly (P < 0.05) affected by bean flour content, moisture content, temperature and the interaction between moisture content × temperature. The most suitable extrusion conditions were 30 g/100 g bean flour content, 14 g/100 g moisture content and 80C die temperature, which resulted in a product with a high radial expansion index and crude protein of 9.5 and 13 g/100 g, respectively, and a low apparent density of 0.20 g/cm3. Practical Applications There is a dynamic growth trends taking place in the gluten-free market due to its relationship to celiac disease, wheat allergy, gluten intolerance and gluten sensitivity. To date, most gluten-free products in the market are in the form of pasta and bakery products. However, there is an open niche for gluten-free foods in the form of expanded snack-type products. The flours of underutilized broken rice and beans (“bandinha”), processed under the selected range of extrusion conditions in this study, have great potential for the development of value-added, protein-rich, gluten-free foods in the form of expanded, low-density, snack-type products. The factorial design used to determine the relationship between the independent and the response variables aided to determine the most suitable processing conditions to generate a quality end product.

Optimization of Extrusion Conditions for GABA Tea Powder/Corn Grit Blend Extrudates

γ-aminobutyric acid (GABA) tea powder blended with corn grits to develop a puffed snack foods by the extrusion technology was studied. Response surface methodology (RSM) was used to analyze the effects of screw speed (179, 200, 250, 300, 321 rpm) and GABA tea powder levels (6, 8, 13, 18 and 20%) on the objective attributes of a corn-based GABA tea powder extrudates. Areas of optimum performance were located by superimposing contour graphs for longitudinal expansion, maximum shear force, hardness and water solubility index for compositions and screw speed levels, which established limits of acceptable quality for each factor. Individual contour plots of the different responses were overlaid, and regions meeting the optimum longitudinal expansion of 18.3883 cm/g, hardness of 39.9659 (N), maximum shear force of 5.1670 (N) and water solubility index of 9.1190 (%) were identified at the GABA tea powder level of 12.9577% and the screw speed of 240.6332 rpm, respectively. Practical Applications According to the optimum conditions given for the variables, the process can be referred for industrial production and the extrudates are suitable for extruded snack food with GABA tea powder. In this study, the parameters of optimum operation condition for extruded corn-GABA tea powder snack products were suggested based on the product characteristics by RSM. Hence, the effects of extruder operation conditions on the physiochemical properties of corn extrudate blended with GABA tea powder are worthy of further exploration in the future.

Some physicochemical properties of dextrin produced by extrusion process

Dextrinization of corn starch by twin screw extruder was studied. The effect of extruder operating conditions (five different screw speeds: 35, 45, 55, 65, and 70; and three temperatures: 125, 130, and 135°C) on some physicochemical properties of dextrin (total soluble solid, water absorption index, water solubility index, and total color difference) was investigated. Results showed that as the screw speed and temperature of extrusion were increased the water absorption index of dextrin tended to drop meanwhile the total soluble solid, water solubility index, and color were inclined to rise. The range of total soluble solid, water absorption index, water solubility index and total color difference was 2.1–4.6 Brix, 159–203%, 20–51%, 3.5–14.1, respectively.

Thermal optimisation of polymer extrusion using in-process monitoring techniques

Polymer extrusion is an energy intensive process, which is often run at less than optimal conditions. The extrusion process consists of gradual melting of solid polymer by thermal conduction and viscous shearing between a rotating screw and a barrel; as such it is highly dependent upon the frictional, thermal and rheological properties of the polymer. Extruder screw geometry and extrusion variables should ideally be tailored to suit the properties of individual polymers, but in practice this is rarely achieved due to the lack of understanding of the process. Here, in-process monitoring techniques have been used to characterise the thermal dynamics of the extrusion process. Novel thermocouple grid sensors have been used to measure melt temperature fields within flowing polymer melts at the entrance to an extruder die in conjunction with infra-red thermometers and real-time quantification of energy consumption. A commercial grade of polyethylene has been examined using three extruder screw geometries at different extrusion operating conditions to understand the process efficiency. Extruder screw geometry, screw rotation speed and set temperature were found to have a significant effect on the thermal homogeneity of the melt and process energy consumed.

Influence of Extrusion Conditions on the Rheological Behavior of Nuclear Bituminized Waste Products

Abstract In France, bitumen has been used since four decades as a container material for low/intermediate activity and long lifetime radionuclides. Industrial Bituminized Waste Products (BWP) are produced by continuous extrusion of 60 wt.% bitumen and 40 wt.% salts, in which a very small fraction is radioactive. These incorporated salts are, in majority, of two types: soluble or insoluble. During storage, the organic matrix subjected to irradiation produces gases, which can give rise to BWP swelling in the container and then to a possible overflow. The extent of gas production is directly linked to the degree of dispersion of the salts into the bitumen matrix. To quantify this dispersion, the effect of extrusion operating conditions, such as feed rate and screw speed, have been studied using a laboratory scale co-rotating twin screw extruder. BWP rheological characterization shows the development of a pseudo-solid plateau at low frequency and a change in the linear viscoelastic domain when screw speed and feed rate are varied, indicating a modification of the dispersion state. Samples characterization with environmental scanning electron microscopy (ESEM) confirms in the case of insoluble and soluble salts a change in the number of agglomerates, accompanied by an improvement of the dispersion at high screw speed but less remarkable with the feed rate. A Carreau-Yasuda law with a yield stress is proposed to describe the rheological behaviour of these materials. The effects of volume fraction and maximum volume fraction on viscosity are described using a Krieger-Dougherty equation.

Influence of Thermomechanical History on Chemical and Rheological Behavior of Bitumen

It is well-known that asphaltene content plays an important role in determining the high viscosity of bitumen. This paper presents an experimental study of the specific effects of extrusion operating conditions on the physical and chemical properties of bitumen. Five bitumen samples were prepared by twin screw extrusion with different operating conditions (feed rate Q and screw speed N). Physical properties were studied by rheological measurements. Viscosity values were measured by steady state flow tests. Chemical changes in the bitumen structure were followed in the infrared region with attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy by measuring the evolution of the bands areas at 1700 cm–1 (C═O), 1030 cm–1 (S═O), and 1600 cm–1 (aromatic C═C) and the bands between 900 and 730 cm–1 attributed to aromatic C—H. An increase in feed rate Q induces a decrease in the Newtonian viscosity, as a result of a decrease in the asphaltene volume fraction. The characterization by ATR confirms that the decrease in feed rate entails the creation of C═O functional groups and the increase in sulfoxide (S═O) functional groups and C═C bonds, accompanied by a decrease in the C—H aromatic bonds. These results indicate a structure that is more oxidized and more aggregated at low feed rate, certainly as the result of an increase in the residence time into the extruder. The increase in screw speed also induces decreases in the viscosity and the volume fraction of asphaltenes, until a point after which the situation reverses. This change may be explained by the appearance of new peaks between 1200 and 1050 cm–1, attributed to C═S bonds, and between 640 and 540 cm–1, for S—S bonds. A competition between shear rate and residence time takes place. The thermomechanical history has, thus, a great influence on the chemical and rheological behavior of pure bitumen, and the chemical changes observed show that the asphaltene volume fraction is not the unique parameter that explains the variations in viscosity.

Improved wood–plastic composites through better processing

Abstract Wood–plastic composites (WPCs) undergo cyclic dimensional changes due to periodic absorption and desorption of moisture, and the resulting loss of mechanical integrity can be ameliorated using a coupling agent. Another solution is better processing. Here, we examine injection-molded, polypropylene (PP)-based wood–plastic composites and investigate why the rate of moisture absorption can be reduced by changing extruder operating conditions. At a given wood content, the mechanical properties were found to be similar, but the use of high screw rotation speeds, whether in the co-rotation or counter-rotation modes, and long residence times gave lower rates of moisture absorption even in the absence of a coupling agent.

EFFECT OF BARREL TEMPERATURE ON REHYDRATION KINETICS OF DIRECT‐EXPANDED TEF FLOUR BREAKFAST CEREAL

ABSTRACT The effect of barrel temperature (110, 130 and 150C) on the rehydration kinetics of tef flour extrudates was investigated. Rehydration was conducted in distilled water for 300–420 min using a constant‐temperature water bath at 25C (±1C). Water absorption rate was high at the early stages (60–90 min) of hydration, decreased subsequently and finally approached an equilibrium. Three models, namely, Peleg's equation, first‐order kinetic and normalized Weibull model, were fitted to the rehydration data. The three models described the rehydration characteristics adequately (R2 = 0.95–0.99). The water absorption rate and equilibrium moisture content were found to be barrel temperature‐dependent (P &lt; 0.05). Extrudates processed at a barrel temperature of 150C exhibited a high water absorption rate, followed by those extruded at 130 and 110C, respectively. The equilibrium moisture content of extrudates processed at 150 and 130C was significantly (P &lt; 0.05) higher than those extruded at 110C. In view of the values of the shape parameter βof the normalized Weibull model, the mechanism of water absorption appeared to be by diffusion for extrudates processed at 130C (β = 0.67), whereas in extrudates processed at 110 (β = 0.89) and 150C (β = 1.03), external resistance to mass transfer and relaxation phenomena, respectively, were found to be the water absorption mechanisms. In comparison, the normalized Weibull model described the rehydration characteristics relatively better, resulting in smaller RMSE value.PRACTICAL APPLICATIONSSome extruded food products, like breakfast cereals, are consumed after being rehydrated (e.g., in milk). The rehydration characteristics, in turn, are influenced by the extrusion operating conditions. Fast rehydration without much change in the crispiness is a required attribute of breakfast cereals. Describing and modeling the kinetics of moisture uptake as a function of the operating conditions could lead to a better understanding and control over the mechanisms underlying the sorption process and the ability of the product to rehydrate. Such information is vital in process and quality optimization.