Food Technology
Mohammad Sadegh Arab; Hannan Lashkari; Mehrdad Niakosari; Mohammad Hadi Eskandari
Abstract
This study aimed to evaluate the effects of intelligent pH-sensitive composite film based on gelatin and Persian gum incorporated with purple carrot extract (PCE) on the freshness of wrapped mozzarella cheese. In this regard, the color, pH, yeast and mold count of control and treatments wrapped with ...
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This study aimed to evaluate the effects of intelligent pH-sensitive composite film based on gelatin and Persian gum incorporated with purple carrot extract (PCE) on the freshness of wrapped mozzarella cheese. In this regard, the color, pH, yeast and mold count of control and treatments wrapped with intelligent pH-sensitive composite film during 60 days were evaluated. The results showed that the pH significantly reduced in wrapped cheese with and without PCE (control) samples during storage. However, this reduction was more pronounced in the control sample (P<0.05). Additionally, the application of composite film on cheese affected the color during storage. It was observed that L* and a* values of the composite film-wrapped cheese were significantly higher than the control sample, but the b* values were significantly lower than the control sample. Moreover, poor microbial growth (yeasts and mold) was observed in cheese samples wrapped by composite film with purple carrot compared to the control. Also, the pH of the composite film with extract significantly decreased from 6.33 to 4.85 during storage (P < 0.05), which showed the changes of color from purple to pink. After 40 days, the color changed to pink, indicating the end of the cheese storage. Therefore, it was concluded that the pH-sensitive film, while being an effective method to improve the shelf life of mozzarella cheese, can also use as an indicator for freshness.
Mohammad Ganjeh; Seyed Mahdi Jafari; Mehrdad Niakosari; Ali-Mohammad Tamaddon; Yahya Maghsoudlou
Abstract
Introduction: In recent years, production of nutraceuticals by adding bioactive compounds and nutrients has been grown substantially. These compounds are generally sensitive to environmental or gastrointestinal conditions and their bioavailability is limited due to destructive reactions. One of the common ...
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Introduction: In recent years, production of nutraceuticals by adding bioactive compounds and nutrients has been grown substantially. These compounds are generally sensitive to environmental or gastrointestinal conditions and their bioavailability is limited due to destructive reactions. One of the common methods to reduce or prevent these kind of problems, is microencapsulation of valuable compounds in some materials which can protect them against environmental conditions, and enabling them to controlled release from trapped compounds at specific time and place. Orange peel oil, contains some important bioactive compounds such as limonene that is used in a variety of beverages, foods, cosmetics, pharmaceuticals and chemicals. D-limonene is the main constituent of orange peel oil, because it makes an 80-95% fraction of the orange peel oil volatile compounds, depending on fruit variety. In addition to its technological characteristics (flavor), D limonene can stop or delay the initiation of cancer. It can also be used as a safe alternative to antimicrobial compounds. Nevertheless, technological limitations (hydrophobic structure, high reactivity, sensitivity to oxidation and volatility) often avoid suitable use of this compound as a dietary supplement. Polysaccharides are among of the basic materials which are applied more in this field. Several factors such as cheap and easy access, having active groups interacting with hydrophobic and hydrophilic compounds, biodegradation, biocompatibility and relatively high thermal resistance, have turned them to be superior to lipid and protein carriers. One of the most important polysaccharide compounds existing in nature, is starch. It can be used as a carrier in encapsulation processes with different purposes, having advantages such as inexpensive, non-toxic, capable of recrystallization, the ability to form film and complex and resistant to various degrees of enzymatic hydrolysis. Spatial configuration of amylose is changed in the presence of ligands such as iodine and linear alcohols, resulting in a left-handed helix which can trap ligands within or between curvatures derived from glucose connections. One of the major structures which is created in the interaction of amylose and lipophilic substances, is known as V-amylose structure. V-amylose is a left-handed helix with an inner hole which ligands can be placed within it. The aim of this study was to determine the effectiveness of amylose in nanoencapsulation of limonene as a bioactive compound with desirable sensory characteristics using a thermo-mechanical stress.
Materials and methods: Based on the analysis of pure limonene samples (Sigma-Aldrich) as well as samples used in this study, more than 92% of examined sample comprised of D-limonene. In order to prepare amylose nanoparticles containing limonene, 0.1 molar solution of potassium hydroxide (Merck, Germany) was prepared in deionized water and then high amylose corn starch (HACS) (Sigma-Aldrich (St. Louis, MO, USA) with 70% amylose was added to it in the ratios of 2: 4% while stirring continuously for 30 minutes at 80°C. Limonene was then used in the ratios of 5: 10% of HACS was added to the suspension and stirring continued for 1 minute. Initial suspension has been processed by using ultrasound system (Model UP100- Hescheler Company, Germany) with 100 W power and frequency of 30 kHz for 9 and 18 minutes. The viscosity of amylose suspensions containing nanoparticles with different formulations was measured by using a capillary viscometer (Schott-Gerate-Capillary-Viscometer-525-00- Germany). Size and zeta potential was measured by using dynamic light scattering (DLS) and Nanotrac Flex In-situ Particle Size Analyzer devices and Microtrac ZETA-check determined. The morphology of nanoparticles was studied using a scanning electron microscopy (TESCAN-Vega3- Czech Republic). Microencapsulation efficiency and loading efficiency were determined by using spectrophotometry.
Results and Discussion: In all formulations, particle sizewere less than 50 nm. Starch granules were exposed to cavitation stress by applying the ultrasonic process .The constant formation of bubbles creates a mechanical impact with high energy on starch granules during bursting. Fast impingement of fluid to granule surfaces, hitting particles to each other as well as resistant of the granules against fluid stream cause breaking of starch particles into nanoparticle scales. The highest amount of zeta potential was related to the sample which had the highest starch and limonene concentration. Amylose concentration had the main effect on zeta potential changes. Electrostatic charges can be the main reasons for the higher zeta potential in samples with 4% amylose concentration. More increasing in surface active agents of amylose, namely ionized hydroxyl groups of glucose molecules leads to increasing in surface charge, and results in zeta potential. The most impact on solutions viscosity is related to amylose concentration. Generally, increasing the amylose concentration leads to increasing the solution viscosity, in other side, with ultrasound treatment, the amount of this index was reduced and the solution became more fluent. Microencapsulation and loading efficiency values ranged between 28-82% and 0.38-1.63% respectively. The limonene concentration had the most impact on the efficiency in various formulations. At similar treatments with %4 amylose concentration and 9 min sonication period, by increasing the amount of limonene from %5 to 10, microencapsulation and loading efficiency were increased from %31 to %82 (%62 growth) and from 0.52 to 1.41 (%63 growth) respectively.
Maryam Nejadmansouri; Seyed Mohammad Hashem Hosseini; Mehrdad Niakosari; Gholam Hossein Yousefi; Mohammad Taghi Golmakani
Abstract
Adequate consumption of ω-3 essential fatty acids (EFAs) has a positive impact on human health. EFAs-enriched functional foods may be used for this purpose. Nanoemulsion is a promising delivery system for incorporating EFAs into a variety of foods and beverages. In this work, fish oil nanoemulsions ...
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Adequate consumption of ω-3 essential fatty acids (EFAs) has a positive impact on human health. EFAs-enriched functional foods may be used for this purpose. Nanoemulsion is a promising delivery system for incorporating EFAs into a variety of foods and beverages. In this work, fish oil nanoemulsions developed by sonication method were subjected to various analyses as a function of hydrophilic lipophilic balance (HLB) and surfactant to oil ratio (SOR). Analyses were performed upon production and during 1-month storage at two temperatures (4 and 25 ˚C) in the presence (100 ppm) or absence of α-tocopherol. Increasing in HLB and SOR decreased the particle size and surface tension; while, increased the refractive index and viscosity. During storage, the particle size of α-tocopherol-loaded nanoemulsions decreased; whereas, that of α-tocopherol-free nanoemulsions increased in a temperature-dependent manner. Irrespective of the storage temperature, surface tension values of antioxidant-loaded nanoemulsions remained constant. However, their viscosity values increased. Antioxidant incorporation fairly increased the nanoemulsions stability likely due to partitioning at the interface. TEM micrographs confirmed the results obtained by static light scattering. The results of this study may help the rational design of functional foods using nanoemulsion-based delivery systems.
Sareh Boostani; Marzieh Moosavi-Nasab; Mahmoud Aminlari; Mehrdad Niakosari; Gholam Reza Mesbahi
Abstract
Introduction: Proteins play a fundamental role in biological systems and are often sensitive against organic solvents, heat and other damaging factors. Proteins are the basic component of food formulations and enhancement the functional characteristics and stability of the proteins has always been the ...
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Introduction: Proteins play a fundamental role in biological systems and are often sensitive against organic solvents, heat and other damaging factors. Proteins are the basic component of food formulations and enhancement the functional characteristics and stability of the proteins has always been the main goal of food industry engineers. One of the natural ways used for protein modifications is Maillard reaction. Maillard reaction as a result of covalent binding between the available amino groups of the proteins and carbonyl containing moiety of the polysaccharides, causes a loss in free amino group content of the mixture. Protein- polysaccharide hybrids, as a result of dry heating of two biopolymers mixture under controlled reaction conditions, cause the emergence of conjugates with novel functionalities. Much research has shown that conjugation can increase thermal stability and functional characteristics of food proteins and also reduce the allergenicity of suspected proteins. Although many studies have been conducted on the effects of conjugation on functional properties of proteins, the impacts of conjugation on proteins behavior after food processing have been less investigated. So, in this paper the influences of Maillard reaction on functional properties of soy proteins have been investigated. In addition, characteristics of conjugated proteins after pasteurization treatment was also studied. Materials and methods: Construction of protein- polysaccharide conjugates was done in several steps. First, soy proteins and dextran were mixed with phosphate buffer (0.1 M, pH: 8.5) and 1 to 4 ratio of protein to polysaccharide. After mixing and incubating at ambient temperature for some hours, solutions were frozen at –80 ℃ and freeze dried. Then the lyophilized powder was incubated at different times, at 60℃, under the 79 percent relative humidity in presence of saturated KBr. For each treatment a non conjugated sample was prepared in the exact same condition. Conjugation of proteins to polysaccharides was monitored by SDS-PAGE electrophoresis, browning intensity measurement and UV absorbance analysis. SDS-PAGE was conducted according to Laemmli procedure using a discontinuous buffer system. A vertical gel electrophoresis unit was used with 3% acrylamide stacking gel and 10% acrylamide running gel. Evaluation of the color changes as an indicator of grafting intensity was investigated by monitoring absorption at a wavelength of 420 nm. To investigate the UV absorption of conjugated proteins, the samples were diluted with SDS (Sodium dodecyl sulfate) solution and the absorption was read by a UV-visible spectrophotometer at 294 nm. The impact of modification on characteristics of soy proteins was monitored by examining the functional properties changes of protein samples. In the last stage soy drinks were prepared from conjugated and non conjugated proteins then the prepared beverages were subjected to thermal processing conditions and the influences of Maillard conjugation on the stability of soy drinks was monitored over time. Results and Discussion: SDS-PAGE electrophoresis profile showed that proteins-polysaccharide conjugates were formed. As a result of conjugation, the protein-dextran covalent binding occurs, leads to the formation of higher molecular weight components, resulting in its accumulation on the top of the separating gel. When heating time increased a wider and higher molecular weight bands appeared near the top of the running gel however they were not observed in the native soy pattern. Covalent linkage between amino group of proteins and carbonyl group of polysaccharides causes a color changes from light yellow to brown, browning intensity results showed that the even during early incubation time, a significant absorption was observed at 420 nm compared to the control samples. UV absorption results showed similar trend of changes in browning intensity measurement. Increasing UV absorption is due to the intermediate Maillard reaction products (MRP). Increasing UV absorption with increasing heating time indicates the fact that Maillard reaction products (MRP) formation are more favorable in the long incubation time. Data of UV absorption are a good evidence for SDS-PAGE and browning intensity results. Functional properties results indicated that grafted proteins had better functional properties. The storage stability of soy drinks prepared from conjugated proteins was significantly higher than the samples prepared from non conjugated proteins. Stability of beverages after thermal processing and during storage is one of the most important features of protein drinks and many efforts have been made to develop mentioned characteristics. Stability of soy drinks produced from the conjugated proteins was significantly higher than those prepared from non conjugated soy proteins. Functional characterization of proteins is dependent on several factors, the majority of soy drink composed of proteins that could be denaturated by heating applied during thermal processing, as the results showed conjugation with dextran caused an increase in denaturation temperature of soy proteins which enhance the resistance of proteins during thermal processing treatment. In addition, the solubility and emulsifying properties of soy proteins increased with conjugation which can be a good reason for improvement the relation between protein and surrounding water molecules and therefore increases the protein storage stability. It can be concluded that Maillard reaction could be applied as a means to prepare soy proteins–dextran conjugates with better functional properties and more stable during processing and storage.
Sareh Boostani; Mahmoud Aminlari; Marzieh Moosavi-Nasab; Mehrdad Niakosari; Gholam Reza Mesbahi
Abstract
Introduction : Soybean is an excellent plant protein source with diverse applications in food systems. Despite numerous commercial applications and rich nutritional properties of soybeans, soy proteins are sensitive to heat and other damaging agents during food processing which can limit their applications ...
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Introduction : Soybean is an excellent plant protein source with diverse applications in food systems. Despite numerous commercial applications and rich nutritional properties of soybeans, soy proteins are sensitive to heat and other damaging agents during food processing which can limit their applications in food industries. Maillard reaction includes a series of chemical reactions between the free carbonyl groups of carbohydrates and the un-protonated amino groups of proteins under mild experimental conditions. This is one of the most desirable approaches for applying in food systems, because of the safety of the procedure and the independency of adding extra chemicals. Natural occurring Maillard reaction can be a relatively safe and inexpensive method in order to improve functionalities of food proteins. The production of conjugates haspositive influences on food proteins functionality such as solubility, water holding capacity, emulsion activity and stability, foaming properties, thermal stability, whipping ability, textural and gelation properties and also reduce allergenicity of proteins. Due to the positive characteristics and reasonable price of both soy proteins and maltodextrin in food industries, the aim of current study was to enhance the heat stability and functional properties of soy proteins through glycosylation with maltodextrin. In addition, assessment of changes in protein properties as a function of incubation time were evaluatedMaterials and methods: Preparation of purified soy proteins (Acid precipitated soy proteins) was done by a multistage process of washing, centrifugation, dialysis and freeze drying. The resulting powder contained pure soy globulins. Conjugation of acid precipitated soy proteins with maltodextrin was performed according to the method described as follows: protein-polysaccharide at a weight ratio of 1: 3 were dissolved in 0.01 M phosphate buffer, at pH values of 8, and were incubated at ambient temperature for 1 hr. Solutions were frozen at –80°C and then freeze dried. Lyophilized powders were incubated at 60 °C for 1, 3, 5 and 7 days, under 79% of relative humidity provided by saturated KBr. For each treatment an un-conjugated (control) sample was prepared under the same conditions. The formation of protein-polysaccharide conjugates was confirmed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration chromatography (Sephadex G-100 chromatographic system was used to separate the conjugated proteins from the un conjugated samples). Determination of protein denaturation temperature changes were carried out using METTLER TA Q100-DSC thermal analyser.The emulsifying properties of the samples including emulsifying activity and emulsion stability were assessed according to the procedure established by Pearce and Kinsella. Protein solubility was measured by calculating the amount of nitrogen in the supernatant and total nitrogen content of the samples and reported as percentage of protein solubility at pH 3, 5, 7 and 9. Foaming properties of the samples including foaming capacity and foaming stabilitywere determined using calibrated measuring cylinderDiscussion & Results: When the heating duration is increased, wider and heavier molecular weight bands emerge near the top of the running gel of SDS-PAGE, and yet these were not observed in the control. As a result of conjugation, the protein-carbohydrate covalent binding occurs, producing heavier molecular weight species, and thus leading to its accumulation on top of the separating gel. Compared with un-modified soy proteins, the conjugated soy proteins eluted in the void volume of G-100 gel permeation chromatography column, suggesting increase in the size and molecular weight of soy proteins due to the covalent attachment of maltodextrin. According to differential scanning calorimetry (DSC) analysis, thermal stability of soy proteins was remarkably increased by conjugation with maltodextrin and maximum denaturation temperature was observed for the mixture incubated for 7 days. The improved thermal stability is manifested in increase in denaturation temperature of globular proteins, hence conjugation leads to significant improvement of soy proteins stability. Increase in thermal stability is the result of inclusion of the hydrophilic carbohydrate moiety to the surface of the proteins. Compared to control sample, the solubility, foaming characteristics and emulsifying properties were significantly improved by increasing incubation time. The protein solubility of conjugate remarkably increased at all pH’s compared with the un-conjugated proteins. Covalent links between hydrophilic maltodextrin and soy proteins could enhance the reaction tendency between proteins and water molecules under unfavorable conditions. Improvements in the emulsifying properties of the conjugated samples can be explained by the fact that there is a combination among the emulsifying activity of proteins and the stabilizing impacts of polysaccharides per molecule. Foaming capacity of proteins can be affected by the solubility of proteins. Furthermore, maltodextrin is a hydrophilic carbohydrate which can improve the stability of soy proteins foams by acting as a thickener, thus increasing the strength of bubbles. It should also be considered that functionality of proteins are frequently influenced by protein solubility, and this could also serve the understanding of why improvements occur in functional properties of conjugated proteins, compared to un-conjugated ones. The results indicate that physiochemical and functional properties of soy proteins were modified and improved by conjugation with maltodextrin.
Sareh Boostani; Mahmoud Aminlari; Marzieh Moosavi-Nasab; Mehrdad Niakosari; Gholam Reza Mesbahi
Abstract
Introduction: Engineering of food proteins with improved functional properties and higher resistance to heat is the main goal of food scientists. Food technologists are always seeking for innovative, simple and effective methods to manipulate proteins, hence natural modification has had the most attention ...
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Introduction: Engineering of food proteins with improved functional properties and higher resistance to heat is the main goal of food scientists. Food technologists are always seeking for innovative, simple and effective methods to manipulate proteins, hence natural modification has had the most attention in last decades. One of the natural ways used for protein modifications isMaillard grafting reaction. Maillard reaction as a consequence of covalentbindingbetween the available amino groups of the proteins and carbonyl containing moiety of the polysaccharides, causes a loss in free amino group content of the mixture that can be measured through different methods. Protein-polysaccharide hybrids, as a result of dry heating of two biopolymers mixture under controlled reaction conditions, cause the emergence of conjugates with novel functionalities.Selecting appropriate reaction conditions has a significant impact on the properties of the final conjugates. Among the factors affecting the degree of conjugation, temperature, pH and incubation time have considerable roles in determining the degree of conjugation. There are various methods by which conjugation degree can be assessed and factors such as accuracy, cost, accessibility and etc. must be considered when selecting a measuring method. Therefoe, in this study the effect of different Maillard reaction conditions on the conjugation degree of soy proteins-dextran heated mixtures have been investigated. In addition, the glycation degree was compared and reported by both OPA assay and UV absorbance methods.Materials and methods: Soy proteins–dextran conjugates were prepared as described later. First, soy proteins and dextran were mixed with phosphate buffer (0.1 M, pH: 8.5 and 7) and 1 to 4 ratio of protein to polysaccharide. After mixing and incubating at ambient temperature for some hours, solutions were frozen at –80 ℃ and freeze dried. Then, the lyophilized powder was incubated at 40 ℃ for 0, 4, 8, 24 hours and 2, 4, 6, 8, 12 days, at 60 ℃ for 0, 1, 2, 3, 4, 6, 8 days and at 80 ℃ for 0, 1, 2, 4, 8, 16, 24, 48 hours, under the 79 percent relative humidity in presence of saturated KBr. For each treatment a non conjugated sample was prepared in the exact same condition. Conjugation of proteins to polysaccharides was monitored by two methods (OPA assay and UV absorbance). Determining degree of glycation by OPA method was done as follows, in this procedure the level of available amino groups was estimated using the ortho- phthaldialdehyde (OPA) reagent, the absorbance was measured at 340 nm and degree of glycation was measured using a formula. To investigate the UV absorption of conjugated proteins, the samples were diluted using distilled water and the absorption was read using a UV-visible spectrophotometer.Results & Discussion: Covalent linkage between amino group of proteins and carbonyl group of polysaccharides causes depletion in the amount of available amino groups. The extent of soy proteins-dextran conjugation under various Maillard reaction conditions was evaluated by the reduction of available amino groups of proteins, the more reduction in amount of amino groups, the more conjugation between protein and polysaccharide. OPA results showed that, in the samples heated at 40 °C and 80 °C (at both pH 7 and 8.5), the amount of free amino groups slightly reduced compared to 60 °C heated samples. The disappearance of available amino groups at 60°C was faster than other temperatures and formation of conjugates in this temperature was more successful. A stepwise reduction in free amino group content observed with increasing incubation time. When soy proteins were incubated at pH 8.5 for 8 days at 60 °C, a considerable decrease in available amino group contents occurred. UV absorption results showed similar trend of changes in OPA method. Increasing UV absorption is due to the intermediate Maillard reaction products (MRP). Increasing incubation time, temperature and pH cause a significant increase in UV absorbance. Increasing UV absorption with increasing heating time indicates the fact that Maillard reaction products (MRP) formation is more favorable at alkaline pH. Data of UV absorption are a proper evidence for OPA assay results. Conclusion: As a conclusion, both OPA assay and UV absorption methods are cost effective, accurate and simple methods which can represent valuable information concerning the Maillard conjugation.
Mahdi Moradi; Mehrdad Niakosari; Armaghan Etemadi
Abstract
This research, presents mathematical modeling of drying process of Aloe vera slices with dimensions of 7×4×0.5±0.1 cm. Peeled Aloe vera slices with the initial moisture content of 5750% (d.b) were osmosed for 5 hours in NACL solution of 10% and temperature of 40 °C at a constant ...
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This research, presents mathematical modeling of drying process of Aloe vera slices with dimensions of 7×4×0.5±0.1 cm. Peeled Aloe vera slices with the initial moisture content of 5750% (d.b) were osmosed for 5 hours in NACL solution of 10% and temperature of 40 °C at a constant solution to fruit ratio of 5:1. Osmosed and unosmosed Aloe vera samples were hot air dried at 55, 70 and 85°C with different air flow rates of 0.015, 0.036 and 0.054 m3/s for 13200s. The moisture content of Aloe vera samples were measured over different intervals of drying time (1200, 2400, 6000, 9600, 13200s) for each experiment. The experimental results were used to obtain two different dimensionless models based on Buckingham’s pi-theorem for both drying methods. To this end, three independent π terms were identified and then the relation between dependent π term and each independent π term was sought. Finally, the dimensionless models incorporating the effect of all the independent π terms on the dependent one derived and evaluated. The RMSE, (R2), MRD and MBE for the modeling of osmotic-convective drying method were calculated as 0.0185, 0.99, 0.05 and 0.034, respectively. Also these statistical parameters for the convective drying method were as: 0.027, 0.98, 0.061 and 0.051, respectively. Therefore the dimensionless models could predict the moisture content of Aloe vera samples during drying, properly.
Alireza Yousefi; Shahla Khodabakhsh Aghdam; Mahdi Pourafhar Chenar; Mehrdad Niakosari
Abstract
In this study, mathematical modeling of hot air-drying of thin-layer papaya (Carica papaya L.) slices with 5±1 mm thickness pretreated in osmotic solution (50% sucrose) was investigated. Thin-layer drying was conducted under three different drying temperatures of 40, 50 and 60 °C at a constant ...
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In this study, mathematical modeling of hot air-drying of thin-layer papaya (Carica papaya L.) slices with 5±1 mm thickness pretreated in osmotic solution (50% sucrose) was investigated. Thin-layer drying was conducted under three different drying temperatures of 40, 50 and 60 °C at a constant air velocity of 0.9±0.1 m/s and absolute humidity of 0.6 ± 0.02 g of water/kg of dry air. It was found that the drying process occurred in falling rate period over the drying time. The osmosis dehydration characteristics obtained by solid gain (SG), water loss (WL) and weight reduction (WR) parameters that increased with increasing immersion time. The effective diffusivity for papaya slices was within the range of 2.13×10-9 to 4.84×10-9 m2/s over the temperature range. The activation energy was 38.63 kJ/mol indicated the effect of temperature on the diffusivity. Based on the statistical analysis using coefficient of determination (R²) and root mean square error (RMSE), it was concluded that the best model in terms of fitting performance for hot air-drying of papaya pretreated in osmosis solution in all temperature range was Midilli et al. model.
Hassan Afshari Jooybari; Asgar Farahnaki; Mahsa Majzoobi; Gholam Reza Mesbahi; Mehrdad Niakosari
Abstract
Mazafati date is a wet and semi-dried date fruit type with dark red to black color that has premier quality. Because of its high moisture content, date fruits of this variety are very perishable at room temperature and therefore must be refrigerated during storage. In this study, effect of air temperature ...
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Mazafati date is a wet and semi-dried date fruit type with dark red to black color that has premier quality. Because of its high moisture content, date fruits of this variety are very perishable at room temperature and therefore must be refrigerated during storage. In this study, effect of air temperature (50, 60, 70, 80 and 90 ˚C) and air flow rate (1, 1.5 and 2 m/s) in hot air drying of Mazafati date were investigated. The results showed that for all samples, drying occurred at the falling rate stage of drying and the main factor affecting the drying rate was air temperature. Air flow rate did not have significant effect on drying rate. Overall, it was concluded that moisture of Mazafati dates can be reduced by cabinet drying and therefore using drying process, the need for their cold storage can be eliminated.
