Food Technology
Mahshad Lavarsetagh; Nafiseh Zamindar; Yasaman Esmaeili
Abstract
Color is the most important indicator of the quality of food that affects consumer acceptance. In order to replace the color lost during the process, increasing the existing color and minimizing variation during processing; natural colors, synthetic and inorganic colorants are added to the food. Red ...
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Color is the most important indicator of the quality of food that affects consumer acceptance. In order to replace the color lost during the process, increasing the existing color and minimizing variation during processing; natural colors, synthetic and inorganic colorants are added to the food. Red beet is one of the most important natural sources of color; In this study, the overall results showed that increase in the extraction pH and time, increased the extraction of betacyanine and betaxanthine. It would be better to extract betacyanine at temperatures below 25 ° C since this pigment is sensitive to high temperatures and at the temperature above, 25 °C will be destroyed. The maximum yield was observed when pH value, temperature and time were 5, 21 °C and 20 min, respectively. Comparison of experimental and predicted values of the proposed responses at the proposed optimal point by t-test showed no significant difference (p< 0.05). Quadratic model was suggested for the responses and lack of fit was not significant (p<0.05). The extraction of betaline from red beet using ultrasonic method causes the reduction of time, temperature, energy and solvent consumption. The maximum yield was observed when pH value, temperature and time were 5, 21 °C and 20 min, respectively. Comparison of experimental and predicted values of the optimal points showed no significant difference by t-test (p< 0.05).
Food Engineering
Saeede Hamidi; Nafiseh Zamindar; Nayyere Gholipour Shahraki
Abstract
IntroductionThermal processing is an important method of canned food production (Farid & Abdul Ghani, 2004). Estimation of the heat transfer rates is essential to obtain optimum processing conditions and to improve product quality. In addition, a better understanding of the mechanism of the heating ...
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IntroductionThermal processing is an important method of canned food production (Farid & Abdul Ghani, 2004). Estimation of the heat transfer rates is essential to obtain optimum processing conditions and to improve product quality. In addition, a better understanding of the mechanism of the heating process will lead to an improved performance in the process and to some energy savings (Abdul Ghani et al., 1999). Computational fluid dynamics (CFD) is an efficient way to study flow behavior and temperature distribution of thermal processing in the food technology (Ghani et al., 2003). As the semi-rigid aluminum packaging market recently has been introduced, there is limited information about the temperature distribution during the heating process of such containers. In this paper the temperature distribution was predicted and location of cold zone was determined. The effect of headspace (air and water vapor) in heat transfer mechanism was investigated. Materials and MethodsPhysical propertiesMalt extract properties such as density, specific heat, thermal conductivity and viscosity values are necessary for the equations solution. Viscosity and density of the sample was measured as a function of temperature (Vatankhah et al., 2015). Specific heat and thermal conductivity of sample were estimated using the mass fraction of its constituents. For simulation, the experimental results were applied by piecewise-linear method in the material part of the software to describe viscosity, thermal conductivity and specific heat. Experimental methodologyFor the experimental, a thermocouple probe was located at point (0, 0, -2.76) in a semi rigid aluminum based packaging to measure the temperature distribution inside the container. Then the package was filled with malt extract (°Brix ~ 60) and then the package was sealed at 280 °C using Alcan machine. Another thermocouple was placed near the containers, in the water cascading Barriquand steriflow retort. The thermocouples were attached to Ellab data logger by PT100 cables. The data logger was connected to a personal computer and E-val 2.1 software was used to export time temperature profile of each thermocouple in 1 min intervals. Geometry and meshingGambit 2.3.30 was used to develop geometry and set of grid (0.2 cm, and 0.1 cm mesh size) was performed. Then software of fluent 6.3.26 with 3-D, double precision, pressure-based solver, implicit formulation, unsteady time, laminar flow was applied to solve the system of the governing equations (Vatankhah et al., 2015). Boundary conditions and initial valuesUnsteady temperature function was imposed to all faces of the geometry in 1 min time intervals. No-slip boundary condition was supposed for velocity components relative to boundaries. The boundary conditions used at top surface, bottom surface and side walls included: T = Tw, Vx = 0, Vy = 0 and Vz = 0. The initial temperature was assumed as the first temperature which was measured by the thermocouple at the starting time of processing. Solution methodologyFluent software was used to solve the Navier-Stokes and energy equations simultaneously. A preset convergence limit of 10−3 for continuity and momentum equations and 10−8 for the energy equation were used, in order to achieve an appropriate convergence. The under-relaxation factors were adjusted smaller than 1 to obtain a good convergence of the numerical solution. SIMPLEC algorithm was used for pressure-velocity coupling. Results and DiscussionThere was no significant difference between predicted and experimental temperatures for point (0, 0, -2.76) in models with and without head space using t-test (p<0.01). Temperature contours of predicted models (with headspace) were similar to model without headspace at the different stages of the process. Simulation result showed slowest heating zone located in (0.02 <X< 0.8, -1 <Y< 0.3 and -3.27<Z< 3.27) for model of malt extract with headspace and in (-3.58 < X< 3.76, -3.44 <Y< 0.48 and -3.46 <Z< -3.05) for model of malt extract without headspace. ConclusionThe heating process of malt extract in semi rigid aluminum container during thermal processing was simulated successfully using CFD. The CFD based model showed that the position of SHZ was located in the third end of the container.
Food Technology
Ali Hosseini; Nafiseh Zamindar; Yasaman Esmaeili
Abstract
IntroductionToday, carrots are widely used in freshly cut products, including ready to eat salads, however, its shelf life is reduced due to the damage caused on the texture of the product which accelerate the reduction of nutritional value as well as the growth of microorganisms, (Azizian et al., 2020). ...
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IntroductionToday, carrots are widely used in freshly cut products, including ready to eat salads, however, its shelf life is reduced due to the damage caused on the texture of the product which accelerate the reduction of nutritional value as well as the growth of microorganisms, (Azizian et al., 2020). To increase the shelf life of freshly cut products, it is recommended to use coatings on the surface of these products. Alginate is a hydrophilic biopolymer and having unique colloidal characteristics, it demonstrates a suitable coating function. Olivas et al. (2008) showed that by coating fresh apple slices with alginate and antimicrobial agents increased the shelf life of apple and decreased weight loss. Among the native plants of Iran, we can mention the Oliveria plant, which belongs to the Amblifra family. The aerial parts of this plant have a significant amount of essential oils (EOs). Researches by Amin et al. (2005) on the antimicrobial properties of Oliveria essential oils have shown a broad-spectrum antimicrobial activity against all studied organisms, and this effect is comparable to that of commercial antibiotics. Packaging with modified atmosphere is one of the best ways to increase the shelf life of fruits and vegetables. The purpose of this study was to investigate the effect of alginate and Oliveria essential oils on the physicochemical and microbial characteristics of grated carrots in polypropylene packages with modified atmosphere during storage. MethodsEssential oil of Oliveria plant was extracted, dehydrated by sodium sulfate and placed in sealed glass container and stored at 4˚C until using. Carrots prepared from Wilmoren cultivar. An industrial crusher crushed the carrots, and samples were coated by treatment solutions. Two treatments of coating were prepared, one as control with 0% and the other one with 1.5% alginate with stirring and moderate heat (50-60°C) (Lu et al., 2009). Then the Oliveria EO was added to the alginate solution at the specified concentration. The resulting solution was deaerated at 25˚C.T1: control sample (without coating)T2: 1.5% alginateT3: 150 ppm Olivieria EOT4: 250 ppm Olivieria EOT5: 1.5% alginate and 150 ppm of Olivieria EOT6: 1.5% alginate and 250 ppm of Olivieria EOAfter weighing (250 g), the grated carrots (control and coated) were placed in 10 g polypropylene packages of suitable food grade in dimensions of 50 × 190 × 144 cm and the package was injected with 5% O2, 5% CO2 and 90% N2. The packages were then stored in the refrigerator for 12 days at 4±1˚C. All experiments were performed on days 1, 3, 6, 9, and 12. Evaluation of Chemical, Microbial and Sensory CharacteristicsA pH meter used for pH determination (Rad et al., 2020). The acidity measured based on Rocha et al. (2007) method.The weight was reported using pre and post-storage weight. The carotenoid concentration calculated by Rocha et al. (2007) method. Total soluble solids determined by refractometer (Rad et al., 2020). Ascorbic acid content measured by Falahi et al. (2013) method. The L*, a*, b* and WI (white index) indicators of grated carrots evaluated by Hunter lab system. A 5-point hedonic test was used to assess sensory attributes(Ajnevardi et al., 2002). The internal gas concentration evaluated by Ullsten & Hedenqvist (2003) method. Total count microorganisms, mold, and yeast were counted according to the method of Azizian et al. (2020). Data AnalysisThis study was conducted in a completely randomized design with factorial form to investigate the effect of independent variables of type of alginate coating (2 levels), essential oil (3 levels) and time (5 levels) on the physicochemical properties of grated carrots (3 replications) and total counting, mold and yeast (2 replications). Mean comparison was performed using LSD test at 5% probability level and SPSS software was used to statistically analyze data. ResultThe results showed that the level of acidity, carotenoid and acid ascorbic, the amount of L* and sensory (color, quality, flavor, odor) scores reduced during time. By contrast the level of pH, weight loss, the amount of a*, b*, CO2, TSS and total counts increased (P<0.05). Also, with increasing the concentration of essential oils and alginates, the amount of acidity, carotenoids, ascorbic acid, L* increased and pH, weight loss, TSS, a*, b*, CO2 and total count decreased (P<0.05). Escherichia coli, mold and yeast count of the samples did not show any growth from the mentioned treatments until the 12th day. Overall, the Oliveria essential oil and alginate were effective in improving the properties of grated carrots under the modified atmosphere during storage. ConclusionThe study showed that Oliveria EO and alginate added to grated carrots in modified atmosphere packaging during storage was effective in reducing respiration, water loss, microbial load and increased the shelf life. Treatment containing 1.5% alginate and 250 ppm Oliveria EO showed the best chemical, microbial and sensory characteristics. The results indicated that by packing under modified atmosphere and coating by alginate and Oliveria EO, a new carrot product provided to the market with maintaining durability and quality characteristics during storage.
Shahnaz Fattahi; Nafiseh Zamindar
Abstract
Introduction: Fish is the most extremely perishable food products (Roiha et al, 2018) and its quality may be affected by many elements (García et al, 2015). The techniques used for freezing and thawing processes play an essential function in maintaining the quality of the frozen foods. If freezing ...
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Introduction: Fish is the most extremely perishable food products (Roiha et al, 2018) and its quality may be affected by many elements (García et al, 2015). The techniques used for freezing and thawing processes play an essential function in maintaining the quality of the frozen foods. If freezing and thawing processes are carried out accurately, the quality of frozen fish will be near to fresh quality after thawing (Duygu and Ümit, 2015). There are various methods for thawing of frozen food products like still air thawing, air blast, refrigerator thawing, cold and warm water thawing, warm salt-water thawing, static water thawing and a number of innovative approaches such as high voltage electrostatic field (HVEF) thawing, ohmic, microwave, pressure-assisted, acoustic, radio frequency, infra-red and high hydrostatic pressure thawing (Mousakhani-Ganjeh et al, 2015; Mousakhani-Ganjeh et al, 2016). During Ohmic heating (OH), electrical energy is altered to thermal energy within a conductor by applying an alternative current across the food product (Darvishi et al, 2013). The energy is approximately completely dispersed within the heated food product (Shim et al, 2010). A large number of applications exists for ohmic treatments including heating, cooking, thawing, blanching, evaporation, dehydration, pasteurization, fermentation and extraction (Athmaselvi et al, 2017; Boldaji and Borghei, 2015). Materials and methods: Tuna fish (Thunnus albacares) obtained from Esfahan Pegah Co., Isfahan, Iran and transferred to the laboratory. The white fresh fish muscles were divided into cubes (3 × 3 × 3 cm3) and instantly frozen at -30°C after vacuum packaging in polyethylene bags. The frozen samples kept at -18°C until the day of experiments. The experimental apparatus of ohmic heating comprised of a power supply, an isolating variable transformer, power analyzer and a microprocessor board. The ohmic cell was made of PTFE cylinder with two displacement stainless steel electrodes. Temperature was measured with a K-type thermocouple. The electrical conductivity (σ, mS/cm) of the brine solutions was determined before thawing at 25°C. The electrical conductivity of fish minced paste was also measured at 4°C. In the present study, the tuna cubes (27 cm3) were thawed under constant ohmic power intensity (50 V) at three different brine concentrations (0.3, 0.4 and 0.5 NaCl, %w/v) during three time intervals (0, 24 and 48 hours). The parameters associated with the quality of tuna such as thawing time, thawing rate, thawing, cooking and total losses, centrifugal loss, lipid oxidation, texture and color were investigated during OH thawing. Changes in the thawing, cooking and total losses, WHC, texture, L*, a*, b* and color changes were studied as kinetic models. Results and Discussion: Results showed that, thawing under immersion ohmic thawing significantly decreased the thawing time of frozen tuna fish cubes. Suitable kinetic models with the highest regression coefficient described dependent parameters. In addition, kinetic models were validated by R2 and RMSE. Statistical analysis showed that the interaction effects of two parameters (concentration * time) on thawing loss were significant (p0.05). The lowest thawing loss was observed at 0.3 and 0.5 %w/v NaCl immediately after thawing. The lowest cooking loss was seen at highest brine concentration and the lowest total loss was observed at time zero after thawing (p0.01). The WHC of meat product is one of the most important factors affecting economical value and meat quality due to the weight change during thawing. In this study, WHC increased by increasing the brine concentration. In addition, oxidation of lipids did not occur, and TBA index did not differ significantly. This was probably due to the high speed of immersion ohmic thawing. The highest shear force was related to the treated sample with the lowest brine concentration. The highest a* was indicated immediately after thawing. Immersion ohmic thawing saved time and led to reducing the losses parameters. In addition, WHC was maintained at the highest possible level. Fish and fishery products are very perishable materials and no oxidation was observed during immersion ohmic thawing regarding the presence of NaCl,.
Maryam Keshani; Nafiseh Zamindar; Reza Hajian
Abstract
Introductıon: The Scombridae family of fish consists of tuna, bonito and mackerel species that are found in warm waters. Tuna species is important because of economic value and prevalence in global trade. Although, they are usually not consumed fresh because of the limited fishing season, lack of accessible ...
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Introductıon: The Scombridae family of fish consists of tuna, bonito and mackerel species that are found in warm waters. Tuna species is important because of economic value and prevalence in global trade. Although, they are usually not consumed fresh because of the limited fishing season, lack of accessible markets at certain locations and cost of transport to other areas. Therefore, long-term preservation methods must be used. For many years, freezing has been the method of preserving food for a longer period without a significant quality decrease. Thawing with minimal damage to the products quality is very important. Since common thawing methods are usually slow and reduce food quality, a substituted technique seems necessary. Ohmic thawing is a thermal-electrical method with a more uniform heat compared to other thermal-electrical methods. The speed and relative uniformity of ohmic heating is possible by passing direct electrical current through the product. In this process, the electrical resistance of frozen food is utilized. Electrical energy passes through food by means of electrical current and is dissipated in the form of heat (Joule effect). Based on Ohm’s law, the amount of dissipated heat is directly related to the used voltage and the electrical conductivity of the product or its parts. Materials and Methods: Muscles of the frozen tuna fish were cut into 3x3x3 cm cubes and kept in zip lock bags and stored at -30 for 24 h. Then the samples maintained at -18 until the experiments time. The ohmic cell was filled with saline solution (0.3%, 0.4% and 0.5% respectively) and the thermocouple was connected to the geometric centre of the frozen fish at -18. Then a voltage of 50 volts with 50Hz frequency was applied until the sample centre reached -7. The samples were then removed from the cells and protein solubility, pH, TVBN, centrifuge loss, thawing loss, drip loss, evaporation loss, and press juice were measured at 0, 24 and 48 h after thawing. Completely randomize design in factorial form with three replications was carried out for the experiments. Data were analyzed by SAS software. Results and Discussion: In this research, ohmic thawing was evaluated as a new method for thawing fish. According to the results of ANOVA, with passing of time the protein solubility, pH, TVBN, centrifuge loss and press juice was increased. With further study of ANOVA of thawing loss and drip loss, it was concluded that salt concentration had a significant effect on dependent parameters (P<0.05). While keeping a high thawing speed, no burning marks appeared on the edges and around the samples in the ohmic method.
Foroozan Jafari; Nafiseh Zamindar; Mohammad Goli; Zahra Ghorbani
Abstract
Introductıon: In developing countries, camel meat is used to provide nutrients, proteins, vitamins, and minerals but it usually has a tough texture. Marinating meat may improve its flavor and tenderness. It has been shown that plant enzymes such as papain, ginger, and Cucumis increase the meat's tenderness ...
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Introductıon: In developing countries, camel meat is used to provide nutrients, proteins, vitamins, and minerals but it usually has a tough texture. Marinating meat may improve its flavor and tenderness. It has been shown that plant enzymes such as papain, ginger, and Cucumis increase the meat's tenderness and improve the flavor and aroma of the products.Ginger extract (GE) could improve the tenderness of camel meat by “Zingibain”. Marination in acidic solutions has been used both traditionally and industrially for the tenderization and flavoring of meat (Abdeldaiem and Hoda., 2013; Tsai et al., 2012). The tenderization effect of marination on meat have been examined by using organic acids such as citric acid (Aktas et al., 2003; Berge et al., 2001; Ke et al., 2009; Kim et al., 2013; Ke, 2006; Ke et al. 2009).The objective of this study was to evaluate the effect of ultrasound and marination with different concentrations of citric acid and Ginger extract 30% on the physicochemical characteristics of camel meat. Materials and methods: Fresh ginger rhizome (Zingiber officinalis roscoe) purchased from a local market was washed, peeled, sliced and immediately homogenized with an equal quantity of chilled and distilled water (4ºC) for 2 min to extract the crude enzyme. The homogenate was filtered through Buchner funnel and the water to get the GE. Marinade solutions were prepared by the addition of 0.5, 1 and 1.5% citric acid to 30% GE, and distilled water was used as control. To prepare the required 30% GE, the crude fresh GE was diluted with distilled water (He et al., 2015).The portions from Biceps femoris muscles of aged male camel carcasses (4 years of age) were prepared according to the method described by Abdeldaiem et al (2013). Uniform sized (3×3×3 cm) of aged camel meat chunks were dipped in the curing solutions at the ratio of 3:1(meat: liquid) and immersed in the polyethylene bags and kept at 4±1°C for 24 and 48 h (Abdeldaeim et al., 2014; Garge et al., 2006).The pH values were measured directly using a probe-type electrode (Naveena et al., 2004). Uptake of the marinade (%) was measured according to the method described by Garg et al (2006) and Hosseini et al (2012).The color measurements; lightness (L*), redness (a*) and yellowness (b*) were performed at the surface of the marinated meat samples (Barbut, 2004).Cooking loss of meat samples was determined so that He et al (2015) and Kim et al (1995) described.Shear force values of cooked samples were determined using texture analyzer with Warner-Bratzler shear apparatus, while muscular fibers were almost parallel to the force as normally occurs during chewing. Six meat cores (1.27 cm diameter) parallel to muscle fiber were sheared once through the center by a warner-Bratzler shear attachment using 50 kg compression load cell and 200 mm/min cross-head speed (Karimi et al., 2008; Hosseini et al., 2012).After 24 and 48 h marination, samples were prepared for (SEM) as described by Naveena et al (2004).A completely randomized design in a factorial experiment with 3 replications was employed by using analysis of variance (ANOVA) to study the effect of ultra-sonication, and time on the physicochemical properties of camel meat. Least significant difference (LSD) test was used to determine differences between treatments means (P<0.05). Data were analyzed using the procedure of SAS version 8 (Burke et al., 2003). Results and discussion: Ultrasonication caused a decrease in pH while increasing marination time caused an increase in pH of all samples compared with control. Cooked samples showed higher pH compering with raw marinated samples. Ultration and increasing marination time caused a significant increase in marinade uptake due to structural changes. Application of ultrasound, the higher concentration of acid in marinade solution and longer marination period resulted in lower shear forces of meat samples.Marination by 30% GE in addition to 1.5% citric acid and ultration illustrated maximum tenderness, lower pH and L*-value but caused less water holding capacity and higher cooking loss.
