Food Technology
Fayza Hussein Alhasan; Mostafa Mazaheri Tehrani; Mehdi Varidi
Abstract
Preparing air-in-oil-in-water (A/O/W) double emulsion involves two key steps: oleofoam formation and dispersion of the oleofoam in an aqueous solution containing protein as an emulsifier and hydrocolloid as a thickening agent. This study aimed to investigate the effect of oleofoam level and varying concentrations ...
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Preparing air-in-oil-in-water (A/O/W) double emulsion involves two key steps: oleofoam formation and dispersion of the oleofoam in an aqueous solution containing protein as an emulsifier and hydrocolloid as a thickening agent. This study aimed to investigate the effect of oleofoam level and varying concentrations of protein-polysaccharide ratios on the thermal stability, encapsulation yield and rheological properties of A/O/W double emulsion. An oleofoam was obtained using a lipophilic emulsifier (distilled monoglyceride MG) and sunflower oil at 5°C with maximum stability. Two levels of oleofoam (20% and 25 wt %) were added to an aqueous solution containing different concentrations of sodium caseinate (SC) (5, 8, and 10 wt %) and kappa carrageenan (KC) (0.4 and 0.8 wt %). Results indicate that oleofoam level did not significantly affect air encapsulation efficiency and particle size, while protein-polysaccharide ratios could significantly impact all properties of A/O/W double emulsion. Increasing the concentration of sodium caseinate and kappa carrageenan improved thermal stability and encapsulation yield while simultaneously reducing particle size. All A/O/W emulsions exhibited shear thinning behavior among the range of shear rates studied, indicating significant potential for food applications.
Food Engineering
Fatemeh Heydari; Mohebbat Mohebbi; Mohammad Javad Varidi; Mehdi Varidi
Abstract
The effect of various levels (5, 10 and 15%) of fish protein concentrate (FPC) in batter formulation was investigated. The physicochemical properties of chicken nugget were evaluated in order to find the optimium level of FPC in batter formulation. Flow behavior showed that the control batter and a treatment ...
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The effect of various levels (5, 10 and 15%) of fish protein concentrate (FPC) in batter formulation was investigated. The physicochemical properties of chicken nugget were evaluated in order to find the optimium level of FPC in batter formulation. Flow behavior showed that the control batter and a treatment contains of 7.5% FPC had higher viscosity. Moisture loss and fat uptake in control sample was higher than all treatments contain FPC in both deep fat and air fryer. Thicker crust resulted by higher level of FPC in batter leads less oil uptake during frying. Moreover, the samples contain FPC had the highest score in terms of texture and overall acceptability. In spite the fact that nuggets contain FPC had the high rate of our research priorities, however, the level around 15% considered as a limitation. Using desirability optimization, the range between 7.5- 8% of PFC in batter formulation was selected as the best level.
Shakiba Kianiani; Mohammad Javad Varidi; Mehdi Varidi
Abstract
Introduction: Meat and meat products contribute about 20% to human fat consumption. Fat is the main source of energy and the base of fat soluble vitamins. Besides, it improves cooking yield and water holding capacity, conserves taste and flavor of products and affects the emulsion stability, juiciness, ...
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Introduction: Meat and meat products contribute about 20% to human fat consumption. Fat is the main source of energy and the base of fat soluble vitamins. Besides, it improves cooking yield and water holding capacity, conserves taste and flavor of products and affects the emulsion stability, juiciness, costumer acceptability and structural and rheological properties of meat products. But Animal fat contains a relatively high amount of saturated fatty acids and cholesterol, which can increase the risk of cardiovascular disease, diabetes, cancer types and obesity. Thus, the meat industry is interested in merchandising fat-reduced meat products without neglecting the positive effects of fat on flavor and texture.
Various researches have shown that the substitution of fat on a polysaccharides base such as fibers, starch, gums, and gels have improved and modified the texture, residual moisture and freeze stability, and decreased the price of the products.
Aloe vera leaf gel contains about 99 – 99.5 % water and 1 - 0.5 % of the total solid content. On dry matter basis aloe vera gel consists of 55% polysaccharides, 17 % sugar, 16 % mineral, 7% protein, 4% lipids and 1% phenolic compounds (Lawless et al., 2014). The most important carbohydrates of aloe vera gel are the long chain polysaccharides, comprising glucose and mannose, known as the glucomannans [β (1, 4) – linked acetylated mannan]. All the solid content of aloe vera gel are surrounded by polysaccharide mucilage layer.
Literature review pointed out there have been little investigations into the functionality of aloe vera gel in the emulsion meat products. According to the importance of producing low - fat meat products from one hand as well as the nutritional values and health characteristics of aloe vera gel on the other hand, this study was designed to replace the fat with aloe vera gel in the production of low - fat German sausage.
Material and Methods: Sausage samples containing 40% of red meat (German sausage) were produced based on the conventional plants formula. animal fat and vegetable oil replaced by 0, 50 and 100% aloe vera gel in the German sausage formulation. All samples were cooked at 90°C temperature to achieve the core temperature of 70° C, followed by cooling, they were kept in the refrigerator (4°C) until the subsequent experiments. The AOAC (2000) methods were used for measuring the moisture content, the amount of fat, ash and protein. The amount of carbohydrate was calculated based on the calculation of the total weight difference from the sum of ash, protein, fat and moisture (according to the method FAO / WHO). The amount of energy was computed based on the total amount of energy from fats, proteins and carbohydrates. To measure the pH of samples by pH meter, method of choe et al (2013) was followed. The color analysis was done on the surface of sausage cuts by chromometer. The parameters of color include L* (lightness), a* (redness) and b* (yellowness) were measured. Texture parameters include hardness(N), cohesiveness, springiness (cm), gumminess (N), chewiness (N.cm), adhesiveness were determined by texture analyzer as described by Bourne (1978). The sensory attributes were evaluated by 10 trained panelists. A five-point hedonic scale rating (1= very bad, 2=bad, 3= neither bad nor good, 4= good, 5= very good) was carried out.
Results and Discussion: Physicochemical properties analysis indicated significant differences among meat products (p ≤.0.01). The addition of aloe vera gel resulted a decrease in fat percentage and amount of energy, an increase in moisture and carbohydrate, but the amount of pH, protein and ash content did not change. This study showed that reducing the fat content and replacing by aloe vera gel caused a significant difference in the amount of energy (p≤.0.01).With respect to the significant contribution of fat in the production of energy, the amount of energy was reduced as expected by reducing the fat of the formulation. The results indicated that the value of L * showed the negative and positive trends with animal fat and vegetable oil changes, respectively (p≤.0.01). b* decreased by reducing the amount of fat and oil (p≤0.01), but the value of a* always remained constant (p˃0.05). The presence of aloe vera gel in sausage caused a reduction in hardness, adhesiveness and gumminess (p<0.05), while it did not affect the amount of adhesiveness and cohesiveness of samples (p˃0.05).
The substitution of fat with aloe vera gel had a significant effect on the sensory characteristics of German sausage (p≤.0.01). By reducing fat and oil and adding aloe gel to the German sausage formulation, color acceptance score was decreased. In terms of panelists, the blank sample had the best color and the fifth sample color had the lowest score. Juiciness of the samples was increased by increasing the amount of gel. The results also showed that the fifth sample received the maximum score of juiciness. Sausages smell acceptance negatively changed by reducing the fat content and adding aloe vera gel. Third and fourth treatments got the highest texture score. Also, the third sample had the highest scores for taste and general acceptance. Chewiness analyzing showed that by increasing the amount of fat replacement the rate of this factor decreased. as well as the maximum rate of chewiness was related to the blank sample.
Mahsan Irajifar; Mohammad Javad Varidi; Mehdi Varidi; Younes Zahedi
Abstract
Introduction: Camel carcasses has lower fat content in comparison with cow, moreover, camel meat has relatively higher polyunsaturated fatty acids and lower cholesterol contents (Kadim et al., 2009a & 2006). However, calcium amount of camel meat is greater than that of cow, and its lower consumption ...
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Introduction: Camel carcasses has lower fat content in comparison with cow, moreover, camel meat has relatively higher polyunsaturated fatty acids and lower cholesterol contents (Kadim et al., 2009a & 2006). However, calcium amount of camel meat is greater than that of cow, and its lower consumption is partly related to this issue. With increasing demand of camel meat, more attention has been paid to the quality and chemical composition of it. Acid marinade can be used through the diffusion of the solution and its propagation over time as an extensive method to improve the meat tenderness (Yusop et al., 2010). Lactic acid is often used in the meat industry as an antimicrobial during carcass slaughter. In addition, lactic acid can improve meat tenderness (Hinkle et al., 2010). The aim of the present study was to determine the influence of lactic acid and sodium chloride on textural and sensory properties, also and proteolysis pattern of biceps femoris muscle of camel.
Materials and Methods: Six 4 to 7 years old camels were transported to the slaughterhouse in Mashhad (Iran). Slaughtering and dressing of camels were carried out according to Islamic methods. All chemicals and reagents in the experiments were of analytical grade and purchased from Merck and Sigma-Aldrich companies. Biceps femoris muscle was used as an experimental material, cutting into 2×2×5 cm3 pieces, and laid in lactic acid solutions (0, 0.5, 1, and 1.5% v/v, all accompanied with 2% w/v NaCl) at a ratio of 1 to 4 (meat to marination solution) within plastic bags. Marination process was carried out for 0, 24, 48, 72 h at 4 °C. The meats were then removed from the marinade and dried lightly. After that, moisture, ash, protein and fat contents of the meat were specified by AOAC (2002). Shear force was measured by TA.XT plus texture analyzer (Stable Micro Systems, UK) provided with a Warner-Bratzler shear force blade method in order to evaluation of meat tenderness (Byrne et al., 2000). Myofibrillar fragmentation index (MFI) was determined as described by zahedi et al. (1393). Sarcomere length was measured with the method of Botha et al. (2007). One-dimensional gel electrophoresis was determined as described by zahedi et al. (1393). Collagen content was specified by AOAC (1993). Sensory properties including color, texture, flavor, juiciness and overall acceptance were performed using a 5-point structured hedonic scale (Hoffman et al., 2006 & 2008). One-way analysis of variance (ANOVA) was used to determine the significant differences between treatments using SPSS software (version 19). Duncan’s multiple range test was used to compare the means.
Results and discussion: Acid concentration and marination time had a significant effect (p <0.05) on sarcomere length. It was likely due to the fact that the addition of acid led to increase in pure positive charges on myofibrils and cytoskeletal proteins. As a result, more repulsive forces were generated between the protein molecules of myofibrils. Eventually, myofibrils swelling caused distancing Z lines from one another, and increasing the sarcomere length (Ke et al., 2008). The results of analysis of variance showed that the concentration of lactic acid had a significant effect on MFI (p<0.05), and MFI value was less than zero at 0% concentration, however, it was non-significant in relation to the time (p> 0.05). The higher MFI values of the marinated samples may be due to the proteolysis of myofibrile proteins using D-cathepsins which activated at acidic pH (range 3-6). Meat samples marinated in the highest concentration for 72 h showed the lowest WBSF (p<0.05). The tenderising mechanism of acid marinades was believed to be including weakening of structures due to swelling of meat, increasing proteolysis by cathepsins, and conversion of collagen to gelatin at low pH during cooking (Berge et al., 2001; Offer & Knight, 1988). The retention time and acid concentration did not have a significant effect (p> 0.05) on the collagen amount of lactic acid treated samples. It was likely that low acid concentration, although affecting some of the parameters, is not suitable for degradation of connective tissue (Hinkle et al., 2010). Sensory analysis showed that tenderness of the samples marinated at with 1.5% acid received the highest score (p<0.05), which was consistent with the instrumental results. Acid concentration significantly affected (p<0.05) total acceptance of the samples. Higher levels of acid can be used for marinating without adversely affecting the consumer acceptance. Results from SDS-PAGE showed that number of seven bands on gels, on average, were belonged to intact proteins, and other bands were considered as peptides which resulted from proteins proteolysis, especially heavy proteins. Also, time had non-significant effect on band area of myosin heavy chain (p>0.05), while, acid concentration had a significant effect on the area of this protein (p<0.05). The band area of proteins C, α-actinin and actin proteins enhanced as a function of acid concentration and marination time (p<0.05).
In conclusion, we can claim that lactic acid and sodium chloride can be used as an effective acidic marination to improve biceps femoris muscle of camel meat. This method can be advice as a trick for tenderizing camel meat in household consumptions, restaurants and also meat industry, thereby increasing demand for camel meat in order to gain further healthy benefits of it.
Somayeh Niknia; Seyed Mohammad Ali Razavi; Mehdi Varidi
Abstract
In this study, sodium caseinate was hydrolyzed with Withania coagulans extract and the response surface methodology (RSM) was applied to optimize the effects of hydrolysis conditions including hydrolysis temperature, enzyme concentration and hydrolysis time on the degree of hydrolysis, solubility, and ...
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In this study, sodium caseinate was hydrolyzed with Withania coagulans extract and the response surface methodology (RSM) was applied to optimize the effects of hydrolysis conditions including hydrolysis temperature, enzyme concentration and hydrolysis time on the degree of hydrolysis, solubility, and foaming properties. The analysis of variance in RSM showed that the linear effects of enzyme level and hydrolysis time and quadratic effects of hydrolysis temperature were important factors affecting the hydrolysis process remarkably (P<0.0001). Results were indicative of the fact that the increase in responses was obtained by an increase in hydrolysis time and enzyme level. The generated quadratic model showed that the optimum conditions for maximizing the responses were when enzyme concentration of 1.75 (%w/w), temperature of 55.43°C and hydrolysis time of 490 min.
Fatemeh Heydari; Mohammad Javad Varidi; Mehdi Varidi; Mohebbat Mohebbi
Abstract
In the present study the cow meat was replaced with camel meat (0, 25, 50, 75 and 100%) in burger formulation. Principal component analysis (PCA) was performed to understand quality variables differences and similarities of thirty-five sample burgers. Score plot, represents Principal component analysis ...
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In the present study the cow meat was replaced with camel meat (0, 25, 50, 75 and 100%) in burger formulation. Principal component analysis (PCA) was performed to understand quality variables differences and similarities of thirty-five sample burgers. Score plot, represents Principal component analysis of datasets derived from evaluated variables of thirty-five samples (samples contain of 0, 25, 50, 75 and 100% camel meat). Overall, six principal component was obtained which 65.8% of the total variance was concentrated into three first PCs. Cooked L*, cooked b* shrinkage, springiness, flavor, texture, juiciness, color and overall acceptability were the variables which separated by the first PC. The PC2 is characterized by the rest of instrumental texture parameters and the third by cooked a* and fat. The evaluation of score plot shows burgers contain higher amount of camel meat (50, 75 and 100%) had the higher moisture and fat content after cooking, higher scores in flavor, texture, juiciness and overall acceptability.
Shahram Beiraghi-Toosi; Mohebbat Mohebbi; Mehdi Varidi
Abstract
Introduction: Extrusion is one of the technologies used for solid foams production. In this process, pressure is the most important parameter and the most important variables affecting pressure are feed mixture, die diameter, barrel temperature and screw speed. A reduction of die diameter or plasticizer ...
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Introduction: Extrusion is one of the technologies used for solid foams production. In this process, pressure is the most important parameter and the most important variables affecting pressure are feed mixture, die diameter, barrel temperature and screw speed. A reduction of die diameter or plasticizer contents such as moisture and fats in the feed mixture or an increase in the screw speed or barrel temperature can increase the extruder barrel pressure. Also, the increased barrel temperature, in addition to changing cooking properties, escalates the temperature difference inside and outside of the die, raising the rate and amount of evaporation from melted mixtures, therefor affecting the solid foam structure and characteristics. On the other hand, the type and amount of feed mixture components are key factors affecting the extrudate properties (Moraru et al., 2003; Plews et al., 2009; O’Shea et al., 2014).
Sesame seed is one of the ancient edible oil seeds used in many food products. In addition to oil, it contains carbohydrate, protein and fiber (Namiki et al., 2001) which can provide a variety of compounds in the feed mixture to change the properties of foam. This study investigates the effect of partial replacement of corn starch with edible oil seed containing a mixture of various compounds and the effect of the extrusion process on the changes in the physicochemical properties of the produced solid foam relative to the foam produced from corn starch. In this regard, different proportions of sesame seeds were added to the corn starch with specific moisture contents, and following the application of the extrusion process, the effect of feed mixture, operation temperature, screw speed and die diameter on physicochemical properties of solid foams was evaluated.
Materials and methods: Solid foams made from corn starch with 0, 10, 20 and 30 percent of sesame seed in the formulation and 15 percent of moisture content were processed in a co-current twin-screw extruder at a screw speed of 120, 150 and 180 rpm, a barrel temperature of 120, 145 and 170°C, a die diameter of 2.5 and 4 mm, and a constant feed rate of 40 kg per hour. A completely randomized design was employed to investigate the effect of these variables on chemical and physical properties of extruded products. The moisture content of samples was measured using oven method at 105°C (AOAC, 1990). Water absorption and water solubility indices were measured through solving the sample powder in distilled water, which was followed by centrifuging, weighing gel, drying supernatant and weighing dried matter (Singh et al., 2015; Huang et al., 2014). In addition, particle density was measured using the rapeseed displacement method (Singh et al., 2015) and solid density was calculated by the weight /volume ratio of the sample powder, as measured by the gradient cylinder (Ushakumari et al., 2004; Yagci et al., 2008). The porosity of samples was measured in terms of the ratio of particle density to solid density (Plews et al., 2009; O’Shea et al., 2014) and the radial expansion ratio was calculated in terms of the ratio of sample diameter, as measured by the caliper, to die diameter (Chanlat et al., 2011; Huang et al., 2014).
Results and discussion: Results showed that adding 10% sesame seed, due to the variety of compounds and their increased interactions, produced foams of maximum expansion and porosity, and minimum particle density. Adding 30% sesame seed had an opposite effect due to increased fat content and reduced pressure effect on the melted mixture in the barrel. Moreover, increased die diameter demonstrated augmented residual moisture content, water absorption index, density and porosity, as well as decreased water solubility index and expansion ratio of solid foams caused by pressure reduction on the melted mixture in the barrel. The increased barrel temperature was associated with greater changes in cooking, escalated temperature difference between inside and outside of the die and production of foams with higher water solubility index and expansion ratio, as well as lower residual moisture content, water absorption index and solid density. The higher screw speed increased the applied energy, and despite decreasing the time of temperature effect, produced foams with properties comparable to those caused by temperature increase.
In general, it can be stated that the process factors that raise the energy applied to the extrusion material leads to the increased water solubility index and the expansion ratio of the solid foams and decreased residual moisture, water absorption index and density. Consequently, by selecting the right type and amount of feed mixture to create proportions in various compounds and determine the appropriate process conditions, solid foams with desired properties can be produced by means of extrusion using available raw materials.
Atefeh Pourmahdi; Mohebbat Mohebbi; Ashraf Gohari Ardabili; Mehdi Varidi; Mohammad Reza Salahi
Abstract
Introduction: Potato is one of the most consumed and highly nutritious vegetables with high energy, dietary fiber, phytochemicals, vitamins, and minerals which offer great benefit for utilization as functional food ingredient. The dried potato powder can be used in formulation of many foods like soups, ...
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Introduction: Potato is one of the most consumed and highly nutritious vegetables with high energy, dietary fiber, phytochemicals, vitamins, and minerals which offer great benefit for utilization as functional food ingredient. The dried potato powder can be used in formulation of many foods like soups, snacks, sauces, noodles, etc. The foam mat drying involves the dehydration of a thin layer of foam followed by its disintegration in order to obtain a powder which can be easily reconstituted in water when added to other foods. Because of the porous structure of the foamed materials, mass transfer is enhanced leading to shorter drying times and consequently acquiring higher quality in the dried product. Food foams can be considered as biphasic systems where a gas (dispersed phase) is embedded in a continuous liquid phase. The foam properties such as structure, density and stability have important influence on moisture migration during drying and accordingly, the quality of final product. Foams that do not collapse for at least 1h are mechanically or thermally stable for the entire drying process. Response surface methodology (RSM) is a combination of mathematical and statistical techniques which used to investigate the interaction effects of independent variables on responses. There is considerable information on foam-mat dried food powders, but there is not any scientific literature that related to study on foam-mat drying of potato puree. The present research was thus focused on optimizing the foaming conditions (potato puree: gum solution ratio; Arabic gum (AG) concentration as the stabilizer and whipping time [WT]) to minimize foam density (FD) and drainage volume (DV) using RSM. Likewise, choosing a suitable model for thin-layer drying of foam and the effect of different drying temperatures (45, 60 and 80°C) on drying behavior were investigated, and the effective moisture diffusivity and activation energy were calculated. The effects of drying temperatures on water activity (aw) and water binding capacity (WBC) were also investigated.
Material and methods: Fresh potato was purchased from a local market (Mashhad, Iran). Arabic gum was procured from Sigma Chemical Company (USA). For preparation of potato puree, fresh potatoes were washed and peeled by steel knife and were washed again and additional water was taken absolutely and then crushed by Phillips home crusher (600W) with maximum speed for 3 minutes to get a homogeneous puree. Based on preliminary tests, AG solutions were prepared by dissolving a suitable amount of the selected gum powder in distilled water and stirring with a magnetic stirrer to obtain a uniform solution. This solution was refrigerated at 4°C overnight to complete hydration. RSM was used to estimate the main effects of the process variables on FD and DV in potato puree foam. The experiment was established based on a face-centered central composite design (FCCD). The experimental range was chosen on the basis of the results of preliminary tests. The independent variables were consisted of potato puree: gum solution ratio (1:1 –2:1 w/w), AG concentration (0.1–0.9% w/w) and WT (3–9 min). According to the experimental design, to prepare 100 g of samples, appropriate amount of potato puree and AG solution were mixed in a 250-mL beaker. The mixture was then whipped with a kitchen mixer (model no. SM88, Sonny, China) at a maximum speed of 1,500 rpm at ambient temperature during given time which was recommended by Design-Expert software. The density of foamed potato puree was determined in terms of mass over volume and expressed in g/cm3. In order to assess foam stability, the drainage test was performed for 1h. To evaluate drying behavior of the optimized foam, drying was carried out in a batch-type thin-layer dryer at temperatures of 45, 60 and 80°C on 3 mm thickness. Ten thin-layer drying models were evaluated in the kinetics research. The higher value of R2 and lower values of χ2, RMSE and SSE were selected as the basis for goodness of fit. Fick’s diffusion equation for particles with a slab geometry was used for calculation of effective moisture diffusivity. The foamed potato puree spread on a tray was considered as slab geometry. Activation energy was calculated by a simple Arrhenius-type relationship, by plotting the ln (Deff) against the reciprocal of absolute temperature (1/T). Furthermore, the effects of drying temperatures on aw and WBC of powders were investigated.
Results and discussions: The quadratic model was selected as a suitable statistic model for both FD and DV. ANOVA showed that this model is significant for both responses. Moreover, lack-of-fit was not significant for response surface models at 95% confidence level, indicating this model is adequately accurate for predicting responses. The optimum values of variables for best product quality in terms of minimum FD and DV corresponded to potato puree to gum solution ratio 2:1(w/w), AG 0.77% (w/w) and WT 6.80 min. The amount of FD and DV for foam at these optimum conditions were 0.30 g/cm3 and 5 ml, respectively.
The result showed that when the drying temperature increased, the drying time decreased. This was due to the quick removal of moisture at higher temperature. Drying rate (DR) versus moisture content of potato puree foam-mats figure showed that DR was higher during the initial stage as compared with the final stage and foam-mat drying was occurred principally in the constant rate period. Due to the increase in surface area and the porous structure, removal of water from the inner surface of potato puree foam to the outer surface was fast enough to preserve the surface moisture. The rate of movement of moisture from the inner surface to the exposed surface decreased with decreasing moisture content, which indicates that the DR decreased and the falling rate period started. The effective moisture diffusivity varied from 3.286×10-9 to 8.032×10-9 m2/s with activation energy value of 30.97 kJ/mol. Statistical analysis results showed that the Weibull distribution model provide the highest R2 and lowest values of χ2, RMSE and SSE at all drying temperatures. The temperature elevation reduced aw. This is due to the fact that at higher temperatures, the rate of heat transfer to the sample would increase, therefore, it provides greater driving force for moisture evaporation which results the dried foams with reduced aw. Drying temperatures did not show any significant effect on WBC of powders.
Fatemeh Rahmati; Arash Koocheki; Mehdi Varidi; Rassoul Kadkhodaee
Abstract
Introduction: Proteins are food ingredients with critical functional properties and participation in developing food products. So far, functional properties of several plant proteins such as pea, chickpea and lentil, groundnut, beach pea and bayberry have been investigated. Nowadays, there is an increasing ...
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Introduction: Proteins are food ingredients with critical functional properties and participation in developing food products. So far, functional properties of several plant proteins such as pea, chickpea and lentil, groundnut, beach pea and bayberry have been investigated. Nowadays, there is an increasing demand for plant proteins because they are available and inexpensive. Legume proteins are important plant protein sources. However, except for soy, due to the inadequate information about their structural and functional properties, they do not have appropriate application as functional ingredients in food products. Beans are a great source of nutrients such as protein, carbohydrate, dietary fiber, minerals and vitamins. Based on the several research reports, different dry beans have 15-25% protein and they are the second group of legume seeds, after soy, cultivated throughout the world. As mentioned earlier, insufficient information about structure of legume proteins is the main reason why they are unexploited in food industry. Therefore, the goal of this research was to evaluate the functional properties of proteins from three types of common bean (Speckled Sugar, Red Mexican and Great Northern bean). We also have attempted to evaluate the structure-function relation of these three sources of bean proteins because it is known that there is a direct relation between chemical conformation and the function of a protein which must be considered in food processing. Materials and methods: Protein of three types of common bean (Speckled Sugar, Red Mexican, and Great Northern) was extracted (pH 9, water flour 10:1). Afterwards, their physicochemical (including protein electrophoresis pattern, solubility, hydrophobicity), and functional properties (including emulsifying capacity, heat stability, gelation and foaming capacity) were evaluated to understand how bean protein structure influences its structure. Electrophoresis pattern was obtained based on 2 dimensions (pH and molecular weight). Protein solubility was evaluated by biuret method at pH range 3-9. ANS (8-anilino-1-naphthalenesulfonic acid) was used to measure surface hydrophobicity (pH 3-7).Emulsion samples (1% protein, 25% sunflower oil, pH 3-7) were produced, then emulsion capacity and emulsion heat stability (80°C for 30 min) were evaluated. Gelation of proteins was evaluated at protein concentration of 4-12% at different pH values (3-7). Foaming capacity (%) was measured as the difference between volume after and before whipping. Foam stability (%) was recorded during 90 minutes. Results and Discussion: Results showed that all proteins were rich in Phaseolin. In fact, this fraction was the major building fraction of all three bean proteins. Evaluation of solubility indicated that isoelectric point of three proteins was located at acidic pH range (pH 4.5). Results confirmed an indirect relation between protein solubility and hydrophobicity. All three protein isolates, similar to the other legumes protein, were more soluble at alkaline pH, while the highest surface hydrophobicity was observed at pH 3. Generally, Speckled Sugar bean protein had the most solubility, while Great Northern bean protein showed the highest surface hydrophobicity. Among three bean protein isolates, Speckled Sugar bean protein performed better as an emulsifier, whereas Great Northern bean protein formed gel at the lowest concentration (6% at pHs 3 and 7). In addition, foaming was higher at acidic pH (pH 3). Therefore, it was concluded that emulsifying capacity is mostly influenced by protein solubility, while gelation and foaming properties are affected by protein hydrophobicity. As the main consequence, the results achieved in this research confirmed that there is a direct relation between structure and the function of a protein. In fact, special structural properties are responsible for special functions.
Mohammad Farhadi Chitgar; Mehdi Varidi; Mohammad Javad Varidi; Ahmad Balandari
Abstract
Introduction: Extensive researches into native plants as a source of functional food have been conducted over the resent years. Meanwhile, barberry has been utilized as one of the main medicinal plants in Iran and many other countries, from the past decades. Currently, it has been known pharmaceutical ...
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Introduction: Extensive researches into native plants as a source of functional food have been conducted over the resent years. Meanwhile, barberry has been utilized as one of the main medicinal plants in Iran and many other countries, from the past decades. Currently, it has been known pharmaceutical active ingredients like berberin have wide application in pharmaceutical industry. The genus of Berberis includes about 450–500 species of deciduous or evergreen shrubs in which four species B.integerrima, B.crataegina, B.vulgaris and B.orthobotrys are found in Iran. Iran is the first largest producer of barberry (B.vulgaris) in the world. Apart from that, other species in different parts of Iran grow in wild conditions. B. Integerrima is a thorny shrub with fragile branches to a height of 1 to 3 meters. Its fruits are small and red with a mild sour taste. There are 1-4 small oblong seeds inside. The changes in this species are important and can produce hybrid with other species. B. Integerrima fruits are consumed fresh or used in the preparation of traditional foods. Barberry fruit, which contains large amount of anthocyanins, can be used as an alternative to synthetic colorants. In addition, aqueous extract of barberry has beneficial effects on both cardiovascular and neural system suggesting a potential use for treatment of hypertension, tachycardia and some neuronal disorders, such as epilepsy and convulsion. The physical properties of barberry genotype are important to design the equipment for sorting, transportation, separation, processing and packaging. Identification of the chemical characteristics of Berberis genotype can lead in using them in the pharmaceutical or food industries. Therefore, in order to introduce these native species, physicochemical characteristics of three wild barberries were evaluatedMaterials and method:Three native seed genotypes from Semnan province were manually collected from Research Institute of Food Science and Technology (Mashhad). The harvested fruits were instantly stored inside ice box to minimize damages and transported to the laboratory. Over ripened and damaged fruits were separated. Some physical properties (size, geometric mean diameter, sphericity, area, mass and the weight ratio of seeds to fruit) of fruits were determined using 100 repetitions at the natural moisture content of fruits. Chemical properties of samples were determined as follows: total anthocyanin content by the pH differential, total phenolic content by modified Folin–Ciocalteu method, mineral elements amounts such as Potassium(K), Sodium (Na) and Calcium (Ca) by Flame Photometer and microelements (Fe, Cu, Mg, and Zn) by Atomic Absorption Spectrophotometer, Moisture, crude oil, crude protein, ash, reducing sugar, water-soluble extract, pH and acidity were determined according to Indrayan et al,1989 and Iranian National Standard No. 2685. All experiments (except physical properties) were repeated at least three times and results were expressed as mean ± SD. The significant differences between mean values of juice samples were determined by analysis of variance (one way-ANOVA) using Duncan’s test at a significance level of p< 0.05. Data analysis was performed using the SPSS 19.0 software.Results and Discussion: Results showed that in physical properties such as, fruit length there was statistically difference between genotypes. The number of seeds in the three genotypes varied between 1 and 4 numbers. The weight ratio of seeds to fruit was 11.88%, 10.84% and 10.68 in Noshin, Negarin and Parchin genotypes, respectively. All three genotypes contained high amount of protein, total carbohydrate, fat and ash (3.82-5.255%, 21.68-23.97%, 2.04-2.70% and 0.94-1.27%). Noshin contained the highest reduced sugar (8.03±0.222). So, it is sweeter taste than others. In accordance with result, the amount of anthocyanins (950.17-3927.60mg/L) and total phenol (9.75-12.35gr/L) were higher than these fruits in comparison to the other fruits like mulberry and blueberry that represents the health benefits of these wild plants. All the three genotype emerged as good source of minerals, especially K, Ca, Mg and Zn.
Atefeh Farahmand; Mehdi Varidi; Arash Koocheki
Abstract
Introduction: Exploiting natural substances with dual or multiple functionalities is getting more attention in food industry due to the requirement from the health- conscious consumers and the trends for sustainable environment. Hydrocolloids are high molecular weight macromolecules that can be easily ...
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Introduction: Exploiting natural substances with dual or multiple functionalities is getting more attention in food industry due to the requirement from the health- conscious consumers and the trends for sustainable environment. Hydrocolloids are high molecular weight macromolecules that can be easily dissolved and dispersed in water under appropriate conditions. They can modulate rheological properties of foods, and are generally used as food thickeners, texture modifier, stabilizers and emulsifiers for various applications. Mucilage is a high molecular weight polyuronides consisting of sugar and uronic acid units. It is partially soluble in water and can form highly viscous solution. It exhibits hampering effect on the diffusion of glucose, help to postpone the absorption and digestion of carbohydrates. The mucilage extracted from the seeds of the quince fruit contained cellulose micro-fibrils strongly associated whit a glucuronoxylan possessing a very high proportion of glucuronic acid residues. Analysis of quince seed mucilage (QSM) has shown the presence of more cellulosic fraction and hydrolysable polysaccharide.Quince seed mucilage is one of the endemic hydrocolloids, which due to high viscosity, its extraction needs a method to reduce the extraction time, energy consumption and especially raise the extraction efficiency. The traditional extraction method of polysaccharide from plant tissues are maceration, mechanical rabbling and heat reflux. Theses extraction methods depend largely on energy input and agitation to improve the solubility and mass transfer efficiency of polysaccharides. Usually, the convention extraction method requires long extraction time and high extraction temperature with low extraction yield, but high energy consumption. Ultrasound in combination with conventional extraction is a potential technique, which is a fully reproducible food process, completed in shorter time with high reproducibility, reduced processing cost, simplified manipulation and work-up. To achieve this goal, in this study ultrasound- assisted extraction (UAE) as a novel extraction method was used.Materials andMethods:Quince seed used in this study was purchased from a local market (KhorasanRazavi, Mashhad). They were cleaned manually by removing the foreign matter such as stones, dirt and broken seeds. They were packed in hermetic plastic vessels and stored at 5ºC until further use. For mucilage extraction, first conventional extraction was optimized to select the best hydration conditions and after that UAE (24 KHz probe and 400 W power) was performed at three different levels of intensity (20, 60 and 100%) and times (5, 15 and 30 min).All chemicals used were analytical grades. Yield value of hydrocolloid was calculated by dividing the weight of dried hydrocolloid by the weight of initial dry seeds. Emulsion heat stability was determines by the method described in previous studies. In order to measuring the water absorption capacity (WAC), 0.05 g of mucilage was added to deionized water until QSM was completely wet (~ 10ml). The tubes were then centrifuged at 1600×g for 10 min. Excess water was discarded and residue was weighted. Apparent viscosity of QSM solution with 0.1% (w/v) concentration was measured using a rotational viscometer (Brookfield, DV- ІІІ, USA). Shear rate increased linearly from 2.5 - 35 s-1 at 25˚C.For measuring the foam stability and emulsion heat stability, the mucilage dispersions were prepared at 0.25 and 0.5 (w/v) respectively, and kept overnight at 4˚C. After complete hydration, 2% (w/v) egg white powder was added and then foamed by whipping at 8600 rpm for 2 min using adisperser.Results and Discussion: Optimized conditions of conventional extraction were 45 min, 47˚C and 32.5: 1 water to seed ratio. The results showed that extraction at 30 min with 100% intensity raised the extraction yield to 42.7% in comparison with control sample.Improvement in hydrocolloid extraction by ultrasound is attributed to ultrasound pressure wave diffusion which results in cavitation phenomenon.Amplitude level and exposure time had a significant (p
Samira Feyzi; Mehdi Varidi; Fatemeh Zare; Mohammad Javad Varidi
Abstract
Introduction: Plant proteins play a significant role in the human diet, and among which legumes are excellent foods with several nutritional and functional advantages and low price. Among legumes, fenugreek (Trigonella foenum graecum) seed, belonging to the Fabaceae family, is a great source of plant ...
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Introduction: Plant proteins play a significant role in the human diet, and among which legumes are excellent foods with several nutritional and functional advantages and low price. Among legumes, fenugreek (Trigonella foenum graecum) seed, belonging to the Fabaceae family, is a great source of plant proteins, with a total protein content of about 25.00 – 38.60%. Functional properties are defined as physical and chemical properties, which could be altered due to the protein source and procedures used for flour preparation, protein concentrate and isolate extraction. Physiochemical parameters such as pH, temperature, salt and ionic strength can also highly affect proteins, functional properties.Therefore, in this study color parameters and functional properties of fenugreek protein isolate (FPI) were investigated. Also, the effect of pH changes on protein solubility, foaming capacity (FC) and stability (FS), emulsifying capacity (EC) and stability (ES) was studied. Materials and methods: Fenugreek seeds were obtained from a retail market in Isfahan, Iran. All chemicals were of analytical grade, and were purchased from Sigma Chemical Co. (St Louis, MO, USA), and Merck KGaA (Darmstadt, Germany). Protein Isolation: Protein from 10g defatted fenugreek flour (DFF) was extracted with 0.33M sodium chloride solution; the ratio of DFF to NaCl solution was set at 1:20 (w/v) and pH was adjusted to 9.25. The stirring period was 2 h, during which pH was also adjusted. Aliquots were then centrifuged and supernatants were adjusted to pH 4.5 (isoelectric pH of fenugreek protein). Again, the protein solution was centrifuged in order to precipitate the protein. Protein precipitate was washed twice with deionized water, followed by centrifugation and resolubiliztion by adjusting the pH to 7.2. The extraction process was carried out at room temperature (25°C). Color parameters: A digital colorimeter was used to measure the color of full fat and defatted fenugreek flours, and FPI samples. Color parameters were recorded in L*a*b* space. Protein solubility: Protein solubility of FPI at pH 2-10 was determined. A 1.5% (w/v) solution of sample was made in deionized water for each pH. The solutions were treated with either 0.5M HCl or 0.5M NaOH to obtain certain pH (2-10), while stirring. The slurry was centrifuged to separate the supernatant. Protein content was determined by the Biuret method using spectrophotometer at 540nm wavelength. Calibration was done using bovine serum albumin (BSA) as external standard. Viscosity: A suspension of 5% (w/v) FPI in distilled water was prepared. Viscosity of sample was determined using a programmable Brookfeildrheometer, using spindle ULA at room temperature. Coagulated protein: Percent of coagulated protein was measured by preparing 0.2g of FPI in 10mL of 0.025M citrate-phosphate buffer (pH 7.0). The solution was stirred, followed by centrifugation. The remaining supernatant was heated for 15min in a 100°C water bath, after cooling the same procedure was repeated. The absorbance of both samples, before heating (A1) and after heating (A2), was measured at 540nm according to Biuret method. The percent of coagulated protein was calculated by the following equation: Coagulated protein = (A1 – A2 / A1) × 100 (1) Foaming capacity and stability: FC and FS were determined using 2% (w/v) FPI solution in distilled water. For each sample solution, the pH was adjusted to desired level (2, 3, 4.5, 6, 8, and 10). The solution was stirred slightly for 5min and then was whipped vigorously by a disperser. The volume of solution before whipping, also the total volume of solution and foam after whipping were recorded as V0 and V1, respectively. The foam capacity percentage was calculated as: FC (%) = (V1- V0/V0) × 100 (2) Foam stability was determined as the total volume of solution and foam at 30, 60, 90 and 120 min at room temperature and it was recorded as V2. Foam stability (FS) was calculated as: FS (%) = (V2 - V0) × 100/ (V1 - V0) (3) Emulsifying capacity and stability:For EC and ES, a 1% (w/v) FPI solution in distilled water was prepared. The pH was adjusted to desirable level (2, 3, 4.5, 6, 8, and 10) followed by stirring for 5min, then sunflower oil was added. The mixture was homogenized to make emulsion, followed by centrifugation. Then the height of both emulsified layer after centrifugation (H1) and the total height of content before centrifugation (H0) were measured. Emulsion capacity was calculated as: EC (%) = (H1/H0) × 100 (4) The ES (%) was calculated at 0, 30, 60, 90 and 120 min by measuring height changes (H2). ES (%) = (H2/ H1) × 100 (5) Results and Discussion: FPI with 89.1% protein content had significantly (p < 0.05) lower L* than DFF, while its L* was higher than the full fat fenugreek flour. Also, FPI showed shear thinning behavior with viscosity equal to 1150, 922.5 and 787.5 cP at 15, 30 and 50 (1/s) shear rates, respectively. pH changes had noticeable effect (p
Akram Arianfar; Fakhri Shahidi; Rassoul Kadkhodaee; Mehdi Varidi
Abstract
Introduction: Tea (Camellia sinensis), is the most widely beverage after water across the world. The most important chemical composition in tea is phenolic compounds (catechins) that have antioxidant and anticarcinogenic properties and are benefited for cardiovascular disease. There are two major kinds ...
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Introduction: Tea (Camellia sinensis), is the most widely beverage after water across the world. The most important chemical composition in tea is phenolic compounds (catechins) that have antioxidant and anticarcinogenic properties and are benefited for cardiovascular disease. There are two major kinds of tea, black tea and green tea. Green Tea, is originated in China and dates back to several thousand years ago. In the production of green tea, young leaves are rolled and oxidized to decreasing oxidation but in production of black tea, tea leaves are oxidized (fermented) for 90-120 min after rolling and then catechins are converted to complexe compounds (theaflavins and thearubigins). The conventional method for extraction of green tea polyphenols compounds are heating, boiling, cold and heathing refluxe extraction, with long extraction periods and low extraction efficiency. In this study 3 techniques for extraction of polyphenol compounds from Green tea leaves were investigated and compored together.The main objective of this study was to determine the effects of differrent extraction conditions, temperature ( 40, 60, 80 and 100° C), different time ( 15, 30, 45 and 60 min ), microwave power (300, 600 and 900 % ) and ultrasound amplitude (40, 60, 80 and 100 W) on Green tea polyphenol content and antioxidant activity in three methods including Heat Reflux Extraction(HRE), Microwave Assisted Extraction(MAE) and Ultasound Assisted Extraction(UAE).Materials and Methods: Dried green tea leaves (supplied from Lahijan (Iran))were grinded for increasing the contact surface area between the solvent and solute. 1 g of green tea was extracted with 100 mL of water at various methods, Heathing Reflux Extraction(HRE), Microwave Assisted Extraction(MAE), by microsynth laboratory system (Milestone-ACT-36-Rev01) at 50 Hz and output 2450 MHz with adjustable power output (100-1000 W), temperature 180° C and Ultrasound Assisted Extraction (UAE) in double jacket vessel by using a 25 kHz ultrasonic system (model VCX 750, Sonics & Materials, Inc., USA), at a maximum nominal power output of 750W. All measurements were carried out in triplicate. The results were analysed statistically using the minitab 16 Program to determine the average value and standard error. Variance analysis, with a significant level of α= 0.05% was performed to determine the effect of time, temperature, microwave power and ultrasound amplitude on polyphenols content and antioxidant activity. Total phenol were determined spectrophotometerically by Folin-Ciocalteu method at 765 nm )Hewlett- Packard spectrophotometer model 8452A, Rockville). The antioxidant activity evaluated with the DPPH test spectrophotometrically at 517 nm. Results and Discussion: These results showed that polyphenol content is increased with increasing the time, temperature, ultrasound amplitude and microwave power of extraction. By increasing temperature to 80°C , time to 45 min, ultrasound amplitude from 40 to 80 and microwave power from 300 to 600, polyphenol content and antioxidant activity was increased and after that was constant. These results showed that, H.R.E require long extraction time and have low efficiency. Polyphenol compounds are thermally unstable and maybe degredate in thermal processing. Also, the best method for extraction was MAE, because of higher yield, higher contents of pol-yphenol and shortend time and this method was very efficient in the extraction of polyphenl compounds. The efficiency of extraction by UAE method is higher than HRE and lower than MAE method. Conclusion: UAE method compared to HRE method is enhanced the extraction of polyphenol, facilating solvent peneteration and increase the product releasing from intracellular. This method agitated the solvent to material and increased the contact surface between material and solven, and peneteration of solvent in to the green tea leaves. UAE canbe carried out at a lower temperature than HRE and decreased thermal damage.
Mohsen Zandi; Mohebbat Mohebbi; Mehdi Varidi; Navid Ramazanian
Abstract
.Introduction: Flavor release from food during consumption in the mouth plays an important role in flavor perception and influenced by the food matrix. Since, food matrix changes biochemically and physically during eating, therefore, food flavor microencapsulation results in controlled release at specific ...
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.Introduction: Flavor release from food during consumption in the mouth plays an important role in flavor perception and influenced by the food matrix. Since, food matrix changes biochemically and physically during eating, therefore, food flavor microencapsulation results in controlled release at specific situations. On the other hand, stability and availability of flavors are affected by food processing and storage. To control the flavor release at specific condition during consumption or stability and availability during food processing and storage; it is essential to encapsulate flavor components before use in food complex. Encapsulation is the term for a collection of technique that used as delivery of active and bioactive parts. This novel technology enables isolated of gases, liquid droplets, or solid particles in the core of microscopic vesicular system with porous or non porous semi permeable shell that release occurs in response to the specific situations. Controling release of active compound depends on microcapsule characteristics such as pore size, mechanical stability of the colloidal shell, shell thickness and shell permeability; molecular size and solubility of active parts in the shell and properties of the release media including shear force, temperature, pH, ionic strength, etc. This paper presents the formation and characterization of novel diacetyl encapsulated alginate-whey protein concentrate (AL-WPC) microcapsules. Diacetyl release was investigated at simulated mouth condition in different ratios of artificial saliva (0, 1:4 and 1:8) and three various oral shear rates (0, 50 and 100 s-1) and the diffusion coefficient was estimated using Fick’s law. The main aim of this work was to develop a prediction model to study the flavor release from microcapsules. Materials and Methodes: Aiming to show the applicability of our agent-based model platforms, the release of 2,3-butanedione (diacetyl) from alginate-whey protein concentrate (AL-WPC) microcapsules was used as a case study to validate our simulation model based on NetLogo platforms. For this purpose, our previous work on evaluation of diacetyl encapsulated alginate-whey protein microspheres release kinetics and mechanism at simulated mouth conditions was used (Zandi, M., Mohebbi, M., Varidi, M., Ramezanian, N., 2014). In previous our work, encapsulated diacetyl release was measured at three oral shear rates (0, 50 and100 s-1) and various ratios of saliva to microcapsule (0, 1:4 and 1:8) simulating mouth conditions. Then, experimental release data were fitted using different kinetic models. It was found that release from these microcapsules followed a classical Fickian diffusion. We use release data for calculating release rate. For model validating, diffusion equation was fitted to the experimental data, and diffusion coefficient was obtained for diacetyl release at various mouth conditions. To this purpose, the following model was obtained by solving unsteady diffusion equation in spherical coordinate:(M(t))/M_0 =100-exp(-(3×D×(R+b))/(R^2×b)×t) (1)where M (t) and M0 are the diacetyl release at time t and 0 respectively, R is a microcapsules radius (m), t is time, D is the diffusion coefficient and b is the shell thickness (m). We also use diffusion coefficient to calculate permeability for each specific condition by equation (2): P=(D×K)/b (2)Where P is the permeability coefficient, D is the diffusion coefficient and K is the partition coefficient.Finally, the model and experimental data were analyzed using Matlab software (R2007).Result and Discussion: In our study, AL-WPC microcapsule was fabricated by emulsification/internal gelation method, and diacetyl was loaded into microcapsule. Most of microspheres had a completely spherical shape with smooth surface, and range in size from 20-150 μm. The diacetyl encapsulated microsphere had a porous and smooth shell with some holes that caused the quicker diacetyl release initially. The mean hydrodynamic diameter 112.8 ± 0.9 μm (mean value ± SD for n= 2) was measured via particle size analyzer (DLS). the high efficiency of 79.34% was obtained for diacetyl encapsulated AL-WPC microcapsule. About 20% of diacetyl was loosed because of the solubility and volatility of the diacetyl molecule (diacetyl is a low molecular weight and water soluble component).. Conclusion: It was showed that the shear rate of release media had a significant (p
Mohammad Farhadi Chitgar; Mohammad Javad Varidi; Mehdi Varidi; Fakhri Shahidi
Abstract
Barberry is an agricultural product, which is cultivated in large amounts, only in Iran. Its popularity as an ingredient for many by-products has grown recently. It contains anthocyanins which can be used as natural food colorants. These compounds are useful for human health and have high economic value. ...
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Barberry is an agricultural product, which is cultivated in large amounts, only in Iran. Its popularity as an ingredient for many by-products has grown recently. It contains anthocyanins which can be used as natural food colorants. These compounds are useful for human health and have high economic value. Magnitude and duration of heating has a strong influence on anthocyanin stability. Temperature degrades the anthocyanins and the rates of degradation depend on the presence of oxygen, pH and their chemical structure. In this study the effect of temperature and solid content on degradation kinetic of anthocyanins in Berberis vulgaris var asperma were determined over a temperature range of 70-90◦C. Analysis of kinetic data suggested a first-order reaction for the degradation of barberry juice and concentrate anthocyanins. The half-life values were calculated 6.02, 3.32 and 1.06h for juice, 3.32, 1.84 and 0.76h for concentrate of 30 Brix and 3.19, 1.31 and 0.49h for concentrate of 50 Brix between 70 and 90◦C, respectively.The temperature-dependent degradation was modeled using Arrhenius equation. By increasing solid content, the activation energy value was increased but D-value and Z-values were reduced. The results shows that the degradation of anthocyanins in concentrates occurred at a faster rate than in juice. By increasing the temperature degradation rates were increased both in juice and concentate.
Seyed Amir Tavakoli Lahijani; Fakhri Shahidi; Mehdi Varidi; Mohebbat Mohebbi
Abstract
Spirulina platensis is a blue-green microalga with unique nutrient content and several therapeutic aspects which has been used for fortification of different foods. In this study, the effect of Spirulina platensis powder in different levels (0, 0.5, 1 and 2 percent), added in two stages (before pasteurization ...
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Spirulina platensis is a blue-green microalga with unique nutrient content and several therapeutic aspects which has been used for fortification of different foods. In this study, the effect of Spirulina platensis powder in different levels (0, 0.5, 1 and 2 percent), added in two stages (before pasteurization and at same time with starter culture) was studied on the microstructure and acidification characteristics of yogurt during fermentation time. The results showed that different levels of Spirulina biomass had significant effect on acidification kinetics parameters of yogurt samples (p
Fatemeh Heydari; Mohammad Javad Varidi; Mehdi Varidi
Abstract
The objective of this study was the evaluation of pH, Color parameters [lightness (L*), redness (a*), yellowness (b*), chroma (C*), hue (H*), a*/b* ratio, and color differences (ΔE)], Mb, MetMb, OxyMb, DeoMb and WHC in minced meat. Three types of meat ( Beef, camel and ostrich) and four mincing ...
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The objective of this study was the evaluation of pH, Color parameters [lightness (L*), redness (a*), yellowness (b*), chroma (C*), hue (H*), a*/b* ratio, and color differences (ΔE)], Mb, MetMb, OxyMb, DeoMb and WHC in minced meat. Three types of meat ( Beef, camel and ostrich) and four mincing processes (three using a grinder with 7.5, 4 and 3 mm diameter holes in the plate, and a fourth in which a cutter was used to obtain a finely minced product) were studied. The intact meat was used as the control. Significant differences were observed in the pH, Color parameters [lightness (L*), redness (a*), yellowness (b*), chroma (C*), hue (H*), a*/b* ratio, Mb, MetMb, DeoMb and WHC of various types of meat (P 0.05). WHC and chroma showed statistically significant differences (P 0.05) for the mincing treatment. The ΔE and OxyMb showed no significant differences (p>. 0.05) for mincing and also in meat types. High correlation between pH and L* (R2=0.999), pH and WHC (R2=0.997) confirms the decrease in L* and increase in WHC along with increase in pH.
Homa Baghaei; Mohammad Javad Varidi; Mehdi Varidi
Abstract
Determination of the body composition weight due to the growing ostrich farms in Iran is a beneficial subject. It is so important for dependent industries to know the effects of sex and slaughter conditions on carcass quality. In present study, the mean value for hot yield (55.93%) was higher than cold ...
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Determination of the body composition weight due to the growing ostrich farms in Iran is a beneficial subject. It is so important for dependent industries to know the effects of sex and slaughter conditions on carcass quality. In present study, the mean value for hot yield (55.93%) was higher than cold yield (54.70%). Blood, feather and skin were evaluated as the maximum and the hide as the minimum body weight parts. Effect of sex on the body composition weight was insignificant (p>0.05). The mean value for cooling loss in carcasses was 2.2% that did not influence by sex significantly (p>0.05). The average values for drip loss in 1 and 7 days of postmortem were 1.52% and 1.68% respectively. The mean value for cooking loss in male and female ostriches were calculated 31.85% and 33.55% respectively while this parameter in stunned ostriches were evaluated 33.30% and in non-stunned one were 32.10% (p>0.05). Although drip and cooking losses increased during 14 days, there were no significant effects of ageing, sex and slaughter conditions (p>0.05).
Behdad Shokrollahi Yanchedhmeh; Mohebbat Mohebbi; Mehdi Varidi; Elham Ansarifar
Abstract
In recent decades, as the result of industrial life, consuming fried and fast foods have increased significantly. Excessive use of fat, especially saturated fats and trans fatty acids is one of the important factors that increases heart diseases, weight gain, and cancers. Therefore, using effective methods ...
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In recent decades, as the result of industrial life, consuming fried and fast foods have increased significantly. Excessive use of fat, especially saturated fats and trans fatty acids is one of the important factors that increases heart diseases, weight gain, and cancers. Therefore, using effective methods for decreasing fat absorption not only retains desirable features but also seems essential. In this study, the effect of subtituting wheat flour with lentil flour on the batter formulation (in different level of 10, 25 and 50 percent) on the rheological properties of batter, amount of moisture and oil content, and color of fried crusts investigateded by using a deep-fried crust model at three temperature (140, 160 and 180oc) and for 90, 180, 270 and 360 s frying times. Consistency index showed a significant increase by increasing subtitution of lentil flour in batter formulation. Moreover, all the batters showed shear-thinning behaviour. The findings indicated that Batter formulations, temperature and frying time significantly (p < 0.05) affected moisture content, oil content and color of fried Crusts. Results of the study indicated that as frying time increased, the amount of moisture content reduced and increased the oil content of the final product. Also, with increasing substitution of lentil flour, moisture removal decreased and therefore, oil uptake decreased. 50% lentil flour substituted samples was found to be an effective formulation in decreasing oil content of fried crusts at all the times . Conrol sampel showed the lowest moisture content and highest oil content among all the formulations. 50% lentil flour substituted samples was found to be an effective formulation in decreasing oil content of fried crusts at all the times . Conrol sampel showed the lowest moisture content and highest oil content among all the formulations. Temperature leaded to an increase in moisture removal and an increase in oil content. By increasing frying time, temperature and subtitution of lentil flour in battre formulation, L*parameter decreased and a* and b* increased.
Zahra Ahmadian; Mehdi Varidi; Mohammad Javad Varidi; Hashem Pourazerang
Abstract
High nutritional value and existence of bioactive components in sesame seeds converted it to a valuable food. One of the methods to increase per capita consumption is processing of sesame with different ways such as production of sesame milk. In this study, the effect of blanching time (0 as a control ...
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High nutritional value and existence of bioactive components in sesame seeds converted it to a valuable food. One of the methods to increase per capita consumption is processing of sesame with different ways such as production of sesame milk. In this study, the effect of blanching time (0 as a control sample, 15 and 30 min) at 95°C and roasting temperature (0 as a control sample and 145°C) for 20 minutes was evaluated on the physicochemical and sensory characteristics of sesame milk using completely randomized factorial design. Blanching of sesame before the milling, resulted in significant decrease of the fat content, viscosity and physical stability of sesame milk .Also, roasting of sesame seeds significantly reduced the total solid content, fat and physical stability of sesame milk, while the amount of ash and specific gravity significantly increased. The results of color analysis showed a significant increase in brightness (L *) of sesame milk from 83.864 in control sample to 88.941 with increase of blanching time to 30 minutes. Moreover the total color differences showed a significant decrease from 15.371 in control sample to 10.435 with increase of blanching time to 30 minutes. Finally, by optimization of processing, the best physicochemical and sensory properties of sesame milk achieved with blanching for 15 minutes at 95°C and roasting at 145°C for 20 minute.
Mohebbat Mohebbi; Mohammad Hossein Hadad Khodaparast; Mehdi Varidi; Bijan Malaekeh Nikooei
Abstract
In this study, the oil yield, fatty acid (FA) composition and the physicochemical and quality characteristics of Salvia macrosiphon crude seed oil were determined. The main fatty acids ranked in the following order of abundance: α- Linolenic Acid> Linoleic Acid> Oleic Acid. The n3 /n6 FA ...
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In this study, the oil yield, fatty acid (FA) composition and the physicochemical and quality characteristics of Salvia macrosiphon crude seed oil were determined. The main fatty acids ranked in the following order of abundance: α- Linolenic Acid> Linoleic Acid> Oleic Acid. The n3 /n6 FA ratio and polyunsaturated FA/ Saturated FA ratio were 1.6 and 7.23, respectively. The FA composition revealed that the oil had great potential to use as nutritional dietary component and also was very susceptible to oxidation. The physicochemical properties such as Iodine ( 168.7 gI2/100g oil) , Acidic ( 0.5) and Peroxide ( 1.9) Value, color ( L: 59.22, a: -5.09, b: 22.94) and refractive index (1.4723) were also determined. Total phenol, tocopherol and sterol content were 165.22 mg GA/kg oil, 629.59 and 2540.6 ppm. In addition Oxidative Stability Index was 3.94 h.
Elham Ansarifar; Mohebbat Mohebbi; Fakhri Shahidi; Mehdi Varidi
Abstract
The objective of this study was to evaluate the effect of frying temperature, time and different batter formulations on the rheological properties and mass transfer during deep fat frying of Kurdish cheese nuggets. The effects of white egg (0, 5, 10%) addition to the batter formulation of cheese nuggets ...
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The objective of this study was to evaluate the effect of frying temperature, time and different batter formulations on the rheological properties and mass transfer during deep fat frying of Kurdish cheese nuggets. The effects of white egg (0, 5, 10%) addition to the batter formulation of cheese nuggets and frying at 150, 170 and 190◦C for 0, 1, 2, 3 and 4 min have been investigated. The results showed an interaction effect of these processing conditions on mass transfer. The most reduction in fat absorption was observed when samples were coated with batter containing 10% white egg and fried at 150 ◦C. The kinetic model based on the Fick’s law was used to describe moisture transfer data. The effective moisture diffusivity of batter without white egg was within the range of 3.97×10−8 and 7.51×10−8m2/s with R2 between 0.91 and 0.86 .In the samples coated with the batter including white egg, the effective diffusivity ranged between 2.26×10−8 and 5.96×10−8m2/s with R2 between 0.98 and 0.87, and fat transfer rate constant was between 1.1×10−3 and 8.9×10−3 s−1 with R2 from 0.82 to 0.99. Activation energy obtained from the Arrhenius plot for the effective moisture diffusivity of batter with and without white egg was 30.01 kJ/mol and ranged from 38.42 to 36.52 kJ/mol, respectively
Atena Pasban; Mohebbat Mohebbi; Hashem Pourazerang; Mehdi Varidi
Abstract
Enzymatic browning and formation of brown pigments are some of the most important problems in preparation of mushroom purees. In this study, the effect of some anti browning agents including sodium metabisulphite, ascorbic acid, and citric acid on the whiteness and foaming properties of mushroom purees ...
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Enzymatic browning and formation of brown pigments are some of the most important problems in preparation of mushroom purees. In this study, the effect of some anti browning agents including sodium metabisulphite, ascorbic acid, and citric acid on the whiteness and foaming properties of mushroom purees was investigated. The results showed that soaking with acids and sodium metabisulphite significantly (p
