Kowsar Kakaei; Mohammad Noshad; Behzad Nasehi; Mohammad Hojjati; Shahram Beiraghi-Toosi
Abstract
Introduction: In the past years, snack consuming in all age groups, special children have increased due to their low cost and eating readiness. Generally, these products have high starch content, but low nutrients such as vitamins, minerals, amino acids and fiber. In fact, most of the snacks are known ...
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Introduction: In the past years, snack consuming in all age groups, special children have increased due to their low cost and eating readiness. Generally, these products have high starch content, but low nutrients such as vitamins, minerals, amino acids and fiber. In fact, most of the snacks are known as foods with high energy content and glycemic index, but low nutritional value. Adding fruits processing by-products to extruded snacks improves the nutritional value of snacks due to their high content of dietary fiber, bioactive compounds and minerals. Pomegranate (Punica granatum L.) is a perennial plant and is generally cultivated in tropical and subtropical regions the pomegranate seed is one of the pomegranate processing by-products including approximately 15-20% of total fruit. Pomegranate seed contains 36.5-42.4% fiber, 13.5-16.9% lipid, 8.5-11.3% protein and 24.09-33.41% carbohydrates. Therefore, pomegranate by-products rich in bioactive compounds and dietary fiber can be used as a functional ingredient. Since no research have been performed on using the pomegranate seed powder in making snacks yet, this research aimed to investigate the effect of pomegranate powders as a fiber supplement on the extruded physicochemical properties.
Material and Methods: The fruit of pomegranate were purchased from Khuzestan province in Iran. After peeling of pomegranate fruits, arils were pressed. The remaining pomaces were dried at 50 C for 48h. Dried pomace was powdered using a mixer grinder. The corn grits (Golden Corn Company, Iran) were prepared. The moisture and chemical component of raw materials were analyzed. The two screw extruders (model DS56, Jinan Saxin Company) was used to formulate and prepare snacks. First, response surface methodology (RSM) was used to optimize the amount of pomegranate powder to be added to the snacks. For this purpose, the influence of adding the pomegranate seed powder (0-20 %), extruder temperature (120-160 °C) and screw rotation speed (120-180 rpm) on the physicochemical properties of extruded samples were considered. For this reason, the moisture level of the input food was adjusted to 15 % and the feeding speed was 40 (kg/hr). The obtained results from optimization of the snacks formulation and process conditions shows that the optimum amount of factors are fallowing addition of fiber supplementary 11.8 %, the temperature of the extruder 160 °C, the screw speed of 147.1 rpm. After preparing optimal and control samples (without adding pomegranate powder), in order to evaluate the addition of pomegranate powder to the physicochemical properties of snacks, for this purpose, the effect of adding pomegranate powder on fat and protein content, total phenolic compounds, antioxidant activity, density, hardness, water and oil absorbance index, solubility index, soluble and in soluble fiber content, moisture content and microstructure of the produced snacks during 60 days of storage were investigated.
Results and discussion: By adding the pomegranate seed powder, the product moisture content decreased, which is probably due to high insoluble fiber content of pomegranate seed powder like apple residue. Moreover, by adding the pomegranate seed powder, the oil absorption index increased, which is probably due to presence of non-polar amino acids in the pomegranate seed powder. Existence of greater quantities of non-polar amino acids and presence of non-polar side chains in the extruded products may absorb oil hydrocarbon chains, leading to increase oil absorption index. Based on results, adding the pomegranate seed powder increases the hardness of the samples, which is probably due to the high amounts of oil and protein in the pomegranate seed powder. Researchers have reported that the use of food ingredients with high fat, protein, and fiber content increase the product tissue hardness. Also, the addition of pomegranate powder reduced water absorption of samples, which is probably due to the presence of insoluble water compounds such as fat and insoluble fibers in pomegranate powder and the reduction in the starch content of the samples due to the replacement of pomegranate powder. According to the results, addition of pomegranate powder increased the total phenol content and antioxidant properties of samples. While increasing the storage time, the total phenol content in the samples was reduced, which is probably due to the oxidation reactions that occur during storage. The results of this study showed that the addition of pomegranate powder increased the density, a * value, and nutritional value (such as iron, zinc, soluble and insoluble fiber, protein and fat content) in samples. While L* and b* values and water activity of the samples was reduced. Also, the addition of pomegranate powder decreased porosity and created heterogeneous and irregular cavities in the texture of snacks.
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.
Elham Sadati gol afshani; Seyed Mahdi Jafari; Mahdi Kashani-Nejad; Shahram Beiraghi-Toosi; Mohammad Ganjeh
Abstract
Introduction: Osmotic dehydration involves the partial removal of water by direct contact of a product with a hypertonic medium such as high concentration of sugar, salt or sugar-salt solutions. In this process, food pieces are immersed in a hypertonic solution. The natural membrane of food cells acts ...
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Introduction: Osmotic dehydration involves the partial removal of water by direct contact of a product with a hypertonic medium such as high concentration of sugar, salt or sugar-salt solutions. In this process, food pieces are immersed in a hypertonic solution. The natural membrane of food cells acts as a semipermeable layer so the water moves across the membrane from an area of high water potential (low solute concentration) to an area of low water potential (high solute concentration), meaning the driving force for water removal is the concentration gradient between the solution and the intracellular fluid. During osmotic dehydration, osmotic solute is absorbed by food materials and has undesirable effects on water removal, nutritional and organoleptic properties. Use of coating improves the osmotic processing. Best factor for evaluation of coating material is performance ratio (WL/SG). So a coating should reduce solid uptake without negative effects on water removal.
Materials and methods: The apples (Golden delicious) used in this study were purchased from a local market in Mashhad (Iran) and stored at 4-6°C before processing. The sucrose (99.9%, Fariman sugar company, Iran), carrageenan (kappa type, Negin Khorak Pars Company, Iran), carboxy methyl cellulose (sandros, Japan) and calcium chloride (Dr. Mojallali Lab., Iran) were also used. In this work, apple cubes were single and double coated in three concentrations (0.5, 1 and 1.5% w/w) of carboxy methyl cellulose (CMC) and carrageenan solution and dehydrated osmotically in different concentrations (30, 45 and 60˚ BX) of sucrose solutions.
Results and Discussion: The results of this study indicated that increasing coating solution concentration from 0.5% to 1.5% decreased water loss. Also the water loss increased when the number of coating layers and the concentration of osmotic solution increased (from 30 to 60 ˚ BX). Generally, water loss and solids uptake in the samples coated with carrageenan was higher and lower than their CMC counterparts, respectively. The solids uptake in the samples coated with CMC increased by increasing the number of layers, osmotic solution concentration (from 30 to 60˚BX) and coating solution concentration (from 0.5 to 1.5%). The solids uptake increased and decreased with increase in layer number and coating solution concentration (from 0.5% to 1.5%), respectively. Increasing the osmotic solution concentration up to 45 ˚ BX increased solids uptake but, more increasingly did not have a significant effect on it. Finally, it cannot be said strictly that one coating type would facilitate osmotic process or not. It depends on various process factors. Among the 36 treatments studied in this research, the single coated samples with 1% carrageenan treated in 60 ˚ BX sucrose solution and the single and double coated samples with 0.5% CMC treated in 45 ˚ BX sucrose solution were the best, as they had 50% higher performance ratio than control (uncoated) sample.
Elahe Eshraghi; Mahdi Kashani-Nejad; Yahya Maghsoudlou; Shahram Beiraghi-Toosi; Mehran Alami
Abstract
The aim of this research was to use Osmosis-Ultrasound Compound pre-treatment and studying the time of drying and the potentiality to rehydration in dried samples of kiwi fruit (Hayvard variety). The samples were drained in three timed phases, 10, 20 and 30 minutes in room temperature in 30, 50 and 70 ...
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The aim of this research was to use Osmosis-Ultrasound Compound pre-treatment and studying the time of drying and the potentiality to rehydration in dried samples of kiwi fruit (Hayvard variety). The samples were drained in three timed phases, 10, 20 and 30 minutes in room temperature in 30, 50 and 70 BX in Ultrasound bath osmosis solutions. The results of drying time showed that by decreasing the concentration of kiwi fruits samples from 8 to 6 mm and increasing the concentration of osmosis solution and ultrasound time, the time of gaining 20% moisture decreased for each treatment. The studies showed that the minimum time for getting 20% moisture in 6 and 8 mm kiwi fruits in pre-treated samples with 70 BX and 30 minutes ultrasound time is 263 and 313 minutes respectively. The results of rehydration in pre-treated compound samples showed that by increasing the concentration of osmosis solution, as well as the time for Ultrasound waving and increasing the kiwi fruits samples concentration from 6 to 8 mm, the rehydration decreased compared to control sample. The results of perceptive assessment in general acceptance of dried kiwi fruit showed that using pre-treated compound sample was more acceptable than the control sample.
Hashem Razavi Setoti; Seyed Ali Mortazavi; Monirosadat Shakeri; Shahram Beiraghi-Toosi; Elham Asadolahi
Abstract
In this study, antimicrobial effects of Zataria Multiflora boiss added to sodium caseinate film on four bacterial species: Staphylococcus aurous, Escherichia coli, Bacillus subtilis and Salmonella intertidis was investigated. Disk diffusion method was used to study the antimicrobial activity of Zataria ...
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In this study, antimicrobial effects of Zataria Multiflora boiss added to sodium caseinate film on four bacterial species: Staphylococcus aurous, Escherichia coli, Bacillus subtilis and Salmonella intertidis was investigated. Disk diffusion method was used to study the antimicrobial activity of Zataria multiflora Boiss in sodium caseinate film. 9 mm disks were prepared from produced films with different concentrations of Zataria multiflora Boiss. with 1, 2, 3 and 4%. Surface culture was done under sterile condition using 0.1 ml of broth culture of each bacterial (106 -107 cfu/ml) on BHI agar. Then the disks were placed. Diameter of inhibition zone was considered as an index of antimicrobial activity of the film. Statistical analyses were done by means of SigmaSDAT software and mean comparison was carried out by LSD test. Results showed that disks containing essential oils of Zataria multiflora Boiss. in each concentration inhibited growth of E.coli, Sa.interitidis and B.cereus. Since there was no significant differences between 3% and 4% concentrations for these bacteria (p>0/05), concentration of 3% is the most appropriate and cost-effective concentration with the highest antimicrobial effect. Only the film containing 1% of essential oil of Zataria multiflora Boiss. Made no inhibition zone on S.aurous, in the other word had no inhibitory effect in this concentration. But inhibition zones created by 2, 3 and 4% for S.aurous were significantly different (p
Elahe Eshraghi; Yahya Maghsoudlou; Mahdi Kashani-Nejad; Shahram Beiraghi-Toosi; Mehran Alami
Abstract
The aim of this research was to use ultrasound pre-treatment and studying the time of drying and rehydration in dried samples of kiwifruit (Hayvard variety). The samples were dehydrated for different lengths of time, 10, 20 and 30 minutes at room temperature in distilled water in Ultrasound bath (45 ...
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The aim of this research was to use ultrasound pre-treatment and studying the time of drying and rehydration in dried samples of kiwifruit (Hayvard variety). The samples were dehydrated for different lengths of time, 10, 20 and 30 minutes at room temperature in distilled water in Ultrasound bath (45 kHz). The results of drying time showed that by decreasing the thickness of samples from 8 to 6 mm and increasing the ultrasound time, the time required reducing the moisture content down to 20% for each treatment. It was also found that the minimum time for bringing the moisture down to 20% in 6 and 8 mm kiwi fruits in pre-treated samples with 30 minutes sonication time was 299 and 404 minutes, respectively. The results of rehydration in samples showed that by increasing the time of sonication and decreasing the kiwifruits samples thickness from 8 to 6 mm, the rehydration increased compared to control sample. The results of organoleptic valuations about to totality acception of dried kiwifruit product showed that using pre-treated ultrasound sample was more acceptable than the control sample.
Keywords: Rehydration, Drying, Kiwifruit, Ultrasound
Reza Abolghasemi; Bagher Emadi; Mohammad Hosein Aghkhani; Shahram Beiraghi-Toosi
Abstract
The tissue of fruit varies at different stages of growth and storage and by determining its characteristics; the stage of fruit maturity can be found. Depending on the type of tissue, the ultrasonic waves will attenuate and its speed will change too while crossing the fruit tissue. Thus, by calculating ...
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The tissue of fruit varies at different stages of growth and storage and by determining its characteristics; the stage of fruit maturity can be found. Depending on the type of tissue, the ultrasonic waves will attenuate and its speed will change too while crossing the fruit tissue. Thus, by calculating the attenuation coefficient value and its speed in no destructive way, the characteristics of fruit tissue and the rate of its maturity will be determined. In this study, peach fruits -the Tabrizi variety- were classified in ripen, semi-ripen, large and small groups and the validity of ripen and semi-ripen groups were confirmed by taste panel. Then, in addition to measuring the attenuation coefficient and velocity of ultrasonic wave parameters, the physic-chemical parameters of fruit, including dimensions, mass, density, hardness, reducing sugar, acidity, pH, dry weight and soluble solids contents, which are the maturity indices of peach, were measured and compared with ultrasonic parameters. Results showed that fruit size and degree of maturity significantly affect on the wave attenuation and wave velocity, respectively. The correlation coefficients between attenuation coefficient and hardness (without skin) in ripen and semi ripen groups were higher than 0.8 and also the correlation coefficients of attenuation coefficient in relation with the hardness (by skin) in ripen and semi ripen groups were higher than 0.7. Also, the correlations for both attenuation coefficient and wave velocity in relation with the pH were higher than 0.8 as well as correlation between wave velocity and acidity.
Key words: Chemical, mechanical and physical characteristics, Ripening, Ultrasound, Peach
