Research Article
Masoumeh Pourseyed; Ali Motamedzadegan; Jafar Mohammadzadeh Milani
Abstract
Introduction: Converting milk into milk powder increases its shelf life up to almost 1 year, without substantial loss of quality, even at ambient temperatures. Dairy powder is frequently used because of convenience in applications for transportation, handling, processing, and ease of product formulations. ...
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Introduction: Converting milk into milk powder increases its shelf life up to almost 1 year, without substantial loss of quality, even at ambient temperatures. Dairy powder is frequently used because of convenience in applications for transportation, handling, processing, and ease of product formulations. Functional properties of milk powder are important due to its wide range of applications, especially in bakery products requiring desirable texture and moisture content. These functional properties include emulsification, foaming, water absorption, viscosity, gelation, and heat stability. Fresh milk and milk products such as condensed or dried milk which have not been exposed to sufficient heat treatment are not suitable for good quality bakery products as properly heated milk, mainly due to the destruction of proteolytic enzymes by heat, denaturation and coagulation of the proteins, changes in the colloidal properties of the salt and alterations in the oxidation-reduction systems. Kirk (1971) has outlined a list of functional contributions provided by skim milk powder (SMP) in various bakery food products, such as increased absorption, buffering value, lactose color reaction, tenderizing effect, improved body and resilience of crumb. This is in agreement with the results showed by Pyler who added SMP to bread and cake affected. Pyler noted the advantages of lactose in food systems. Lactose mostly affect relative sweetness, browning reaction, protein stabilizing properties, alteration of crystallization patterns, flavor accentuation, selective fermentation, and has nutritional value.
Materials and methods: Yazdi cake was produced using baking wheat flour (from Golha factory), sugar (sucrose), hydrogenated vegetable shortening, baking powder, and baking soda. Eggs were bought the day before baking and refrigerated at 4°C. The dough was prepared in ratio of 30 % oil, 46 % sugar, 50 % water, 11.7 % eggs, 4 % baking powder and 1 % baking soda rather than flour. For improvements of flavor and taste, an equal value of vanilla was added to the whole dough formulations. Skim milk powder containing 1.5 % fat, 3-4 % moisture has bought from Pegah factory. 25 and 50 percent of skim milk powder was also added to the dough. Dough was prepared based on the method of double mixture steps and was baked at 180°C in oven for 30 min. Samples were vacuumed and kept at ambient temperature for further experiments
Result and discussion: The differences in specific volume and consistency of the dough values were found to be significant (p>0.01). According to Baeva studies, there is an inverse relationship between specific gravity and the entry air bubbles in the dough, so the sample with 50% had the lowest specific volume. The consistency of the dough increased significantly by increasing in SMP content (P
Research Article
Laleh Golchoobi; Mazdak Alimi; Hossein Yousefi
Abstract
Introduction: Mayonnaise, a semisolid oil in water emulsion containing vegetable oil, vinegar, egg yolk and optional ingredients such as salt, sugar and mustard, is a conventional old condiment containing high fat ingredient (minimum of 65%). The need to reduce the amount of saturated fat in diets, has ...
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Introduction: Mayonnaise, a semisolid oil in water emulsion containing vegetable oil, vinegar, egg yolk and optional ingredients such as salt, sugar and mustard, is a conventional old condiment containing high fat ingredient (minimum of 65%). The need to reduce the amount of saturated fat in diets, has led to the development of alternative processes to produce law fat mayonnaise. Cellulose and its physically-treated derivatives i.e. microcrystalline cellulose (MCC) and microfibrillated cellulose (MFC) lately investigated as NFC is one of the conventional fat replacers used in low-fat products formulation such as mayonnaise. Nanofiber cellulose (NFC) is a glucose polymer connecting together by β (1-4) glycosidic bonds. This low-cost new kind of cellulose can be obtained from physical modification of cellulose as naturally occurring carbohydrate that is renewable, biodegradable and nontoxic. Increased specific surface area, enhanced mechanical and hydrophilic properties of nanoscale cellulose are affected by the number of hydrogen bond in nanofiber chain of cellulose and low concentration of NFC suspension can form a stront and viscous semi-gel network. As a result, because of all the functional properties, NFC can be employed as a fat replacer in reduced or low calorie food products, and as an improver of the product structure consistency. In fact, because of downsizing cellulose to nanoscale, the surface to volume ratio of NFC increases and the surface hydroxyl groups participate in the formation of hydrogen bonds in the network. Hence, more appropriate mechanical properties for NFC are achieved, even in a lower dosage. Therefore, NFC is theoretically a proper thickener and stabilizer for low-fat systems. Carboxy methyl cellulose (CMC) is a synthesized derivate of cellulose which is gained by adding carboxy methyl groups (- CH2- COOH) to cellulose. CMC is used in different food systems with the E number E466 as emulsions stabilizer, control and modification of texture in various products. In this research, application of combination of nanofiber cellulose (0%-1%) and CMC (0%-1%) to optimize rheological properties and production of low-fat mayonnaise (30% oil) with desirable characteristics were studied. Due to the hydrophilic nature of cellulose derivatives, several research works have been focused on the stabilization of oil-in-water (o/w) emulsions specially salad dressing or low-fat and fat free mayonnaise by NFC. However, no information is available on NFC/CMC mixtures. The main aim of this study was to investigate the possible mutual interactions between NFC and CMC in mayonnaise formulation regarding to the nutritional benefits that each can be individually contribute to low-fat healthy products. Rheological characterization and particle size of low fat mayonnaise, containing NFC and CMC, were conducted to validate the practical applicability of the proposed formulation in food industry.
Materials and methods: The nanofiber cellulose of each formulation (0.25, 0.5, 0.75 and 1%) was first mixed with the related formulation water and pasteurized using a EUROSTAR power control-visc 6000 homogenizer for 5 min inside water bath at 85°C. Then, it was added to the raw materials of its treatment. After production of 5 samples, viscosity test was performed using a rotational viscometer. Then, particle size measurement (D[4,3] with distilled water as the solvent, a Mastersizer 2000 equipped to quartz cell and laser beam with ƛ= 634 nm), light microscopy (optical microscope, magnification of 100×) and rheological tests such as flow behavior (shear rate: 0.01-200 1/s), complex viscosity and frequency sweep (frequency: 0.01-100 Hz) were performed on 3 selected samples (stress-controlled rheometer with a serrated parallel-plate geometry). Commercial low fat mayonnaise (30% fat) produced by Behrouz factory was selected as the control sample.
Results & discussion: Overall, the viscosity results revealed that by the addition of NFC and CMC, only the sample containing 0.5% nanofiber cellulose and 0.5% CMC did not show significant difference compared to the commercial control sample (pG˝) that has revealed the predominating of the elastic features in the mentioned samples, similar to the trend of commercial control sample. The obtained data of complex viscosity was in consistency with this data. With respect to the obtained results of particle size distribution, the sample containing 0.5% nanofiber cellulose and 0.5% CMC were considered to have the minimum value of D[4,3] and desirable uniformity in comparison with other samples.
Conclusion: Considering the aforementioned results, in this study NFC50/CC50 sample containing 0.5% nanofiber cellulose and 0.5% CMC was employed to formulate low-fat mayonnaise with interesting particle size and rheological properties that is attributed to the synergistic interaction between 0.5% NFC and 0.5% CMC. In fact, the effect of fat reduction is balanced by replacing of 0.5% nanofiber cellulose and 0.5% CMC. Therefore, these hydrocolloids generated a robust gel-structure in the network of this sample. In addition, tridimensional gel structure was formed by physical entanglements among polymeric chains along with the development of the crosslinked network formed between both hydrocolloids. On the other hand, reduction of dispersion phase size and suitable uniformity of droplets in NFC50/CC50 sample resulted in appropriate monodispersity, which increases the resistance to deformation and the enhancement of its viscosity.
Research Article
Zahra Najafi; Sara Movahhed; Hossein Ahmadi Chenarbon
Abstract
Introduction: Cake is one of the most important and widely used cereals and a product of wheat flour. Usually, high-calorie in a variety of cakes is attributed to oils, eggs and sugar in their formulation. Nowadays, the risk of cardiovascular diseases is increasing in most parts of the world and the ...
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Introduction: Cake is one of the most important and widely used cereals and a product of wheat flour. Usually, high-calorie in a variety of cakes is attributed to oils, eggs and sugar in their formulation. Nowadays, the risk of cardiovascular diseases is increasing in most parts of the world and the demand for using the low fat and low cholesterol foods is increasing due to the relationship between excess fat and various diseases. Therefore, it seems that the partial or complete removal of oil and egg and replacing them with other substances in the formulation of the cake is very important. In recent years, the use of dietary fiber of different sources in food products is increasing due its beneficial effects on human health. Among agricultural products, the residues from the processing of oranges are rich in fiber that can be used as a dietary fiber in the food industry. Fiber is a general term for many different types of carbohydrates that is obtained from plant cell walls and is not decomposed by digestive enzymes in the human body. Formulating the food with citrus fiber could be very beneficial since the exisence of a variety of fiber compounds in the peel of citrus with neutral pH that the property may leads it to be widely used in a variety of foods. Others advantage is that it lead to improve the cooking performance, increase the water binding capacity, the oil absorption and improve the final texture of product with lower costs.
Materials and methods: In this study, the use of citrus fiber was studied in order to improve the structure and nutritional properties of muffin with a new formulation. In this regard, the orange fiber at three levels (0.5%, 1% and 2%) and with 25% of decrease in oil and egg was used in the muffin production process. In this study, the raw materials, including null flour, sugar, liquid oil, eggs, milk, salt, vanilla, baking powder and orange fiber were prepared from France ID Food Company. Two-step mixing method was used to prepare the dough. The cakes were placed at 180 ° C for 30 minutes. In all tests, the control treatment with code T, treatment containing 0.5% of orange fiber with code T1, treatment containing 1% of orange fiber with code T2 and treatment containing 2% of orange fiber with code T3 were determined. First, the chemical tests including moisture, ash, fiber and pH were conducted on the wheat flour. Then, viscosity determination was carried out usinga Brookfield viscometer, Also the density measurement performed on the muffin cake dough. Afterwards, the production of different treatments, the chemical tests including moisture, ash, fiber and pH as well as the staling tests were performed by two sensory and instrumental methods by Instron device and also the organoleptic characteristics (volume, crack, balance of shape, taste and aroma, chewiness, apparent texture, uniformity of pores in the cake center and the color of cake center and the outer shell) were conducted by using five senses on the produced Muffin Cake according to the standard method.
Results and discussion: For statistical analysis of data from physicochemical and sensory tests, completely randomized design and data from staling test from factorial experiment in a completely randomized block design was used and the mean comparisons were conducted by Duncan's multiple range test at probability level of 1% (α=1%) and by using SPSS software, version 16. Considering the results of viscosity and density of the muffin cake dough, the highest amount of viscosity and density belonged to the treatment containing 2% of orange fiber (T3) and control (without orange fiber). The highest percentages of moisture, ash and fiber were calculated for the treatment T3 and the lowest amounts were calculated for control. Also, the highest and the lowest amounts of pH were observed in the treatments of control and T3, respectively. Also, considering the results of staling test by both sensory and instrumental methods and in the intervals of 24, 48 and 72 hours after baking and in all time periods of treatment T3 had the highest score of freshness (delay in staling) and the treatment containing 1% of orange fiber (T2), containing 0.5% of orange fiber (T1) and control (T) had the lowest score of freshness, respectively. The control sample had the highest amount of staling in all days and the amount of staling increased in all treatments over time. It is noteworthy that at all time intervals, the control sample had the highest rate of staling and the staling rate increased for all treatments over time. Considering the results of sensory test, T1 was introduced as the best treatment and in most of the organoleptic characteristics such as taste, flavor, uniformity of pores, chewiness, and overall acceptance had no significant difference with the control sample and was the nearest sample to the control and had the highest score and the highest level of consumer acceptance.
Conclusion: The results showed that adding different levels of orange fiber has a significant effects on physicochemical and organoleptic properties of the muffin cake and replacing 25% of oil and egg used in muffin cake with 0.5% of orange fiber is possible and has enough acceptances.
Research Article
Hossein Jooyandeh; Erfan Danesh; Mostafa Goudarzi
Abstract
Introduction: Health-conscious consumers are interested in eating dairy products including ice cream with less fat. As a consequence, the dairy industry has developed a variety of reduced-fat ice cream products. However, quality aspects of many of these products do not meet consumer expectations for ...
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Introduction: Health-conscious consumers are interested in eating dairy products including ice cream with less fat. As a consequence, the dairy industry has developed a variety of reduced-fat ice cream products. However, quality aspects of many of these products do not meet consumer expectations for ice cream flavor, texture, and appearance. The formation of the ice cream structure is hindered when the fat content is reduced and attributes related to quality, such as viscosity, ice crystallization, hardness, melting rate and flavor, are affected. Low melting resistance, high firmness and undesirable flavor are the most cited defects in reduced-fat ice creams. Enzymatic treatment of reduced-fat milk with microbial transglutaminase has been found to improve the textural and sensory properties of the final dairy products. The transglutaminase enzyme (MTGase; protein-glutamine gamma glutamyl transferase, EC 2.3.2.13) catalyses “acyl” transfer reactions between γ-carboxyamide groups of glutamine residues (acyl donor) and the ɛ-amino group of lysines (acyl acceptor) in proteins, leading to inter- or intra-molecular cross-linking. The enzyme-catalyzed cross-linking of milk proteins results in the formation of high molecular weight polymers that not only are able to lower the melting rate thorough increasing the viscosity of ice cream mix, but they could also provide a smoother texture for the product by mechanically obstructing ice crystal growth. However, the extensive cross-linking of milk proteins may even adversely affect the physical properties of the resultant ice cream and thus, the added amount of enzyme needs to be adequate for the desired effects. The aim of this study was to investigate the effects of different concentrations of TGase enzyme on physical and sensory properties of light ice cream in order to selct the appropriate amount of enzyme concentration that provides the best results.
Materials and methods: The light ice cream (5% w/w fat) was treated with different concentrations of TGase enzyme (2, 4 and 6 units/g milk protein). The enzyme-treated samples were investigated for flow behavior characteristics (apparent viscosity, flow index, consistency index), overrun, melting rate, hardness and sensory properties (flavor, texture, color and total acceptability) in comparison with control light ice cream with no added Tgase.
Results and discussion: The results revealed that TGase treatment effectively increased the viscosity of light ice cream.The higher the enzyme concentration, the greater the viscosity of ice cream samples. This could be attributed to TGase-catalyzed formation of large protein polymers in ice cream mix that resist to flow. All enzyme-treated ice cream mixes exhibited shear-thinning behavior, where the viscosity decreased with increasing shear rate. The power law model was used to find consistency and flow indices for different treatments. The results showed that consistency index increased and flow behavior index decreased with TGase concentration. The stronger shear-thinning behavior (lower flow index) of the samples treated with higher concentration of TGase might be arisen from formation of higher number of large protein polymers in theses samples, which decrease in size during shearing. The enzyme treatment significantly increased the overrun of the light ice cream that could be due to the increasing effect of TGaes on the viscosity. The increase in viscosity promotes the retention of air in the ice cream which is concomitant with increased overrun; however, high viscosity reduces the whipping rate leading to lower incorporation of air into the ice cream and thus decreased overrun. This may account for significantly lower overrun of the light ice cream treated with 6 units TGase/g milk protein than the samples treated with 4 units TGase /g milk protein. It was observed that the enzyme treatment caused a significant improvement in melting resistance of light ice cream. In fact, the light ice cream treated with 6 or 4 units TGase /g milk protein took the longest time to melt, followed by the samples treated with 2 and 0 units TGase /g milk protein. This is somehow in accordance with the results of overrun; that is, the ice cream with higher overrun melted slower attributed to a reduced rate of heat transfer due to a larger volume of air. The overrun could also affect the hardness of ice cream as evidenced by the results of the present study. The results showed that the samples with greater overrun were softer. It could be assumed that the air cells, together with large protein polymers formed via catalytic action of TGase, limited the size of ice crystals by exerting mechanical hindrance, providing a softer texture for the enzyme-treated ice creams. Not surprisingly, the enzyme treatment did not considerably influence the flavor of light ice cream albeit the sample treated with 6 units TGase /g milk protein received significantly lower score than the other samples. Conversely, the color of enzyme-treated samples was more appreciated by consumers than the sample without added TGase possibly because of light scattering properties of enzymatically formed protein polymers in theses samples. Consistent with the results of physical properties, the texture of light ice cream treated with 4 or 6 units TGase /g milk protein were ranked as the most desirable samples, followed by the samples treated with 2 and 0 units TGase /g milk protein. The order of light ice cream samples for total acceptability scores was the same as that for texture scores with the exception of the sample treated with 6 units TGase /g milk protein whose total acceptability score was lower than the sample treated with 4 units TGase /g milk protein.
Research Article
Aisan Falaki; Narmela Asefi
Abstract
Introduction: Nutrition research on the health benefits of substances in plant foods (phytochemicals) has recently advanced to a new stage, as ascorbic acid, these phytonutrients is abundant in citrus fruit, and all show physiologic actions that may contribute to cancer prevention. Citrus lemon is an ...
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Introduction: Nutrition research on the health benefits of substances in plant foods (phytochemicals) has recently advanced to a new stage, as ascorbic acid, these phytonutrients is abundant in citrus fruit, and all show physiologic actions that may contribute to cancer prevention. Citrus lemon is an important source of this nutritional qualityand it has low durability due to its high water content (87%). Therefore, some practical solutions such as drying could help to increase their sustainable necessary for improve production. Different drying methods have considerable impact on the quality of final product. Vacuum drying can preserved nutrients and increased the nutritional quality of the final product. This behavior could be related to drying process at low temperatures in the absence of oxygen. In vacuum drying, removal of moisture from food products takes place under low pressure. The lower pressure allow drying temperature to be reduced and higher quality to be obtained than with classical air conventional process at atmospheric pressure. Osmotic dehydration can be used to remove water from heat-sensitive products with low energy consumption at a low temperature. Since osmotic dehydration cannot remove whole moisture but it is good as a preliminary partial dehydration step. Higher osmotic concentration, long time and oxygen resulted in higher loss of antioxidant activity but fit osmotic concentration and time. The osmotic process has received considerable attention as a pre-treatment to reduce energy consumption and improve food quality, besides reducing the drying time in different research studies. The osmotic dehydration as a pre-treatment also inhibits enzymatic growing, retains natural color and retains volatile aromas during the subsequent drying. Sodium metabisulphite is an inorganic compound. It is used as antioxidant (through oxidation prevention) and preservative agent. The purpose of this study was to quantify the flow of soluble micronutrients, such as ascorbic acid, antioxidant agent during osmosis and its effects on the changes of organoleptic characteristics (flavor, taste, color and texture) in final product.
Materials and method: In this study, lemons (shirazi) of uniform quality were purchased from the local market Tabriz city (Iran) and stored at 4ºC then the local temperature reached before use. The prepared slices of lemon with a thickness of 4 mm, were immersed in a solution of sodium metabisulphite (1500ppm) for 10 minutes at room temperature. Then, the influence of three different osmotic solution, (40 % sugar, 15 % salt and 20%:%20 sugar/ salt) on osmotic dehydration (water loss and solid gain) prior to vacuum drying oven (Memmert, Schwabach, Germany) at temperature: 60C and pressure: 70mbar, were investigated the (Shulka and Singh, 2007) method. Moisture content was determined by the oven drying method (AOAC, 1990). The effects of various drying parameters such as osmotic solution and metabisulphite treatment on the quality of dried lemon slices were evaluated. Drying kinetics were presented in terms of the temperature of the product during drying, drying curve and drying time and quality aspects were studied in terms EC50 by the 2, 2-diphenyl-1-picrylhydrazyl absorption rate in spectrophotometer method (Cemeroglu, 2010), ascorbic acid by the 2, 6-dichlorophenol Indophenol titration method (Cemeroglu, 2010), shrinkage by the fluid movement (by ethanol) method (yasaemehrjerdi et al, 2012), and sensory evaluation by the ratings table method. Also the experiment was conducted according to a completely randomized design in triplicates. Data were evaluated by analysis of variance (ANOVA), using Design Expert software, and version dx7-trial.
Result & discussion: The result showed that the pretreatment with osmotic solution, has significant effect (level 1%) on physicochemical and organoleptic characteristics. In this study, shrinkage levels were reduced to an average of 20 percent because of the evolution of volume of dried lemon tissue throughout osmotic dehydration in osmotic aqueous solution were closely supported by microstructural and ultrastructural changes. The observed behavior of structural parameters could be partially explained in terms of the multicomponent diffusion process occurring during osmosis as well as the relaxation of structural stresses of the compressed viscoelastic cell walls. Water loss in samples immersed in sodium metabisulphite was increased, while EC50 (reduced EC50 amount that’s mean increased antioxidant capacity) and that ascorbic acid content were decreased. Also combined osmotic solution (salt 20%- sugar 20%), considerable in water loss and solid gain due to the combined osmotic solution were increased. Mass transfer in samples was increased by increasing the osmotic pressure using salt. The sugar solution can be preserved fruit nutrients and increased the sensory quality of the final product through preserved antioxidant capacity and ascorbic acid content. model presented the best fit for the observed data and sample immersion in sodium metabisulphite with sucrose osmotic solution selected. Since, changing the original taste of fruit in osmotic dehydration considered to be a negative factor. Therefore, the selection of the best solution must be based on the sensory properties. Based on the obtained results, the best osmotic solution for dried lemon was found to be the sugar solution.
Research Article
Keivan Ali Asgari; Sakineh Yeganeh; Seyed Ali Jafarpour; Reza Safari
Abstract
Introduction: Nowadays, use of new processing method is important for converting by-products into more marketable and acceptable forms to achieve a better utilization. Sea food processing generate protein rich by-products that their quantity depends on processing method. One of the methods for effective ...
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Introduction: Nowadays, use of new processing method is important for converting by-products into more marketable and acceptable forms to achieve a better utilization. Sea food processing generate protein rich by-products that their quantity depends on processing method. One of the methods for effective protein recovery from this protein rich by-product is preparation of protein hydrolysate through enzymatic, autolytic and chemical hydrolysis. Enzymatic hydrolysis is widely employed to improve the functional and nutritional properties of the fish byproducts. Hydrolysis may be conducted as a method of separating soluble nitrogenous compounds from insoluble particles and fish oil, and offers good predictability of the products. So nitrogen recovery assay can determine enzyme efficiency in separation of soluble protein from insoluble protein. Different factors (Enzyme level, temperature, pH, enzyme to substrate ratio) can effect on the hydrolysis degree, nitrogen recovery and functional properties of protein hydrolysate, so optimization method is used for obtaining the best condition. RSM is a statistical model frequently used for the optimization of complex systems and uses quantitative data from an appropriate experimental design to determine and simultaneously solve multivariate problems. Based on the experimental data, RSM could tell us the optimum conditions to obtain the desired responses, as well as the mathematical model in explaining the relationship between the experimental variables and its responses. Alcalase has great ability to solubilize fish protein and is nonspecific, with an optimum temperature that ranged from 50 to 70°C. It has optimal pH range at the value of 8 to 10 that could reduce the risk of microbial contaminations. Moreover, it has been reported that produced protein hydrolysate by Alcalase had less bitter principles compared to those prepared with papain. Furthermore Alcalase has been documented to be a better candidate for hydrolyzing fish proteins based on enzyme cost per activity.
The Cuttlefish (Sepia offıcinalis) can be found in the south water of Iran including Persian Gulf and Oman Sea and their catch has been recorded about 5102 t according to FAO Statistic. This species has been considered for exporting to other country. During Cuttlefish processing, 30-35 % byproducts including head, arms and viscera are generated that can be invaluable products and environmental pollution while it is protein rich source. The objective of this study was to optimize nitrogen recovery in the enzymatic hydrolysis of head and arms of cuttlefish (Sepia pharaonis) using Alcalase.
Materials and methods: Response surface methodology (RSM) based on Box-Behnken was employed to investigate the effects of different operating conditions including temperature (45, 50 and 55˚C), pH (7.5, 8 and 8.5) and alcalase enzyme to substrate ratio (1, 1.5 and 2) on the nitrogen recovery as a surface response. Referring to the R2 of 0.96 for nitrogen recovery, the mathematical model showed acceptable fitness with the experimental data, which indicated that major part of the variability within the range of values studied could be explained by the model.After obtaining optimum condition for nitrogen recovery, freeze dried protein powder was produced by optimized condition and analyzed for amino acid composition, chemical score of cuttlefish protein hydrolysate and protein efficiency ratio.
Results & Discussion: The obtained results showed the interactive effect of temperature and enzyme to substrate ratio was not significant (P> 0.05) but the interaction effect of enzyme to substrate ratio and pH and the interaction effect of temperature and pH was significant (P
Research Article
Elahe Maghsoudlou; Reza Esmaeilzadeh kenari; Zeynab Raftani Amiri
Abstract
Introduction: Lipid oxidation is a complex series of reactions that occurs during processing, storage and final preparation of foods containing lipids (Bera et al., 2006). Among the various methods of protection against oxidation, specific additives are used which are antioxidants (Pokorny et al., 2006).Polyphenols ...
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Introduction: Lipid oxidation is a complex series of reactions that occurs during processing, storage and final preparation of foods containing lipids (Bera et al., 2006). Among the various methods of protection against oxidation, specific additives are used which are antioxidants (Pokorny et al., 2006).Polyphenols are natural antioxidants that possess characteristic properties, such as free-radical scavenging and inhibition of oxidizing processes in the body. For using of phenolic compound, they must be extracted from plant material. Traditional methods of extraction are labor-intensive, time consuming, and require large volumes of solvent (Wang and Weller, 2006(. In recent years, ultrasound-assisted extraction (UAE) has become an effective method for edible oils and fats from natural product extraction. UAE is an inexpensive, simple and efficient alternative to conventional extraction techniques (Chen et al., 2010). The mechanism of UAE is attributed to mechanical and cavitation efficacies which can result in disruption of cell wall, particle size reduction, and enhanced mass transfer across cell membrane (Wang, Wu, Chen, Yue, Liang, & Wu, 2013). Figs are an excellent source of phenolic compounds and some studies have described the presence of several phenolic compounds in this species (Solomon et al., 2006; Teixeira et al., 2006; Vaya and Mahmood, 2006). However, according to our knowledge, there are no studies about the detailed investigation of different parts of the fig and evaluation of its oxidative stability. Therefore, the objective of this study was to evaluate antioxidant activity of pulp and skin of two varieties of fig (Siyah and Sabz) and its application as natural antioxidant in canola oil.
Material and methods: Fig fruit (F. carica L.) from two selected commercial varieties: Siyah and Sabz wwere collected from Gorgan, Iran in September 2014. Canola oil was purchased from Alia Golestan Company (Kordkooy, Iran). All other chemicals used in this study were of analytical grade and were purchased from chemical suppliers such as Merck and Sigma-Aldrich Chemical Companies.
The figs were weighed and immediately peeled. The pulp was cut and made into flat sheets. Thereafter, the pulp and skin of each fruit were shade-dried for 5 days followed by drying at 60 ℃ in an oven for 24 hours to ensure complete drying (Memmert 100-800, Germany). The samples were then milled and sieved. Samples obtained were kept in polyethylene bags.
Dried fig powders were mixed with ethanol (1:10), then placed in ultrasonic bath, and then sonicated at 37 kHz for 20 min at 40°C by Elma Transsonic ultrasonic bath model 690/H (Cottbus, Germany). The extract was filtered and subsequently evaporated at 40 ℃ in an oven. The concentrated extracts were stored at -18 C until further analyses (EsmaeilzadehKenari et al., 2014).Extracts were used in concentrations of 0.5, 1, 1.5, 2, 2.5 and 3 mg/ml.
Phenolic compounds and flavonoids were measured by Folincio-calteu and aluminum chloride, respectively. The antioxidant activity of the extracts was evaluated using DPPH and reducing power tests. Then we assessed the efficiency of extract of skin fig of Siyah variety at 1 mg/ml the oxidative stability using Peroxide, thiobarbituric acid, conjugate di en, acid value, Oxidativestabilityindexand colorindex in canola oil during thermal conditions (180 ℃, 24 hours) compared with Synthetic antioxidants of TBHQ.
Results and discussion: The fig extracts contained different antioxidative fractions which were able to inhibit lipid oxidation effectively, by different mechanisms of action. Antioxidant activity of Siyah variety extract was higher than that of Sabz variety extract; furthermore, skin extracts were found to render higher antioxidant activity than pulp extracts. The stabilization effect of Siyah fig skin extract on canola oil (using peroxide, thiobarbituric acid, conjugate di en, acid values, oxidative stability index and color index) was comparable with the synthetic antioxidant (TBHQ).Therefore, skin of Siyah fig can be used as a potent source of natural antioxidant in food system.
Research Article
Forough Gillani; Zeynab Raftani Amiri; Reza Esmailzadeh Kenari
Abstract
Introduction: Cornelian cherry (Cornus mas L.), which belongs to the family Cornaceae, grows in Iran, in areas such as Qazvin and Arasbaran. The fruit possesses anti-inflammatory and antioxidant properties and it is used as an herbal remedy in medicine. Separation of natural antioxidant compounds from ...
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Introduction: Cornelian cherry (Cornus mas L.), which belongs to the family Cornaceae, grows in Iran, in areas such as Qazvin and Arasbaran. The fruit possesses anti-inflammatory and antioxidant properties and it is used as an herbal remedy in medicine. Separation of natural antioxidant compounds from plant sources requires an appropriate method of extraction, which is effective factor to achieve the higher efficiency of these valuable compounds. In this study, the effect of extraction methods (immersion and ultrasound) and different solvents (ethanol 100%, ethanol – water (50:50 V/V) and water) on amount of phenolic compounds and antioxidant properties of cornelian cherry fruit extract were investigated.
Materials and Methods: Qazvin cornelian cherry was purchased from the local market of Amol city, Mazandaran province, Iran. All solvents and chemicals used in this study were of analytical reagent grade and were prepared from Merck (Darmstadt, Germany) and Sigma–Aldrich (St. Louis, MO). Cornelian cherry was washed, core separated, dried in front of the sun for 5 days and then powdered with kitchen miller. Powdered cornelian cherry fruit was extracted using immersion extraction techniques, ultrasound and different solvents (ethanol 100%, ethanol –water (50:50 V/V) and water). In the immersion method, powdered cornelian cherry fruit were mixed with each solvent in the ratio of 1:10, individually. Then, the mixtures were shaken overnight at room temperature. After 24 hrs, the extracts were filtered through Whatman No. 42 filter paper and the solvents were evaporated in an oven at 55°C. In the ultrasound technique, the mixture of powdered samples with any solvent (1:10) was sonicated in an ultrasonic bath for 45 min at 35°C. The extracts were then filtered and the solvents were evaporated using an oven at 55°C. Finally, the extracts obtained from extraction methods were kept in a freezer for furthere experiments. The total phenolic content of the extracts was determined with the Folin-ciocalteau method, briefly, 0.5 mL of cornelian cherry fruit extracts with concentration of 1mg/mL were mixed with 2.5 mL of Folin–Ciocalteu reagent (previously diluted 10-fold with distilled water) and 2 mL of 7.5% sodium carbonate solution, then the samples were kept for 30 min at room temperature in the dark and at the end the absorbance of the solutions was read at 760 nm. The ability of the extracts to scavenge 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH) was determined. 0.3 mL of each extract with a different concentration (500-3000μg/mL) was mixed with 2.7 mL of methanolic solution of DPPH (6 × 10 -5 mole/L), then the mixture was shaken vigorously and was placed in the dark for 60 min. Absorbance was recorded at 517 nm. The percentage of the DPPH radical scavenging was calculated according to the following equation:
% inhibition of DPPH radical= [(ADPPH – AS) / ADPPH] ×100
AS and ADPPH are the absorbance of the solution the absorbance of the DPPH solution, respectively. Reducing power of extracts on iron ion was measured. 1mL of each extract with a different concentration (500-3000μg/mL) was mixed with 2.5 ml of phosphate buffer (0.2 M, pH= 6.6) and 2.5 ml potassium ferricyanide [K3Fe(CN)6] (1%), then the mixture was incubated at 50° C for 30 min. After that, 2.5 ml of 10% trichloroacetic acid were added to the mixture, then, was centrifuged at 1000g for 10 min. Subsequently, 2.5 ml of the upper layer solution was mixed with 2.5 ml of distilled water and 0.5 ml of 0.1% FeCl3. Finally, the absorbance values of the solutions were read at 700 nm.
Results and discussion: The result of this study showed that the type of solvent and extraction method has been effective on amount of phenolic compounds of extracts, and also concentration dependent of phenolic compounds with antioxidant activity was observed in all extracts. The highest amount of phenolic compounds with 142.72 mg/g (based on Galic acid) was observed in sample extract obtained from solvent of water- ethanol (50:50 V/V) employing ultrasound method. Also, this extract with the lowest IC50 value with the amount of 0.955 mg/ml in the DPPH free radical scavenging method and the highest absorption with the amount of 0.601 in the reducing power of Iron III test, the highest antioxidant performance is shown. A negative correlation was observed between the total phenolic content and the IC50 value in the methods of measuring the antioxidant activity (DPPH and reducing power), which revealed the higher total phenolic content will give the lower IC50, that means the higher antioxidant activity. The results of present research showed that cornelian cherry fruit is a natural source of phenolic compounds and have considerable antioxidant activity.
Research Article
Sajad Ghaderi; Mostafa Mazaheri Tehrani; Seyed Mohammad Ali Razavi
Abstract
Introduction: In the food industry, it is preferred to alter the formulations rather than modifying the legislations, so as to reduce the risk of facing consumer health. For instance, animal fats and oils could be replaced with vegetable oils to manufacture products with low cholesterol and saturated ...
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Introduction: In the food industry, it is preferred to alter the formulations rather than modifying the legislations, so as to reduce the risk of facing consumer health. For instance, animal fats and oils could be replaced with vegetable oils to manufacture products with low cholesterol and saturated fatty acids. Application of vegetable-based products like vegetable-based milks as the sources which provide vegetable proteins and lipids in ice cream not only incorporates the nutritional values and health-promoting effects of vegetable compounds into ice cream, but also leads to the production of a novel product with specific properties such as lactose-free products, which could be attractive and useful for consumers. Soymilk is avegetable-based milk with a suitable lipid and protein content. The main objective of this study was to investigate the aging time on physicochemical, rheological and textural changes of vegetable-based ice cream of soy and sesame, compared with the typical ice cream.
Materials and methods: Optimization of the vegetable-based ice cream was carried out by the textural parameters related to each other using RSM and the D-optimal design. The best soymilk: sesame milk ratio was found to be 55:45. Subsequently, all parameters including overrun, melting resistance, rheological properties and the textural variables during the aging times of 0, 2, 4, 6, 8 and 24 hours were examined for the evaluation of aging. The textural variables were measured in this method that after the 50-g samples of vegetable-based and typical ice creams were kept at ambient temperature for 5 min. A texture analyzer (Brookfield CT3-10kg,US) was employed to analyze their texture. To that end, a probe of 6 mm in diameter was selected to penetrate 15 mm into the sample at a rate of 2 mm/s. Rheological analysis was measured in this method that after 24 h of aging, the apparent viscosity of the ice cream mix samples was determined using a rotational viscometer (Bohlin Model Visco 88, Bohlin instruments, UK) equipped with a thermal circulator (Julabo, Model F12-MC, Julabo Labortechnik, Germany) with the shear rat of 51.8 1/s at 5±0.5°C.
Results and discussion: Investigation of the rheological and textural behavior of the samples showed that aging was significantly (p
Research Article
Hadi Bagheri; Mahdi Kashani-Nejad; Mehran Alami; Aman Mohammad Ziaiifar
Abstract
Introduction: Roasting is one of the processing steps involved in the nut industry to improve the flavor, color, texture and overall acceptability of the product. Ppeanut is a fruit or pod of the order Leguminosae and contains 47–50% oil, 25–30% protein and is an essential source of minerals and ...
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Introduction: Roasting is one of the processing steps involved in the nut industry to improve the flavor, color, texture and overall acceptability of the product. Ppeanut is a fruit or pod of the order Leguminosae and contains 47–50% oil, 25–30% protein and is an essential source of minerals and vitamins; thus it makes a substantial contribution to human nutrition. Peanuts are readily acceptable as a cheap protein source and popular snack item that can be eaten alone or combined with other foods. Recently, peanuts have gained much attention as functional food and roasted peanuts is one of the most popular snack foods, in which roasting is a key step in the process and directly impacts the quality (crispness, taste, and flavor) and shelf-life of the final product. Understanding of the roasting process is of interest because roasting is a critical processing step not only for peanuts, but many other food products such as coffee, cocoa, grains and other tree nuts. Roasting is a process to develop color, flavor and textural characteristics of product through chemical reactions, therefore proper roasting is critical to flavor and texture development as well as nutritional content of the final product.
Materials and methods: In this study, dried Goli peanuts were supplied from a local market in Minodasht, Iran in 2015 and stored at 4°C until processing. The average moisture content of peanut kernels was measured as 5.1 % (d.b.). Kernels were sorted manually to get the uniform sizes for roasting. 100 g peanut kernels were soaked in 500 ml of 25% salt solution for 30 min. After soaking, the salt solution was drained using a strainer and the excess water was removed by a cloth filter. After soaking, the moisture content of soaked peanut kernels increased to 8.27 % (d.b.). For roasting, three temperatures (140, 160 and 180°C) and three times (10, 20 and 30 min) and constant air velocity (1 m/s) were applied. Roasting was performed in a hot air roaster equipped with a controller to adjust the roasting temperature. After roasting, the whole kernels were allowed to cool at room temperature (23 ± 2°C). Roasting process was performed in 3 replications. Instrumental texture measurements (Uniaxial compression test) were carried out at room temperature using a TA-XT Plus Texture Analyzer using cylinder probe (diameter 25 mm) on peanut halves. The textural parameters of peanut halves were expressed as fracture force (initial peak or first fracture force (N)), hardness (highest peak compression force (N)), initial tangent modulus or apparent modulus of elasticity that shows sample rigidity in the linear part of the force-deformation curve (N/m) and compressive energy or area under the curve for the compression that is the work (N×m) required to attain deformation, indicative of internal strength of bonds within product. Sensory attributes including colour, texture, flavor, odour, total acceptance and final acceptance were assessed according to a five-grade hedonic scale (5 points – the best, 1 point – the worst). A completely randomized factorial design was used to evaluate the results and analysis of variance (ANOVA) was carried out to compare the mean values. All significant differences were reported at P ≤ 0.05 levels. Minitab statistical software (Minitab Release 16, Minitab Inc., USA) was used for all statistical analyses in the present research. However, MSTATC (Version 2.10, Michigan State University) was used to determine significant differences.
Results & discussion: Roasting is one of the most important steps in peanuts processing that leads to the development of the desired aroma, taste, texture and color of the final product. The results showed that increasing the roasting temperature and time decreased the fracture force (75.19–45.92 N), instrumental hardness (81.74–48.90 N), apparent modulus of elasticity (7.508-5.446 N/s), compressive energy (469.0–199.1 N.s) and improved the sensory characteristics of peanut kernels. During roasting process, moisture content of peanut kernels decreased and they became more crumble and fragile which causes to break easier and moisture reduction helps to create a desirable crisp texture. The results of the consumer test showed that the roasted peanut kernels have good acceptability for color (4.50), texture (4.15), flavor (3.89), odor (4.05), total acceptance and final acceptance (3.97) on roasting temperature and time (160°C and 30 min). The results obtained for VIP coefficients (standard coefficients) in PLS regression for fracture force, instrumental hardness; apparent modulus of elasticity and compressive energy variables indicated that apparent modulus of elasticity could be able to predict the individual sensory attribute of peanut kernels except color. PLS results showed that apparent modulus of elasticity could successfully predict quality sensory characteristics of peanut kernels. Thus, instrumental apparent modulus of elasticity could be replaced with sensory analysis for evaluation the quality of peanut kernels.
Research Article
Elham Ansarifar; Fakhri Shahidi; Mohebbat Mohebbi; Arash Koocheki; Navid Ramazanian
Abstract
Introduction: Microencapsulation has become an important technique in the food industry. One of the methods of producing microcapsules is to use layer-by-layer adsorption, in which oppositely charged polyelectrolytes are adsorbed consecutively onto a colloidal template. Creating multilayer films based ...
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Introduction: Microencapsulation has become an important technique in the food industry. One of the methods of producing microcapsules is to use layer-by-layer adsorption, in which oppositely charged polyelectrolytes are adsorbed consecutively onto a colloidal template. Creating multilayer films based on electrostatic interactions between oppositely charged components was introduced in 1991 by Decher et al. Layer-by-layer (LbL) polyelectrolyte deposition has become a popular technique for preparing polyelectrolyte capsules because of its ability to create highly tailored capsule shells through a simple, inexpensive and easily controllable adsorption process. It has been applied to produce capsules of various sizes, ranging from the nanometer to micrometer scale, with well-defined barrier properties. In this technique, assembly is driven by the electrostatic attraction of oppositely charged materials to form polyelectrolyte shells. The structure of the polyion layered capsule shell is determined mainly by the electrostatic interactions between the polyions used. The mechanical strength and permeability of the capsules can be controlled by varying the number of layers or by changing the characteristics of the encapsulating materials. The purpose of this study was to produce microcapsules using supramolecular assemblies consisting of common food ingredients such as soy protein isolate (SPI) and high methoxyl (HM) pectin. Moreover, some features of the developed microcapsulation were studied.
Materials and methods: SPI fibrils were prepared based on the method developed by Akkermans et al., (2008) and its morphology was studied using transmission electron microscopy (TEM) and atomic force microscopy (AFM). 0.5% (w/w) SPI fibril and pectin solutions were prepared by mixing at pH 3.5 were left stirring overnight. The LbL process for the production of microcapsules with protein fibril-reinforced nanocomposite shells has been described in Humblet-Hua et al., 2012. It starts with the production of A 2% w/w emulsion of (0.05 gr diacetyl in 1.95gr sun flower oil) in fibril SPI solution is produced using a homogenizer with a rotor-stator dispersion tool using a setting of 13500 rpm for 90 S. Because the proteins are below their isoelectic point, the emulsion droplets have a positive charge. To avoid interactions between the nonadsorbed SPI and the biopolymer of the next layer, the droplets are separated from the serum by means of centrifugation. After the isolation, the droplets are dispersed into a solution of HMP. The HMP is negatively charged at the chosen pH of 3.5. The bilayered droplets can be isolated again and dispersed in a fibril solution to deposit a third layer of a positively charged mixture of SPI fibrils. Subsequently, additional layers of HMP and SPI fibrils can be deposited by repeating the same procedures. Some features of the microcapsulation, including size, zeta potential, and morphology and release kinetics were studied.
Results & discussion: TEM and AFM micrographs showed that SPI fibrils obtained had a contour length of a few hundred nanometers, thickness of between 1 and 10 nm and its structure is highly branched. One of the most common problems reported in previous studies using the LbL technique to produce multilayer particles, is the tendency for flocculation. In the present system, this problem was not observed. The size distribution of isolated emulsion droplets (templates) did not change significantly from 1-layer droplets to 5-layer droplets. In other words, the emulsion droplets were stable against flocculation after applying more layers of polyelectrolytes. The Sauter mean diameters D (3, 2) of these droplets fluctuated between 5 and 7 µm and slightly increased as the number of layers increased; noting that the emulsion droplets were poly-dispersed. Another possible problem that may occur using the LbL technique is the complex formation between non-adsorbed protein and the pectin molecules. These complexes with a typical diameter smaller than 1 mm were not detected here. Result showed that the zeta potential distribution of emulsion droplets reverses from about plus (+) 30 mV (odd number of layers with SPI fibrils as outer layers) to about negative (-) 20 mV (even number of layers with HMP as outer layers) confirming the layer-by-layer adsorption based on electrostatic attraction. Comparing SEM of microcapsules with various numbers of layers, an improvement in shell strength can be seen. Indentation is observed on 1-layer microcapsules showing that there are defects on the shell. They could be formed during the drying process or they are shell defects due to incomplete coverage of materials, meaning more layers are needed to fully cover the microcapsule shell. These defects are seen less on 5-layer microcapsules. These observations indicate that the more layers the more consistent the shells and the more resistant. It is against the physical drying process. Results showed that the time of the maximum in release shifts to higher values as the number of layers of the capsules increased. We clearly see that increasing the number of layers in the shell of the capsules leads to a delay of the release of diacetyl and maximum release time as a function of the number of layers is increasing steadily which show the release can be delayed even more by adding additional layers. These results prove that the release properties of the multilayer capsules can be tuned by controlling the number of layers in the shell of the capsules. The modeling results of four different kinetic models are indicated that the Rigter–Peppas was an appropriate model for diacetyl release prediction from multilayer microcapsulation. It could be attributed that the release mechanism is mostly governed by the Swelling–Fickian mechanism.
Conclusion: In this study, the microcapsules were produced using the LbL technique and food-grade SPI fibrils and HMP. The microcapsules had a poly-disperse size distribution. No flocculation of microcapsules during applying of additional layers was observed. It was found that increasing the number of layers, decreases the release rate of diacetyl. The diacetyl release data were kinetically evaluated by zero-order, first-order, Higuchi, and Rigter–Peppas models and the results showed that the release phenomena is mostly governed by the Fickian mechanism. Since the materials are food-grade, the applications of these microcapsules can include food products or pharmaceutical purposes.
Research Article
Minoo Rastegar; Seyed Esmaeil Razavi; Pouneh Ebrahimi
Abstract
Introduction: White button mushroom (Agaricus bisporus) has a high moisture content (~90%) which makes it more vulnerable to the germs and chemical reactions. The contents of fungus coating are beneficial for shelf-life extension of mushroom. Coated mushrooms loss less moisture and have firmness, better ...
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Introduction: White button mushroom (Agaricus bisporus) has a high moisture content (~90%) which makes it more vulnerable to the germs and chemical reactions. The contents of fungus coating are beneficial for shelf-life extension of mushroom. Coated mushrooms loss less moisture and have firmness, better appearance and color features than uncoated mushrooms (Zahedi et al., 1390). Application of food coatings is widely used in order to extend the shelf-life of foods including mushrooms. These methods include improved packaging methods, coated treatment with a solution of anti-microbial, plant extracts and anti-browning agents. The essential oil of thyme plant (Zataria multiflora) contains derivatives of phenol such as carvacrol and thymol (Aligiannis et. al, 2001). The interaction of essential components with each other plays an important role in determining antimicrobial effect. Therefore, the synergistic antimicrobial effects of thymol and carvacrol are enhanced (Didry et. al, 1994). It is worth noting that carvacrol through changes in permeability of H+/K+ ion channel in the cell membrane leads to the suppression of cell dysfunction and ultimately death (Ultee et al, 1999).
Materials and methods: Cap of button mushroom was coated by carboxymethyl cellulose, glycerol and thyme extract. In order to identify the thyme components, GC Mass model VARIAV CP3800 and VF5MS column was used. Also to measure the amount of thymol in thyme extract, HPLC method was used. The cap of button mushroom was sampled in three days (first day, seventh and fourteenth) and cultured in the food culture of PDA and NA.
Results and discussion: The results showed that the bacteria Psudomonas sp. and the mold Aspergillus sp. in various stages of maintenance of the control samples are observed in the warheads. The coating with thyme extract reduced the population of bacteria and mold. The results also showed that the medium level of microbial density was reduced with increasing concentrations of thyme extract. Therefore, the bacteria and mold did not grow in the extract concentration of 5.187 mgL-1. Thymol in a concentration of 70 and 105 ppm inhibited the growth of bacteria and mold, respectively. According to the results, 5.187 ppm thyme extract and 105 ppm thymol are suitable for coating and prevent the growth of bacteria and mold. The population of bacteria and mold in the treated and untreated samples of mushroom cap were identical. It was much more in the control sample with increasing storage time and was maximum at the end of the fourteenth day. The population of bacteria and mold in the coated samples and thyme extracts was lower than control samples. The direct relationship was observed with increasing storage time in the population growth of bacteria and mold. Lyzhyans et al. (2001) showed that the amount of phenolic oil is higher, the more antibacterial activity. The extract of thyme also contain phenolic compounds of thymol and carvacrol which have the most important role in creating antioxidant properties.
Research Article
Sara Movahhed; Elham Kakaei; Hossein Ahmadi Chenarbon
Abstract
Introduction: The most important treatment for celiac disease is a gluten-free diet throughout the lifetime of the patient. Corn flour is one of the alternatives for wheat flour in baking of bread and bakery products that are of high nutritional value and because of lack of gluten are suitable for people ...
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Introduction: The most important treatment for celiac disease is a gluten-free diet throughout the lifetime of the patient. Corn flour is one of the alternatives for wheat flour in baking of bread and bakery products that are of high nutritional value and because of lack of gluten are suitable for people with celiac disease. Moreover, potato flour is one of the best wheat flour alternatives in bread-making and is consistent with that; and now, not only in production of bread but also in production of other bakery products. Hydrocolloids are a branch of additives which are widely used in food industry. One of the most widely used gum in food industry and bakery is hydroxy propyl methyl cellulose gum, which is a derivative of cellulose. Considering the above mentioned facts; the aim of this study was to prepate baguette bread with a mixture of equal parts of corn and potato flour with hydroxy propyl methyl cellulose gum. In this regard, the effect of different levels of gum on qualitative properties of produced baguette bread was investigated.
Materials and methods: Treatments included an equal mix of corn flour and potato flour with 0.25, 0.5, 0.75, 1% hydroxy propyl methyl cellulose gum were prepared. Different chemical tests such as moisture content determination, ash, proteins, fiber and pH measurement were performed on samples of corn and potato flour and after baking on baguettes bread. Yield of dough and bread was calculated in order to determine the strength of dough, porosity and hollow of bread. To evaluate the organoleptic characteristics of baguette bread samples, the analysis of properties of bread with the five senses were using. Staling test based on sense and instrument method at intervals 24, 48, 72 hours after baking was performed on all samples of gluten-free baguettes. Simon Henry method was used for determining the volume of the sample bread. In order to analyze the results of test, a completely randomized design with three replications was used and the means by Duncan's multiple range test, in probability level a=1% by SPSS software in 16 versions compared.
Results and discussion: According to results, addition of hydroxy propyl methyl cellulose gum causes yield of dough to increase significantly comparing to the control sample. Generally, gums are hydrophilic compoundsand usually they are interacting with water to reduce the spreadability and stability of the presence of water in the system. Also, adding HPMC gum, decreases yield percent of baguette gluten free bread comparing to contrl samples. Reason of diminishing returns of bread samples containing gum is structural nature of HPMC gum that is capable of properly maintaining carbon dioxide. But there was no significant difference in ash and protein that it was for structure of used gum. By adding HPMC gum, water content of samples in compared to C treatment increased due to the high water holding capacity of used gum. Also adding HPMC gum will increase the amount of fiber in samples containing gum compared to instance treatment. Moreover, HPMC gum increases the volume and improve the color appearance of baguette bread samples containing gum in compare to instance treatment (C) but there was no significant difference in uniformity characteristics of back of gluten-free baguettes samples. Its reason is because of gum hydrophilic property which by increasing the viscosity can keep gas in dough and bread. Color improvement of baguette bread samples containing gum is increasing browning reaction because of adding gum. According to the results, HPMC gum at level of 0.75 and 1% of weight had positive impact on internal characteristics of baguette. Increasing porosity of baguette bread containing gum and improving their hole and seeds shape is for gum ability to maintenance of carbon dioxide and increase bread volume, also this gum prevent dry and hardening of bread texture due to water absorption. Aroma of bread is depend on maylard and caramelization reaction, so scent in bread with suitable browning reactions, increased and as gums are effective in increasing browning reactions of maylard so has desired effect on bread aroma. Also more used gum, will reduce water consumption, improve freshness and softening of bread tissue due to the interaction of hydrocolloids with water and reducing water retention during cooking and was thus a positive effect on the texture of bread. According to results, adding HPMC gum in level of 0.75 and 1% causes the staling time to reduce in three 24, 48 and 72 hours after cooking baguette bread containing gum (by sensory and device) compare to the treatment C. Furthermore, adding HPMC gum increases the volume of baguette bread samples containing gum compare to the instance treatment (C). Volume increasing is because of hydrophilic properties of gum that improve dough spread and maintenance of CO2 gas.
Conclusion: According to the results, treatments containing 1% HPMC gum had the highest water content and fiber. The amount of ash and protein in the samples containing hydroxy propyl methyl cellulose to the instance samples had a slight increase, but this difference was not significant. On the other hand treatment containing 1% gum had the highest dough yields and the control sample had the lowest. Also, yields decreased with increasing gum than the control bread. Other treatments containing 1% gum had the highest privilege organoleptic than other treatments. Also according to the staling test results in sensory and device method, at intervals 24, 48 and 72 hours after baking, treatment with 1% gum has the lowest time of staling. Also treatment containing 1% gum had the most volume and the control the lowest one.
Research Article
Vahid Alizade; Hassan Barzegar; Behzad Nasehi; Vahid Samavati
Abstract
Introduction: The environmental effect of synthetic plastic wastes is of increasing global concern. There is an urgent need to develop and apply renewable biopolymer materials. Development of edible and biodegradable films can help solving the waste disposal problem by partially replacing synthetic plastics ...
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Introduction: The environmental effect of synthetic plastic wastes is of increasing global concern. There is an urgent need to develop and apply renewable biopolymer materials. Development of edible and biodegradable films can help solving the waste disposal problem by partially replacing synthetic plastics (Martins et al., 2012). Chitosan; a linear polysaccharide composed of (1, 4)-linked 2-amino-deoxy-b-d-glucan, is a deacetylated (to varying degrees) product of chitin, which is the second most abundant polymer found in nature after cellulose. It has been proved to be biodegradable, biofunctional, biocompatible, nontoxic and have strong antifungal and antimicrobial properties (Aider, 2010). Thus, this work was undertaken to investigate the physical, optical, barrier, mechanical, microstructural, and antimicrobial properties of chitosan films incorporated with PEO, to examine its potential applications as a packaging material.
Materials & method: The films were prepared according to the solvent casting technique reported by (Abdollahi et al., 2012) with some modifications. Tensile strenght (TS) and elongation at break (E) of the films were measured with texture analyzer according to Barzegar et al. (2014) method. Equilibrated film strips (at 53% RH for 48 h) were fixed between the grips with an initial separation of 50 mm and the cross-head speed was set at 50 mm/min. TS was calculated by dividing the maximum force by the initial area of the film and E% was calculated through dividing the extension at the moment of specimen rupture by the initial gauge length and multiplying by 100. The WVP of the films was determined at according to the Shojaee-Aliabadi et al. (2013). The test cups containing anhydrous calcium chloride (0% RH) were sealed by the test films, then were placed inside a desiccator containing sodium-chloride-saturated solution (75% RH). Weight gain of the cups along time were recorded periodically and plotted as a function of time. Antimicrobial properties of the films were assessed using the disc-diffusion method according to Dashipour et al. (2015). Four gram-positive or gram-negative bacteria, including B. cereus, S. aureus, E. coli and S. typhimurium were used for testing.
Results and discussions: The influence of PEO incorporation on thickness, TS, EAB, WVP and water solubility of films can be seen in Table 1. The incorporation of PEO into the film-forming dispersion led to an increase in the thickness of the films, which varied between 0.131 mm and 0.185 mm. It could be due to the entrapment of PEO micro droplets by the polymer matrix (Dashipour et al. 2015). By increasing PEO concentration from 0.5 to 2 % in the film solutions, WS decreased markedly from 22.46 to 16.15 (P < 0.05). This behavior can be explained by the cross-linking effects of PEO components to esters and/or amide groups. Cross-linking in the chitosan film leads to a polymer with lower water solubility, which is useful when product integrity and water resistance are intended (Hosseini et al., 2009).
Table 1. Physical and mechanical properties of chitosan films.
PEO (% v/v) Thickness (mm)
Solubility in water (%) WVP
(g s-1 m-1 Pa-1 × 10-10) TS
(MPa) EAB
(%)
0.0 0.131 ± 0.01d 22.46 ± 0.73a 1.04 ± 0.05c 21.22 ± 1.97a 49.05 ± 1.63c
0.5 0.153± 0.01c 21.19 ± 1.22a 1.12 ± 0.06c 20.09 ± 1.40a 50.36 ± 2.98c
1 0.167 ± 0.01b 18.47 ± 0.53b 1.35 ± 0.09b 17.04 ± 1.26b 55.25 ± 2.95b
2 0.185 ± 0.01a 16.15 ± 0.54c 1.73 ± 0.09a 13.23 ± 1.35c 59.37 ± 2.49a
The incorporation of PEO into chitosan-based films leads to an increase in WVP values from 1.04 to 1.73 g s-1 m-1 Pa-1 × 10-10. A similar trend has been found by Bonilla et al., (2011) in chitosan-based films incorporated with thyme essential oil. The structural discontinuities induced in the polymer network by the addition of PEO could be the reason for the lowest resistance to breakage of the emulsified films. These discontinuities greatly reduced the film cohesion and mechanical resistance (Bonilla et al., 2012). Conversely, the EAB value of the films increased significantly (P < 0.05) from 49.05% to 59.37%, because the essential oil acted as a plasticizer even at small concentrations and enhanced the flexibility of the polymer chains.
The effects of PEO on the antimicrobial properties of the chitosan films are shown in Table 2. The films containing 1% PEO showed a certain inhibitory effect against B. cereus and S. aureus but no inhibition against S. typhimurium and E. coli. As the concentration of PEO increased, the zone of inhibition also increased significantly (P < 0.05). The films containing 2% PEO were effective against all studied bacteria and a greater inhibitory power was observed on S. aureus with the zone area of 49.67 mm2. The inhibitory effect of PEO is due to the two monoterpene hydrocarbons, α-pinene, and β-pinene (Barrero et al., 2005).
Table2. Antimicrobial activity of chitosan films.
PEO (% v/v) Inhibition zone (mm2)
S. aureus B. cereus E. coli S. typhimurium
0.0 0.00c 0.00c 0.00b 0.00b
0.5 0.00c 0.00c 0.00b 0.00b
1 22.58 ± 1.76b 15.63 ± 0.63b 0.00b 0.00b
2 49.67 ± 3.02a 41.96 ± 1.40a 21.12 ± 1.87a 12.49 ± 1.57a
Conclusion: The results obtained in this study showed that the chitosan films incorporated with PEO has a good potential to being empolyed as an active film to preserve food products. Addition of PEO decreased water solubility and tensile strength, while increased the thickness, WVP and percent elongation of the films. Overall, this study demonstrates that PEO-containing films present a good potential for their application in the food industry.
Research Article
Vahid Mosayebi; Farideh Tabatabaei Yazdi; Zahra Emam-Djomeh
Abstract
Introduction: Pectin is a complex heteropolysaccharide presented naturally in the middle lamella and primary cell walls of plant tissues. Pectin is mostly composed of a linear backbone of α-(1, 4) linked D-galacturonic acid residues which are partially esterified with methyl alcohol or acetic acid at ...
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Introduction: Pectin is a complex heteropolysaccharide presented naturally in the middle lamella and primary cell walls of plant tissues. Pectin is mostly composed of a linear backbone of α-(1, 4) linked D-galacturonic acid residues which are partially esterified with methyl alcohol or acetic acid at the carboxylic acid. Pectin is widely used as a gelling agent in food systems such as jams and jellies, fruit juices, confectionaries, bakery fillings and as a stabilizer in acidified milk drinks. Black mulberry (Morus nigra.L), originating from Iran, is a juicy fruit with dark red color and slightly acidic flavor. Black mulberry has gained an important position in fruit markets and food industry due to its distinctive flavor and phytonutrients in recent years. Black mulberries can be consumed as fresh or processed into several products such as juice, marmalades, liquors, natural dyes or even be used as frozen fruit in ice cream production. However, due to short harvesting season and susceptibility to spoilage, black mulberries are mostly processed into juice besides its fresh consumption. Press cake residue or pomace is the main by-product which is generated in large amounts from the commercial juice extraction processes from berry fruits which contain several bioactive compounds and valuable ingredients including antioxidants, phenolics, pigments, pectin and so on. These berry pomaces are considered suitable for pectin recovery although their pectin content is somewhat lower in comparison to rich known sources of pectin. Recently, ultrasound assisted extraction technique, as a novel method of extraction, has gained remarkable attention due to its some advantageous effects including shorter extraction time, reduced solvent and energy consumption and higher yield and better quality of extracted compounds as compared to conventional acid extraction method. Therefore, the present work was aimed to evaluate and optimize the ultrasound assisted extraction parameters (time of extraction, ultrasound power and liquid/solid ratio) to maximize the extraction yield, degree of esterification and galacuronic acid content of pectin from black mulberry pomace using three level three factor face centered central composite design.
Materials and methods: Fresh and fully ripe black mulberry fruits were purchased from a local fruit market in Karaj (Iran) and subsequently pressed to separate pomace from juice. The obtained pomace was then vaccuum dried (until 7.8±1% moisture content), ground to obtain a homogenous powder, sieved, filled into polyethylene containers, and stored at refrigerator. Pectin extraction from this powdered pomace was carried out using an ultrasonic bath at operating frequency of 35 kHz under different parameters including extraction time (20-60 min), ultrasonic intensity (40-100%) and liquid-solid ratio (15:1 to 30:1 mL/g). The initial pH value of the solution was adjusted to 2.0 by adding 1.0 N HCl solution. At the end of extraction, extracts were quickly cooled, centrifuged, filtered using Buchner funnel, concentrated by 5 fold, coagulated with 96% ethanol (ER=1.5) and left for 8 hours in room temperature. The precipitated pectin was separated by Buchner funnel, rinsed twice with 96% ethanol, dried under vacuum (45°C) and finally powdered. The degree of esterification of pectin was determined by titrimetric method according to Bochek et al. (2001). The galacturonic acid content was quantified by the colorimetric method with m-hydroxydiphenyl reagent using a spectrophotometer at 520 nm. The intrinsic viscosity [ƞ] of pectin was determined using a capillary tube viscometer and accordingly the viscosity average molecular weight [Mv] was calculated from the Anger-Berth equation. Finally, the frequency sweep test was performed using a controlled stress rheometer to determine the values of storage modulus (G′) and loss modulus (G″). The experimental design and statistical analysis were performed using response surface methodology (RSM).
Results and discussion: According to the obtained results, the extraction yield, degree of esterification and galacturonic acid content of pectin varied in the range of 4.73-7.68%, 42.42-58.33 and 18.70-31.45%, respectively. The extraction yield of pectin was linearly affected by the extraction conditions and its value significantly increased with increasing all the studied independent variables (p
Research Article
Seyed Amir Oleyaei; Babak Ghanbarzadeh; Ali Akbar Moayedi; Parisa Poursani; Fateme Mousavi Baygi; Mohammad Reza Bakhsh Amin
Abstract
Introduction: Biopolymers are a class of polymer, which are disintegrated by an enzymatic or bio-path and the products disseminated to the surroundings do not induce negative effects. Nowadays, non-degradable polymers are quid pro quo with biodegradable ones particularly in agricultural applications, ...
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Introduction: Biopolymers are a class of polymer, which are disintegrated by an enzymatic or bio-path and the products disseminated to the surroundings do not induce negative effects. Nowadays, non-degradable polymers are quid pro quo with biodegradable ones particularly in agricultural applications, environmental and food industry use. Starch is an example of natural biopolymers, biocompatible, which is completely biodegradable in environment. It has been considered as one of the best candidates for oil based polymer substitution due to its low cost, availability and processbility. The main disadvantages of starch based polymers are their high hydrophilic nature therefore; they have poor mechanical properties and are permeable to water vapor. However, these aspects could be considerably reclaimed by shuffling it with nanodimension materials such as itanium dioxide (TiO2) and Montmorillonite (MMT). The main reason for this improvement in comparison with conventional composites is the large surface area of these nanomaterials which results in high interactions between the nanofillers and starch. The functional behaviors of nanocomposite films have been depended to the compatibility and degree of nanoparticles dispersion in the biopolymer matrix. TiO2 is a 3D nanosphere has been perused widely because it is inexpensive, chemical inert and, has a high refractive index with visible and UV shielding potential. MMT as a 1D, platelet is the most commonly used layered silicates. The investigation of biodegradable films containing two different nanofillers simultaneously has been rarely done. TiO2 and MMT as two different inorganic nanofillers have different physical and chemical structures, so simultaneously use of TiO2 and MMT clearly had a new effect on the nanoparticle distribution and functional properties of starch films. The aim of this study was investigate the synergistic or antagonistic effect of combination of TiO2 nanoparticles and MMT platelets on the functional properties such as surface hydrophobicity, water vapor permeability (WVP), moisture uptake (MU), Water Solubility (WS) and mechanical properties of plasticized starch-MMT-TiO2 nanocomposites.
Materials and methods: 100 ml of potato starch solution with a concentration of 4% (w/v) was prepared by dispersion of starch in distilled water. It was gelatinized at 80 ºC for 15 min. Different amount of TiO2 (0.5, 1 and 2% w/w starch) and MMT (3 and 5% w/w starch) were dissolved in distilled water and added to the gelatinized starch after treatment with ultrasound for 30 min. Glycerol with concentration of 50% (w/w starch) was added to the starch-nanofillers filmogenic solution. Bionanocomposite plasticized starch (PS) films were produced by casting and were dried in an oven at 45 °C for 15 hours. The X-Ray diffraction (XRD) measurements were performed for MMT and TiO2 powder and starch-MMT and –TiO2 nanocomposite films. The methodology of WVP measurements was based on the ASTM E96-05 (ASTM, 2005). Mechanical properties of the films were determined according to ASTM standard method D882-10 (ASTM, 2010). With some modifications, the methods described by Tunc et al., (2007) and Rhim et al., (2006) were used to determine MU and WS, respectively. Water contact angle (WCA) measurements were performed by the sessile drop procedure. The statistical analyses on a completely randomized design and were carried out using analysis of variance (ANOVA). Duncan’s multiple range test (p < 0.05) was used to detect differences among the mean values of the functional properties.
Results and discussion: XRD demonstrated the change of MMT layers dispersion pattern from exfoliation in binary PS-5%MMT films to exfoliation-intercalation in ternary PS-5MMT-TiO2 films. These results showed that TiO2 agglomerates are formed in the starch matrix with MMT level more than 3% wt. This could be due to the interaction between starch and MMT tends to be more favorable than TiO2. Good dispersion of TiO2, high miscibility of with clay, and continuous phase can be obtained when the content of MMT discs is low. Due to the strong interfacial interaction between the starch and MMT, the tensile strength (TS) increased considerably from4.86 to 5.24 MPa, while the elongation at break (EB) decreased significantly from 78.23 to 71.93%, As the MMT concentration varied from 3 to 5%. The TS of nanocomposite films were further improved after the incorporation of TiO2. Suitable dispersal of TiO2, and creation of new interactions in the PS-MMT network, causes to increase the tensile strength of nanocomposites. The TS and EB values of PS-3MMT-1TiO2 nanocomposite film was higher than that of the other films. This is indicative of a synergistic effect between TiO2 and MMT which increases the tensile strength and does not decrease the EB. In the PS-5% MMT films, both mechanical characteristics were reduced. WVP shows more evidences of synergistic effect of combination of 1D MMT and 3D TiO2 on starch films. WVP reduction by MMT has been attributed to tortuous pathway which created by clay layers in the starch matrix. MMT platelets are water vapor impermeable, thus exfoliation of MMT reduce the voids in starch matrix. The PS-3MMT-2TiO2 nanocomposite showed the lowest WVP as compared to other PS films. WVP was reduced significantly from 5.84 × 10-7 g/m.h.Pa in the PS-3%MMT binary film to 3.04 × 10-7 g/m.h.Pa in the PS-3%MMT-2%TiO2 ternary film. TiO2 have low water solubility and hydrophobicity compared with starch and MMT. Thus, significant decrement of WVP in the prophase of TiO2 connoted that TiO2 was obstructing the nano- and micro-pathways in the PS films network. With addition of MMT and TiO2 content the water solubility and moisture absorption were reduced significantly. Results of water contact angle test confirmed the results of moisture absorption, solubility in water and water vapor permeability and showed that the addition of TiO2 increased the surface hydrophobicity of starch-MMT films as with addition of 2% titanium dioxide in PS-3% MMT and PS-5% MMT films, the contact angle after 60 seconds increased 4 and 15 degree respectively. As a result, 1% wt TiO2 nanoparticles (FDA maximum allowable) can be regarded as the optimum concentration and the developed starch based nanocomposite films can enable undertaking applications as appropriate candidates in food packaging systems.
Research Article
Mohammad Farhadi Chitgar; Mehran Alami; Elnaz Milani; Yahya Maghsoudlou
Abstract
Introduction: Barberry (Berberis vulgaris) from the distant past has been used as one of the main medicinal plants in Iran and many other countries. Currently, it has been known for pharmaceutical active compounds such as berberine, which has wide application in pharmaceutical industry. Barberry fruits ...
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Introduction: Barberry (Berberis vulgaris) from the distant past has been used as one of the main medicinal plants in Iran and many other countries. Currently, it has been known for pharmaceutical active compounds such as berberine, which has wide application in pharmaceutical industry. Barberry fruits are used in preparing sauces, jellies, candies, marmalades and especially fruit juices. Also, the fruit contains health promoting compounds such as polyphenols and anthocyanins. Anthocyanins are bioactive compounds present in many fruits, vegetables and their products. They are responsible for the wide array of colors present in flowers, petals, leaves, fruits and vegetables and are a sub-group within the flavanoids characterized by a C6-C3-C6 skeleton. A substantial property of anthocyanin is their antioxidant activity, which plays an important role in prevention of neuronal and cardiovascular illnesses, cancer and diabetes, among others. Therefore, preservation of these compounds during processing of barberry juice is very important. Conventional thermal pasteurization is the common preservation technique used for fruit juice processing. Although this method inactivates microorganisms and enzymes causing spoilage and extends the shelf life of juices, but also it causes degradation of anthocyanins and loss of the nutritional quality of these products. Moreover, the increasing demand for natural and fresh fruit juice resulted in the development of various non-thermal technologies, such as radiation processing, osmotic dehydration, pulse electric field, sonication and high pressure. Power ultrasound has shown important advances in food processing and has a potential to meet the FDA requirement of a 5 log reduction in pertinent microorganisms found in fruit juice. Physical (cavitation, micromechanical shocks and mechanical effects) and chemical (formation of free radicals) mechanisms are responsible for the biocidal effect of sonication. Other advantages of this technology include low cost, reduced processing time and environmentally friendly technique. However, ultrasound by itself is not very effective for microbial inactivation and the use of other technologies during sonication such as temperature (thermo-sonication) and pressure (mano-sonication) has shown efficient results in inactivation of microorganisms. Thermosonication has been reported as an alternative to thermal pasteurization for processing of fruit juices such as strawberry juice, blackberry juice and orange juice. According to the negative effect of thermal processing on color and anthocyanins of barberry juice this study aimed to evaluate the effect of thermo-sonication as an emerging technology in two intensities 18.32 and 27.62 W/cm2 at 45°C for 5 and 10 minutes on the quality of barberry juice.
Material and methods: Barberry (B. vulgaris) ripe fresh fruits were collected from gardens of Qaen. Fruits were crushed into pieces in an electric blender. The mixture was then filtered through a nylon filter and kept in dark condition at 4°C before subjecting to thermosonication. Barberry juice was sonicated at 200W capacity batch sonication system (Sonopuls HD 3200 BANDELIN, Germany) and a constant frequency of 20 kHz with a 13mm probe. Barberry juice samples of 60 mL were placed in a 100 mL double wall cylindrical vessel pyrex glass through which water at 4±1°C and a flow rate of 0.5 L/min was circulated to attain a constant temperature in the juice sample during sonication. The samples were sonicated at 70 and 100% amplitudes levels for 10 and 15 min at 45°C with pulse durations of 15s on and 5s off (US70-5, US70-10, US100-5 and US100-10). After the sonication treatment, juice samples were kept in sterilized bottles and were stored at 4°C until further analysis. Total anthocyanin content of barberry juice was determined by the pH differential method and the color of juice samples was determined using a Chroma Meter (Color Flux, USA). The color values were expressed as L* (lightness), a* (redness/greenness) and b* (yellowness/blueness). The total phenolic content and antioxidant activity was determined by modified Folin–Ciocalteu method and DPPH radical scavenging activity. The counting of microorganisms was made using standard techniques (AOAC 1984), and included total plate counts and yeasts and molds. All experiments were carried out in at least three replicates and the 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 Dunkan’s test at a significance level of P< 0.05. Data evaluation was performed using the SPSS software version16.
Results and discussion: The result showed that the processing in all treatments completely inactivated the microbial population. The reduction of total plate counts and yeast and mold counts after processing was equal to 3.68±0.1 and 3.34±0.48, respectively. Thermo-sonication, especially in low intensity (32/18 w/cm2) had little effect on total anthocyanin compounds of barberry juice. The losses in total anthocyanin content of juice samples were 0.03%, 1.14%, 1.56% and 10.79% in TS-70-5, TS-70-10, TS-100-5 and TS-100-10, respectively. Hydroxyl radicals produced by cavitation can be involved in the degradation of anthocyanins by opening of rings and formation of chalcone. Thermosonication had significant effect on color parameters of barberry juice. All the color values (L*, a*, b* and C*) of barberry juice treated with thermosonication treatment were decreased as compared to control. The color loss of barberry juice samples decreased with increasing the amplitude and time of thermosonication. Extreme physical conditions which occur within the bubbles during cavitational collapse at micro-scale reaction may be responsible for the degradation of color in fruit juices. A significant increase (p˂0.05) in both total phenolic content and antioxidant activity of samples treated at TS-70-5 and TS-70-10 was observed. However, higher amplitude significantly decreased the total phenolic content and antioxidant activity of barberry juice. It has been shown the enhancement of total phenolic content in juices after sonication might be attributed to the facilitation the release of bound phenolic present in the suspended particles. Since there is a correlation between total phenolic content and antioxidant activity, the extraction of bound polyphenols due to cavitation can be presumed the increase in antioxidant activity. The result of this study showed that thermo-sonication could be used as an alternative to thermal treatment.
Short Article
Farnaz Hajieghrary; Aziz Homayouni; Zeinab Rahimzadeh Sani
Abstract
Introduction: Non-alcoholic beverages are consumed in many countries. There are many people who avoid alcohol because of their health concerns, and in Muslim countries alcoholic beverages are religiously banned. Malt beverages are classified based on the alcohol content as alcoholic (more than 1.2%), ...
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Introduction: Non-alcoholic beverages are consumed in many countries. There are many people who avoid alcohol because of their health concerns, and in Muslim countries alcoholic beverages are religiously banned. Malt beverages are classified based on the alcohol content as alcoholic (more than 1.2%), low alcoholic (0.5-1.2%) and with no alcohol (less than 0.5%). Malt beverages are generally produced by dissolving wort granulates in water, filtration, and adding pure hop aroma. The malt beverage has some health benefits such as protection against coronary heart diseases, cancers and ulcers. Malt beverages are usually produced using barley malt and in some cases from other sources such as wheat, oats, rye and sorghum. In Iran, malt beverage is prepared without fermentation and is generally produced using barley malt. Malt beverages usually sweetened with sucrose. Sucrose is often preferably replaced with other sweeteners since it is the main cause of obesity, as well as diabetes and dental cavities. There are several known intense sweeteners which provide little or no energy intake. Since intense sweeteners are amongst the most controversial food additives due to suspicions of adverse health effects only few of them are allowed to be used in food industries. On the other hand, there is a wide range of natural sweeteners, which besides providing sweetness to the product, they contain various bioactive compounds, such as vitamins, minerals or polyphenols that are known to exhibit positive health effects and contribute to the concept of functional foods. Though not widely used, several natural alternatives to sugar are available.Date fruit from date palm (Phoenix dactylifera) is one of the important cultivations in Iran. The importance of the date in human nutrition comes from its rich composition of carbohydrates (70–80%), salts and minerals, dietary fiber, vitamins, fatty acids and amino acids. Date juice concentrates, are condensed products made out of date extract. They differ in appearance, taste and consistency depending on the type of the raw juice and the degree of concentration. Three main products can be distinguished as date spread, date syrup and date liquid sugar. Date syrup is the most generally derived date product. It is a high energy food rich in carbohydrate, a good source of minerals but it also contains a very complex mixture of other saccharides, amino and organic acids, carotenoids and polyphenols. Besides its nutritional compounds, it is rich in antioxidants. The components responsible for antioxidative effect are flavonoids, phenolic acid, ascorbic acid and carotenoids. Date syrup as an innovative and main by-product in date processing was used as a substitution of sucrose in non-alcoholic malt beverage. In this study, the effect of sucrose replacement with date syrup on physicochemical and organoleptic properties of malt beverage was studied within 1, 7, 14, 21, 28, 60, 90,120, 150 and 180 days during 6 months of storage.Materials and methods: The materials including barley malt and hops pellets, sucrose and date syrup were supplied from local market. Barley malt and hops pellets were obtained from Sard Sahra Company (Tabriz, Iran). Sucrose was purchased from Khoy sugar factory (Khoy, Iran) and date syrup from Shahd Bab Pars factory (Tabriz, Iran). For preparing malt beverages barley malts were milled using a roller mill, then steeped with hot water in a mash tank. Malt extract was filtered to produce thick, sweet liquid called wort. The wort was then boiled for an hour and date syrup and sugar were added together to the boiling wort at the ratios of 0:100, 25:75, 50:50, 75:25 and 100:0. Hops pellets were also added to the extract. The wort was then chilled using heat exchanger plate to avoid fermentation and filtered. The pH and brix of extracts were adjusted to 3.8 and 6 and they were transferred into 300 ml green Polyethylene Terephthalate (PET) bottles, then were pasteurized at 70°C for 30 minutes and stored in refrigerator at 4°C for further analysis.Malt beverages which were sweetened with ratios of 0:100, 25:75, 50:50, 75:25 and 100:0 of date syrup to sucrose, physicochemical and sensory properties were evaluated during six months of storage. The data reported are the means of triplicate observations. Analysis of the data was done by Duncan’s test. Results and discussion: According to results pH and Brix were not changed during 6 months. There was a significant difference (p
