Food Technology
Narges Akafian; Hajar Shekarchizadeh
Abstract
[1]Introduction: In the last decade, nanotechnology approaches have been used to improve the functional properties of packaging materials. The main focus is on creating new packaging materials that extend the shelf life of food, which in turn improves food safety performance. The use of nanostructures ...
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[1]Introduction: In the last decade, nanotechnology approaches have been used to improve the functional properties of packaging materials. The main focus is on creating new packaging materials that extend the shelf life of food, which in turn improves food safety performance. The use of nanostructures can also improve the mechanical properties of the packaging. Many traditional packages are made from non-degradable materials that double the environmental pollution in addition to using fossil fuels to produce them. Resin is a natural or synthetic compound that is very viscous and hardens under certain conditions. It is usually soluble in alcohol r. Natural resin is obtained from plants. This material is very sticky but hardens over time. Due to environmental concerns and the possibility of depletion of oil reserves, the construction of composites based on natural resins from renewable sources has become important. In previous studies, Javashir gum has been used to prepare an edible film with high water vapor permeability and solubility, as well as poor physical properties. Since Javashir gum is a natural, native and inexpensive gum, so in this research, the improvement of the properties of the film prepared from Javoshir gum is considered using.a combination of nanoparticles and resin obtained from Javoshir gum Materials and methods: Javshir nanoparticles were sprayed on Javashir film (4% gum and 2.5% glycerol) at two different times of 30 and 60 minutes. In order to increase the hydrophobicity of the films, Javashir resin was covered as a layer on the surface of the films. Then different physical and mechanical properties of the film such as thickness, water solubility, and water vapor permeability, elongation at break, tensile strength, contact angle and morphology were determined. Results and discussion: The results of thickness measurement showed that adding large amounts of nanoparticles as well as coating the film surface with resin increased the film thickness. Solubility results showed that all films have a very high solubility due to the hydrophilic nature of Javashir. However, the addition of nanoparticles and coating with resin reduced the water solubility of the film. The water vapor permeability of nano-60 film was increased compared to the control film which can be attributed to the increase in film surface due to the addition of nanoparticles. However, coating the surface with resin significantly reduced the water vapor permeability of the film. The tissue test showed that nano-30 resin film had 6.54 ± 2.72% elongation to tear point and 302.9 ± 47.1% tensile strength. Nano 30 resin film had the highest tensile strength and the lowest tensile percentage. The results of the contact angle showed that the lowest contact angle, which indicates high hydrophilicity, was related to the control sample, and the contact angle increased by adding nanoparticles and coating with resin, resulting in increased hydrophobicity. SEM images also showed that the addition of nanoparticles and resin coating reduced the film roughness.Finally, it can be said that the addition of Javoshir nanoparticles could well increase the tensile strength of Javashir film, and coating the surface of the film with resin was very effective in reducing the hydrophilicity and water vapor permeability of Javashir film.
Food Engineering
Ghazale Amini; Fakhreddin Salehi; Majid Rasouli
Abstract
Introduction: The dispersion of water soluble hydrocolloids (gums) in the aqueous system provides great technical importance, because they can improve the gel or enhance the thickening properties of food products. Wild sage seeds have significant amounts of gum with good functional properties that after ...
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Introduction: The dispersion of water soluble hydrocolloids (gums) in the aqueous system provides great technical importance, because they can improve the gel or enhance the thickening properties of food products. Wild sage seeds have significant amounts of gum with good functional properties that after extracting from seeds (mucilage) and drying, can be used in formulation of various products (Salehi, 2017, 2020a). The physicochemical properties and rheological behaviour of seed gums depend on the method and condition of drying. Also, the color of dried product is an important quality factor, which is affected by drying conditions (Amid and Mirhosseini, 2012; Nep and Conway, 2011). For example, effect of different drying methods (oven drying (40-80°C), freeze drying and vacuum oven drying) on rheological behaviour, color and physicochemical characteristics of BSM were investigated by Salehi and Kashaninejad (2017). Drying is one of the simply available and the most common processing approach that has been used traditionally for preservation of food product. One of the best way to reduce the drying time is to use IR radiation heating. IR methods could be used as substitution to the current drying methods for producing high-quality dried hydrocolloids. IR heating has many advantages include high heat transfer rate, uniform heating, low processing time, high efficiency (80-90%), lower energy consumption, lower energy costs, and improves final product quality (Aktaş et al., 2017; Salehi, 2020c). The performance of artificial neural networks (ANN) as an analytical alternative to conventional modeling techniques was reported by some researchers. They reported that these approaches are able to estimate the drying kinetics of various fruits and vegetableswith high precision. It has been shown that nonlinear approaches based on ANN are far better in generalization and estimation in comparison to empirical models (Bahramparvar et al., 2014; Salehi, 2020b; Zhang et al., 2014). It is difficult to predict the combined effects of treatment time, IR power, lamp distance and mucilage thickness on drying kinetics (moisture content and moisture ratio) of fruits and vegetablesusing conventional models. Therefore, the target of this study was to investigate the effect of IR dryer parameters on moisture content and moisture ratio of wild sage seed mucilage during IR drying and studying the performance of ANN method for estimation of these parameters. Materials and methods: Wild sage seeds was physically cleaned and all foreign stuffs were removed. Then, the pure wild sage seeds were immersed in water for 20 min at a seed/water ratio of 1:20 at 25°C and pH = 7. In the next step, the gum was separated from the inflated seeds by passing the seeds through an extractor (M-J-376-N, Nikko Electric Industry Company, Iran) with a rotating disc which scratches the mucilage layer on the seed surface. The initial moisture content (MC) of WSSM was 99.4% (wet basis). Finally, the obtained WSSM was immediately placed into IR dryer. In this study, for wild sage seed mucilage drying, infrared radiation (IR) method was used. The effect of infrared lamp power (150, 250 and 375 W), distance of samples from lamp (4, 8 and 12 cm) and mucilage thickness (0.5, 1 and 1.5 cm) on drying time of wild sage seed mucilage were investigated. Results and Discussion: The results of wild sage seed mucilage drying using infrared method presented that by increasing the lamp power and decreasing the sample distance from the heat source, drying time was decreased. With lamp distance increasing from 4 to 12 cm, the average drying time of wild sage seed mucilage increased from 72.04 minutes to 160.81 minutes. When it comes to sample thickness, we found that by increasing the thickness of mucilage (0.5 to 1.5 cm) drying time of sample increased from 55.59 to 173.67 min. The process was modeled by an artificial neural network with 4 inputs (radiation time, lamp power, lamp distance and thickness) and 2 output (moisture content (MC) and moisture ratio (MR)). The results presented that mucilage drying time significantly increased by decreasing power of lamp (375 up to 150 W) and increasing the heat source distance from sample (4 to12 cm). The results of artificial neural network modeling showed that the network with 8 neurons in a hidden layer and with using the sigmoid activation function could predict the moisture content and moisture ratio of wild sage seed mucilage during infrared drying in various times (r=0.974 for MC and r=0.997 for MR).
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.
Seyed Mohammad Ali Razavi; Mostafa Mazaheri Tehrani; Bahareh Emadzadeh
Abstract
Introduction: Recently, consumers have directed their interest towards low fat products as they associated them with a reduced risk of well-known health problems such as obesity and coronary heart diseases. Fat is a multifunctional ingredient in ice cream system. Thus, in attempts to provide desirable ...
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Introduction: Recently, consumers have directed their interest towards low fat products as they associated them with a reduced risk of well-known health problems such as obesity and coronary heart diseases. Fat is a multifunctional ingredient in ice cream system. Thus, in attempts to provide desirable flavor and physical characteristics of full fat ice cream, manufactures looking for fat replacers (Drake et al. 1999). Hydrocolloids have functionalities such as thickening, gelling, fat replacing, which allow them to use in different industries (Roller and Jones, 1996; Williams and Phillips, 2000). Guar gum is used as a stabilizer in ice cream and provides smoothness in texture, retards ice crystal growth, and increases freeze-thaw stability (Wielinga, 2000). The rheological properties and potential of basil seed gum (Rayhan) as a novel stabilizer for structure formation and reducer for ice recrystallization in regular ice cream have been recently investigated (Hosseini-Parvar, 1388; Bahram-Parvar, 1391). In this research, the physicalproperties of light (5% fat) and low fat (2.5% fat) ice creams as a result of replacement of milk fat by guar gum (as a commercial hydrocolloid), basil seed gum (as a novel hydrocolloid) and their blend (50:50) at different concentrations were investigated and compared to those of control sample (10% fat). Materials and methods:The ice cream formulations were prepared based on the following composition: 2.5% (L), or 5% (R) or 10% (B) milk fat, 11% MSNF, 15% sugar, 0.1% vanilla, 0.15% emulsifierand 0.35%, 0.45%, 0.50% or 0.55% selected gums (guar gum, basil seed gum or blend (50:50) of them). Liquid materials including milk and cream were mixed together and warmed up to 50˚C. After that, the pre-weighed and mixed dry ingredients were dispersed into them, under agitation. The mixes were pasteurized at 80˚C for 25 s, homogenized at 23000 rpm for 2 min, cooled rapidly to 5˚C and then aged at constant temperature overnight (12 h) at 5˚C. The freezing was carried out in a batch soft ice cream maker. Apparent viscosity of ice cream mixes were evaluated using a rotational viscometer at 5˚C and 51.8 s-1. Before melting rate determination, samples were tempered at –18°C overnight, Ice cream samples (30 g) were put on a wire screen mesh and allowed to melt at ambient temperature. Melting rates were measured from the slop of linear portion of drained mass vs.time graphs. The pH values for mix samples were measured with a pH meter. After the mix was frozen in a batch freezer, Draw temperature of ice creams was obtained using a digital thermometer.Mix and ice cream samples (3 g) were diluted 1: 500 in two steps with deionized water and absorbance was measured by a spectrophotometer at 540 nm. Turbidity (%) was calculated as (absorbance in mix - absorbance in ice cream)/absorbance in mix 100%. A known volume of ice cream and mix were weight and overrun was determined as (weight of the mix - weight of the ice cream)/ weight of the mix 100%. Results & discussion: Reducing fat in any food formulation will cause a decrease in viscosity (Cody et al., 2007). Fat reduction decreased apparent viscosity (P0.05), ranging from 6.31 to 6.34. Draw temperature as a measure of freezing point of ice cream is dependent on the type and concentration of the soluble constituents and varies with the composition. Addition of some ingredients such as sweeteners, lactose and salts decrease the freezing point. Fat is immiscible with the aqueous phase and carbohydrate polymers are very large molecules, depression of the freezing point is caused indirectly by using of these materials, as a result of decreasing the water content (Marshall and Arbuckle, 1996). In this study, a reduction of fat content of full fat ice cream resulted in higher draw temperature. However, there was not a specific trend in the temperature values of samples with same fat content and different fat replacer levels. There was no significant difference between turbidity of samples with same kind of gum. Similar results were obtained by Schmidt et al. (1993), which related to sufficient amount of milk fat (2.1 and 4.8 %), milk proteins and emulsifiers in ice cream formulations. Conclution: Decreasing the fat content generally caused an increase in the value of overrun. But, very high viscosity of mix may prevent vigorous agitation and air incorporation that seems the reason of why increasing fat replacer concentration resulted in overrun reduction
Habib Jahandideh; Masoud Taghizadeh; Mohammad Hossein Hadad Khodaparast; Arash Koocheki
Abstract
Introduction: Nowadays, one of the most important nutritional problems in different societies is the protein mal-nutrition. Since bread is the main food material being consumed in all over the world, bread enrichment using the grains rich in protein such as sesame seeds would be an appropriate alternative. ...
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Introduction: Nowadays, one of the most important nutritional problems in different societies is the protein mal-nutrition. Since bread is the main food material being consumed in all over the world, bread enrichment using the grains rich in protein such as sesame seeds would be an appropriate alternative. However, addition of sesame products such as Tahini meal would cause some technical difficulties such as dough stability, water absorption, dough extension time, etc. in bread manufacturing processes.In this study the effect of addition of xanthan gum to on physical and textural properties of Baguette bread containing tahini meal was investigated.Materials and methods: Wheat flour and tahini meal were supplied from Damghan and Ardakan cities, respectively. They were then refrigerated prior to baking process and different chemical tests were carried out according to standard methods. Protein was measured based on Kejeldahl method. Moisture content as well as ash content were determined using oven method.Raw fat was calculated according to AACC-No. 30-10 and raw fiber was measured using appropriate instrument (Scientific velp-FIWE6 F30530201). Starch determination was carried out using Small universal polarimeter (SUP-Germany). Xanthan gum was purchased from Provisco Ltd. (Switzerland) in food grade quality. Bread yeast (Saccharomyces cerevisiae) was also supplied in dried form. All other chemical enhancers were purchased from Merck Ltd. (Germany). Baguette dough was produced from mixture of wheat and Tahini meal flour based on protein content and the amount of protein in final dough was increased from 10.28% in flour free of tahini meal to 12, 14 and 16% in different treatments. The rest time for all flour samples was fixed at 15 min and the baking process was carried out for 15 min at 300°C. Baked breads were exposed to room temperature for two hours and then were packed using poly-ethylene (PE) film for further tests. Specific volume of bread samples was measured using rapeseed displacement method (AACC, No. 54-30, 2000). Samples porosity was determined using image processing techniques. Samples were cut to 2cm×2cmcubes and an appropriate scanner (Canoscan 8800F, Japan) with 300 pixel resolution was used to acquire the images for further process using Image J(1.6r, 2010). Apparent color for the baguette samples (in terms of CIE ‘L*’- lightness,“a*” - redness and greenness, and “b*”- yellowness and blueness) were also measured using image processing techniques (Image J, 1.6r, 2010).Texture profile analysis (TPA) test was carried out using a texture analyzer (QTS Texture Analyzer, CNS Farnell, Hertfordshire, UK) to study the effect of xanthan gum and tahini meal on parameters such as hardness, gumminess and cohesiveness in all baguette samples.Results and discussion: ANOVA test showed the significant effect of xanthan gum and tahini meal on the porosity of samples. The porosity of samples containing less than 0.5% xanthan gum at all tahini meal levels, was significantly less than control sample.Similar results were obtained in the case of specific volume meaning that the employed treatments have significant effect on bread’s specific volume. Increasing tahini meal from 9.45% to 14.53% caused significant decrease in specific volume. This could be due to the weakness of dough gluten matrix. These results are in agreement with other works reported by other researchers (Paraskevopoulouet al., 2010; Mohammad Idrisset al., 2012; and Guardaet al., 2004). The results obtained for apparent color of bread core also showed the effect of xanthan and tahini meal. The only exception was found in case of a* value when studying the effect of xanthan gum, meaning that xanthan gum has no significant effect of this parameter. In the case of apparent color in bread crust, the studied treatments (xanthan gum and tahini meal) showed significant effect on all color parameters. Different textural properties of baguette samples including hardness, gumminess and cohesiveness were also measured. Conclusion: The results indicated obvious effect of xanthan gum and tahini meal levels on these mentioned parameters. Increasing tahini meal and xanthan gum levels would increase hardness as well as gumminess. However, addition of xanthan gum and tahini meal cause significant decrease in cohesiveness. This could be due to dilution effect of these substances which decrease the concentration of protein matrix existed in flour’s gluten.