Research Article
Marzieh Mirzaaghaei; Amir Hossein Goli; Milad Fathi
Abstract
Introduction: Flavor, taste, odor and color of fresh apple juice is unstable during concentration process and storage. Pectic substances and phenolic compounds are responsible for these physicochemical changes. So, decreasing of these compounds is necessary to improve the appearance and marketability ...
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Introduction: Flavor, taste, odor and color of fresh apple juice is unstable during concentration process and storage. Pectic substances and phenolic compounds are responsible for these physicochemical changes. So, decreasing of these compounds is necessary to improve the appearance and marketability of apple juice. In fruit juice industry, clarification is one of the most important steps which removes pectin, polyphenols and other unfavorable components and prevents haze formation during storage. Enzymatic clarification (depectinization) can be applied for removal of pectic substances by using pectinase. This enzyme can hydrolyze pectin and produce pectin-protein complexes which would be settled easily. Also in depectinization step, some enzymes such as amylase and amyloglucosidase can be used to degrade starch. Fining agents such as gelatin, bentonite, activated carbon, silicasol or a combination of these compounds can be used in conventional clarification. Sepiolite is a natural fibrous phyllasillicate clay mineral with a formula Mg8Si12O30(OH)4(OH2)4. nH2O(n=6-8) which has specific physicochemical properties such as high porosity, surface area and adsorption capacity. This clay clay has been used in several important applications such as decolorization of sugar juice, removal of phosphorus from vegetable oil and enhancing decoloration of crude palm oil. In this research, efficiency of Sepiolite for apple juice clarification was evaluated. First, the response surface methodology (RSM) was used to optimize apple juice clarification conditions. Then, a comparison among Sepiolite and other commercial fining agents in respect to clarification efficiency was accomplished. Finally, three types of zero-, first- and second-order kinetic models were used for explanation of changes in turbidity, color, viscosity and total phenolic content (TPC) during clarification process of apple juice.
Materials and Methods: The pasteurized and unclarified apple juice, Bentonite, Gelatin (Bloom= 80-100), Amylase (Alphamyl MG) and Pectinase (Pectofruit XL) were gratefully obtained from Behnoosh Iran Co. (Shahrekord, Iran). Sepiolite (with specific surface area of 105 m2/g) was purchased from Farapooyan Isatis Yazd Co. (Yazd, Iran). The kieselgel and chemicals with analytical grade were purchased from Merck Co. (Germany). Sepiolite was activated with hydrochloric acid according to Balci’s method with slight modification. For evaluation of Sepiolite changes, some analysis like pH, acidity, density and the moisture content of Sepiolite clay were done before and after the activation by the method of Sabah and Çelik. Specific surface area was measured by using the BET method (Belsorp mini II, Japan). XRF method (PW148, Philips Co.) was used for determining of difference between Sepiolite elemental compositions before and after the activation. A pretreatment was conducted to improve the performance of fining agents according to Türkyilmaz et al.’s method with slight modification. The swelling capability of fining agents in water increases their clarification capacity. In the method of RSM, the independent factors at three levels were concentration of activated Sepiolite (0.05-0.1% w/v), temperature of clarification (50-60˚C) and process time (2-10 h). Juice turbidity was regarded as response. As the first step in clarification of apple juice, amylase and pectinase enzymes were applied (25 µl of each enzyme per 100 mL juice at 20˚C). The mixture was stirred and heated in an incubator at 55˚C for 1 h. Sepiolite was mixed with juice in certain concentrations, stirred and placed in definite temperature and time according to each run of RSM. Finally, the juice was centrifuged (12000 rpm for 5 min) to remove the clay from clarified juice. For kinetic studies, the above steps were done in the optimized conditions using 0.05% fining agents at 50˚C for 7 h. A portable turbidometer (MARTINI, Mi 415, Romania) and the capillary viscometer (Ubbelohde-Viscometer, Fisher, USA) were used for measuring the juice turbidity and viscosity at 20˚C and expressed as NTU (Nephelometeric Turbidity Unit) and centipoise (cp), respectively. Color was measured at 20˚C by using a color meter (ZE 6000, Nippon DENSHOKU). The parameters which used for color expression were L* and a* parameters based on CIE Lab system. The Folin-Ciocalteu reagent was used for measuring the total phenolic content of juice and expressed as mg gallic acid equivalent per 100 mL juice. To evaluate Sepiolite performance in juice clarification, following fining agents were applied at optimal conditions: sepiolite (S), commercial bentonite (B), and combination of these agents with gelatin (G) and kieselgel (K) (S+G, B+G, S+G+K, B+G+K). The used concentrations of bentonite, gelatin and kieselgel were 0.05%, 0.015% and 0.04% (w/v), respectively. Sampling was conducted at 1 h intervals to evaluate the changes in juice turbidity, viscosity, color and TPC during clarification process. The rates of changes were determined by three types of zero-, first- and second-order kinetic models.
Results and Discussion: Results showed that the activated Sepiolite had less amounts of weight loss, density and pH than the native sample. On the other hand, moisture content and acidity increased. Also, acid activated Sepiolite had higher amounts of SiO2 groups. The second-order polynomial (quadratic) model was suggested as the best for describing the optimum conditions of clarification with insignificant lack of fit and high R2 (0.9845). Based on the results, process time had a significant (p
Research Article
Hamid Bakhshabadi; Habibollah Mirzaee; Alireza Ghodsvali; Seyed Mahdi Jafari; Aman Mohammad Ziaiifar
Abstract
Introduction: Black Cumin seed (Nigella sativa L.) as one of the novel edible oil resources used commonly nowadays as seasoning in food product industries due to considerable medicinal properties and high nutritional impacts. Oil extraction by pressing method as an approach compared to other methods ...
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Introduction: Black Cumin seed (Nigella sativa L.) as one of the novel edible oil resources used commonly nowadays as seasoning in food product industries due to considerable medicinal properties and high nutritional impacts. Oil extraction by pressing method as an approach compared to other methods including solvent extraction is faster, safer and cheaper. In the oil extraction process, the preparation of the seeds is a substantial stage for obtaining oil with high quality and efficiency. Microwaves are electromagnetic waves that have a frequency ranged from 300 MHz to 300 GHz with corresponding wave lengths ranged from 1 mm to 1 m. On the other hand the artificial neural network as a powerful predictive tool in a wide scale of process parameters has been studied on an industrial scale in this research in order to achieve a simple, rapid, precise as well as effective model in the oil extraction of Nigella sativa L seed.
Materials and Methods: In the present study Black Cumin seeds after preparation including cleaning and passing resistance of the samples in front of air and moisture were stored in a plastic bag until the day of experiments. Then, they have been pre-treated with microwave within different processing times (90, 180 and 270 S) and powers (180, 540, and 900 W). Afterwards, seeds’ oil was extracted by screw rotational speed levels approach (11, 34 and 57 rpm). Different selected parameters including extraction efficiency, oil acidity value, color and oxidative stability were determined. To predict the alterations trend, the artificial neural network (ANN) design in MATLAB R2013a software was used.
Results and Discussion: According to MSE and R2 values obtained in this study, feed forward neural network with transfer function sigmoid hyperbolic tangent and Levenberg- Marquardt learning algorithm with topology of 3-10-5 (input layer with 3 neurons– a hidden layer with 10 neurons – output layer with 5 neurons) were selected as the optimal neural network with R2 more than 0.995 and MSE equal to 0.0005. Also, the results of the optimized and selected models were evaluated and these models with high correlation coefficients (over 0.949), were able to predict the changes' trend. According to the complexity and multiplicity of the effective factors in food industry processes and the results of this research, the neural network can be introduced as an acceptable model for modeling these processes. By determining the activation function in neural networks which was a function of sigmoid hyperbolic tangent in this study and also, with having the amounts of weight and bias, the connections created by the neuro-fuzzy model can be extracted. By defining this simple created mathematical equation, in computer software such as Excel, we can have a useful, simple and accurate program for predicting the desired parameters in the process of oil extraction by using microwave pre-treatment. Due to high accuracy of neural model we can trust the prediction of these models with high confidence, and this model can be used to optimize and control the process, which can lead to saving in energy and time, and on the other hand, can create a better final product.
Research Article
Seyed Mahdi Ojagh; Akbar Vejdan Taleshmikaeil; Mehdi Abdollahi
Abstract
Introduction: Natural polymers have gained increasing attention for the development of packaging to reduce ecologically-related problems caused by plastic packaging (environmental pollution). Among these natural polymers, proteins such as gelatin is considered a good candidate for food packaging. However, ...
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Introduction: Natural polymers have gained increasing attention for the development of packaging to reduce ecologically-related problems caused by plastic packaging (environmental pollution). Among these natural polymers, proteins such as gelatin is considered a good candidate for food packaging. However, several studies have shown that gelatin films are brittle, and their hydrophilic nature connotes high water vapor permeability and water solubility. Different solutions have been suggested to overcome these weaknesses, including adding crosslinking agents and chemical modification, adding nanoparticles and developing bio-film blends and bilayers with polysaccharides. Agar is a polysaccharide extracted from marine red algae, which is biocompatible, has good mechanical properties and possesses good film-forming properties. Preventing food spoilage from light and oxygen-induced oxidation is one of the greatest concerns in the food industry. Despite having good mechanical and relatively good water vapor permeability properties, protein- or polysaccharide-based films don't have sufficient barrier properties against oxygen and UV light that can't properly prevent the oxidation of food products. Among nanoparticles, metal oxides like TiO2 (such as antiradiation and antimicrobial activities) and Montmorillonite (such as improved mechanical and barrier properties against moisture, WVP and gases) have evidenced good potential to improve functional properties of bio-films. Thus, the present study aimed to develop a new biodegradable bilayer agar/gelatin film incorporating nanoclay and TiO2 for food packaging, with maximum water sensitivity and maximum UV light and oxygen barrier properties.
Materials and Methods: Agar/gelatin bilayer films were prepared by a two-step casting technique. First, the agar layer was produced by solubilization of 1.5 g of agar powder (agar-agar analytical grade were obtained from Merck Co., Germany) in 100 mL of distilled water. Then, glycerol (obtained from Merck Co., Germany) was added as plasticizer. The agar film-forming solution was casted onto petri-dish. In the next step, the gelatin (obtained from cold water fish skin was purchased from Sigma-Aldrich, St. Louis, MO, USA) solutions were prepared by dissolving 4 g of the fish gelatin in 100 mL of distilled water. Glycerol was also added as plasticizer. The TiO2 dispersions (in ratios of 0 and 2% of the gelatin) and MMT (Na+–montmorillonite (in ratios of 0, 3, 5 and 10% of the gelatin)) were added to the gelatin solution and stirred and sonnicated. Finally, produced solutions were then casted. The agar/gelatin films, with or without TiO2 and MMT, were characterized using SEM analysis. Film transparency, water vapor permeability, water solubility, swelling, surface color and mechanical properties of the bilayer films were also examined.
Results and Discussion: In this study, bilayer films based on agar and gelatin incorporated with TiO2-MMT nanoparticles have been successfully developed. Results demonstrated that some properties of the bilayer films were greatly influenced by TiO2 and MMT nanoparticle content. So that, the addition of TiO2 decreased water vapor permeability of the bilayers more than 15%, upon increasing TiO2 content to 2%. However, swelling ratio and moisture content increased with the increase in the nano-TiO2 content, probably due to the hydrophilic nature of the TiO2 nanoparticles. Also, whiteness index (WI) increased by adding 2% of TiO2 nanoparticles. As shown in the surface photograph of the bilayer films, TiO2 generated more opaque and whiter films, which might be related to the white color of TiO2 nanoparticles in solution form. Also, the addition of MMT (0, 3, 5, and 10%) to bilayer-2% TiO2 significantly decreased water vapor permeability and transmission of UV light of the bilayer films. However, tensile strength (TS) decreased with further increase of the nanoparticle concentration. Increasing the concentration of nanoparticles' MMT to 5%, the tensile TS of the agar/gelatin films increased from 12.86 to 20.54 MPa; it might also be related to the interactions between sulphydryl and carboxylic groups from certain amino acids in the gelatin structure with MMT and TiO2 nanoparticles. However, the TS decreased again with further increase of the filler content up to 10% MMT. Also, the addition of MMT from 3%-10% concentration significantly reduced the elongation at break value (EB) of the bilayer films from 41.77 to 28.90% for the bilayer films (p
Research Article
Sarvenaz Osia; Zeynab Raftani Amiri
Abstract
Introduction: The Phaseolus Vulgaris on a global scale of cultivation has been categorized in the first rank and considered as the seventh staple food in the world. Proteins are usually classified into 3 groups including flours with 50 to 65 percent protein, concentrate with 65 percent protein and isolates ...
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Introduction: The Phaseolus Vulgaris on a global scale of cultivation has been categorized in the first rank and considered as the seventh staple food in the world. Proteins are usually classified into 3 groups including flours with 50 to 65 percent protein, concentrate with 65 percent protein and isolates with over 90 percent protein. Protein concentrate is produced by defatted flour through removal of soluble sugars, soluble fiber and minor compounds by alcohol, water or diluted acid with pH around 4-4.8. Protein isolate is affected by further refining processes compared to protein concentrate. In addition to the importance of the nutritional properties, crop proteins have a key role as a functional agent in the formulation of food products. Solubility, water binding capacity, oil absorption capacity, emulsifying and foaming abilities are noticed as the main functional properties. One of the specific and unique varieties of beans is Phaseolus Vulgaris var (aroos bean). The aim of this study was to determine the chemical composition of flour and bean protein isolate. In addition, some of the functional properties such as emulsification properties, foaming and stability as well as the effect of pH and ionic strength on above-mentioned characteristics were investigated.
Materials and Methods: The seed of Phaseolus Vulgaris and refined soybean oil (0ila) were purchased from Sari local supermarket. Phaseolus Vulgaris protein isolate was extracted and obtained powder was kept in impervious polyethylene plastic bags against moisture and air and placed at -18 ° C until analysis. The efficiency was calculated based on the sediment. Also, chemical composition and purity of the isolates were determined. Some functional properties, including emulsifying properties and foaming capacity at pH 4, 7, 8 and 10 were tested; and impact of the ionic strength of NaCl in concentrations of 0, 0.5 and 1 molar were examined. The results of all treatments were expressed based on the average of triplicate. Means were subjected to analysis of variances (one way-ANOVA) using (SPSS Statistics version 16) software program. Differences among the mean values of the various treatments were determined by Duncan test and the significance was defined at p < 0.05. The graphs were drawn using Excel software.
Results and Discussion: Phaseolus Vulgaris had 9% protein isolate efficiency and purity of 89.06%. The amount of protein in Phaseolus Vulgaris flour was less than the amount of protein that has been reported for other crops. While in terms of purity, protein isolate was similar to legumes in other studies. Foaming ability and emulsifying properties of Phaseolus Vulgaris protein isolate at 7 = pH were 42% and 65%, respectively. The value of this parameter using exposure to alkaline region and keeping far from the isoelectric point at pH = 10 were risen to the highest amount of 70.23% and 77.33%, respectively. During 90 minutes, stability of emulsions and foams were gradually decreased. With increasing of NaCl concentrations, foaming capacity and emulsifying properties were significantly reduced. Considering the efficient functional of Phaseolus Vulgaris protein isolate, further investigation required in order to be used in the formulation of meat products, cakes, cookies, crackers, sauces and soups.
Research Article
Hossein-Ali Tash Shamsabadi; Seyedeh Hoda Yoosefian; Ayat Mohammad Razdari
Abstract
Introduction: Tomato is one of the most important vegetable crops in Iran and is grown commercially in every state in the country. Tomatoes are climacteric in nature and climacteric fruits submitted to gamma irradiation exhibit a delay of ripening. In the specific case of tomatoes, irradiation generally ...
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Introduction: Tomato is one of the most important vegetable crops in Iran and is grown commercially in every state in the country. Tomatoes are climacteric in nature and climacteric fruits submitted to gamma irradiation exhibit a delay of ripening. In the specific case of tomatoes, irradiation generally delays ripening when the treatment is applied at the pre-climacteric stage. Mechanical properties are very important quality property in tomato. Determination of the storage time effect on the evolution of this quality is a desirable objective for producers, distributors and marketing agencies, who need reliable firmness measuring instruments for commercial purpose. Previous studies carried out by different researchers show that impact techniques can be used to evaluate firmness of fruits successfully. Quick and nondestructive methods for measuring texture are critical for controlling postharvest quality of crops and fruits. Polymer films are ubiquitous in the food industry, fulfilling a range of functions including a significant role in reducing food waste. Also, it can be possible to extend shelf-life with some coatings, including polymer films.
Materials and Methods: In this study, tomatoes were irradiated in Atomic Energy Organization of Iran. For irradiation of samples, cobalt 60 (Gamma Cell 220) was used. The samples were irradiated with doses of 0 (control), 0.25, 0.5 and 1 kG, then transferred to the laboratory and kept in a refrigerator at 6 ± 1 ° C and 65 ± 4% relative humidity for 21 days. In order to pack, polyethylene film with medium density (thickness of 0.3 mm and depth and width, respectively, 6.5 and 19 cm) were obtained from the Iranian Polymer Research Institute. Experiments were performed on samples coated with polyethylene film in 7 days intervals. Acoustic tests were performed using Impact Test System. The system was covered with aluminum chamber and inside with wood and clouds. The system was internally equipped with the sample location on the floor, the impact mechanism and the receiver of the signal. In this audio excitation system, samples were taken with the help of a blow. By applying a blow to the sample surface, the audio signal was sent to the sample and then measured by a receiver placed at a distance of 7 mm from the sample. The experiments were performed every 7 days. During the experiment period, the physical and mechanical properties of the samples were measured. Data were analyzed using SPSS.20 software. Correlation between hit parameters and firmness of penetration test were checked out using regression in Excell .2013 software, and predicted a suitable model for determining the firmness of tomato.
Results and Discussion: The results showed that after 21 days of storage time, the amount of mass and density for irradiated sample with a 0.5 kGy dose in polyethylene film compared to control sample (uncoated) decreased to 22.53 and 12.34 %, respectively, and had more resonant frequency to 26.58%. Also, irradiated sample with a 0.5 kGy dose in polyethylene film compared to samples irradiated with doses of 1 kg and non-irradiated samples in polyethylene film had higher modulus of elasticity and firmness to 37.74, 26.48 % and 25% and 18.12%, respectively. The maximum penetration force in destructive testing had strong relationship with the parameters obtained from Acoustic test such as resonant frequency, Strength index and Modulus of elasticity with a correlation coefficient to 0.893, 0.913 and 0.886, respectively. Combination of polyethylene film with 0.5 kG irradiation on the changes in mass and volume, strength coefficient, resonance frequency, elasticity modulus and rigidity obtained from the impact test have the best results. Also, combination of polyethylene coating and 21-day storage time on mass and volume changes, strength coefficient, resonant frequency, elasticity modulus and stiffness from the impact test reduced the storage performance. According to the results of this study, by irradiation of a sample of tomatoes with a 0.5 kG and using a polyethylene film, it can be stored with a slight change in stiffness and texture for a period of 21 days, and possibly more, which causes increase the shelf-life in the warehouse, reduce storage costs in the warehouse by conventional methods and increase the possibility to export. As a summing up, irradiation in combination with Polyethylene films is a good way to preserve tomatoes tissue and Acoustic textures is a useful way to be replaced with Penetration test
Research Article
Elham Shokooh Saremi; Mohammad Bagher Habibi Najafi; Mohammad Hossein Hadad Khodaparast; Masoumeh Bahreini
Abstract
Introduction: It has been well demonstrated that vegetables provide, in addition to other basic nutrients, bioactive substances with beneficial effects on human health. In fact, the consumption of vegetables has been associated with lower incidence and lower mortality rates of cancer and cardiovascular ...
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Introduction: It has been well demonstrated that vegetables provide, in addition to other basic nutrients, bioactive substances with beneficial effects on human health. In fact, the consumption of vegetables has been associated with lower incidence and lower mortality rates of cancer and cardiovascular diseases in humans. Increasing demand for natural additives has shifted the attention from synthetic to natural antimicrobial agents. Leafy vegetables are found to be good source of antimicrobial agents. This study was aimed to examine the antimicrobial activity of leaf extracts of pimpinella affinis. Pimpinella affinis is a member of the family Apiaceae. This biennial herb grows up to 110 cm tall and is native in central and northern parts of Iran. In traditional medicine this herb is being used as carminative agent, appetizer, diuretic, antispasmodic drug, antimicrobial, sedative and lactation medication. It has also been distinguished as an antioxidant and antibacterial agent. There are several methods of obtaining extract from plants including maceration, super critical fluid extraction, subcritical water extraction, microwave and ultrasonic assisted method.
Materials and Methods: After collection from natural habitats of Pimpinella affinis in Mazandaran Province, it was then approved by the Department of Botany of Faculty of Agriculture of University of Sari. The plant was dried in a dry and dark place away from the sun and then was pulverized in the mill and sieved by a mesh of 80 (800 microns). Pimpinella affinis extract obtained by using maceration extraction (ME), ultrasonic assisted method (UAE) and supercritical fluid extraction (SFE). Ethanol: water in 50:50 ratio used as solvent for extraction. Total phenolic content of different extracts was measured by Folin-ciocalteu method. The phenolic compounds fractions were determined using Liquid chromatography–mass spectrometry system. After preparing the mother culture medium, the bacteria were cultured in MHB medium (37 ° C) for 24-18 hours. Stock solutions were prepared from each of the extracts. Serial dilutions of the extracts at concentrations of 0.01 to 10 mg / ml in 2.5% dimethyl sulfoxide were prepared and then sterilized with 0.22 μm pore size syringe filter. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration assay (MBC) were determined by micro dilution method for listeria monocytogenes (ATCC19112), staphylococcus aureus (ATCC25923), pseudomonas aeruginosa (ATCC9027) and Escherichia coli (ATCC25922). Antimicrobial growth was inhibited by measuring the absorbance and ELISA Reader was used to determine the growth rate of microorganisms, and the first house with the lowest absorption read as MIC (mg /ml) was determined. Statistical analysis of MIC, MBC and phenolic compounds of extracts results was done in a completely randomized design and using SPSS software version 20. The comparison of the means was done using Duncan’s test and one-way ANOVA method. In order to reduce the error, all experiments were performed in triplicate.
Results and Discussion: Total phenolic content of extracts ranged between 1502.25 to 1836.69 mg GA/100g E. The results showed that the ultrasonic assisted method have highest total phenolic content and the least phenolic content was observed in extract which obtained by supercritical fluid extraction. Chlorogenic Acid, Cafeic acid and Apigenin-6-C-glucoside were the predominant fractions in Pimpinella affinis which detected by Liquid chromatography–mass spectrometry system. The least and highest amount of MIC and MBC were belonged to ultrasonic assisted and supercritical fluid extracts, respectively. Staphylococcus aureus was most sensitive and Escherichia coli and Pseudomonas aeruginosa were most resistance bacteria. Pimpinella extract due to having phenolic compounds such as Gallic acid, Cafeic acid, Chlorogenic Acid, Kaempferol and Apigenin showed antimicrobial activity and can be used as natural antimicrobial agent.
Research Article
Hamed Saberian; Zohreh Hamidi-Esfahani; Hassan Ahmadi Gavghili; Mohsen Barzegar
Abstract
Introduction: Ohmic heating or direct resistance heating is one of the several electromagnetic based methods, occurs when alternating electrical current is passed through a conductive material, with the primary purpose of heating it due to the electrical resistance of the foods. There are many applications ...
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Introduction: Ohmic heating or direct resistance heating is one of the several electromagnetic based methods, occurs when alternating electrical current is passed through a conductive material, with the primary purpose of heating it due to the electrical resistance of the foods. There are many applications that can use ohmic treatment technology, such as blanching, evaporation, dehydration, fermentation, extraction, sterilization and pasteurization of foods (Saberian et al. 2015; Assiry et al. 2010). Pectins are complex heteropolysaccharides, consisting of α-1, 4-linked D-galacturonic acid units and interrupted by L-rhamnose residues with side chains of neutral sugars, mainly L-rhamnose, L-arabinose and D-galactose. In the industrial extraction process, pectin is usually extracted from waste plant material such as citrus peels, apple pomace, sugar beet pulp and sunflower head using hot water (60–100°C) acidified with a mineral acid (such as sulfuric, phosphoric, nitric, hydrochloric) or organic acid (especially citric acid) within the pH of 1.5–3 for 0.5–6 h. The aim of this study was to explore the effect of enzymatic extraction on the yield and quality properties (degree of esterification, Galacturonic acid, emulsifying properties and viscosity) of the pectin, and to compare this pectin with the pectins extracted by ohmic and conventional methods. Finally, the best extraction method was selected.
Materials and Methods: Extraction of pectin was done with the assistance of an ohmic heating system at working frequency of 50 Hz under different parameters including voltage gradient (7-15 V/cm), temperature (50-90°C), and time (5-30 min). Then, the effect of enzyme dose (0-20% v/w) of Celluclast and Rohament CL, solid/liquid ratio (S/L ratio) (1:10 to 1:50 g/ml) and extraction time (1-18 h) on the yield of the extracted pectin from orange waste was investigated.
After the time of extraction (enzymatically, ohmically or conventionally), the sample was cooled to room temperature and centrifuged (10000 rpm, 15 min), and the supernatant was precipitated with two volumes of 96% (v/v) ethanol at 4 °C for 1 h. The precipitated pectin mass was washed twice with 96% ethanol in order to remove impurities. The pectin was dried in a forced circulation oven at 55°C until a constant weight (14 h).
Galacturonic acid content was determined according to Scott (1979) with some modifications. The degree of esterification (DE) of pectin samples was determined by titrimetric method according to Santos et al. (2013).
Emulsifying activity and emulsion stability were measured according to the method described by Yapo et al. (2007).
The viscosity and the flow behavior of the selected pectin solutions (2%, w/v) extracted conventionally and ohmically at 90°C for 30 min (the optimum extraction condition) and the highest pectins extracted enzymatically, were measured at 25°C.
Pectin powder samples were mixed with KBr and pressed into KBr pellets before FTIR analysis. PerkinElmer FTIR spectra (PerkinElmer, Frontier model, USA) was applied at the transmission mode in the frequency range of 4000–400 cm-1 at a resolution of 1 cm-1.
Results were analyzed by analysis of variance (ANOVA) using SPSS 19 statistical software and the Duncan’s test with 95% confidence interval was used to compare the means of the tests. The results which were presented in this research, have been obtained from the average values of the minimal two replicate experiments.
Results and Discussion: first, the effect of enzyme dose, solid/liquid ratio (S/L ratio) and time of extraction on the yield of the extracted pectin from orange waste by using Celluclast and Rohament CL enzymes was studied. Then, the yield, of esterification, galacturonic acid, emulsifying properties and viscosity behavior of the pectins extracted in the optimum condition by enzymes were compared to the extracted pectins by ohmic and conventional methods. Results indicated that the highest yield of pectin was obtained by using Celluclast and Rohament CL enzymes at enzyme doses of 15 and 17.5%, S/L ratio of 1:20 and 1:40 (g/ml) and time of 3 h for both, which were 5.92 and 10.70 %, respectively. The highest yield of pectin by ohmic heating was obtained at the voltage gradient of 15 v/cm, the temperature of 90°C during 30 min (14.33%), which was higher than the amount obtained by conventional method (13.53%) may be due to the electroporation (disruptive pores which were made on the cell membrane by the electric field) (Cho et al., 1996). de Oliveira et al. (2015) reported that the moderate electric field (at 45°C, 50 and 100 V) extracted the pectin significantly (p < 0.05) more than the conventional extraction. The emulsifying activity of the extracted pectins by ohmic and conventional methods were 65.47 and 67.18%, respectively, although the pectins extracted by enzymatic method had not any emulsifying activity. It seems that during the pectin extraction, enzymes hydrolyzate the pectins. The viscosity of the pectins extracted by ohmic and conventional methods at the concentration of 2% was higher than those obtained from the enzymatic method. Therefore, pectin extracted by ohmic and conventional methods had the highest yield, emulsifying properties, and viscosity.
Research Article
Firooze Bazrafkan; Soheila Zarringhalami; Ali Ganjloo
Abstract
Introduction: In recent years special attention has been paid to the use of natural sources contain healthy bioactive compounds. Fruit and vegetable juices are a good source of many biologically active compounds, particularly vitamins, minerals and phenols. Phenolic compounds are secondary metabolites ...
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Introduction: In recent years special attention has been paid to the use of natural sources contain healthy bioactive compounds. Fruit and vegetable juices are a good source of many biologically active compounds, particularly vitamins, minerals and phenols. Phenolic compounds are secondary metabolites widely found in fruits, mostly represented by flavonoids and phenolic acids. Phenols are known for their antioxidant, anticancer and cardio-protective properties among bioactive compounds. The health benefits of these phytochemicals are directly linked to a regular intake and their bioavailability. Berries with dark blue or red colors have the highest bioactive compounds and antioxidant capacities among all common fruits and vegetables. Anthocyanins which are one of the largest and most important group of water-soluble pigments in most species in the plant kingdom are largely responsible for diverse pigmentation from orange to red, purple and blue fruits, such as: blackberry, red and black raspberries, blueberries, bilberries. White mahlab (Prunus mahaleb L.) fruits with a dark red color, which known also as English cherry, Rock cherry, St. Lucie cherry, of the Rosaceae family, subfamily Prunoidae, is a deciduous tree with 1–2 m high. Mahaleb cherry tree which grows abundantly in West Asia such as in Iran used just as basic link for cherry trees because of bitter taste of their fruits. In order to reduce the bitterness and improve the taste of mahaleb juice, a debittering process is considered as an effective solution to overcome the commercial application problem. Several debittering techniques have been used to reduce the content of bitter compounds, such as biodegradation by enzymes, addition of bitterness suppressing agents, ultrafiltration.
Material and Methods: All chemicals used were analytical grade and purchased from Merck (Darmstadt, Germany) and Sigma-Aldrich (St. Louis, MO. USA).
Selected microorganisms including Staphylococcus aureus (PTCC: 1112), Escherichia coli (PTCC: 1338), Aspergillus flavus (PTCC: 5004) and Penicillium chrysogenum (PTCC: 5037) were obtained from the Iranian Research Organization for Science and Technology (IROST), Iran.
The ripened fruits of mahaleb were collected from the orchard of Zanjan University, and transported to the laboratory. Harvest involved a random sampling from 5 trees. Stem and leaves were then discarded, and fruits stored at -18 ℃ until further use.
Frozen fruits were removed from the freezer, thawed and pitted. The fruit juice was obtained using a domestic juicer (Moulinex PC302, France). The juice was filtered through a stainless steel sieve (1 mm) to separate pomace from juice. The juice obtained was placed in dark glass bottles until further analysis.
Vitamin C content was determined using spectrophotometric method. Total phenolic content of the fruit juice was determined using Folin–Ciocalteu’s assay. Total flavonoid and anthocyanin contents of the fruit juice were determined according to the colorimetric assay at 510 and 526 nm, respectively. Antioxidant activity was determined using Diphenyl Picrylhydrazyl (DPPH) free radical scavenging and reducing power of H2O2 methods.
Antimicrobial activity of mahaleb juice against E. coli, Staphylococcus aureus, Aspergillus flavus and Penicillium chrysogenum was evaluated using agar well diffusion, and minimum inhibitory concentration and minimum bactericidal concentration was determined using broth microdilution and surface methods.
Results and Discussion: According to the result obtained, vitamin C, total phenolic, total flavonoid, total anthocyanin content was 39.26±0.01 mg/100 mL, 303.00±0.06 mg GAE/100 mL, 17.00±0.01 mg Rutin/mL and 871.63±0.93 mg Cyanidin/100 mL, respectively. Free radical scavenging activity and reducing power of H2O2 was 72.30% and 6.33%, respectively. Based on these results the white mahaleb juice had bioactive compounds such as other fruits with blue and purple color. According to other researchers there was a higher positive correlation between the amounts of carotenoids, total phenolics and anthocyanins and the antioxidant activity. Of course, it should be noted that several factors such as the plant growth region and the harvest period might have an impact on plant growth and metabolite concentration. Some studies also showed that dark red sour cherries contain higher total phenolic and total anthocyanin content compared to sour cherries with lighter red color. Therefore, mahaleb juice which was used in the current research with dark blue color and high total phenolic and anthocyanin content have high antioxidant activity.
The results also revealed that mahaleb juice had no inhibitory effect on Aspergillus flavus and Penicillium chrysogenum whereas the minimum inhibitory concentration on 102 CFU/ml of E. coli and Staphylococcus aureus was obtained at 0.9 and 0.8 % concertation of mahaleb juice. In addition, no minimum bactericidal concentration was observed. So, mahaleb juice likely has no or little antifungal activity compared to antibacterial effects. Previous studies also showed that antimicrobial activity of many extracts related to their phenolic compounds and anthocyanins. Blueberry methanol extract was shown strongly inhibit the pathogenic bacteria, such as E. coli O157:H7. The antimicrobial properties of blueberry morelikely is due to the compounds of monomeric phenolics, anthocyanins and proanthocyanidins. Therefore, mahaleb juice as a source of natural bioactive compounds such as vitamin C, phenols, carotenoids and anthocyanins is recommended as functional food in industry, especially, after debittering.
Research Article
Layla Zaghari; Alireza Bassiri; Somaye Rahimi; Ali Zonousi
Abstract
Intoduction: Probiotic products have been used worldwide in the last decades. They are significantly gaining popularity and their consumption is associated with increasing levels of health-consciousness. Probiotics can be defined as microbial cells that have a beneficial effect on the health and wellbeing ...
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Intoduction: Probiotic products have been used worldwide in the last decades. They are significantly gaining popularity and their consumption is associated with increasing levels of health-consciousness. Probiotics can be defined as microbial cells that have a beneficial effect on the health and wellbeing of the host. In this sense different probiotic products have appeared on the market with different formulations and applications. Bread is the major type of bakery products and a staple food in most part of the world. Despite attempts to develop functional breads containing viable microorganisms, this has not been fully developed yet because of the high temperature during baking process. Viability of probiotic bacteria in the product at the point of consumption is an important consideration for their efficacy, as they have to survive during the processing and shelf life of food. Lactobacillus reuteri which naturally occurs in the human intestine possess probiotic properties with good colonization potential. The main purpose of probiotic encapsulation is to protect cells against an unfavorable environment, include high processing temperatures and storage. The fluid bed encapsulation process consists of spraying a coating solution into a fluidized bed of solid particles. After several cycles of wetting–drying, a continuous film is formed. The main parameters affecting the process are flow-rate and pressure of the spraying liquid, composition and rheology of the coating solution, flow-rate and temperature of the fluidizing air. Double microencapsulation for probiotics by air-suspension fluidized-bed coating is a good alternative method to achieve greater resistance to high temperatures during bread baking. The aim of this study was to evaluate the survival of Lactobacillus reuteri that had been double layered using chitosan, calcium chloride and Arabic gum for microencapsulation and which had been exposed to bread baking conditions.
Materials and Methods: Pure freeze-dried Lactobacillus reuteri PT-1655 were obtained from Persian Type Culture Collection (Tehran, Iran) and were activated by inoculation in the MRS broth at 37°C for 36-48 h. The air-suspension process was performed in a Wurster coater system with a bottom spraying atomizer. In various pretests, the fluidization pressure, the atomization pressure and the spraying rate of the microencapsulation process were varied to examine their influence on process conditions, especially on the particle development. In this study, chitosan, calcium chloride and Arabic gum at concentrations (0.5, 1 and 1.5% w/v), 5% w/v and (1.5, 3 and 6% w/v) were used as second layer in double microencapsulation, respectively. Heat resistance of unencapsulated and double encapsulated microorganisms was determined by placing in an oven which was preheated to 80°C for 15 and 30 minutes. The prepared dough after adding of unencapsulated and double encapsulated bacteria was shaped into loaves of 50 g each, placed in aluminum pans, and baked in a preheated oven at 180°C for 20 min and 70 – 80% relative humidity and then cooled at room temperature. The temperature during baking process was checked by putting a thermocouple at the crumb center. The viability of bacteria at controlled conditions was measured after 1 and 24 h after baking process. Experimental data have been represented as the mean with standard deviation (SD) of different independent determinations. The significance of differences was evaluated by analysis of variance (ANOVA). Differences were considered statistically significant at p
Research Article
Battol Attar; Seyedeh Zahra Seyed Alangi; Sara Jorjani
Abstract
Introduction: Value-added products, referring to the fact that a raw commodity or commodities are transformed into a processed product through use of materials and technology, may have different appearances, textures, tastes and smells than their raw material. Fried product is one of the most popular ...
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Introduction: Value-added products, referring to the fact that a raw commodity or commodities are transformed into a processed product through use of materials and technology, may have different appearances, textures, tastes and smells than their raw material. Fried product is one of the most popular ready to eat foods all around the world. They have excellent sensory qualities due to their appealing flavor and texture. Products such as shrimp usually coated with breading before frying to induce additional sensory and quality attributes. The process of battering and breading provides special functions in food products, including improved appearance of the products, increased texture crispness, reduced oil uptake during the frying process and increased the shelf life of the coated products.
Hydrocolloids are used extensively in food technology as thickening and gelling agents, stabilizers, and emulsifiers. In addition, the hydrocolloid coatings are of great interests due to their desirable barrier properties to gas/moisture and good mechanical characteristics. Thus, a variety of foods have been coated with hydrocolloids to prevent moisture loss, preserve texture, and maintain color, consequently extending the product shelf-life. Specifically, the hydrocolloid coatings are often known to reduce the oil uptake of fried foods. The mechanisms of the oil uptake during frying are associated with heat transfer from the frying oil to the food and the migration of water and oil. Various hydrocolloids have been tested as an oil barrier coating material and the effectiveness of hydrophilic and thermo-gelling hydrocolloids in reducing oil uptake during frying has been well reported in previous studies.
Material and Methods: Fresh peeled shrimp (Litopenaeus vannamei) was purchased from Gomishan city, Golestan province, Iran. Xanthan gum was bought from Asia Research Petrochemisry (Iran). White flour, corn flour, breading powder, oil and salt were prepared from the local supermarket. All other chemicals used in this study had analytical grade and were gained from Fluka or Merck companies.
The freezed shrimps were thawed at room temperature before processing. Four different formulations were applied in pre-dusting and battering as following:
Control= without xanthan in pre-dust and batter,
A=2% xanthan in predust,
B=2% xanthan in batter,
C=1% xanthan in predust + 1% xanthan in batter.
The batter formulation was consisted of wheat flour (75%), corn flour (24.5%), salt (0.5%). The dry ingredients were blended for 3 min at speed 2 m/s in a Kenwood Major Classic mixer (Kenwood-BL460) with water (1:1.4 solid to water ratio). In each treatment, firstly, pre-dusting was done and then, battering. Afterwards, it was allowed to drip additional batter for 30 s. For final coating, orange bread crumbs were used (Gols Company). The samples were pre-deep-fried by sunflower oil at 190 °C for 30 s (Fritaurus Professional 3 domestic fryer, Barcelona, Spain). The treatments were cooled to room temperature for 30 min. Then, they were placed in plastic freezer bags (LDPE film, thickness 150 μ) and stored at -18 °C.
Moisture content in the samples was determined in quadruplicate according to the Association of Official Analytical Chemists (AOAC) (2000) method. Fat content of fried products was distinguished using Soxhlet extractions according to the AOAC (2000) method No. 992.15.
Batter pickups (%) were determined as following equation:
Batter pickup (%) = (Weight of coated shrimp–Weight of uncoated shrimp)/(Weight of coated shrimp)×100
Product yield (%) was calculated by weight of the cooked shrimp block/ weight of the raw shrimp block × 100.
Quantitation of fatty acid methyl esters in raw and fried breaded shrimp was carried out by gas chromatography (Unicam-4600) with 30 mm×0.25 mm column (Film Tekness-0.22 μl) and FID detector, using glyceryl tritridecanoate (C13:0) as an internal standard (Sigma, Barcelona, Spain). Fatty acids were expressed as percentage of total fatty acid methyl esters or in absolute content (mg/100 g food).
Fried shrimp coated with the selected formulations was evaluated by a trained sensory panel of 12 members. Each sample was randomly numbered and presented to the panel member. A hedonic panel was also performed by the same panelists, who evaluated aroma, taste, texture, color, appearance and overall acceptability characteristics. A hedonic 5-point scale was used, 1s unusable, 2s dislike, 3s acceptable, 4s like and 5s like very much. All data are reported as mean± standard deviations of triplicate. One-way analysis of variance (ANOVA) was used to compare the means of all evaluated parameters. Differences were considered significant at P
Research Article
Ali Motamedzadegan; Elahe Omidbakhsh Amiri; Mahboubeh Jamshidi; Tandis Khosravi rad
Abstract
Introduction: In industrial operations, a product is submitted to a range of shear rates. The knowledge of the changes in rheology with temperature, frequency and shear rate is needed to design the equipment of operations. The lemon juice is used extensively in the food industry. Information about rheological ...
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Introduction: In industrial operations, a product is submitted to a range of shear rates. The knowledge of the changes in rheology with temperature, frequency and shear rate is needed to design the equipment of operations. The lemon juice is used extensively in the food industry. Information about rheological and physicochemical properties is important for scale up and optimization of processes such as transport and storage of concentrated lemon in commercial applications. The aim of this study was toevaluate the rheological and physicochemical properties of the concentrated lemon produced using vacuum evaporator.
Materials and Methods: Lemon juice was concentrated to 25, 35, 45, 55 and 65 Brix by a rotary evaporator under vacuum at 65°C. The content of soluble solids in terms of brix using refractometer, pH, acidity in terms of citric acid, color in terms of a* , b* and L*, flow behavior and viscoelasticity as function of strain, frequency and temperature using rheometer were investigated. Mean comparison carried out using the least significant difference.
Results&Discussion: As brix increased, pH reduced and acidity increased. An increase in the concentration resulted in a decrease in L* and b* parameters and an increase in a* parameter. Enzymatic browning in this study could be ignored due to the sensitivity of enzymes to temperatures above 50°C. Millard's non-enzymatic browning (formation of hydroxyl methyl furfural and its polymerization) and the degradation of pigments might be a major contributor to color variation, although a decrease in moisture content and an increase in soluble solids are other reasons for darkening of color. Based on coefficient of determination (R2) and root mean square error (RMSE), we could state that the Newtonian and Bingham models had the best fit with laboratory data of the stress-strain obtained for the control sample with the 7Brix, and the samples with 25 and 35 Brix. Newtonian and Bingham viscosity increased as brix increased (p
Research Article
Zeinab Noori Hashemabad; Bahareh Shabanpour; Hamed Azizi; Seyed Mahdi Ojagh; Alireza Alishahi
Abstract
Introduction: The importance of maintenance and supply fresh fish instead of frozen due to the consumers interested in fresh fish is highly regarded. Titanium dioxide is a non-toxic nanoparticle that the American Food and Drug Administration approve its using at levels that are in contact with food. ...
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Introduction: The importance of maintenance and supply fresh fish instead of frozen due to the consumers interested in fresh fish is highly regarded. Titanium dioxide is a non-toxic nanoparticle that the American Food and Drug Administration approve its using at levels that are in contact with food. The antimicrobial and anti-fungal effects of this nanoparticle have been proven in a wide range of microorganisms (Saito et al, 1999).The use of titanium dioxide nanoparticles in polyethylene and polypropylene coatings has been investigated. The results showed that this nanoparticle, in addition to reducing the oxidation content of the package, could be effective in reducing silicone recovery of polyethylene and polypropylene in nature (Manangan et al, 2010). Rainbow trout is one of the most widely consumed breeding fish in Iran. Due to the high production and consumption of this fish, it is vital to take the necessary measures to maintain quality and increase its shelf-life. Therefore, this research was conducted to investigate the effect of titanium dioxide nanoparticle polyethylene packaging on quality and shelf-life of rainbow trout fillets during storage in a refrigerator.
Material and methods: Chemical (Peroxide value (PV) )Pearson,1997(., Tiobarbioritic acid (TBA) (Egan et al., 1997(, total volatile basic-nitrogen (TVB-N) (Pearson, 1997), pH), microbial (Total viable, Total viable counts, psychrophilic counts, lactic acid bacteria and Enterobacteriaceae) and Sensory analysis of samples was calculated and determined. The results of ANOVA using SPSS 16 software analysis and comparison of data using Duncan's multiple range test was 0.05 Sensory evaluation and analysis of non-parametric Mann-Whitney U test was used to test.
Result and Discussion: The process of microbial changes in the rainbow trout fillet was increased, except for the psychrophilic bacteria that were in the packaged nanocomposite treatment until the 4th day of the growing trend and then until the end of the period was reduced. Nanocomposites containing titanium dioxide containing nanoparticles prevent the growth of pseudomonas. (Bodaghi et al, 2013).The total amount of all chemical factors during the storage period showed an increasing trend in both treatments except for the factor observed in the packed sample. The results showed that in the control sample, the sensitivity rating on the day 8 was kept to a limit of less than 4, while in the sample packed with the nanocomposite until the 16th day, the points were less than the limit and the color score on day 12 Limiting receipts. Fat oxidation and microbial decomposition, and the production of esophagus combustion agents and fish tissue were changed. The antioxidant and antimicrobial effects of the packaged sample resulted in prolonging the shelf life and maintaining the quality of the fillets until the 16th day. Sensory, chemical and microbiological analysis results showed that the rainbow trout shelf life in nanocomposite packaging is suitable for 16-18 days.
Research Article
Elnaz Ghaem far; Seyed Mahmoud Reza Hojjati
Abstract
Introduction: Adding color to Foods can make them more appealing to consumers, to allow consumers to identify what taste to expect from a product, and to protect sensitive flavors from light. Color has always played a vital role in food selection and acceptance, and colorants are added to foods to alleviate ...
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Introduction: Adding color to Foods can make them more appealing to consumers, to allow consumers to identify what taste to expect from a product, and to protect sensitive flavors from light. Color has always played a vital role in food selection and acceptance, and colorants are added to foods to alleviate color lost during processing. Caramel color, from the palest yellow to the deepest brown, accounts for more than 80% (by weight) of all colorants added to the foods we eat and drink (Sengar, et al., 2014).Because of sensitivity of liquid colors to oxidation, light and heat and difficulties in their handling and incorporating, dried pigments have been developed. Microencapsulation is a technique to package materials in the form of micro- and nano-particles. There are different methods for encapsulation in the food industry. Freeze drying which has a long dehydration period, has been used as a simple technique in encapsulating water-soluble essential oils and natural aromas or drugs (Khazaei, et al., 2014). In this work, in addition to liquid caramel color production, encapsulation of liquid color with freeze drying technique through wall materials of maltodextrin and Arabic gum were carried out. The stability of microencapsulated color was then evaluated.
Materials and Methods: Rish baba grape and Kabkab date syrup were obtained from local market. Ammonium chloride, citric acid, sodium hydroxide, tween 80, Arabic gum were purchased from Merck (Germany). Glycine and maltodextrin were obtained from Sigma-Aldrich (USA) and Dextrose Company (Iran), respectively. In this study, the effect of factors such as type of catalyst (ammonium chloride-glycine), concentration of catalyst (0.5-2 molar), the pH of reaction (4-5), reaction time (60-120 minutes) on liquid color intensity of caramel produced from two natural sources of date and grape were investigated based on fractional factorial experimental design. For production of liquid caramel color, grape/date syrup was heated while being stirred to 65ᵒ C. Catalysts were then added to syrup and heated to 110ᵒC. water was added to reaction product and centrifuged. The solvent was removed by rotary evaporator (IKA HB 10, Germany).The resulting caramel color was stored under refrigeration at 4ᵒ C. In order to produce powder of caramel color, wall materials including Arabic gum and maltodextrin were dissolved in distilled water at ambient temperature to obtain 20% total solids concentration and stirred for 30 minutes at 60ᵒC. The mixture of liquid caramel color, tween80, and wall material solution was mixed in a ratio (w/w) of 1:4 (liquid caramel color: wall material) and stirred for 15 minutes. The mixture was then dried in a freeze dryer (ALPHA 1-2 LD PLUS, Germany) for 24 hours. The blank sample was prepared without wall materials and freeze-dried in similar conditions with other samples in 24 hours. Dried materials were collected and stored in brown glass bottles with screwed caps at 4⁰C until analysis. The powders were characterized using TGA/DSC thermogravimetric analysis (METTLER TOLEDO, USA), scanning electron microscopy (SEM) (TESCAN vegar, Czech Republic) and X-ray diffraction (XRD) (Billerica, MA, USA) to confirm the structural and morphological aspects of powders.
Results & Discussion: The results showed that the type of catalyst had no effect on the intensity of the colors and maximum color intensity (0.174 for color produced from grape and 0.15 for color produced from date) was obtained under these conditions: 120 minutes for reaction time, pH value = 4 and catalyst concentration of 2 molar. Results of thermogravimetric analysis (TGA) and differential scanning calorimetric (DSC) indicated the increase of thermal resistance by microencapsulation process so that initial decomposition temperature for liquid form, without wall material, with Arabic gum and with maltodextrin for grape source were 114,138,162,185°C respectively and for date source were 113,131, 143, 180°C respectively. Results of Scanning electron microscope demonstrated that size of the powders were 11-55 μm. In conclusion, microencapsulation by freeze drying could be recommended as a suitable method for stabilizing caramel color.
Research Article
Soheyl Reyhani Poul; Seyed Ali Jafapour; Reza Safari
Abstract
Introduction: With the growing population and following the efforts of food production industries, more waste is produced which can be recovered by adding value and brought them back into the cycle of production and consumption. The reason behind is firstly the reduction of waste and secondly the economic ...
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Introduction: With the growing population and following the efforts of food production industries, more waste is produced which can be recovered by adding value and brought them back into the cycle of production and consumption. The reason behind is firstly the reduction of waste and secondly the economic importance of value added resultant products. Aquaculture sector produces large volume of wastes including the head, tail, fins, spine, and most importantly their viscera. If the waste managed properly, valuable materials such as hydrolyzed protein powder (the resulting waste hydrolysis using proteases enzymes) and fish oil (byproduct of enzymatic hydrolysis) can be produced. In this study rainbow trout waste was chosen, due to its large volume production in the country. The functional properties and antioxidant activity of hydrolysates as well as the oil fatty acid profile are the main factors to be considered. This study was aimed to investigate the hydrolysis of rainbow trout viscera (oncorhynchus mykiss) by protamex and neutrase enzymes individually and compare the functional properties and antioxidants activity of protein hydrolysate as well as analyze the fatty acid profile of fish oil obtained as by-product of enzymatic hydrolysis process.
Materials and methods: Rainbow trout viscera (Oncorhynchus mykiss) were obtained from the fish market in Sari and transported in ice containers to the laboratory. Protamex and neutrase enzymes were purchased from Novozymes Company and protein hydrolysates prepared enzymatically according to the method of Guerard et al. (2002). Proximate analysis was carried out according to the procedures outlined by the AOAC (1995). Degree of hydrolysis determined as described by Hoyle and Merritt (1994). Peptide chain length (PCL) was measured using the method of Adler-Nissen and Olsen (1979). Protein recovery (PR) determined using the method used by Ovissipour et al (2009). Protein solubility for hydrolysates was determined using the method of Robinson and Hodgen (1940). Foam stability index was measured according to the method described by Sathe and Salunkhe (1981). Water holding capacity (WHC) was determined using the method of Rodriguez-Ambriz et al. (2005). DPPH radical-scavenging activity was measured using the method of Yen and Wu (1999). Reducing power was determined by the method of Oyaiza (1986).The chelating activity on Fe2+ was determined, using the method of Decker and Welch (1990).
Results & Discussion: Protamex leads to the production of protein powder with higher degree of hydrolysis (34.76 ± 2.92%) and protein recovery (68/16 ± 1.98%) compared to neutrase (p0.05) despite the difference in L* value. The viscera oil contains 34% monounsaturated, 34.49% polyunsaturated and 31.4% saturated fatty acid. Apart from pH 4 (isoelectric point), the solubility of both protein powders in water was remarkable (more than 90%). The foam activity and stability index of hydrolyzate produced by protamex were more desirable than hydrolyzate produced by neutrase, whereas at pH 6, these indices reached to their maximum values of 200.13± 9.31% and 135.6 ± 5.64 %, respectively. Furthermore, water holding capacity of both hydrolyzates was measured as approximately 4.5 ml/g protein (p>0.05). Protamex leads to the production of protein powder with the higher DPPH radical scavenging activity compared to hydrolyzate produced by neutrase. Conversely, the reducing power of hydrolyzate produced by neutrase was higher than that of protamex (p0.05).
Research Article
Saeedeh Zarbakhsh; Somayeh Rastegar
Abstract
Introduction: The date palm (Phoenix dactylifera L.) plays an important social, environmental, and economic role for many people living in arid and semiarid regions of the world. Fruits of the date palm are very commonly consumed in many parts of the world and considered as a vital component of the diet ...
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Introduction: The date palm (Phoenix dactylifera L.) plays an important social, environmental, and economic role for many people living in arid and semiarid regions of the world. Fruits of the date palm are very commonly consumed in many parts of the world and considered as a vital component of the diet and a staple food in most Arab countries. Nearly 2000 cultivars of date palm are known in the world, but only some have been evaluated for their performance and fruit quality. Dates are rich in certain nutrients and provide a good source of rapid energy, due to their high carbohydrate content (70–80%). Moreover, date fruits contain fat (0.20–0.50%), protein (2.30–5.60%), dietary fiber (6.40–11.50%), minerals (0.10–916 mg/100 g dry weight), and vitamins (C, B1, B2, B3, and A) with very little or no starch. The aim of the present work was to investigate the chemical composition, carbohydrate, and antioxidant capacity of two date palm varieties grown in Hormozgan and Farce province.
Materials and methods: After collection, all date samples were washed with tap water, and the seeds were removed, dried at room temperature under shadow. Moisture content was determined by drying samples in oven at 60 °C until constant weight was attained. The determination of proteins was done by Bradford method. Color measurement of fruit made using a portable CR-400 colorimeter (Minolta Chroma Meter CR-400 Osaka japan).Total polyphenols were determined as described by Waterhouse, 2002.The results were expressed as milligram gallic acid equivalents per 100 g of dry weight (mg GAE/100 g DW). Total flavonoids content (TFC) of the date extracts were measured according to the colorimetric assay of Chang et al., 2002. The hydrogen peroxide (H2O2) scavenging ability of palm dates was carried out using 2, 2-diphenyl- 1-picryl hydrazyl (DPPH) spectrophotometric method described by Choi with some modification.
Results and Discussion: Based on the results, The highest fruit length (43.6 mm), weight of pulp (9.3 g) and antioxidant activity (57 mgFW) were found in Piarom date of Hajiabad and the highest phenol (20.7 mg/gFW), TSS (77.3%) and titratable acid (0.023%) were recognized in Zahedi date of Hajiabad. Although date varieties from Jahrom showed better color index and tannin content than Hajiabad date. In comparison between two varieties, Piarom date was better in fruit weight (28.3 g), moisture content and protein content (7%) and flavonoids (22.2 mg CEQ/gFW) than the Zahedi date. However, the carbohydrate of Zahedi date (85%) was higher than the Piarom date. Therefore, in addition to the variety, location and climate condition also have the important role in determining the nutritional value of date palm fruit.
Research Article
Elham Eshaghabadi; Farajollah Shahriari; Mohammadreza Nassiry; Mohammad Reza Edalatian Dovom; Amin Mirshamsi
Abstract
Introduction: Bread is considered as one of the most important commodity which has provided human nutritional needs for several centuries. In recent decades, bread consumption has witnessed tremendous increase due to rising of other foods expenses. Cereal and bread industries has been always concerned ...
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Introduction: Bread is considered as one of the most important commodity which has provided human nutritional needs for several centuries. In recent decades, bread consumption has witnessed tremendous increase due to rising of other foods expenses. Cereal and bread industries has been always concerned about bread production in an industrial scale along with suitable shelf life, acceptable organoleptic properties and free from any chemical additives and preservatives. Among different methods such as addition of synthetic enzymes, gums, emulsifiers and improvers, sour dough has gained special attention besides shelf life enhancement and improvement of sensorial and nutritional features. The main role of sour dough has been prominent for fermentation and gas production in dough as a result of inclusion of Lactic Acid Bacteria (LAB) as a technology. Fluctuation of process parameters including temperature, dough yield and starter culture composition determine the sour dough quality. The main reason of sour dough application in wheat bread is flavor enhancement. Culture-based microbiological examinations have accompanied with some difficulties in accurate and precise identification of Lactobacilli. So, in recent years, in order to identify precisely, different molecular and PCR assays and gene sequencing have been applied. Thus, in present study, fragment of 253bp from 16 S rRNA gene in Lactobacillus plantarum was amplified with the help of PCR and sequenced in the next step. Also, comparison of nucleotide sequence of this region of traditional Lb. plantarum with nucleotide sequence of industrial starter (Germany) and sequences deposited in Gene Bank was evaluated.
Material and Methods: Sampling: According to sensory properties, sour dough samples were collected from Torbat e jam city and industrial starter sample (sour dough) was prepared from Buker Company, Germany.
Isolation and bio chemical analysis: Ten- fold serial dilutions of samples were prepared and cultured on MRS agar. Gram positive, catalase negative isolates were considered as presumptive LAB.
Molecular Identification: DNA of isolates were extracted according to the procedure of DNA extraction kit (Thermo, K721, USA). In order to amplify the 253 bp fragment of 16S rRNA in Lb. plantarum, specific primers were designed using Primer Premier 5. PCR was performed in Biometra Thermocycler (T- personal, Germany) in 36 cycles. In the following step, PCR products were sent to Macrogen Company for sequencing.
Bioinformatics analysis: Analysis of sequencing results was conducted with the aid of bioinformatics soft wares including CLC Main work bench, Chromas Lite 2.01, MEGA 5 and BioEdit. Phylogenetic tree was designed among different isolates using Neighbor-Joining method (bootstrap=1000) in MEGA 5 software. For determination of genetic distance, Create Pairwise comparison method was used in CLC Main workbench.
Results and Discussion: Quality and quantity of extracted DNA samples were confirmed by Gel electrophoresis. PCR and electrophoresis of PCR products confirmed and proved the accuracy and validity of amplified 253 bp fragment with intended primers. Comparison of Torbat and Germany nucleotide sequences demonstrated that two replacement mutations have been occurred including (A/C) and (T/C) in positions 182 and 205, respectively. These changes resulted in replacement of Histidine by Proline, and Glutamine by stop codon. Nucleotide content of 16S rRNA gene sequence in Lb. plantarum isolated from Torbat e Jam and Germany sour dough samples displayed both sequences contained 49.4% (G+C) and 50.6% (A+T). Phylogenetic results demonstrated that Lb. plantarum isolated from Torbat e Jam and Germany samples were classified in the same sub group. This implies the close phylogenetic relationship between these two lactobacilli. In order to identify Lb. plantarum, 16S rRNA gene was sequenced in sour dough samples of Germany and Belgium and phylogenetic tree showed that Lb. plantarum had the lowest genetic distance with Lb. pontis and highest one with Lb. sanfranciscensis and Lb. salivarius
Research Article
Jafar Nabati; Farshad Izadi; Reza Abbasi; Farshid Hassani
Abstract
Introduction: Potato (Solanum tuberosum) belongs to Solanaceae family and is a perennial plant which is herbaceous in nature. Potato is the world’s number one non-grain food commodity and 75% of the total production are being harvested in densely populated developing countries such as China and India, ...
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Introduction: Potato (Solanum tuberosum) belongs to Solanaceae family and is a perennial plant which is herbaceous in nature. Potato is the world’s number one non-grain food commodity and 75% of the total production are being harvested in densely populated developing countries such as China and India, and thus alleviates the food crisis in third world countries. Potato is the most imperative and widely cultivated vegetable crop in Iran, per capita consumption in the country is more than 35 kg. Potatoes are the World’s most widely grown tubural crop and the fourth largest crop in terms of fresh produce after rice, wheat and maize. According to the National Policy on Potato Industry, the potato is an important food and cash crop that plays a major role in food security and is only second to maize in terms of utilization. Potato production is increasing due to the economic decline of competing cash crops such as maize, pyrethrum, and barley, and increasing demand from consumers and processors. Potato tuber undergoes physiological dormancy period during the postharvest storage. The length of the dormancy period is dependent on the varietal genetic profile, environmental factors and storage conditions. Commercial potato cultivars grown for the processing industry has shorter dormancy periods and associated with different storage disorders like sweetening, greening, toxicants, etc.; therefore it is vitally important to employ suitable storage conditions to ensure their continuous supply. Potato is semi perishable crop, however placed under low temperature storage to prevent them from sprouting and to ensure their regular supply whenever required. Low temperature potato storage is however, associated with low temperature sweetening and is specifically undesirable in processing potato varieties. The phenomenon is primarily associated with the potato storage under low temperature and as a result of which the insoluble starch is enzymatically hydrolyzed into soluble glucose, fructose and sucrose. Tuber sweetening deteriorates the tuber commercial quality and causes the fried products to turn brown and bitter in taste due to subsequent acrylamide formation. Packaging is an essential component of post harvest supply chain management in horticultural crops. In Iran and other developing countries, potatoes stored in polyethylene bags with a capacity of 40 to 80 kg that causes many problems during storage. Therefore, this study was conducted to evaluate the different potato packing methods for industry uses.
Material and Methods: Study was conducted in 2015-2016 at cold storage Ravand, in the Toos Industrial Zone, Mashhad, Iran in a completely randomized design with triplicate. Treatments including cold storage of potatoes, storage in a wooden box, kept in mesh bags, storage in polyethylene bags, and storage in punched polyethylene bags and kept in split polyethylene bags. Potato cultivar used in this study was Agria Picked up in the second half of October. Box weight was measured before storing tubers. Tuber store below six degrees Celsius and relative humidity between 85% and 90% were considered for all treatments. The amount of carbon dioxide during storage was set between 700 and 1000 ppm. Storage period took six months. After storage period, the number of healthy, sprouting and rotting tubers were counted and the sugar content, total phenol content and quality of chips, starch content, dry matter and tuber specific gravity were measured.
Results &Discussion: The results showed that the highest and the lowest loss percentage observed in mesh bags and polyethylene bags respectively. The difference between the two treatments was 2.4 percent. Tuber maintenance in polyethylene bags and polyethylene bag split showed the highest and lowest percentage of decay. Most sprouting tuber was observed in polyethylene bags and punched polyethylene bags, and the lowest sprouting tuber observed in a mesh bag and wooden box. The difference between the highest and lowest percentage of sprouting tuber in punched polyethylene bags and mesh bag was 16 percent. There were no significant differences observed in reducing sugars and total phenol component at different storage methods. The highest percentage of starch obtained in split polyethylene bags and mesh bag and the least amount of starch in punched polyethylene bags. Packing tubers in mesh bag showed the maximum and in split polyethylene bags showed the minimum brown color in chips. The difference between the highest and lowest specific gravity was two percent, however, in all treatments specific gravity was more than one. The highest of dry matter percentage observed in a mesh bag and split polyethylene bags with 24 percent and the lowest of dry matter percentage was observed in punched polyethylene bags. Tuber loss weight in polyethylene bags was lower than other treatments, but rotten tubers percentage was higher than the other treatments. In contrast, tuber weight loss in split polyethylene and punched bag's was equal to storage in wooden boxes and tuber decay in split polyethylene bags was lower than other treatments. Chips quality in split polyethylene bags was more than other treatments and equal to wooden boxes. Generally, wooden boxes, split polyethylene bags and punching bags are found suitable to reduce the percentage of rot and sprouting potato tubers and as effective way to store potatoes in storage room.
Research Article
Sakineh Heydari; Bahareh Shabanpour; Parastoo Pourashouri
Abstract
Introduction: One of the most important factors in the production of bread products is the frying process. Deep frying by moving a water mass separated from the product to the outside can cause deformation and fracture of the crust of bread products, therefore, This study aimed to evaluate the effect ...
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Introduction: One of the most important factors in the production of bread products is the frying process. Deep frying by moving a water mass separated from the product to the outside can cause deformation and fracture of the crust of bread products, therefore, This study aimed to evaluate the effect of adding edible wheat and oat dietary fibers and prevent deformation quality of shrimp analogue products, as a value-added product produced from surimi.
Materials and Methods: The shrimps analogue were produced of Hypophthalmichthys molitrix fish surimi by using a composite-molded method with preparation filament of surimi in five treatments including a fiber-free treatment and four others have 5 and 6 percent oats and wheat fiber; coating, pre-fried and were frozen. In order to perform experiments, the shrimp’s analogue were thawed and fried.
Results and Discussion: The results showed that the highest amount of moisture and the lowest amount of fat were in treatments containing 6% 49.06 and 5.51 wheat fiber respectively and 49.56 and 6.47 oat fiber respectively (p
