Full Research Paper
Food Engineering
Mahsa Kamali Sarvestani; Mohebbat Mohebbi; Masoud Taghizadeh
Abstract
Introduction: Celery is one of the most consumed and highly nutritious vegetables with high dietary fiber, phytochemicals, vitamins, and minerals, which offers great benefits for utilization as a functional food ingredient. Fruit and vegetable juice powders have many benefits and economic advantages ...
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Introduction: Celery is one of the most consumed and highly nutritious vegetables with high dietary fiber, phytochemicals, vitamins, and minerals, which offers great benefits for utilization as a functional food ingredient. Fruit and vegetable juice powders have many benefits and economic advantages over their liquid precursors such as reduced volume/weight, reduced packaging, easier handling/ transportation, and much longer shelf-life. Also, powders can be reconstituted to produce juice and used for preparation of products such as snacks, chutney, soups, baby foods, etc. In foam-mat drying, food liquids and pastes are first whipped into stable foam by the addition of different foaming agents or stabilizing agents and then dried in the form of thin layer. This foam structure dries rapidly due to the increase of the surface area of the material by incorporating air/gas and forms a porous structure which gives high quality and instant properties of the dried product. The dried product is scraped off from the drying surface in the form of flakes, which is then converted to a fine powder. Response surface methodology (RSM) is a combination of mathematical and statistical techniques used to investigate the interaction effects of independent variables on responses. There is considerable information on foam-mat dried food powders, but there is no scientific literature related to foam-mat drying of celery juice. The present research was thus focused on optimizing the foaming conditions (WPC as a foaming agent, Xanthan gum (XG) concentration as the stabilizer and whipping time (WT)) to minimize foam density (FD) and drainage volume (DV) using RSM. The effects of drying temperatures on some physicochemical properties of powder were also investigated. Materials and methods: Celery was purchased from the local market.XG and WPC powders were purchased from Sigma Chemical Company (St. Louis, MO) and Milei Company Germany, respectively. Celery juice was extracted by using a juicer machine (Robert Bosch Stand mixer MMB 2000 /05 FD 8611 Type CNSM03EV, 600W, Slovenia). Based on preliminary tests, XG solutions were prepared by dissolving the appropriate amount of the defined gum powder in distilled water and stirring with a magnetic stirrer to achieve a uniform solution. This solution was refrigerated at 4°C overnight to complete hydration. RSM was used to estimate the main effects of the process variables on FD and DV in celery juice foam. The experiment was established based on a face-centred central composite design (FCCD). According to the experimental design, to prepare 100 g of samples, the appropriate amount of celery juice, WPC, and XG solution were poured to a 250 mL beaker. Then the mixture was placed into a water bath for 5 minutes at 55 °C temperature. The mixture was then taken out of water bath and was whipped by a mixer (Gosonic, model No. GHM- 818, 250W, China) with the maximum speed of 5400 rpm at ambient temperature during the given time. The density of foamed celery juice was determined in terms of mass over volume and expressed in g/cm3. To assess foam stability, the drainage test was performed for 1h. Furthermore, the effects of drying temperatures on some physicochemical properties of powders were investigated. Results and discussions: The quadratic model was selected as a suitable statistical model for both FD and DV. ANOVA showed that this model is significant for both responses. Moreover, lack-of-fit was not significant for response surface models at a 95% confidence level, indicating that this model is adequately accurate for predicting responses. Based on the constrain criteria, the optimized foaming parameters were: XG concentration of 0.42% (w/w), WPC concentration of 6% (w/w), and WT of 9.30 min. The amount of FD and FDV for foam at these optimum conditions were 0.4 g/cm3 and 0 ml, respectively. The results showed the moisture content and water activity of the celery powders decreased with the increase in drying temperature. By increasing drying temperature from 40 to 70 °C, bulk density also decreased. Increase in drying temperature results in decrease in moisture content and bulk density. Tapped density generally behaves similar to bulk density because by shaking powder, the space between the particles is filled and occupied volume by the powder is reduced. By increasing in temperature, particle density decreased. Overall, with increasing drying temperature, the porosity of powder increased. Increasing temperature and reducing moisture content, the possibility of approaching and join together of particles is increased and the space between the particles becomes less. The numerical value of the car index parameter in this study was 15.3% to 24.67%. The highest value of flowability related to the sample was dried at 70°c. With decreasing in drying temperature, the moisture content of powders increased and due to forming liquid bridges between particles making them less flowable. The numerical value of the Hausner parameter in this study was 1.15 to 1.32. Except for powder produced at 70 °C, the powder was placed in the intermediate cohesiveness powder class. By increasing drying temperature, the cohesiveness of powder decreased significantly.
Full Research Paper
Food Biotechnology
Sara Momenzadeh; Hossein Jooyandeh; Behrooz Alizadeh Behbahani; Hassan Barzegar
Abstract
Introduction: Probiotics are live microorganisms, if consumed in enough quantity, they exert beneficial effects on human health owing to improvement of intestinal microbiota balance. In addition to the impact on gut microbiota, probiotics have important role on human physical and mental health. This ...
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Introduction: Probiotics are live microorganisms, if consumed in enough quantity, they exert beneficial effects on human health owing to improvement of intestinal microbiota balance. In addition to the impact on gut microbiota, probiotics have important role on human physical and mental health. This matter demonstrates the increasing emphasis on the consumption of diet based on probiotics in order to treat and prevent of different chronic diseases, particularly those related to stress and inflammation cases. Lactic acid bacteria (LAB) are the most common strains used as probiotics. They are useful member of gut microbiota and belong to generally regarded as safe (GRAS) microorganisms. Because of the numerous benefits of LAB, the probiotic potential of different strains of this group of bacteria has been assessed broadly. Although various commercial species of probiotics are available in the market, determination of new strains with individual properties is noteworthy. Therefore, this research was aimed to investigate the probiotic and antimicrobial potential of Lactobacillus fermentum isolated from fermented food. Materials and methods: In the study,the probiotic potential of Lactobacillus fermentum including its resistance to acid (pH 2.5, 3.5 and 5.5) and bile salts (0.2, 0.5, 0.8, 1.2 and 3%) was studied. To evaluate the bile salts resistance, 100 μl of prepared microbial suspension was cultured on MRS Agar media containing bile salts. Plates were incubated at 37 ᵒC for 24 hrs under anaerobic condition. After incubation period, the plates were inspected for bacterial colonies observed by naked eyes. The antimicrobial activity was measured using “Lawn on the spot” method against Listeria innocua, Staphylococcus aureus and Pseudomonas aeruginosa. The resistance of Lactobacillus fermentum was also assessed against commonly used antibiotic drugs (chloramphenicol, tetracycline, penicillin and gentamycin). Results and discussions: Results shown that although Lactobacillus fermentum was not able to grow at pH 2.5, its viability in the pH 3.5 and 5.5 was 92 and 99%, respectively. This strain had also adequate resistance against different bile salt concentrations. In the present research, the growth rate of the examined strains was gradually reduced as the bile salt concentration was increased; so that the higher and the lower growth rate was observed at 0.2 and 3% bile salt concentrations, respectively. Results shown that the tested Lactobacillus fermentum had acceptable bacteriostatic effect on the selected pathogenic bacteria. The inhibition zone diameter for Listeria innocua, Staphylococcus aureus and Pseudomonas aeruginosa was 12.6, 20 and 11.1 mm, respectively. The maximum diameter of inhibition zone was found on gram positive Staphylococcus aureus. Lactobacillus fermentum was susceptible to chloramphenicol, tetracycline and penicillin and was semi-resistant to gentamycin (comparison with table CLSI). Based on the obtained results in this study, it may be illustrated that Lactobacillus fermentum had capability to tolerate the lower pH and different bile salt concentrations. This strain showed the proper proficiency to inhibit pathogenic bacteria. Furthermore, it was susceptible to commonly used antibiotic drugs and therefore there is no concern about the transfer of antibiotic resistant gens into pathogenic bacteria. Consequently, this strain may be used as a probiotic and a natural preservative in production of functional food products.
Full Research Paper
Homa Mahpour; Toktam Mostaghim; Shahla Shahriari
Abstract
Introduction: Dairy products fortification especially ice cream is one of the most important goals and priorities of today's humanbeing to produce health food products. Protein isolate is one of the compounds used to produce health products.The aim of this study was to produce ice cream with new features ...
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Introduction: Dairy products fortification especially ice cream is one of the most important goals and priorities of today's humanbeing to produce health food products. Protein isolate is one of the compounds used to produce health products.The aim of this study was to produce ice cream with new features based on a functional material by partially replacing dry matter with wheat germ protein isolate. Materials and Methods: In present research wheat germ protein isolate with 1%, 3% and 5% was extracted and added to ice cream. In the first step, protein isolate was evaluated by tests of moisture content, fat percentage, acid insoluble ash, particle size and flour grain size. In the next step, protein isolate of wheat germ by 1, 3 and 5 percent was added to ice cream mix and its effects on rheological and texture properties, color, physico-chemical and sensory parameters of ice cream were evaluated. Results and discussion: The results showed that the moisture, fat and acid insoluble ash of protein isolate were 8.41±0.42, 11.34±0.44 and 3.57±0.23 respectively. The particle size and flour grain size was 282±0.01. Laboratory data showed that by increasing protein isolate replacement, the viscosity, melting resistance and volumizing index were reduced significantly. Whereas, texture, hardness and adhesion parameters, density, particle size and diameter, specific distribution and surface area, and yellowness and redness indices were significantly increased. All the laboratory results and sensory evaluation of the samples revealed that the ice cream sample with 1 percent of wheat germ protein isolate was a preferred and optimized sample.
Full Research Paper
Food Biotechnology
Bahareh Majdi; Mohammad Amin Mehrnia; Hassan Barzegar; Behrooz Alizadeh Behbahani
Abstract
Introduction: Antioxidants by Quenching free radicals and preventing lipid oxidation, retard spoilage, discoloration and rancidity of foods. Due to adverse effects of synthetic antioxidants such as carcinogenicity and liver injury, consumers’ attention toward natural antioxidants are increasing. ...
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Introduction: Antioxidants by Quenching free radicals and preventing lipid oxidation, retard spoilage, discoloration and rancidity of foods. Due to adverse effects of synthetic antioxidants such as carcinogenicity and liver injury, consumers’ attention toward natural antioxidants are increasing. Turmeric (Curcuma longa) is a medicinal plant frequently used in food industry and pharmacology. In this research, chemical composition, structure and type of bond, antioxidant capacity, total phenol, flavonoid and cytotoxic effect of Turmeric essential oil (TEO) on colorectal cancer cells (HT29) were investigated. Materials and methods: TEO was extracted using Clevenger apparatus by aqueous distillation method. To identify chemical composition, 1 µl essential oil was injected in gas chromatography-mass spectrometry and essential oil composition and quantity were determined by comparing with standards. Functional groups and qualitative identification of turmeric essential oil were done using Fourier-transform infrared spectroscopy (FTIR) in range of 500 – 4000 cm-1. Antioxidant capacity of TEO was determined suing ABTS, DPPH and β-carotene/linoleic acid bleaching assay. Total phenol and flavonoid were measured by colorimetric methods. MTT test was used to find cytotoxic concentrations of TEO on colorectal cancer cell line (HT29). Results and discussion: The 18 compounds identified in TEO accounted for 97.91% and the highest compound was turmerone by 40%. The other compounds were curlone, zingiberene and benzene with 34, 8.30 and 4.18% respectively. Infrared spectrum in range of 3600-3400 cm-1 (specially 3516 cm-1) and peaks at 2930, 1621, 1515 and 1447 cm-1 were due to stretching vibration of O-H, C-H, C=O, C=C bonds of aromatic ring and aromatic groups of curcuminoids. 1515 cm-1 peak was due to stretching vibration of C=O bond of sesquiterpenes (turmerone). Observed peaks at 1378 and 1308 cm-1 confirmed the presence of alkanes or bending vibrations of CH3 groups in curcuminoids (curcumin). Antioxidant potential of TEO according to DPPH and ABTS methods and β-carotene bleaching assay was 25.15, 93.90 and 72.76 %, respectively. Total phenol and flavonoid content of TEO were 38.91 mg GAE/g and 87.9 mg QE/g. The results showed that by increasing essential oil concentration from 3.125 to 200 mg/mL survival rate of HT29 changed from 66.76 to 9.88%.
Full Research Paper
Food Technology
Delaram Hami; Mohammad Goli
Abstract
Introduction: Ice cream contains a mixture of milk components, sweeteners, stabilizers, emulsifiers, and flavorings. The quality of the finished product depends not only on the processing conditions or the freezing efficiency, but also on the constituents, the amount of entrapped air, and the number ...
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Introduction: Ice cream contains a mixture of milk components, sweeteners, stabilizers, emulsifiers, and flavorings. The quality of the finished product depends not only on the processing conditions or the freezing efficiency, but also on the constituents, the amount of entrapped air, and the number of ice crystals. The physical structure of ice cream has a significant effect on the melting properties (melting rate) and texture (hardness) of ice cream (Mouse & Hartel, 2004). The improvement and expansion of the ice cream structure are attributed to the macromolecules present in the ice cream mixture; milk fat, protein, and carbohydrates (Adapa et al., 2000). Quinoa as a high biologically valuable protein can be used in various food products to enrich and positively affect the physical and sensory properties of the product (James, 2009). The purpose of the present study was to replace skim milk powder with quinoa flour (0 to 100%), hydrogenated vegetable oil (4.5 to 8.5%) and Panisol gum (0.25 to 0.65%) to obtain the optimal formulas of Vanilla ice cream using the response surface methodology. Materials and Methods: After adjusting the ratio of the ingredients in the various ice cream formulations, the amount of raw material of each formula was weighed. The milk was then heated to about 45 ° C, and then the remaining ingredients were slowly added and thoroughly mixed. The mixture was then pasteurized at 85 °C for 15 minutes. After the pasteurization operation, the mixture was immediately kept in a water-ice bath and cold down for 4 hours in a 4 °C refrigerator. After the ripening step, the mixture went through the freezing phase in a homemade ice cream maker. The ice cream samples were packed in plastic containers and stored at -18 °C for the period of hardening. To optimize the process conditions, the independent variables A (quinoa flour replacement from 0 to 100%), B (hydrogenated vegetable oil from 4.5 to 8.5%) and C (Panisol gum from 0.25 to 0.65%) were selected at five levels. To obtain optimal points, 34 experiments were recommended by design expert software. The volumetric overrun (%) and the melting rate (g/min.) were measured according to Hashemi et al., (2015) method. Ice cream textural properties were tested after 3 days storage at -18 °C using a Brookfield texture analyzer. It was equipped with a cylindrical probe with a diameter of 6 mm and a height of 15 mm. The probe was applied to the test samples twice at a speed of 1 mm / s and up to 50% of the probe height and the results were recorded by device software. Ice cream textural data used in this study included hardness (g) and adhesiveness (g. sec) (Hashemi et al., 2015). Results and Discussions: Reducing overrun of ice cream samples by increasing the replacement levels of quinoa flour can be attributed to an increase in the viscosity. As viscosity increases, due to the reduced mixing ability of the ice cream mixture, the ability of air to enter the mixture of ice cream containing quinoa flour has been reduced during freezing (Gelroth et al., 2001). The reason for the decrease in the melting rate of ice cream with increasing percentage of quinoa flour replacement can be attributed to the existence of polysaccharide compounds with high water holding capacity, which led to increase the product water intake intensity and viscosity and subsequently decreasethe overrun. One of the factors affecting the melting properties is the increase in volume. In addition, the role of quinoa flour in enhancing the melting resistance of ice cream can be attributed to the type of protein content, the emulsifier potential and the surface active properties of its proteins and lipids. The presence of high amounts of protein in quinoa flour has a significant effect on the stability of air molecules. Since quinoa flour contains high amounts of protein, this fraction of flour quinoa protein, increases the hardness of ice cream through creating hydrogen bonds between the amide-hydroxyl and hydroxyl-carbonyl groups with other polar groups of other ice cream components such as panisol gum. In addition, hydrogen bonds are likely to be formed by electrostatic interactions between the quinoa protein groups of the polar with the polar part of the gum panisol, which may also be the reason for the increased hardness of the ice cream in the presence of the quinoa flour. With polar groups, quinoa flour traps the water in its structure and ultimately increases the consistency and adhesiveness of the ice cream. It is also possible that the protein portion of quinoa flour binds to the water molecules present in the sample through hydrogen bonding and ion-dipole and dipole-dipole interactions, thereby reducing water activity, increasing sample adhesiveness (Fatemi, 2008). The optimal formulas were predicted for replacement of skim milk powder with quinoa flour at 25 and 53%, hydrogenated vegetable oil 8.5 and 8.2% and panisol gum 0.39 and 0.48%, respectively.
Full Research Paper
Food Technology
Amir Rezaie; Masoud Rezaei; Mahdi Albooftileh
Abstract
Introduction: Films with appropriate mechanical properties and low permeability are very important for food packaging. Natural polymers have gained increasing attention for the development of biodegradable films due to the environmental problems caused by petroleum-based polymers. Carboxymethyl cellulose ...
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Introduction: Films with appropriate mechanical properties and low permeability are very important for food packaging. Natural polymers have gained increasing attention for the development of biodegradable films due to the environmental problems caused by petroleum-based polymers. Carboxymethyl cellulose (CMC) is a linear polysaccharide that exhibited good film forming properties. Gum Arabic (GA) is another polysaccharide that can be used for preparing the edible and biodegradable films. However, several studies have shown that biopolymers like CMC and GA films have high water vapor permeability and poor mechanical properties in moist conditions. One of the strategies that can be used for improving the properties of biopolymers films is blending the different polymers and formation the composite films. Various studies on the preparation of biocomposite films have been performed, however, to the best of our knowledge, studies on combinations of the CMC and AG have not been reported yet. Thus, the main objectives of this study were to prepare CMC/AG composite films using solvent casting method and investigate the effect of different CMC/AG blending ratio on the physical (water vapor permeability (WVP), water contact angle (WCA), color, opacity and light-barrier properties), mechanical and thermal properties. Furthermore, in order to determine the structural characteristics of the films, fourier-transform infrared spectroscopy (FT-IR) and x-ray diffraction (XRD) measurements were also performed. Material & Method: The CMC and AG solutions were prepared by dissolving 1 g in 100 mL of distilled water at 45 °C for 24 h under magnetic stirring. The prepared solutions were then blended in different proportions (75:25, 50:50, and 25:75). After mixing, glycerol (0.3% w/w) was added as a plasticizer and the solution was stirred for 15 min. The prepared solutions were poured into a glass plate, then dried at 45 °C for 24 h in the oven. Finally, the properties of CMC, GA and composite films were determined. Result and Discussion: In this study, biodegradable films composed of CMC and AG were successfully prepared. Results showed that some properties of the composite films were greatly influenced by addition of AG. So that, WVP of films was decreased significantly in the blend films and the lowest WVP was observed in the 25:75 (AG: CMC) films (p < 0.05). The films hydrophobicity was significantly increased from 41.33o to 61.10o by addition of AG to the CMC films (p < 0.05). With increasing the ratio of AG, the tensile strength (TS) of blend films decreased. Opacity and light transmission of the composite films increased and decreased, respectively with increasing the AG ratio. The differential scanning calorimetry (DSC) test demonstrated that the thermal properties of blend films improved with increasing the AG content. The FT-IR analysis indicated that new interaction was generated between the components of the blend films. Generally, it can be concluded that blending the AG and CMC can improve some of the physico-mechanical properties of the blend films
Full Research Paper
Food Technology
Maryam Zamanian; Hassan Sadrnia; Mehdi Khojastehpour; Fereshteh Hosseini; Jules Thibault
Abstract
Introduction: Among the different types of polymers used for packaging and coating, polyvinyl alcohol (PVA), given its very enviable properties, has been used in various industrial applications. It is used for instance as controlled release in pharmaceutical elements, paper, textile and food supplement ...
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Introduction: Among the different types of polymers used for packaging and coating, polyvinyl alcohol (PVA), given its very enviable properties, has been used in various industrial applications. It is used for instance as controlled release in pharmaceutical elements, paper, textile and food supplement coating due to its good physical properties, chemical resistance, thermostability, film-forming capability, efficiency and biodegradability. The aim of this work was to examine the combined effect of montmorillonite (MMT) platelets and titanium oxide (TiO2) spherical nanoparticles on the physical and mechanical properties of PVA/ TiO2/MMT nanocomposites, and to determine the optimal combination to provide good properties, using response surface methodology (RSM). Materials & methods: PVA, PVA/TiO2, PVA/MMT and PVA/ TiO2/MMT nanocomposite films were prepared by the solution casting method. For each sample, 1.8 g of PVA was dissolved in 50 mL deionized water and maintained for 24 h at room temperature. The mixture was then heated to 90˚C and stirred using a magnetic stirrer up to 3 h to ensure the complete dissolution of PVA, followed by cooling down the solution to room temperature. Various amounts of TiO2 nanoparticles (1 and 2 w% on a dry basis) were added to deionized water and agitated with a stirrer for 12 h at 500 rpm. This method was also used for MMT (2 and 4 w% on a dry basis). The nanoparticle suspension was subjected to ultrasonic homogenization for 20 min to ensure a good dispersion. The 50 mL nanoparticle suspension was added to the PVA solution drop by drop during a period of 5 min while maintaining intense stirring (1000 rpm). Mixing was continued and glycerol (30 w% based on the polymer) was added. Vacuum with a rotary vacuum pump was applied to remove air bubbles from the solution. The solution was poured into a 15-cm internal diameter Petri dish with a perfectly flat bottom and carefully aligned horizontally. Homogeneous films were peeled off after drying in an air oven at 40˚C for 72 h. Scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD) were performed for characterizing the morphology of nanocomposite films. The effect of these two nanoparticles on physical and mechanical properties, was evaluated by response surface methodology (RSM). A three-level factorial design was used to define the test points for the series of experiments. Among the various design alternatives suggested by theoretical algorithm, the selected design consisted of 13 experiments including five replicate central points used for variance calculation. Furthermore, PVA film data were analyzed using the Design-Expert program (Version 7.0, Stat-Ease Inc., Minneapolis, Minnesota) to find the optimum combination of constituents for the best properties. Results and discusions: X-ray diffraction patterns showed that the nanoparticles were well dispersed in the polymer matrix of PVA/ TiO2 and PVA / MMT films with layered microstructure. In addition, the linear effect of MMT nanoparticles and the interaction of TiO2 and MMT on tensile strength were significant. The linear, quadratic and interaction effects of both nanoparticles on Young's modulus were also significant. In general, the optimum values of TiO2 and MMT were 1% and 4% respectively for mechanical properties. The presence of both nanoparticles had a significant effect on transparency and ΔE. Results of nanocomposite films indicated that the film with 2% TiO2 and 4% MMT has higher WI and actually is darker than other samples. By analyzing different results with response surface method, the nanocomposite film with 0.5% TiO2 and 4% MMT was proposed as optimum combination for mechanical and physical properties
Full Research Paper
Food Technology
Seyfoallah Hamzeh-Kalkenari; Hojatollah Bodaghi; Ziba Ghasimi Hagh
Abstract
Introduction: Button mushrooms are the main edible mushrooms in Iran and the most important quality indicators of this fungus are the whiteness, having a glossy cap, straight stem, lack of brown spots. The mushroom has a higher respiration rate than other horticultural products and, due to the lack of ...
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Introduction: Button mushrooms are the main edible mushrooms in Iran and the most important quality indicators of this fungus are the whiteness, having a glossy cap, straight stem, lack of brown spots. The mushroom has a higher respiration rate than other horticultural products and, due to the lack of natural protective cover to prevent water loss, its edible quality is rapidly lost. In the last decade, the use of polyethylene films to create a modified atmosphere and natural essential oils to extend the shelf life of crops has been greatly expanded. Mushrooms packaging Polymeric nanocomposites are two-phase systems comprising a polymeric matrix and inorganic nanoparticles. Clay nanoparticles are among the most widely studied nanoparticles. When added to the nanocomposite films, the clay nanoparticles increase the film strength and decrease the permeability of the nanocomposite film. Also, the incorporation of natural essential oils can greatly increase the post-harvest life and prevent deterioration. Recently, essentail oils have been widely used in various fields after harvesting fruits, flowers, and vegetables. So far, there has been no report on the combined use of nanocomposite films and plant essential oils on extending shelf life of buttom mushroom. Materials and methods: Mushroom samples were obtained from Shahwar Company in shahrood. The experiment was conducted as a factorial experiment in a completely randomized design with 3 replications. The first factor Echinophora cinerea essential oil, was sprayed on the product at three levels of 0, 5 and 10 µl /l. The second factor was low-density polyethylene packaging films and 20 μm thick polyethylene-clay nanocomposite films. Subsequently, 100 g bottom mushrooms were packaged in the desired 25×20 cm films, the packed mushrooms were then transferred to 4± 1°C and relative humidity 90% storage conditions. Post-harvest qualitative traits were studied at 5-day intervals for 35 days. The studied traits were: tissue firmness, membrane permeability (electrolyte leakage), membrane lipid peroxidation (MDA), catalase and superoxide dismutase activity, microbial population, browning index, fungal opening percentage and fungal marketability. Results and Discussion: Packed mushrooms in nanocomposite films with and withoutessential oils did not show a significant effect on weight loss during storage, which could be due to the effective performance of nanocomposite films in preventing water vapor and the creation of a favorable modified atmosphere in the microclimate space inside the packages. Tissue softening was delayed in packed mushrooms in nanocomposite films compared to polyethylene films, also coating of essential oil on packed mushrooms in nano films compared to polyethylene films. Polyethylene films had a significant effect on decreasing the firmness parameter during storage. Evaluation of the effect of essential oil coating and the packaging showed that the essential oil was effective in reducing electrolyte leakage and malondialdehyde content in both types of packaging with both concentrations, but the results were better with 100 μl /l. The change in membrane permeability and malondialdehyde content reflects membrane damage as the cellular oxidative damage of MDA content, which is a product of membrane lipid peroxidation, increases. The higher activity of catalase in the mushroom in nanocomposite films coated with essential oils indicates that the process of decay and aging in the mushroom tissue is delayed. The aerobic cells of the plant produce reactive oxygen species such as H2O2 against stress and their toxicity is eliminated by both types of enzymatic and non-enzymatic antioxidant systems. SOD enzyme activity was higher in mushroom packed in nanocomposite films and coated with essential oils than in polyethylene films alone. This enzyme acts as the basic scanengering enzyme for O-2 radicals and catalysis to H2O2 and O2. It seems that the lower permeability of nanocomposite films compared to polyethylene films leads to prevent oxygen entry to a certain extent and the lower activity of this enzyme reduces the browning of the mushroom caps. On the other hand, coating with essential oil has also reduced the browning rate. The marketability of mushroom in polyethylene packaging has decreased significantly since the 20th day of clay nanocomposite, while the marketability of mushroom in the packaging of nanocomposite and essential oil coatings was acceptable by the end of 35th day. The results of this study indicate that although for the better prevention of senescence and contamination of buttom mushrooms during storage at 4°C, use of essential oil in polyethylene packaging can be effective but change in the structure of polyethylene by adding 5% nanoclay, it was highly desirable to increase the shelf life of the mushroom by retaining the quantitative and qualitative characteristics.
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Food Technology
Somayeh Ghandehari alavijeh; Mehran Alami; Yahya Maghsoudlou; Alireza Sadeghi Mahoonak
Abstract
Introduction: Porous starch granules are becoming of great interest such as non-toxic absorbents, owing to their great absorption capacity derived from the major specific surface area. Pores can protect sensitive elements as oils, minerals, vitamins, bioactive lipids, food pigments such as beta-carotene ...
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Introduction: Porous starch granules are becoming of great interest such as non-toxic absorbents, owing to their great absorption capacity derived from the major specific surface area. Pores can protect sensitive elements as oils, minerals, vitamins, bioactive lipids, food pigments such as beta-carotene and lycopene that are sensitive to light, oxidation or high temperature. Alpha-amylases from Bacillus and glucoamylases from Aspergillus niger have the strongest hydrolytic ability toward starch. Ultrasonic treatments have been reported to produce modified starch. In the last years, the effects of sonication on the starch microstructures and properties have been studied. It was shown that the C–C bonds of starch granules were destroyed, and hollows or pores were formed on the surface and inside the granules. Therefore, the main objective of this study was to identify a suitable starch (corn or wheat) to carry and protect iron ions. The enzyme having a fixed concentration of 0.1% within a fixed period of 36 hour, was added to the starch solutions in three different steps - after, simultaneously and before - the ultrasound processes. The power of the ultrasound was 350 watt for 10 minutes. Iron ions (Iron Ammonium Sulfate (II)) were added to the porous corn and wheat starches in concentrations of 40, 60 and 80 ppm. Materials and methods: The ability of water and oil adsorptions were measured in the produced corn and wheat porous starches. The microstructures of porous starches were revealed by using Scanning Electron microscopy (SEM). After adding iron ammonium sulfate (II) to the porous starches of corn and wheat, the amount of iron ions absorbed and the type of bonds formed between starch and iron ions were determined by inductively coupled plasma (ICP) and infrared spectroscopy (FTIR), respectively. Statistical analysis was performed by using SPSS software and the mean comparison test at 5% probability level and in the form of factorial test. Results & Discussion: The hydration capacity in processed wheat starch was lower than corn starch due to the differences in granular structure of wheat and corn starch. The hydration capacity in native wheat and corn starches was significantly (p < 0.05) lower than the processed forms. No significant difference (P>0.05) was observed between the three steps of adding enzyme (e after, simultaneously and before the ultrasound processes). According to the results, the oil adsorption capacity in the processed starches was more than that of the native forms. Scanning Electron Microscopy (SEM) shows that the native corn and wheat starch granules appeared without any clear of fissures, fractures and pores. The corn and wheat starches which were treated by the enzyme after (step 1), simultaneously (step 2) and before (step 3) the ultrasound change and lose their smooth surfaces and become uneven. The surface of corn granules in group 2 and 3 have less pores and porosities with more laminated. In simultaneously processes (phase 2) the ultrasound causes the enzyme to be inactivated. In phase 1, it can be concluded that the ultrasound helps the enzyme performance in creating the porosities and cavities. The wheat granules in step 1, 2 and 3 have a lot of damage on the surface and it is likely that the surface of the wheat granule is more resistant to enzyme penetration than the corn. The results of the ICP test show that processed corn starch has significantly (P <0.05) greater ability to absorb iron ions than processed wheat starch. Also, corn starch had a significant difference in iron uptake in the step 1 than steps 2 and 3 (P <0.05), but the data of the second and third steps did not differ significantly (P> 0.05). Hydroxyl groups of D-glucose units in starch granules bond with iron ions and FTIR spectrums give drop at 575 (cm-1) wavelengths. This study showed that enzymatic treatment and ultrasound led to the native corn starches convert to porous starches. The corn starch is more suitable than the wheat because the wheat is more resistant and the cavities were rarely formed. The corn porous starch is a suitable carrier for iron ions.
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Food Engineering
Mohsen Zandi; Ali Ganjloo; Mandana Bimakr; Narges Nikoomanesh; Negar Moradi
Abstract
Introduction: The base of intelligent methods is using hidden knowledge in the experimental data, trying to extract the inherent relationships among them and generalizing results to other situations. Artificial neural networks are one of the most essential methods used in the field of artificial intelligence ...
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Introduction: The base of intelligent methods is using hidden knowledge in the experimental data, trying to extract the inherent relationships among them and generalizing results to other situations. Artificial neural networks are one of the most essential methods used in the field of artificial intelligence was inspired by how the human brain works, training takes place first, and then the information related to the data is stored in the form of the network's weights. Fuzzy logic is an important decision-making tool that has recently found some applications in food quality. Also, it is possible to find out the reasons for low and high ranking of products evaluated by the judges. The fuzzy model can be used to determine the importance of individual factors to the overall quality of a product. The ANFIS model is a combination of the artificial neural network (ANN) and a fuzzy inference system (FIS) in such a way that the neural networks are applied to determine the parameter of the fuzzy inference system. The fuzzy logic theory effectively addresses the uncertainty problems that solve the ambiguity. Sweet lemon (Citrus limetta) fruit is a popular agricultural product cultivated in tropical countries used to treat common colds, influenza and hypertension. Sweet lemon is quite perishable with postharvest losses such as weight loss, physiological deterioration, decay, and softening texture. The objective of the present study was to investigate grading of sweet lemon fruit based on quality and visual characteristics using fuzzy logic and ANFIS. Material and Method: Ripe sweet lemon (Citrus limetta) fruits and radish (Raphanus sativus L.) leaves were purchased from the local market in Zanjan, Iran. For emulsion solution preparation, 50 ml alginate sodium solution, 1 ml glycerin and 0 or 10 g radish leaf extract were mixed, then the coating solution volume was made up to 100 ml using distilled water. Finally, the mixture was steered for 200 second. Sweet lemon fruits were dipped in coating solutions or distillate water (for control treatment) for 2 minutes at ambient temperature (25℃) and were then air-dried for 2 h using a fan. All treatments stored at 4℃ for 50 days. Firmness, pH, titratable acidity (TA), total soluble solids content (TSS), color, and shape were measured at 10-day intervals. This paper introduces an adaptive neural-fuzzy inference system (ANFIS) model to classify sweet lemon based on the quality parameters and RGB intensity values. The ANFIS with different types of input membership functions (MFs) was developed. A study was performed using fuzzy logic and adaptive neural-fuzzy inference system (ANFIS) to predict the quality parameters of sweet lemon (firmness and ripening index). Results & Discussion: Our results showed that ‘triangle2mf’ MF performs much better than other mentioned MFs for defect inspection. The classification accuracy of the ANFIS with ‘triangle2mf’ MF was 97.5% and 96.6% for quality input and visual input, respectively, and the total correct classification rate was 97.01%. Therefore, this study indicated the possibility of developing a potentially useful classification tool using the ANFIS technique based on quality parameters and RGB values for fruit classification during processing, storage and distribution. Comparing the results obtained from fuzzy logic with various membership function, showed that the RMSE in the fuzzy logic with ‘guss2mf’ MF was lower than other algorithms. The proposed approach focuses on three research motivations. First, to develop a fuzzy rule-based classification system that can detect all the four quality grades of the sweet lemon. Second, the system should be able to predict the quality parameters of sweet lemon. Fuzzy logic deserved high level of accuracy in classification of sweet lemon, indicating high correlation between the data obtained from Mamdani fuzzy rules and experimental ones during storage time.
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Food Chemistry
Ahmad Ehtiati; Massoumeh Mehraban Sangatash; Reza Karazhyan; Zahra Nazari; Farzad Sadeghi
Abstract
Introduction: Shortening is an important ingredient of bakery products, especially the ones with less developed gluten network like cakes and cookies . Shortening thermo-rheological properties are related to the presence of high levels of saturated fatty acids which have the capability of making ...
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Introduction: Shortening is an important ingredient of bakery products, especially the ones with less developed gluten network like cakes and cookies . Shortening thermo-rheological properties are related to the presence of high levels of saturated fatty acids which have the capability of making crystals at room temperature which melt during baking. Consumption of high saturated fatty acids increases the risk of coronary disease. Moreover, hydrogenation is a usual technique for elevating the saturated fatty acid content of vegetable oils. Lowering the saturated fatty acid content of a shortening results in the shortening with less functionality. Transition of an oil physical properties to those of a semi-solid structure can be done using low- or non-digestible oil gelators called oleogelation. Ethyl cellulose is a polymer with oil gelation capabilities at low concentrations. However, its oleogels are firm and brittle, so some low-molecular-weight gelators can improve its texture and increase its plasticity to mimmic commercial shortening functionality. In this study, the functionality of an oleogel based on ethyl cellulose, stearyl alcohol, stearic acid and sorbitan monostearate was evaluated as commercial shortening substitute in cake formulation. Materials and Methods: Based on previous studies and preliminary experiments, an optimized oleogel formulation was prepared as shortening, composed of ethyl cellulose (6.4%), stearyl alcohol:stearic acid (70:30) (7.5%), sorbitan monostearate (0.1%) and canola/soy mixture oil (75:25 ratio) (86%).The gel was formed by heating up the mixture to 150 °C for the complete solvation of the gelator compounds and gradual cooling to room temperature. In the next step, commercial shortening was substituted with the oleogel shortening at 0, 25,50, 75 and 100% in the cake formulation. Moisture content, water activity, specific volume, crust color, Lab color space indices based on image processing, porosity based on crumb image analysis, TPA parameters and sensory attributes were determined and compared using one-way analysis of variance and LSD mean comparison test. Results & Discussion: The results showed that there was no significant difference in the moisture content, water activity and specific volume of the cakes prepared with the oleogel shortening with the one prepared with commercial shortening. This reveals that the oleogel shortening functionality was acceptable compared with commercial shortening. In terms of crust color, there was no significant difference in the lightness index (L*) and red-green range (a*) indicators between different samples and only in the yellow-blue range (b*) index, the cake with 100% substitution showed a lower value than the control. For the porosity index, there was no significant difference between the five samples, proving the oleogel shortening can induce sufficient air bubbles generated during batter mixing and its preserving effect during baking. Examining the texture of the cake samples showed that the texture hardness and springiness indices decreased with a rise in the level of commercial shortening substitution, while the cohesiveness index did not differ significantly. The latter indicated that the oleogel shortening effectively shortened the gluten network; thus, it can be said that the same commercial shortening functionality is attainable using less oleogel shortening content. Furthermore, as the percentage of the commercial shortening substitutes increased, due to texture softening, the chewing energy of the samples decreased resulting in a better mouthfeel. Finally, sensory evaluation of the cake samples did not show a significant difference in taste, texture, appearance, color and overall acceptance based on scores obtained from ten untrained evaluators. In conclusion, the use of oleogel shortening instead of commercial shortening with high saturated fatty acid content in cake formulation not only can result in a cake with acceptable properties at 50% replacement level, but also can replace commercial shortening even up to 100%.The latter just lead to a softer texture. Optimization of the cake formulation based on the oleogel shortening would specifically result in a cake with better properties, while it has significantly lower saturated fatty acid content and nearly zero trans fatty acids.
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Food Technology
Sima Naji-Tabasi; Elham Mahdian; Akram Arianfar; Sara Naji-Tabasi
Abstract
Introduction: Fats have a special place in human nutrition and their main role is supplying energy for the body. But scientific findings approve an association between high fat intake and an increment risk of some diseases, such as atherosclerosis, heart disease, and …. Demand for low-fat foods ...
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Introduction: Fats have a special place in human nutrition and their main role is supplying energy for the body. But scientific findings approve an association between high fat intake and an increment risk of some diseases, such as atherosclerosis, heart disease, and …. Demand for low-fat foods has increased dramatically as people become more aware of fat consumption side effects. However, due to the multiple role of fats in food products, eliminating or decreasing fat lead to poor quality of products. Therefore, it is necessary to use a combination of fat substitutes to maintain the rheological, texture and sensory properties of the low fat food products. The use of emulsion gel structures are new methods for the production of low-fat product that has been studied in this investigation. The Pickering emulsion was used to produce the emulsion. In this method, instead of using surface-active agents, solid particles are used to stabilize the emulsion. The aim of this study was to prepare Pickering Emulsion from Isolated Soybean protein (ISP) and Basil Seed Gum (ISP-BSG) Complex. Finally, emulsion gel systems were applied as fat substitutes in cream. Materials and Methods: Basil seeds were purchased from Mashhad market. Isolated soy protein was purchased from Shandong Yuxin Bio-Tech Co. (China). Sodium azide was purchased from Applichem Inc. (Dramstadt, Germany). Sodium dodecyl sulphate (SDS) was obtained from Merck, Germany. Pickering (solid particles) of soy protein isolate (SPI) and SPI-basil seed gum (ISP-BSG) complex used as emulsifier for stabilization of cold emulsion. ISP-BSG particles were prepared with different mass ratios of ISP: BSG, 1: 0, 1: 1, 2: 1 and 3: 1 and named 1S: 0B, 1S: 1B, 2S: 1B and 3S: 1B, respectively. These solid particles were used as Pickering for emulsion preparation. Cold Emulsion was prepared by adding calcium chloride. The oil leakage, oil leakage after thermal treatments, microscopic structure, textural properties and viscoelastic properties of emulsion gel were studied. Then, the best structures used as a fat substitute in cream (5, 10 and 15%). Results & Discussion: Investigation of emulsion gel properties showed that coating the surface of emulsion droplets with solid nanoparticles formed a rigid shell that acted as a barrier against the deformation and transfer of materials from the interfacial surface. The use of ISP-BSG nanoparticles as picking particles caused more homogeneity and stiffness in emulsion gel structure. The rate of water loss in reduced fat cream was in the range of 1-2% by using the emulsion-gel system, which indicates the effectiveness of these systems in reducing dehydration in cream. The increasing replacement percentages led to increase water loss (p <0.05). However, emulsion type had no significant effect on water loss content (p> 0.05). According to the results, ISP-BSG nanoparticles impart high potential to stabilize emulsion with small oil droplets. Based on the results of the sensory test, it was found that the characteristics of the cream samples depended more on the replacement rate than the type of system used as an alternative. The presence of a fat replacement system maintained the desired quality in low-fat cream samples. Most of the samples scored higher than 3, which indicate the high acceptance of low-fat samples.
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Food Engineering
Fatemeh Karani; Javad Sargolzaei
Abstract
Introduction: The Okra belongs to the family Malvaceae with the scientific name Abelmoschus esculentus (Peyvast, 2009). The viscous property of okra is due to the thick and viscous matter in the fruit pod, called mucilage. Okra mucilage is a polysaccharide currently used in pharmaceutical industry as ...
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Introduction: The Okra belongs to the family Malvaceae with the scientific name Abelmoschus esculentus (Peyvast, 2009). The viscous property of okra is due to the thick and viscous matter in the fruit pod, called mucilage. Okra mucilage is a polysaccharide currently used in pharmaceutical industry as a hydrophilic polymer in tablet coatings (Bakre et al, 2009). Mucilage collectively contains polysaccharides, proteins, and minerals found in a plants or seeds that are more widely used in various industries, including food industry, as a stiffener in dairy products. Mucilage composed of monosaccharide polymers, amorphous and semi-transparent, and are hydrocolloids. These materials are hydrophilic molecules that can be extracted with water and form a concentrated or gel solutions. Gels are widely used in the food, pharmaceutical and non-pharmaceutical industries. The cultivation of okra in Iran is mainly occurred in tropical and subtropical regions and is found in Khuzestan, Ilam, Kermanshah, South Fars, Bushehr and Hormozgan provinces (Mozafarian, 2012). Many studies have been done on the extraction of okra mucilage and its applications in the pharmaceutical and food industries. Faroq et al. worked on the organoleptic properties of okra mucilage and concluded that okra mucilage has good flow properties and high solubility in water that can be used safely without any side effects (Farooq et al, 2013). ). Noorlaila et al studied the emulsifying property of mucilage extracted from okra (Noorlaila et al, 2014). Nazni and Vigneshwar studied the extraction and evaluation of organoleptic properties of mucilage from okra and several other plants and used ethanol and acetone to purify mucilage (Nazni et al, 2012). A study was conducted in 2018 to study the basic properties such as swelling index, emulsion stability, viscosity and antioxidant activity of okra mucilage (Fekadu Gememde et al, 2018). In a study on the use of okra mucilage in pharmacy, Ameena et al after extracting mucilage from okra and measured the physicochemical properties of mucilage, applied it in tablet formulation and many parameters such as diameter, thickness, weight change, hardness and Fragility were assessed. According to observations, low concentrations of okra mucilage can be used as a substitute for starch in tablet formulation, and also high levels of okra mucilage can be used in the drug release system as a natural substance (Ameena et al, 2010). In a study, Mishra et al presented okra mucilage as a new proposal to replace polymer materials used in various industries (Mishra et al, 2008). In 2014, the effect of okra mucilage on the release of propranolol hydrocolloid in tablets was studied. The highest hardness and lowest brittleness were observed for okra tablets (Zaharuddin et al, 2014). In this research, extraction of okra mucilage was investigated by two methods of solvent and supercritical fluid extraction. Optimization the yield and physicochemical properties of the extract obtained from both methods was also investigated. Materials and methods: Fresh okra obtained from local supermarket in Khuzestan province. Chemicals materials such as pure ethanol, acetone, chloroform, acetonitrile purchased from Merck and Sigma Aldrich. After transferring the okra fruit to the laboratory, the contaminants were removed from the plant and then rinsed thoroughly with water. The okra pods were dried at about 40 °C in a digital fan oven model 6882A. It was powdered by a German-made electric milling machine and then it passed through a 30-mesh sieve to be ready for extraction and it was weighted by laboratory scales (0.0001 precision manufactured by Cornell, Germany). In the solvent extraction process, the okra powder was weighed by a digital balanced (GR-200 model made in Japan) and transferred to 250 ml human. The solids stirred in distilled water and various amounts of solvent for 1 to 5 hours until the mucilage is completely released into the water. The solution was filtered and then adjacent to an organic solvent. Then, the filtrate was poured again into Petri dish and placed on a water bath at 45 °C to evaporate the residual solvent inside it. The residue inside the Petri dish was dried in a fan oven (Reyhan Teb Company) at 40 °C and powdered and kept at 20 °C until the day of analysis. In the supercritical extraction method, the supercritical fluid extraction machine which designed and manufactured in the laboratory of the Faculty of Engineering at Ferdowsi University of Mashhad was used. The carbon dioxide was supplied by Khakakan Co., Quchan Road, Iran in a 45 kg cylinder. Results & Discussion: Generally, according to the results of both methods of solvent extraction and supercritical fluid extraction (SFE), the extraction efficiency of mucilage at the optimal point in the solvent extraction and in the supercritical methods was 5.12% and 1.58%, respectively. Due to the less use of organic solvents in the supercritical method, this method is more environmentally friendly, which is significant in converting the laboratory method to pilot or industrial scale. Physio-chemical analysis of mucilage obtained by two methods shows that the index of swelling, moisture and ash of mucilage obtained by maceration is more than that of supercritical mucilage. By comparing the obtained values at the optimal point of both methods, the solvent method has a higher total efficiency and has been more successful. However, in the supercritical fluid method, the solvent utilization is significantly reduced. The extraction time in the supercritical fluid method is also reduced by about 50%.
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Food Technology
Ali Kashani; Maryam Hasani; Leila Nateghi; Mohammad javad Asadolahzadeh; Parvin Kashani
Abstract
Introduction: Nowaday, the demand for low calorie food based and keeping primary features including texture and taste is increasing. Jelly is one of low calorie products produced from fruits and other components, and its consumption is increasing for human health. Jelly is semi-solid and transparent ...
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Introduction: Nowaday, the demand for low calorie food based and keeping primary features including texture and taste is increasing. Jelly is one of low calorie products produced from fruits and other components, and its consumption is increasing for human health. Jelly is semi-solid and transparent product that prepared with the use of sugar or juice and pectin or gelatin and flavor and color may also be added. Potato peels contain valuable substances such as pectin. Using potato peels to produce pectin with appropriate properties can solve the environmental issue resulting from these wastes in addition to make value added product. Pectin is a complex polysaccharide that is found in the wall of early plant texture and in the intercellular layer. Pectin contains a group of rich polysaccharides of galacturonic acid units with lower amounts of different sugars (Baiano, 2014). Two commercial forms of pectin are available: high-methoxyl and low-methoxyl pectin (high ester and low ester pectin). High-ester pectin forms a gel in a solutions containing high soluble solids and acidic systems, whereas low-ester pectins form more gel at wider pH and range of solids content but they do require divalent cations to form the gel (Kratchanova et al., 2012). In the food industry, pectin is used as a jelly-making agent, especially in the production of jellies and jams. Pectin is also used in fillers, medicine, pastries, bakery products and also as a stabilizer in juices and beverages, as well as in dietary fiber (Sharma, 2006). Pectin also has therapeutic benefits such as lowering blood cholesterol levels, removing heavy metal ions from the body, stabilizing blood pressure and facilitating intestinal activity (Ptichkina et al., 2008). Temperature, pH, and acid extraction time are the most important factors affecting the extraction yield and quality of produced pectin (Yapo et al., 2007). Currently, almost all commercial pectins are produced from citrus or apple peels, both of which are juices by-products (Thirugnanasambandham et al., 2014). Therefore, the main objective of this study was to optimize the conditions of extraction of pectin from potato peel by response surface methodology and to compare the physicochemical properties of Jelly produced from potato peel under optimum conditions with Jelly produced from apple and citrus Material and methods: Potato of Granola variety was purchased from the local market in Ardebil. The chemicals used for the tests include: citric acid, sodium hydroxide, phenolphthalein, and Calcium chloride were purchased from Merck Company (Germany). The method of Hoseeni et al (2017) was used for jelly production with slight modification as follows. In the First step,0.5 and 1% pectin extracted from potato peelings, 30 % Sugar, 0.014 % Cherry edible color and 0.75 % Cherry essential oil were mixed then 100 CC Boiling water was added to the mixture and mixed again. After the sugar was completely dissolved, 15, 30, and 45 mg of calcium chloride was added per gram of pectin. The pH of the samples was regulated by citric acid solution on 2.5 and 4. The heating of the samples was continued until the brix of the treated treatments was set to 42. The prepared samples were kept at room temperature for half an hour. The treatments were then refrigerated for 2 to 3 hours to complete the jelly closing process. For this purpose some jelly characteristics such as texture properties, physico-chemical (pH, acidity, brix, moisture and Drainage) and sensory properties of samples were investigated using five point hedonic scale. A one-way analysis of variance and Duncan test (P≤ 0.05) in three replications were used to establish the significance of differences in the experimental data. The results were analyzed using the Minitab version 16. Results & Discussion: Results showed that by increasing calcium chloride, pH and Pectin concentration had a significant effect on increasing the hardness of the gel and the strength needed to make the gel brittle (P≤0.05).The highest hardness of the gel in pectin emulsion extracted from potato peel was 30.0959 N and highest force required to break the gel was 27.3431 N in the most severe extraction conditions at Calcium chloride 35.2286 mg/g, Pectin concentration 1% and pH 4. Results of physico-chemical properties showed that there was no significant difference between pH, acidity, brix and moisture of jelly made from apple pectin and citrus and apple commercial pectin. The results of the syneresis showed that the syneresis by the jelly of potato pectin is not similar with jelly from apple pectin and citrus and apple commercial pectin significantly different. Also Results of sensory properties showed that it was no significant difference between jelly from apple pectin and citrus and apple commercial pectin. The results of this study showed that by optimizing the production conditions, potato pectin can be used in jelly formulation and jelly can be produced with desirable and comparable quality compared to the commercial pectins
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Food Engineering
Hossein Mohebodini; Atefe Maqsoudlou
Abstract
Introduction: Microencapsulation is the most commonly used method of preserving proteins and peptides, which increases the stability in different conditions. Bee pollen with 10–40% protein, is a valuable source of protein that has functional and nutraceutical properties. By hydrolysis and producing ...
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Introduction: Microencapsulation is the most commonly used method of preserving proteins and peptides, which increases the stability in different conditions. Bee pollen with 10–40% protein, is a valuable source of protein that has functional and nutraceutical properties. By hydrolysis and producing bioactive peptides, their functional and health effects will be improved. Fibersol is a dietary fiber that can be used in many foods and supplements. This carbohydrate compound is actually non-digestible maltodextrin and has recently been used as a wall material in encapsulation. Few studies have conducted on the microencapsulation of hydrolysed proteins and their stability during accelerated conditions. On the other hand, by-products of honey bees such as pollen have been less noticed; therefore the aim of this study was the microencapsulation of bioactive bee pollen protein hydrolysate by fibersol and WPC and to study the changes of structure and stability of resulted microcapsules during the exposure to UV radiation. Material and Methods: Bee pollen was hydrolysed by Alcalase (1.5%) for 4 h in shaking incubator. The protein hydrolysate was microencapsulated using WPC, fibersol, and their combination by spray drying. The wall materials and hydrolysed protein were used in ratio of 10:1 (w/w). WPC 2%, fibersol 2%, as well as WPC and fibersol mixtures with 1:3 ratio, were the wall materials. For accelerating the oxidation reactions, the obtained capsules were exposed to UV radiation for 48 h. During the exposure to UV radiation, the DPPH radical scavenging activity of microcapsules and hydrolysed protein was measured. Interactions between hydrolysed protein compounds, WPC and fibersol were identified by the FTIR spectroscopy. The SEM was used to investigate the morphology of the microcapsules. Results & Discussions: Almost at all experimental time, the highest DPPH radical scavenging during exposure to UV radiation was related to the capsules prepared using fibersol and WPC mixture and after that the capsule with WPC as wall material. The FTIR spectroscopy of the hydrolysed protein was changed significantly when it was exposed to UV radiation. This change caused by losing the hydrogen bonds in the secondary structure of proteins, including the separation of two polypeptide chains or the opening of the αhelix and loss of β-sheet structure. The FTIR profile of capsulated hydrolysed protein by fibersol showed that the adhesion of protein and polysaccharide changed the absorbance of C–H bending and N–H stretching bands of amide groups in the hydrolysed protein in 3000–3500 cm-1 and the stretching band of C–H and O–H group in the region of 2000–3000 cm-1 for fibersol in the wall. After exposure to UV, because of cross-linking in fibersol and more involving the molecules of fibersol to protein, the absorbance was increased in the region of 1500–3500 cm-1. The number of peaks and absorbance in the FTIR spectra of hydrolysed proteins microencapsulated in WPC were more than number of peaks and absorbance in the FTIR spectra of WPC. There was no significant difference in the FTIR spectra of hydrolysed protein encapsulated with WPC before and after exposure to UV. The peaks in FTIR spectra of hydrolysed protein microencapsulated with the mixture of WPC and fibersol, showed higher absorbance level than the peaks of fibersol and lower than peaks of WPC. None of the peaks of microencapsuls with the wall of mixture of WPC and fibersol, were changed after exposure to UV radiation. Results of SEM showed that the microcapsules prepared with mix of fibersol and WPC had a uniform and smoother wall than microcapsules prepared with only fibersol. Finally, the mix of WPC and fibersol was selected as the best wall with a proper protective ability for the microencapsulation of hydrolysed proteins and protection against UV radiation.
