Food Engineering
Mohammad Reza Salahi; Seyed Mohammad Ali Razavi; Mohebbat Mohebbi
Abstract
Introduction: Emulsion-filled gel is a sort of gel system that traps oil droplets as a filler and contains a wide range of semi-solid to solid food products. They can also be utilized as a dual system to distribute and control the release of both lipophilic and hydrophilic bioactive and micronutrient ...
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Introduction: Emulsion-filled gel is a sort of gel system that traps oil droplets as a filler and contains a wide range of semi-solid to solid food products. They can also be utilized as a dual system to distribute and control the release of both lipophilic and hydrophilic bioactive and micronutrient substances. The main polymers involved in gel formation in food products are proteins and polysaccharides. Using molecular interactions between biopolymers, a wide range of rheological and physicochemical properties of gels can be methodically created. As a result, the interaction between proteins and polysaccharides has received a lot of attention in order to generate novel products. Because of their functional qualities and high nutritional value, whey proteins are frequently used in the food industry. As a result, mixed gels based on whey protein have gained a lot of attention. k-Carrageenan is commonly utilized in the food industry as a gelling and firming agent. Because k-Carrageenan, like whey protein isolate, can form a gel independently, its interaction with whey protein isolate in emulsion gel systems appears appealing. Therefore, in this study, the effect of k-Carrageenan gum (0.0, 0.1, 0.3, 0.5, and 0.7%) on the textural (uniaxial compression test), rheological (steady shear, strain sweep, and frequency sweep tests), and water holding capacity of cold-set emulsion-filled gel based on whey protein isolate was investigated.Materials and Methods: Whey protein isolate (WPI) (98.9% protein, dry basis) was given as a gift by Agropur Ingredients Co. (Le Sueur, Minnesota, USA). k-Carrageenan and CaCl2 (m_w: 147.01 gr/mol) were purchased from Sigma Aldrich Co. (USA) and Merck Co. (Darmstadt, Germany), respectively. Sunflower oil was bought from a local supermarket. Stock dispersions of WPI and k-Carrageenan were made by dissolving sufficient amounts of their powders in deionized water. To prepare uniform oil in water emulsion, sunflower oil was added to the WPI dispersion and the obtained mixture homogenized first using a laboratory rotor-stator homogenizer (15000 rpm, 3 min), then by an ultrasonic homogenizer (20 kHz, 5 min). The prepared emulsion and k-Carrageenan dispersions were poured into Schott bottles and heated in a water bath (90 C, 40 min). WPI emulsion and AG dispersion were mixed in a cylindrical container on a stirring plate at a speed of 600 rpm for 6-8 min to obtain a homogeneous mixture. After decreasing the temperature to 60 C for the ion-induced gelation, the mixtures were charged with CaCl2 (10 mM). The prepared samples were incubated in a refrigerator overnight to stabilize the 3D network. The final mixed EFG samples contained 5.5% WPI, 20% oil, and 0, 0.1, 0.3, 0.5, and 0.7% (w/w) of k-carrageenan. The tests performed on emulsion-filled gel samples were: 1) steady shear (0.01-10 s-1), 2) strain sweep (strain: 0.1-1000%, frequency: 1 Hz), 3) frequency sweep (frequency: 0.1-100 Hz, strain: 0.5%), 4) uniaxial compression (target strain: 80%, deformation speed:1 mm/s), and 5) water holding capacity (by utilizing a microcentrifuge, 600×g for 10 min).Results and Discussion: According to the steady shear test, all samples had a shear thinning behavior, and based on the power-law model, this behavior was intensified in the presence of k-Carrageenan; and with increasing the gum concentration from 0 to 0.7%, the consistency coefficient increased from 339.9 to 545.7 Pa.s. In the strain sweep test, with the increase in the gum concentration, the values of the elastic and viscous modulus in the linear region and the modulus at the crossover point increased, and Tan LVE decreased from 0.17 to 0.13, which indicated an increase in the strength of the emulsion gel network structure. Based on the frequency sweep test, with the increase in k-Carrageenan concentration, the parameters K^' and K^'', network strength and network expansion, respectively, increased from 5311.8 Pa, 939.9 Pa, 1.5380 Pa.s1/z and 10.05 in the control sample to 25080 Pa, 3574.9 Pa, 16097.7 Pa.s1/z and 16.41 in the sample containing 0.7% k-Carrageenan, respectively. Moreover, the frequency dependency of elastic modulus decreased from 0.095 in the control sample to 0.050 in the 0.7% k-Carrageenan contained sample. According to the large deformation test, in general, in the composite emulsion-filled gels, the values of apparent modulus of elasticity and fracture stress were higher and fracture strain and fracture energy were lower than in the control sample. Also, the results showed that different k-Carrageenan concentrations had no significant effect on the water holding capacity.The obtained results showed that k-Carrageenan had considerable influence on the rheo-mechanical features of cold-set emulsion-filled gels based on whey protein which can add to the knowledge base for the production of new functional foods.
Food Technology
Soheyl Reyhani Poul; Sakineh Yeganeh
Abstract
Introduction: Shrimps are highly sensitive to oxidation at refrigerator temperature. On the other hand, storage of shrimp in freezing conditions leads to a decrease in product quality after thawing. It should be noted that shrimp oxidation also occurs in freezing conditions, but the oxidation rate in ...
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Introduction: Shrimps are highly sensitive to oxidation at refrigerator temperature. On the other hand, storage of shrimp in freezing conditions leads to a decrease in product quality after thawing. It should be noted that shrimp oxidation also occurs in freezing conditions, but the oxidation rate in these conditions is much slower than storage in refrigerated conditions. Therefore, it seems necessary to use a method that can control the oxidation of shrimp in both freezing and refrigerating conditions. The aim of this study was to evaluate the feasibility of controlling shrimp oxidation (at refrigerator temperature) using whey protein coating containing ascorbic acid or α-tocopherol, and to compare the efficacy of these antioxidants (in combination with whey protein). Materials and Methods: In order to advance the purpose of the research, shrimp fillets were stored in four treatments, including treatments No. 1 (control), 2 (shrimp fillet coated by whey protein), 3 (shrimp fillet coated by whey protein + ascorbic acid) and 4 (shrimp fillet coated by whey protein+ α-tocopherol) at refrigerator temperature for 9 days. In order to evaluate the oxidation intensity and also the stability of the treatments against oxidative damage, peroxide indices, free fatty acids, anisidine and thiobarbituric acid of the treatments were determined on days 0, 3, 6 and 9. This study was implemented in form of completely randomized design and data were analyzed by one-way ANOVA. Significant differences among means were tested by Duncan's test at 95 confidence level. Results and Discussion: The results showed that whey protein alone (treatment 2) as shrimp coating can partially control the oxidation process of fillet fats compared to control. But when whey protein was combined with ascorbic acid (treatment 3) and α-tocopherol (treatment 4), the coatings' strength against oxidative deterioration significantly increased (p<0.05). According to our findings, during the storage period, the lowest amount of peroxide, free fatty acids, anisidine and thiobarbituric acid indices were related to treatment 3 (p<0.05). During the storage period, all the mentioned indicators (in all treatments) had an increasing trend, but the slope of this trend was different and the lowest slope was related to treatment 3. Comparison of fresh shrimp fillet fatty acid profile with fatty acid profile of treatments at day 9 showed that the whey protein coating combined with ascorbic acid (treatment 3) had the most protective effect on the structure of fatty acids. Overall, according to the results of the present study, it can be claimed that whey protein- ascorbic acid coating is more effective than whey protein-α-tocopherol coating to increase the oxidative stability of shrimp fillet. Therefore, the ascorbic acid is more efficacious than α -tocopherol (in combination with whey protein) in controlling the oxidation of shrimp fillets.
Mohsen Zandi
Abstract
The aim of the current research was to identify and develop an ideal delivery system in order to protect the vitamin from gastrointestinal conditions. For this purpose, vitamin loaded Alginate-Whey protein micro gels (AL-WPC MGs) developed as a biopolymer carrier. This microcapsule was examined in terms ...
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The aim of the current research was to identify and develop an ideal delivery system in order to protect the vitamin from gastrointestinal conditions. For this purpose, vitamin loaded Alginate-Whey protein micro gels (AL-WPC MGs) developed as a biopolymer carrier. This microcapsule was examined in terms of morphology, ζ-potential particle size and distribution, encapsulation and delivery efficiency, and in vitro gastric and intestinal digestions. Absorbance method was used to monitor B-complex vitamins release over time at the simulated gastrointestinal conditions. Release experiments illustrated beneficial attributes for these microspheres. Release mechanism was predicted by using various kinetic equations. Results indicated that the most of the fabricated spherical shaped AL-WPC MGs was under 100 μm in size, and these microcapsules had an excellent and moderate stability in gastric and intestinal conditions, respectively. It was found that the highest vitamin release rate occurs in the simulated gastric-intestinal situation, and type of the vitamin had a slight effect on the release rate and release profile. Kinetic models suggested that release from group B vitamins mainly was controlled by Fickian diffusion mechanism. In general, this research showed that the AL-WPC MGs protect the vitamin from gastric digestion and could be used as a delivery system.In previous works, a novel AL-WP MGs and use for different active agent encapsulation was developed, while the final purpose of this work was to study the vitamin release mechanism from AL-WPC MGs at the gastro–intestinal situation. Accordingly, this microcapsule showed the highest vitamin release rate at the simulated intestinal situation. This high release could be due to instability of alginate in neutral pH, and also enzymatic digestion of whey protein. The better release of vitamin at intestinal condition is desirable to achieve the nutrient effect during food consumption. This micro gel therefore appears to be potentially beneficial as digestion delivery vehicles for bioactive compounds in the food and nutraceuticals industry as well as non-food industry.
Sanaz Ghassemi; Seyed Mahdi Jafari; Morteza Khomeiri; Elham Assadpour
Abstract
Orange peel oil,a widely used industrial flavoring, is volatile and chemically unstable in the presence of air, light, moisture and high temperatures. Biopolymer Nano complexes, a bunch of Nano carriers, are produced between groups of charged polysaccharides and proteins with the use of electrostatic ...
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Orange peel oil,a widely used industrial flavoring, is volatile and chemically unstable in the presence of air, light, moisture and high temperatures. Biopolymer Nano complexes, a bunch of Nano carriers, are produced between groups of charged polysaccharides and proteins with the use of electrostatic interactions. The nanoparticles are able to carry, protect, and increase their bioavailability of food-drug materials. Hence, in this study, the Nano complexes of pectin- whey protein concentrate, as a carrier of orange peel oil, were produced and the features of prepared Nano complex solution with various concentrations of whey protein (4, 6 and 8%), pectin (0.5, 0.75 and 1%) and different values of pH (3, 6 and 9) were studied. The Viscosity, stability and color (index L *) of the treated designs, done in a response surface methodology, were examined. The results showed that whey protein 4% and pectin 1%( with a pH of 3 and 9) had the lowest and highest stability respectively. Also this treatment with a pH of 3 showed the highest viscosity as well as the highest L *. The lowest viscosity was achieved by whey protein 6% and pectin 0.75% with a pH of 3, and because of the unbalanced compound, the complex did not form and a phase separation occurred. The lowest L * was obtained by whey protein 4% and pectin 0.5% with a PH of 9. Ultimately, whey protein 4% and pectin 1% with a PH of 3 were selected as the optimum sample because of formation the strong and suitable complex. Particle size and zeta potential measurement of optimum sample, were 160 nm and -0.53 mV respectively.
Samaneh Joodi Attar; Vahid Hakimzadeh; Hassan Rashidi
Abstract
Introduction: Cheese is a dairy product that commonly used and has lots of variety in the world. Among the various types of cheese, UF cheese is attracting more consumers in Iran. The need to change the flavor and make a diversity in this product has been considered for long time. Since high fat foods ...
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Introduction: Cheese is a dairy product that commonly used and has lots of variety in the world. Among the various types of cheese, UF cheese is attracting more consumers in Iran. The need to change the flavor and make a diversity in this product has been considered for long time. Since high fat foods such as cheese are the main cause of some disorders like cordial disease, cancer, obesity and diabetes, formulation of dairy products with modified fat or fat replacer was considered by many researchers and suppliers. Vegetable oils can be used as a substitute for milk fat in cheese. Flaxseed oil consists high level of alfa-linolenic acids (Omega-3) and suitable amount of proteins could noticed as a fat replacer. In this study, we investigated the effect of milk fat replacement with flaxseed oil on the production of functional Feta cheese. The rheological, physicochemical, and organoleptic characteristics of such cheese and its optimal formulation were also determined
Materials and methods: The effect of Flaxseed oil (FSO) at a range of 0-100 % and whey protein concentrate (WPC) (0-15%) was investigated on pH, synersis, Dry Matter, hardness, springiness as physicochemical and mechanical properties and mouth feeling, odor, taste overall acceptance as organoleptic properties of UF cheese production by RSM. For the preparation of cheese, a free fat retentate powder was used. To adjust fat to 20%, cream was used with 70% flaxseed oil and homogenized by ultraturrax method. All of the physicochemical, mechanical and organoleptic tests accomplished according to theIranian national Standards/
Results and discussions: Results showed that by increasing the amount of FSO in the formulation of cheese, pH, stiffness and synersis increased. Also, with increasing flaxseed oil, the elasticity was initially decreased and increased in greater quantities afterward. However, by increasing the WPC, the elasticity decreased. The increase of flaxseed oil had a reversible effect on the taste, smell, color and overall cheese acceptance score compared with the control samples due to the presence of some impurities in oil. Increasing the amount of WPC and FSO also caused a decrease in pH and fat during ripening of cheese. Although increasing the level of WPC improved the odor of cheese, but did not have positive effect on appearance, color and general acceptance. The result of optimization of UF cheese production with the following indices: pH 4.82%, synersis 1.35%, fat 20.3%, dry matter 32.45%, hardness 631.46 nm, elasticity 0.94 mm, color 3.4, Odor 3.1, flavor 2.8, texture 3.1 and final acceptance 3.11, showed that the best formulation needs 96.01% of flaxseed oil and 9.73% whey protein concentrate. Finally, the predicted optimal formula by software was also determined as follow: pH 4.78, synersis 1.27%, fat content 19.8%, dry matter 31.4%, the firmness index 618.02, the elasticity 1.03 mm, and the sensory scores included color 3.4 , odor 3.15, Taste 2.97, Texture 3.64 and Final acceptance 3.21.
Samira Abbaspour Monjezi; Mohammad Reza Edalatian Dovom; Mohammad Bagher Habibi Najafi; Arash Koocheki
Abstract
Introduction: Nowadays, consumers prefer foods produced without synthetic preservatives. These chemical preservatives have been gradually replaced by natural preservatives in formulation of edible films and coating. Since, edible films can be applied as carriers of antimicrobial agents, so, these aforementioned ...
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Introduction: Nowadays, consumers prefer foods produced without synthetic preservatives. These chemical preservatives have been gradually replaced by natural preservatives in formulation of edible films and coating. Since, edible films can be applied as carriers of antimicrobial agents, so, these aforementioned ingredients can be incorporated in such films. Among edible films, protein-based films such as whey protein concentrate (WPC)-based films are more attractive because they also supply valuable nutrients and introduce acceptable mechanical resistance. On the other hand, these films present moderate barriers to moisture due to the hydrophilic nature of whey proteins. Essential oils (Eos) can be incorporated in to edible films in order to compensate (overcome) this defect. Since no published research has been found on integrating mastic tree sap (Pistacia atlantica sub sp. kurdica) essential oil into whey protein edible films, this essential oil was applied for WPC-based film in this research. Some species belong to Penicillium have been known as contaminants of dairy and fruit products. Among Penicillium sp., P. expansum is more popular for causing post-harvest damage of apples. In this study, our objective was focused on mechanical and anti-fungal properties of WPC-based films incorporated with mastic gum essential oil.
Materials and methods: WPC, mastic tree sap and P. expansum were obtained from Multi Milk Company, Kurdistan mastic Gum Company and Persian Type Collection Culture, respectively. Extraction of EO from mastic gum was accomplished using water distillation or hydro distillation with the help of Clevenger-type apparatus for 5 hours to obtain a pale yellow oil. Solution (10%w/w) of WPC in distilled water was prepared. Glycerol (as plasticizer) was added to WPC solution at a ratio of 1:1 WPC: Glycerol. Then concentrations of EO (1000, 2000, 3000 and 4000 ppm) was added to solution and mixed for 2 min. In the next step, some characteristics of film were measured including: thickness and density, water solubility, stability in acidic and alkaline solutions, water vapor permeability and light transmission / film transparency. Some mechanical properties of films such as tensile strength (TS) and elongation at break (%E) of films were also determined.
Regarding microbial assays, following the activation and preparation of fungi spore, MIC was determined using Agar Dilution Method. Determination of antimicrobial activity of film was performed according to film disk agar diffusion assay
Results & Discussion: With increasing essential oil concentration, film thickness exhibited increasing trend which was due to entrapment of micro-droplets of essential oil in film. Along with increasing EO concentration in film samples, WVP declined significantly (P-value
Sanaz Ojnordi; Majid Javanmard; Simin Asadollahi
Abstract
Due to environmental risks generated by application of non-degradable and synthetic films, many researches have shown increasing tendency to edible coatings for storing food such as fruits and vegetables. Whey protein is considered one of the most common sources of edible coatings and its use has been ...
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Due to environmental risks generated by application of non-degradable and synthetic films, many researches have shown increasing tendency to edible coatings for storing food such as fruits and vegetables. Whey protein is considered one of the most common sources of edible coatings and its use has been studied in the current research. In this paper, the simultaneous effect of coating with whey protein and Zataria multiflora Boiss extract on the quality of peach kept in refrigerator has been studied. According to response surface methodology, were measured 20 treatments repeating 6 times in the center point and effects of the three factors including whey protein (2. 5 to 5 gr), Zataria multiflora Bioss extract (0 to 500 μL) and glycerol (0. 375 to 2. 25 gr) on the physicochemical characteristics, fungal decay and organoleptic traits of peach, were investigated in the condition 5±2 ̊C and 80% relative humidity during 21 days of storage. According to the results, by increasing Zataria multiflora Bioss extract concentration and whey protein of the coating, microbial decay and weight loss of the fruit was reduced and texture and soluble solids were conserved. Peel colour changes of the coated fruit was not significant compare to control and the coated samples had a light and bright colour. Coating peach resulted in natural ripening of the fruit and the coated fruits were softer and juicier than the fruits without any coating. The coating formulations had significant effect on TSS and TA. Optimized points of variables for achieving a coating with the maximum effect on shelf life improvement of peach (Prunus Persica cv. Anjiri) are: whey protein 4. 7475 gr, Zataria multiflora Bioss extract 498. 00 μL and glycerol 0. 6212 gr.
