Showing 6 results for Calcium Alginate
Forouh Hassani, Seyede Zahra Moosavinezhad, Jamshid Fooladi,
Volume 5, Issue 1 (11-2014)
Abstract
Sugar beet molasses is a well-known, inexpensive and available carbon source for microbial cell growth. Its sugar components are used to produce energy for microbial growth and non-sugar components, especially nitrogen components, have important roles in improvement of cell growth. On the other hand, immobilization of whole cell is establishment and physical limitation of intact cells in specific space that keeps their catalytic activity and provides the possibility of reuse of the cells. This technique allows continuous and accelerated biological processes. It also improves production efficiency and quality and simplifies recycling of product. Immobilized living cells, as controlled catalysts, are able to perform one-step enzymatic reaction and continuous fermentative processes. In this research, E.coli cells were immobilized in calcium alginate hydrogels and using sugar beet molasses as carbon source, were applied for tryptophan production reaction in the presence of its precursors, serine and indole. In comparison between free biocatalysts and immobilized bacterial cells that entrapped in alginate gels, indicated that larger amounts of amino acids (about 42/9%) can produce in calcium alginate. Also the production reaction was followed up for 9 sequential cycles, and results showed that the cells could produce tryptophan amino acid under above conditions. Use of sugar beet molasses (by-product of agriculture industries) for growth of microbial cells and tryptophan production, causes decrease in production cost and more economical production of tryptophan by immobilized E. coli.
Volume 7, Issue 25 (7-2010)
Abstract
The probiotic, Lactobacillus acidophilus PTCC 1643 was encapsulated in calcium alginate beads with the objective of enhancing survival during exposure to the adverse conditions of the gastro-intestinal tract. The probitic was incubated in simulated gastro-intestinal conditions for 0, 30, 60, 90 and 120 min. at 37 oC. The survivability of the probiotic, L. acidophilus PTCC 1643 was expressed as the destructive value (D-value). Particle size distribution was measured using laser diffraction technique. bead appearance was observed by scanning electron microscopy (SEM). The alginate coat prevented acid-induced reduction of the probiotic in simulated gastric juice (pH 1.5, 2 h), resulting in significantly (P < 0.05) higher numbers of survivors due to retarding the permeation of the gastric fluid into the cells. After sequential incubation in simulated gastric (60 min) and intestinal juices (pH 7.25, 2 h), number of surviving cells were 6.5 log cfu ml -1 for encapsulated L. acidophilus while 2.3 log cfu ml -1 was obtained for free cells.
M. Farbodi, A.r. Khoshkbar Sadeghi ,
Volume 9, Issue 4 (12-2018)
Abstract
Aims: In medicine, nanofiber can be used in wound dressing. The aim of this study was to prepare carboxymethyl cellulose/calcium alginate/polyvinyl alcohol/silver (CMC/Alg/PVA/Ag) nanocomposite by electrospinning method and to investigate its performance as wound dressing.
Materials and Methods: In the present experimental study, CMC biofilm was prepared by solution method. Then, calcium alginate/polyvinyl alcohol/silver (Alg/PVA/Ag) nanofiber was prepared by electrospining method in the optimal conditions and deposited on CMC film. Finally, the possibleof application of the product as wound dressing and its antibacterial and morphological properties, as well as permeability to water vapor were investigated.
Findings: CMC/Alg/PVA/Ag film had more permeability in comparison to Alg/PVA/Ag nanofibers and less water vapor permeability value in comparison to CMC film. The most sensivity belonged to Escherichia coli and Klebsiella pneumoniae gram-negative bacteria with inhibition zone diameter of 23mm and 24mm, respectively, and Staphylococcus aureus and Staphylococcus saprophyticus gram-positive bacteria with inhibition zone diameter of 21mm and 17mm, respectively, for CMC/Alg/PVA/Ag film. Also, the wound with CMC/Alg/PVA/Ag dressing significantly showed more healing speed in comparison to CMC dressings and CMC/Ag.
Conclusion: The use of CMC/Alg/PVA/Ag nanocomposite as wound dressing is possible. This dressing, with pores, allows the vapors to flow through the wound secretions, is impermeable to liquids and bacteria, but is permeable to oxygen and vapor; it is not allergenic and does not cause toxicity and chemical stimulation, transparent dressing and the possibility of seeing the wound is easily possible, it provides the moisture level needed for wound healing, it does not stick to the wound and as a result, its replacement is without pain and cheap.
Volume 13, Issue 0 (11-2015)
Abstract
Volume 18, Issue 113 (7-2021)
Abstract
Concerns about the environmental issues have increased the tendency to package the food stuffs with natural biopolymers. However, the use of these compounds has limitations such as the weakness in mechanical, barrier and optical properties. Alginate, as a biopolymer, has a good film forming potential; meanwhile it has poor moisture barrier properties. In order to overcome this problem, in this study, the calcium alginate film was coated with two types of lipids including sunflower oil (as a liquid oil) and tallow (as a solid fat) at two concentrations (0.5 and 5%, with and without 0.1% lecithin). Afterward, the physicochemical, barrier, and mechanical properties of the produced films were investigated. The results showed that the lamination of the alginate films with tallow fat increased the film thickness, which increased with the fat concentration. In addition, sunflower oil significantly reduced the permeability of the films to water vapor, that was more evident in 0.5% sunflower oil coated film. The results also showed that the use of these hydrophobic materials for the coating of alginate films changed the color properties and the turbidity of the films. The mechanical properties of the film, including tensile strength and elongation at the breaking point, improved by coating the alginate film with 0.5% tallow fat. Thickness, water vapor permeability, and the mechanical properties were not affected by the addition of lecithin. The SEM images proved the formation of small holes or cracks on the films surfaces. In general, this study showed that sunflower oil or tallow fat can be used as natural compounds to improve the properties of calcium alginate-based edible films, depending on the goals of packaging.
Volume 19, Issue 122 (4-2022)
Abstract
In recent years, the demand for fried products with lower oil content has increased. Therefore, in this study, the effect of different hydrocolloid coatings including sodium alginate (0.50 and 1.00%), calcium alginate (0.50 and 1.00%), and soy protein isolate (4.00 and 5.00%) on oil absorption and quality properties of eggplant slices during different frying times [0, 90, 180, 270, and 360 seconds] were evaluated. The results showed that the samples pretreated with hydrocolloids had lower moisture loss and oil absorption than that of the control sample. In this regard, among the treatments, calcium alginate (1.00%, with a moisture content of 16.66% based on dry weight and the oil absorption of 0.11 g/g food) and soy protein isolate (5.00%, with the moisture content of 33.66% based on dry weight and the of oil absorption of 0.26 g/g food) had the highest and lowest function, respectively. The moisture content of the fried samples decreased with the frying time increase from 90 to 270 s. Meanwhile, the frying efficiency of calcium alginate coated samples, in all four examined times, was higher than the other treatments, which showed the highest value in 90 s (93.12%). The lowest efficiency was observed in the control sample at 360 s (49.51%). The L* values in the samples coated with soy protein isolate were lower than those of the other samples, which could be due to the increase in Millard reaction. Coating the eggplant samples with calcium and sodium alginate resulted in good sensory parameters for 90 s. Overall, the results of this study showed that the use of calcium alginate coating (1%) can lead to the production of low-fat fried eggplant without adversely affecting the sensory and qualitative properties of the product.
