جستجوی مقالات مرتبط با کلیدواژه "هیدروژل" در نشریات گروه "صنایع غذایی"

This study was conducted with the aim of investigating the composite of biodegradable polymers and nanoparticles in hydrogels in the form of a review article. Biodegradable polymer composites with nanoparticles in hydrogels is an advanced research field that combines the accumulation of new technologies in the field of biodegradable polymers and nanomaterials. These composites are created by integrating biodegradable polymers, which decompose naturally and reduce the harmful effects on the environment, with nanoparticles in hydrogels. The presence of nanoparticles in the structure of these composites has improved the mechanical, electrical, and thermal properties and made these compounds as multifunctional materials with wide applications in the fields of food industry, packaging, medicine, environment, and electronics. Hydrogel, as the main matrix of these composites, guarantees the ability of absorbing water and the controlled transfer of active substances. These advances are important not only in the field of science and engineering, but also in making sustainable solutions for future technologies.

Hydrogels are a three-dimensional network of polymeric matrices with the ability to absorb water through chemical or physical cross-linking. Recently, the development of bio-based hydrogel with the aim of reducing the use of fossil fuel is becoming interested. Wheat filter flour (WFF) is a by-product obtained from air-classification in the modern wheat milling industry. It contains a high level of non-endosperm materials with the ability of water absorption and bio-film making capacity. Nevertheless, hydrogel-based films usually display weak water resistance, flexibility problems, and gas barrier properties. Carvacrol as a phenolic component is used to improve the functional properties of film and reduce the growth of pathogenic and spoilage microorganisms.

Hydrogel based films were prepared by casting technique. Six grams of WFF was added to 100 ml of distilled water, the pH of the solution was adjusted near to 10.7 with NaOH solution (1 N). The dispersion was heated up to 85°C,  with gentle stirring at 250 rpm for 30 min.Glycerol (35 g/100g of dry polymer) was then added and stirred for another 15 min. Carvacrol, as an active agent incorporated at two concentrations (5 and 10% (g/100g of dry polymer)) and stirred for another 15 min at 40°C and dried in a forced-air oven at 35± 5°C for 24 h. Physical (density, water-solubility, moisture content), mechanical, barrier and antimicrobial properties of active hydrogel-based film were determined. Antimicrobial properties of active hydrogel-based were evaluated in the vapor phase by using the micro- atmosphere method and liquid medium (immersion in broth) as a food model system. Statistical analyses were performed on a completely randomized design with the analysis of variance procedure using SAS software.

Increasing the carvacrol concentration in the film making solution led to decreasing the water solubility, moisture content, and hydrophobicity properties of WFF based films. The SEM observations confirmed a porous structure of the active hydrogel-based film. The highest water vapor permeability (1.32×10-10 gm-1s-1Pa-1) and the minimum water solubility (37.01± 0.63%) were observed in hydrogel film with 10% carvacrol. An increase in the concentration of carvacrol produced a greater growth inhibition zone for all microorganisms. The results in vapor phase showed that A.niger exhibited greater sensitivity to carvacrol than other studied bacteria. Hydrogel based films with 5% carvacrol in liquid food model system produced 1.16 and 1.34 log reduction against E. coli and L. monocytogenes, respectively. The greatest antibacterial activity was observed with films containing 10% carvacrol against L. monocytogenes (2.71 log reduction). This work suggested that the WFF hydrogel base film with 10% carvacrol can be used as an active packaging for improving the safety and shelf-life of food products.

In this research hydrogel-based colloidosome with shell of CaCO3 microparticles was used in order to encapsulate caffeine as a model flavor compound. When the CaCO3 particles were dispersed in sunflower oil and then water in oil emulsion was prepared, with adding D-gluconic acid δ-lactone, water droplets containing alginate slowly gelate with outer layer of CaCO3 particles in micrometer hydrogels in the size of a few 10 µm without coagulation. CaCO3 microparticles act as both cross-linker for the alginate and stabilizer of water in oil emulsion. After leaving for 48 h, the hydrogel colloidosomes sank to the bottom of the container due to gravity. The results of infrared spectroscopy showed that indicative peaks of caffeine functional groups appeared in the loaded colloidosome sample spectrum and shifted its position. The results of calorimetric tests showed that the difference between the melting point of colloidosome samples with varying amounts of calcium carbonate microparticles in their formulas are linked. The results of the X-ray diffraction test showed a change in the crystalline degree of caffeine. After 5 h, the colloidosome sample, continued the caffeine release in water up to 55% maximally, while using mouth conditions for this sample, release of the loaded caffeine increased 33%. Generally, the results of instrumental analysis and release test showed that caffeine in the hydrogel colloidosome was well encapsulated within the alginate hydrogel network and have proper release under simulated oral condition.

Because of antioxidant, antimicrobial, and medical properties, bioactive compounds extracted from plants have grown significantly in the development and trade of functional foods containing food-medicine and dietary supplements.However, the volatility, insolubility in the aqueous matrix, and sensitivity to environmental conditions such as temperature, oxygen, and light limite the use of essential oils. Therefore, this study was conducted to investigate the encapsulation technique as a suitable method to protect the essential oil and increase its efficiency. The main purpose of this study was to produce alginate hydrogels containing Thymus daenensis essential oil (Td-EO) loaded with beta-cyclodextrin. The structural properties and antimicrobial features of alginate hydrogel beads incorporated with Td-EO active ingredients were evaluated. The results of hydrogel analysis showed that the particle size and particle size distribution were less than 180 nm and 0.31, respectively, and the encapsulation efficiency of Td-EO for the hydrogel beads was about 90%. A maximum swelling capacity of ~610.3 % was obtained for alginate beads. FESEM, showed that the particle sizes were in the nanometer range and the particles were homogeneous and spherical shapes. FTIR analysis indicated no significant interaction between essential oil, beta-cyclodextrin and alginate, so alginate hydrogel is a suitable material for encapsulating active compounds. Hydrogels had an inhibitory effect on the growth of two strains of bacteria, S. aureus and E. coli. The release of Td-EO from alginate beads in two short-term and long-term periods were studied. The release rate of bioactive compounds can be reduced by encapsulating in β-cyclodextrin and producing its alginate hydrogel, and thus can be used as a suitable tool to control release in food and pharmaceutical systems.

Gelatin is mainly produced by collagen denaturation. Gelatin obtained from cold-water fish has low sol-gel transition temperatures. Chemical and physical treatments can be used to modify the gelatin network by establishing cross-links between the gelatin chains to improve the properties of the gel. In this study, cross-linking in cold-water fish gelatin-based hydrogels was established by tannic acid (TA) and caffeic acid (CA), each at concentrations of 1, 3 and 5%. The effect of CA and TA concentrations on the physicochemical properties of gelatin hydrogels was investigated. The strength of the gel and the degree of crosslinking increased with increasing the concentration of tannic acid from 1 to 3%, which increased the strength of the gel from 325.00 to 343.62 N/mm2 and the degree of crosslinking from 82.01 to 84.99%. At higher levels of tannic acid, a decrease in gel strength and degree of crosslinking was observed 301.90 N/mm2 and 75.48%, respectively. However, these properties of hydrogels increased steadily with increasing levels of caffeic acid (p <0.05). The swelling rate also decreased due to the combination of different levels of tannic acid and caffeic acid. The maximum swelling rate for the control was 1732.30% and the minimum swelling rate for 3% tannic acid was 594.79%. The crosslinked gelatins by tannic acid significantly improved the denaturation temperature and their thermal stability was higher than that of caffeic acid. This temperature was 89° C in untreated hydrogels and increased to 94 °C and 98 °C in caffeic acid and tannic acid treated hydrogels, respectively. Scanning electron microscopy images of the hydrogel samples showed that the structure of the hydrogels based on cold-water fish gelatin was spongy. The addition of crosslinking agents only slightly reduced the pore size of the gelatin and had no significant effect.

In this study, the complex coacervation of plantago major seed mucilage (PSM) and chitosan (CHI), two oppositely charged polysaccharides, was studied as a function of pH (8.0-2.0). Biopolymers concentration 1% and PSM:CHI ratio (10:90 to 90:10), according to electrical conductivity (EC) and turbidity analyses. The solution containing 1% biopolymers with PSM:CHI ratio of 85:15 resulted in maximum complex coacervation at the pHopt 3.7. The EC of biopolymers solutions increased by decreasing pH. The aforementioned optimum condition resulted coacervates with maximum particles size (7 μm) and minimum ζ-potential (+5.5 mV), which were observed as densely agglomerated macro-complexes with highest coacervation yield (87%). These hydrogels be useful for encapsulation and delivery of drugs and (bio-) active compounds.

Hydrogel products constitute a group of polymeric materials, the hydrophilic structure of which renders them capable of holding large amounts of water in their three-dimensional networks. Extensive employment of these products in a number of industrial and environmental areas of application is considered to be of prime importance. As expected, natural hydrogels were gradually replaced by synthetic types due to their higher water absorption capacity, long service life, and wide varieties of raw chemical resources. In this work as an industrial application of hydrogels, Polyvinyl Alcohol (PVA) as a famous hydrogel was used to improve date concentrate quality (increase clarity and color and decrease turbidity). The PVA 0.5 g L-1 was provided in water and mixed with 250 ml of date Juice samples. The Central Composite Design (CCD) and Response Surface Methodology (RSM) were used to study the interaction between tree factors (PVA volume, the time and the temperature of interaction) and optimize factors that affect quality imrovement. Results showed that PVA has good capability to improve date Juice quality. The volume of PVA; 5 ml, time; 40 min and temperature; 34 °C were obtained as optimum conditions.