Reihaneh Jahangiri; Hassan Hamedi; Hamed Ahari
Abstract
The use of new preservation methods based on natural substances of plant and animal origin in food is expanding. Edible coatings can improve the quality of fresh and frozen products such as fish by preventing microbial growth, and decreasing lipid oxidation and moisture loss. The aim ...
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The use of new preservation methods based on natural substances of plant and animal origin in food is expanding. Edible coatings can improve the quality of fresh and frozen products such as fish by preventing microbial growth, and decreasing lipid oxidation and moisture loss. The aim of this study was to evaluate the effect of the edible coating of chitosan (0 and 2%), Baneh gum (0, 1 and 2 %), propolis extract (0, 1 and 2%), and nanoemulsion of ginger essential oil (0, 0.5 and 1 %) on the shelf life of fresh salmon fillets during 12 days refrigeration. The results showed that the coating had a significant effect on reducing the total count, psychrophilic bacteria, coliforms, and Pseudomonas count during storage. Also, coated samples showed lower pH and peroxide values than uncoated, but the coating had little effect on reducing thiobarbituric acid (TBARS) and total volatile nitrogen (TVBN) values. During the sensory evaluation, it was found that the chitosan coating with Baneh gum can maintain or improve the sensory properties and extend the shelf life of refrigerated fish.
Seyed Amir Ali Anvar; Hamed Ahari; Nasim Mojarrad
Volume 3, Issue 1 , March 2020, , Pages 1-5
Abstract
Carvacrol was found in essential oils of thyme, oregano, wild bergamot, and some other plants. Although, a wide range of bioactivities such as anticancer, antioxidant, and antimicrobial has been identified for carvacrol, however, among all therapeutic properties it possesses a potent antimicrobial activity. ...
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Carvacrol was found in essential oils of thyme, oregano, wild bergamot, and some other plants. Although, a wide range of bioactivities such as anticancer, antioxidant, and antimicrobial has been identified for carvacrol, however, among all therapeutic properties it possesses a potent antimicrobial activity. The present study investigates the inhibitory effect of carvacrol as an active compound against the growth of Aspergillus flavus, besides its effect on the expression of aflatoxin-related (aflR) gene. Twelve fungal samples of A. flavus were used and the antimicrobial activity of carvacrol was tested against them using the minimum inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) according to the broth microdilution procedure. The expression of the aflatoxin regulatory (aflR) gene was examined by Reverse Transcriptase polymerase chain reaction (RT-PCR) technique. The results of MIC and MFC tests showed that carvacrol at 0.8 μg/ml and 3.5 μg/ml concentrations displayed antimicrobial activities on A. flavus, respectively. The RT-PCR result indicated that the expression level of aflR gene had decreased to 33% in the presence of carvacrol compared to 67% in the absence of the mentioned active compound. Together the results demonstrated that carvacrol not only exhibited antimicrobial activity against A. flavus but also reduced its gene expression level.
Fatemeh Kalateh Seifari; Hamed Ahari
Volume 3, Issue 1 , March 2020, , Pages 15-22
Abstract
Environmental concerns related to using plastics for food packaging and consumers' demand for the extended shelf life of foods conducted the researches to develop new strategies for food packaging. The shelf life of food systems is related to the existence and growth of food pathogenic and spoilage microorganisms ...
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Environmental concerns related to using plastics for food packaging and consumers' demand for the extended shelf life of foods conducted the researches to develop new strategies for food packaging. The shelf life of food systems is related to the existence and growth of food pathogenic and spoilage microorganisms during food storage. Also, the environmentally friendly aspects of edible films and coatings make them appropriate substitutes for plastics in food packaging systems. Therefore, edible films and coatings which contain a food preservative introduced as hopeful novel systems for extending shelf life and preserving the quality of foods. The antimicrobial agents could be used in edible films and coating for restriction or stopping the microbial growth for prolonging the shelf life of foods. Due to the weak barrier and mechanical characteristics of most edible films and coatings, natural nanocrystals could be employed to improve the properties of them. In this review, the nanoemulsion encapsulation introduced as a technique for improving antimicrobial properties, while minimizing the antimicrobial agent impacts on the foods' organoleptic properties. Also, using natural nanocrystals proposed as a reinforcing agent for edible packaging material. The shelf life of food systems is related to the existence and growth of food pathogenic and spoilage microorganisms during food storage.
Mina Nasiri; Anousheh Sharifan; Hamed Ahari; Amir Ali Anvar; Shapour Kakoolaki
Volume 2, Issue 2 , November 2019, , Pages 26-31
Abstract
In recent years, there has been an increasing interest in the utilization of emulsion and food-grade nanoemulsions and their fabrication methods, and methods have evolved in the food industry and other fields. Emulsions, according to droplet diameter and stability, are divided into three important groups ...
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In recent years, there has been an increasing interest in the utilization of emulsion and food-grade nanoemulsions and their fabrication methods, and methods have evolved in the food industry and other fields. Emulsions, according to droplet diameter and stability, are divided into three important groups of conventional emulsions, nanoemulsions, and microemulsions; therefore, nanoemulsions are a class of emulsions. The small and fine size of the droplet in nanoemulsions (i.e. droplet diameter <100nm) make them applicable in some fields, due to their enhanced bioavailability, solubility, better stability against gravitational separation, appropriateness for delivery of lipophilic active agent’s components, high surface area per unit volume and antimicrobial property. Also, they need less surfactant in comparison with other constructions. There are many kinds of preparation methods that can be classified into low-intensity and high-intensity approaches. The basis of the high-intensity procedure is mechanical energy that comes from flows like cavitation, but the low-intensity procedure is based on physicochemical processes. The most notable ways in high-energy emulsification are high-pressure valve homogenization, microfluidization, ultrasonication, rotor-stator emulsification, and membrane emulsification. Low-energy emulsification is divided into thermal and isothermal methods for nanoemulsions fabrication. Thermal methods consist of phase inversion temperature (PIT) and isothermal methods consist of spontaneous emulsification (SE) and emulsion phase inversion (EPI). Also, today, there is a lot of evidence to compare the low-intensity approach with high-intensity one and some of them express that in the low-energy method, equipment is not expensive and special and this is a very important advantage in saving energy. Also, some researchers express that in the high-energy method, we need much less concentration of surfactant for the formation of small size droplet.
