Food Biotechnology
Dina Shahrampour; Morteza Khomeiri; Seyed Mohammad Ali Razavi; Mahboobeh Kashiri
Abstract
Introduction: Due to the low variety of probiotic food products, it is important to provide appropriate solutions for new products. Trapping probiotic bacteria in the polymers structure of edible films and coatings is a new approach that has been proposed to increase the survival of these microorganisms ...
Read More
Introduction: Due to the low variety of probiotic food products, it is important to provide appropriate solutions for new products. Trapping probiotic bacteria in the polymers structure of edible films and coatings is a new approach that has been proposed to increase the survival of these microorganisms and to develop new probiotic products in the food industry.Materials and Methods: In this study, an alginate-based probiotic bioactive film containing L. plantarum was fabricated. The effect of bacterial addition on physical, mechanical and prevention properties of alginate film was evaluated. In addition, the effect of two temperatures 4 ° C and 25 ° C on the survival of embedded probiotic bacterium in the film structure during one month of storage was investigated by microbial count assay on MRS agar medium. Then, the model food was covered with probiotic film and the survival of probiotic bacterium during food storage was determined.Results and Discussion: The results showed that the population decline of probiotic bacterium after drying of alginate film solution was about 4.61%. Addition of probiotic bacterium to the alginate film increased the thickness, turbidity, and tensile strength of the film, While on solubility, water activity, Elongation(%) and microstructure of alginate film had no significant effect. In addition, the probiotic film containing bacteria had less luminosity, moisture content and water vapor permeability (WVP) than the control film. The survival percentage of L. plantarum in alginate film after one month of storage at 4 ° C was higher than 25 ° C and 96.84 and 47.29%, respectively. Also, the population of embedded bacteria in the film structure on the food model (sausage) surface after three weeks storage in refrigeration was in desired level of probiotic products (> 106 cfu / gr).Conclusion: Therefore, alginate film is recommended as a suitable carrier for probiotic microorganisms to produce new functional products.
Food Technology
Parisa Shahiri Tabrestani; Mahboobeh Kashiri; Yahya Maghsoudlou; Hoda Shahiri Tabarestani; Mohammad Ghorbani
Abstract
Introduction
There ...
Read More
Introduction
There has been an increasing demand for functional analog meat products due to environmental, human health, and animal welfare concerns. Burger analogs are plant-based products that are designed to mimic the taste, texture, and appearance of meat burgers. They are typically made from a combination of plant-based ingredients such as textured vegetable protein, legumes, grains, and vegetables. The goal of burger analogs is to provide a meat-like experience without using animal-based products.These formulations aim to provide a healthier and sustainable alternative to conventional meat products. The organoleptic properties of burger analogs, including texture, taste, and aroma, are crucial for their acceptance by consumers.
Prickly pear (Opuntia stricta) is a fruit from the Cactaceae family that contains various beneficial components, including natural pigments, proteins, fibers, and polysaccharides. Pectic polysaccharides and arabinogalactans are two types of polysaccharides found in prickly pear that have thickening properties and can improve the texture of food products. Moreover, Prickly pear is a nutritious and functional fruit that can provide various benefits when incorporated into the diet or used as an ingredient in food products. To date, no health benefit analog burgers incorporating Opuntia fruit have been developed.This study investigated the effects of adding Prickly pear pulp powder at levels of 0.5-2.5% on the physicochemical, sensory, and textural properties of analog burgers.
Materials and Methods
Analog burgers were formulated according to Iranian national standards using common ingredients (texturized soy protein, water, canola oil, garlic, dehydrated onion, soy sauce, and guar gum) as a control sample. Mature prickly pear fruits (Opuntia stricta) were collected from west of Mazandaran province in February. The fruits were washed, peeled, and dried in a forced oven dryer at a temperature of 45 °C. The dried samples were then ground into a powder and stored at 4 °C until further physico-chemical parameters of the including moisture, pH, ash, protein, lipid, color and total phenolic content. For developing new formulation of analog burgers, the roasted flour was substituted with prickly pear pulp powder at 0.5%, 1.5%, and 2.5% of the base recipe. The average moisture, ash, fat, carbohydrate content, pH, holding capacity, and color of each raw packed burger were measured. The hardness, springiness, cohesiveness, and chewiness of cooked analog burgers were evaluated using a texturometer instrument. Sensory analysis was performed by 10 panelists who judged discrimination scales of color, odor, taste, and texture characteristics. Analysis and sample treatments were repeated at least three times. Statistical analysis was performed using SPSS (version 19.0), and data were expressed as means ± standard deviation (SD).
Results and Discussion
The lowest and highest cooking losses were observed in analog burgers with 2.5% pulp powder (21.03 ±0.47%) and the control (22.2 ± 0.63%), respectively. However, moisture retention and juiciness did not show significant differences (p > 0.05) between analog burgers with prickly pear pulp powder and the control. The results indicated that increasing prickly pear pulp powder levels significantly decreased the redness (+a*) parameter and yellowness (+b*) of raw analog burgers. Moreover, a reduction in cooking loss and shrinkage were observed for cooked soy burger samples using prickly pear pulp powder. However, cooked analog burgers with added prickly pear pulp powder showed significantly higher juiciness. The elasticity of the produced analog burgers significantly decreased with an increasing percentage of pulp powder (p <0.05).
Conclusion
The incorporation of prickly pear pulp powder in analog burger formulation resulted in a significant decrease in cooking loss and shrinkage of the cooked burgers, while not significantly affecting moisture retention and juiciness. An increase in prickly pear pulp powder levels in analog burger formulation led to a significant decrease in the redness and yellowness of the raw analog burgers, as well as a decrease in their elasticity. Based on the sensory evaluation and consumers' overall tendency to consume burgers, it is recommended to use 1.5% prickly pear pulp powder in analog burger formulation.
Food Biotechnology
Maryam Moosavi; Mahboobeh Kashiri; Yahya Maghsoudlou; Morteza Khomeiri; Mehran Alami
Abstract
Introduction: 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 ...
Read More
Introduction: 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. Materials and Methods: 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. Results and Discussion: 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.
Ehsan Azadbakht; Yahya Maghsoudlou; Morteza Khomeiri; Mahboobeh Kashiri
Abstract
Introduction: The edible films and coatings had remarkable growth in recent years to increase the shelf life and to enhance food quality, stability, and safety and expected to have an important impact on the food market in the following years. In addition, these matrices can be used as carriers of antimicrobials ...
Read More
Introduction: The edible films and coatings had remarkable growth in recent years to increase the shelf life and to enhance food quality, stability, and safety and expected to have an important impact on the food market in the following years. In addition, these matrices can be used as carriers of antimicrobials to minimize the risk of foodborne contamination by pathogens and inhibit the development of spoiler microbes. Antimicrobial packaging is a type of active packaging that provides the continuous migration of antimicrobial components to the surface of the foods. Chitosan is a linear copolymer of β-1, 4-linked D-glucosamine and N-acetyl-d-glucosamine. It is a cationic polysaccharide for food packaging applications, due to its unique characteristics of films, including excellent oxygen barrier properties, good mechanical properties, nontoxicity and good antimicrobial activity. Eucalyptus is a plant native from Australia and the Myrtasya family that includes about 900 species and sub-species. There is abundant scientific evidence regarding the efficacy of different species Myrtasya as the antibacterial and antifungal compounds used in health products, and food industry. Using natural antimicrobials are interesting strategies for reducing the use of chemical additives in the food industry. Essential oils (EOs) are defined as a mixture of volatile water insoluble substances to be incorporated into the edible films due to exhibit antimicrobial effects. Moreover, evaluation EOs on the physical, optical and structural properties of the resulting film is also important. Therefore, the aims of this work were to determine the effect Eucalyptus globulus essential oil on antibacterial properties (2) to determine the antimicrobial activity of chitosan based films containing Eucalyptus globulus essential oil against S. aureus, B. cereus, E. coli and S. intertidis.
Materials and methods: The foodborne microbial strains were prepared from Persian Type Culture Collection. The essential oil was analyzed by gas chromatography (GC) (Thermoquest 2000, UK). In this study, the antimicrobial activity of Eucalyptus globulus essential oils (EGOs) was evaluated against two gram positive (S. aureus and B. cereus) and two gram negative (E. coli and S. intertidis) bacteria by the agar diffusion technique and microdilution test. The effect of EGO was evaluated in liquid media and vaporous phase too. Chitosan solution were prepared by dissolving 1.5 % (W/V) of chitosan in aqueous solution containing 0.7% (V/V) of acetic acid under a magnetic stirrer at 40°C until chitosan was completely dissolved. Glycerol as plasticizer (10% weight of chitosan powder) was added to the solution and stirred for 10 minutes. The EGO with concentrations of 0.5, 1 and 1.5% v/v was added to the solution and was stirred for 5 minutes. The film forming solutions using a homogenizer (Heidolph, Germany) were homogenized with 12000 rpm for 4 min, then degassed for 5 min and 25 ml were cast on a 10 cm diameter petri dish. After drying the film in the oven at 38°C for 24 h, they were peeled from the plate surface and were evaluated. The antimicrobial activity of the films was evaluated in contact with liquid and vaporous media.
Results and discussion: Minimum inhibition concentration for gram negative (E. coli, S. enteritidis) and gram positive (B. cerus and S. aureus) bacteria showed 3.125 and 1.562 µg/l respectively. The inhibition zone for gram positive bacteria was bigger than gram negatives. The effect of EGO on bacteria based on Log reduction value (LRV) of S. aerus > B. cerus > E. coli> S. enteritidis. Thses results confirmed that gram positive bacteria were more sensitive to inhibition by plant essential oils than the gram-negative bacteria. Our results showed that chitosan film containing 1 and 1.5 % essential oil was able to reduce the density of bacteria. The Log reduction value of chitosan bioactive film was increased by increasing the concentration of E. globulus essential oil than 0.5 to 1.5 % in liquid media. The results of this work had demonstrated that chitosan bioactive film containing 1.5% EGO can be used an effective antimicrobial film for food packaging in direct contact.
Conclusion: Chitosan is a good biopolymer for active food packaging. The result of this study showed that chitosan films containing EGO could be used as active films due to enhanced the antimicrobial properties which are important in food packaging applications. Films containing essential oil had unique properties that are useful for coating of perishable foods such as fish and poultry.
Mahboobeh Kashiri
Abstract
Introduction: Antimicrobial packaging is a novel preservation technology that is designed base on releaseing of active agents incorporated with the packaging polymer into the packaged food or the surrounding environment for improveing the quality and food safety. Zein, water insoluble proteinof cornof ...
Read More
Introduction: Antimicrobial packaging is a novel preservation technology that is designed base on releaseing of active agents incorporated with the packaging polymer into the packaged food or the surrounding environment for improveing the quality and food safety. Zein, water insoluble proteinof cornof corn, reported to be thermoplastic material with high tensile strength, excellent hydrophobic film, biodegradability.Zataria multiflora Boiss. (Z) is a thyme-like plant belonging to the Laminaceae family that geographically grows wild in central and southern parts of Iran. Antimicrobial activity of Z essential oil (ZEO) has been successfully tested against foodborne pathogens. Most of the studies on antimicrobial packaging mainly focused on the initial screening of newly developed films for ZEO in laboratory media and quantifying the bacterial reductions obtained during storage for different types of packaged food products. it is really important to know the variation in antibacterial activity of the agents when incorporated into the packaging film from its original activity in order to establish the levels that need to be incorporated for effective bacteria inhibition, hence The aims of the present study were to investigate the antimicrobial potential of ZEO incorporated zein film against pathogenic microorganisms inoculated in olivier saladto provide evidence of their applicability in the design of active food packaging systems.Materials and method: Z was collected in the Shiraz province of Iran and extected by using clevenger type apparatus. Chemical composition ZEO was analyzed by gas chromatography.Antibacterial activity of ZEO was studied in the liquid (direct contact) and solid media (vapour phase) against Listeriainnocua and Escherchia coli . Zein powder was dissolved in a hydro alcoholic solution to obtain 16% (w/w) films forming solutions. The solution was stirred for at 80 °C using a magnetic stirrer hotplate. Glycerol (15%) was added to the solution and stirred again for 8 min at 30°Cm, then ZEO was added to the polymer solutions in 5% and 10% with respect to polymer content and stirred for 8 min. Films were obtained by casting, the film forming solutions were extended over it using an extension bar and introduced in a drying tunnel equipped with a heat of 2500 W during 20 min. Control zein films were prepared without active agent. To evaluate the efficacy of developed zein films was tested against two bacteria. Prior to the experiment, a loop of each strain was transferred to 10 ml of TSB and incubated at 37 ˚C for 18 h to obtain early stationary phase cells and100 µl of microorganism were inoculated into tubes with 10 ml of TSB. The tubes were then incubated at 37 °C for 18 h and 4 °C for 5 days. As control, zein film without active agent was also used in every experiment. Antibacterial activity of zein films containing 10% ZEO were evaluaterd for packaing of olivier salad as a real food model for 6 days, by performing serial dilutions with peptone and subsequent plating in Palcam Listeria Selective Agar and Brilliant Green Agar for ListeriainnocuaandEscherchia colirespectively. Plates were incubated at 37 °C for 48 hours.Results and Discussion: GC–MS analysis showed thatthe major compound of ZEO was carvacrol (45.22%). The antimicrobial effects of ZEO in the vapor phase against Escherchia coliand Listeriainnocuaby using the disk diffusion methodshowed that the25 µg of ZEO produced a visible decrease in microbial density retraction zone (+). No inhibition was observed with the addition of lower amounts of the antimicrobial agents, therefore 25 µg was the minimum inhibitory concentration (MIC).Activezein films containing 5% ZEOweren’t able to inhibit the growth of the two bacteria in the vapour pase.. When the concentrations of ZEO was increased to 10%, only active films with a diameter of 80 mm (50.24 cm2)provided a retraction zone (+) against Listeriainnocuaand E. coli. These values were indicative that incorporation of the agent in the zein films produced weaker vapor phase inhibition than its incorporation in the paper disk.The results of this studied showedthat films with 5% ZEO caused a growth reduction of 1.17 log againstListeriainnocuaand 1.14 log against Escherchia coli, while 10% ZEO produced reductions of 2.16 and 2.64 log against Listeriainnocua, Escherchia colirespectively. There was no significantdifference betweenlog reduction values of ZEO incorporated in zein films against Listeria innocuaand Escherchia coli. And also in the liquid media with increasing the concentration of ZEO in zein films, the log reduction values were increased against both bactreia. Despite of the excellent antibactrerial effect of ZEO in zein films in direct contact, bio active zein films were not effective enough for reducing the contamination of packaged Olivier.
Mahdi Kashani-Nejad; Mahboobeh Kashiri
