Eisa Jahed; Hadi Almasi; Mohammad Alizadeh khaled abad
Abstract
Introduction: Due to increasing attention to the environment, as well as consumer demand for healthy, nutritive food products and extended shelf life, in the recent years, the food and packaging industries have paid increasing attention to biodegradable edible packaging prepared from biopolymers such ...
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Introduction: Due to increasing attention to the environment, as well as consumer demand for healthy, nutritive food products and extended shelf life, in the recent years, the food and packaging industries have paid increasing attention to biodegradable edible packaging prepared from biopolymers such as proteins, polysaccharides, and lipids or their combinations. These biodegradable films may act as carrier of wide variety of additives, such as antimicrobial, antioxidant agents, flavors, colorants and spices which improve the functionality of the packaging materials by addition of novel or extra functions. In the present study, an antioxidant/antimicrobial active packaging based on chitosan biopolymer was designed. For this purpose, lignocellulose nanofibers (LCNF) and cellulose nanofibers (CNF) at concentration of 4% were used as reinforcement of biopolymer properties, as well as to control the release of Origanum vulgare subsp. gracile and Carum copticum essential oils (as antioxidant/antimicrobial agent) from the packaging material into the foodstuff.
Materials and methods: The O. vulgare ssp. gracile leaves and C. copticum seeds were obtained from wild plants in mountains of Urmia (Iran). LCNF (average diameter about 55 nm, average length about 2–5 μm, 99% purity) produced from unbleached hardwood pulp through mechanical and acid treatments and CNF (average diameter about 28 nm, average length about 2–3 μm, 99% purity) prepared from softwoods through mechanical disintegration were kindly provided by Nano Novin Polymer Co. (Saari, Iran). Chitosan (medium molecular weight, from shrimp shell with a deacetylation degree of 75–85%), purchased from Sigma-Aldrich (St. Louis, MO, USA). Chitosan based bionanocomposite films incorporated with organic nanofillers and essential oils were developed by solvent casting method. The synthesized films were characterized by XRD and DSC analyses. To determine the prepared films would have potential to be used as an active packaging, water vapor permeability, water solubility, color, transparency, mechanical properties, antimicrobial and antioxidant activity of the films were also evaluated. In order to determine the efficiency of activated nanocomposites, the effect of these films was evaluated on the oxidative stability of rapeseed oil without antioxidants and compared with the effect of TBHQ synthetic antioxidant.
Results & Discussion: The results showed that the addition of essential oils did not have a significant effect on the crystallinity and thermal properties of the films, while organic reinforcement increased the crystalline properties and thermal resistance of nanocomposite films. By applying the essential oils and CNF and LCNF in the structure of the films, the apparent transparency and consequently the amount of light passage from them decreased compared to the control sample. With addition of essential oils separately and in combination, as well as CNF and LCNF in the structure of films, solubility and film permeability decreased compared to pure chitosan film. By adding of two essential oils with a ratio of 50:50, tensile strength (UTS) and strain to break (STB) of films were increased, while organic nanofibers led to an increase in UTS and a significant reduction in STB of nanocomposites. It was also found that active films containing different ratios of essential oil had remarkable antioxidant activity and high antimicrobial activity against E.coli and B.cereus bacteria, which by adding CNF and LCNF these features were reduced due to the role of controlling the release of essential oil compounds by nanofibers. With the numerical optimization of the software, the optimal amount for the essential oils of C. copticum and O. vulgare oils were 2.29 and 2.71% (5% mix) respectively, in combination with the LCNF nanofibers. The results of oxidative stability of Canola oil showed that nanocomposites containing 5% essential oil were considerably able to keep the oil freshness during storage at ambient temperature and delay the oxidation of the oil.
Mehdi Jalali; Mohammad Hossein Hadad Khodaparast; Eisa Jahed
Abstract
In this study , response surface methodology and face central composite design in order to investigate decolorization and clarification extraction of Kaluteh date was used for the production of liquid sugar. The optimum amount of bentonite ( 1-3 g/l ) and gelatin ( 0/02-0/08 g/l ) was determined that ...
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In this study , response surface methodology and face central composite design in order to investigate decolorization and clarification extraction of Kaluteh date was used for the production of liquid sugar. The optimum amount of bentonite ( 1-3 g/l ) and gelatin ( 0/02-0/08 g/l ) was determined that the desired amount of bentonite and gelatin , 3 and 0/05 ( g/l ) , respectively. To determined the optimum conditions for maximum activity of these two compounds for clarification with regard to fixed amount of bentonite and gelatin , three factors determine the temperature ( 30-70 °C) , pH ( 4-6 ) and time ( 40-120 min ) was implemented. Parameters consists of the colors , ash and absorbance. Bentonite and gelatin at low temperature and pH with over time , more active and reduce the mount of impurities. The least amount of this responses for the color at 420( nm) , ash and absorbance at 660 (nm),4302 Icumsa ,0/421 % and 0/059 ,respectively. By comparing amounts in the optimum point the clear syrup by bentonite and gelatin ,the initial syrup ,it was found that this technique able to reduce the mount syrup color ,ash and absorbance ,68/25 % , 8/7 % and 89/46 % ,respectively.
Masoumeh Bahreini; Mohammad Bagher Habibi Najafi; Mohammad Reza Bassami; Eisa Jahed
Abstract
Ozone is a strong oxidant and a potent disinfecting agent. There are numerous application areas of ozone in food industry. While there are many investigations on the application of ozone in food industry, relatively little information is available on the potential of ozone to reduce microbial populations ...
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Ozone is a strong oxidant and a potent disinfecting agent. There are numerous application areas of ozone in food industry. While there are many investigations on the application of ozone in food industry, relatively little information is available on the potential of ozone to reduce microbial populations in fresh-cut fruits and vegetables and the visual quality of lettuce. In this study, ozone water was applied at five concentrations (0.6, 0.8, 1.2, 1.6 and 2 ppm) for four exposure times (1, 3, 5 and 10 min) on natural microflora and E. coli O157:H7 and Salmonella inoculated of lettuce. The reduction in the total bacterial count, yeast and mold, total coliform, as well as lactic acid bacteria counts were examined. The promising results indicated the efficacy of ozone water to reduce the microbial populations on lettuce. In the best condition, the inoculated samples of E. coli O157:H7 (ATCC 35150, NCTC 12900), Salmonella typhi morium ( ATCC 14028, NCTC 12023) and Salmonella enterica subsp, enterica (PTCC 1709) on lettuce were decreased further than 2 log10 cfu/g. The results showed the population of aerobic mesophilic bacteria, yeast/ moulds, total coliforms and lactic acid bacteria were decreased to 1.54, 0.94, 1.94 and 1.35 log10 cfu/g respectively. The method of ozone generation, type of application, as well as the optimal exposure time and concentration of ozone as an antimicrobial agent on lettuce is mentioned in detail.
Eisa Jahed; Mohammad Hossein Hadad Khodaparast; Khalil Behzad; Mohammad Elahi; Arash Koocheki
Abstract
In this study, response surface methodology was used to determine the optimum raw sugar beet juice purification process conditions using bentonite to produce inverted liquid sugar. For this purpose, impact of factors on the purification process such as bentonite concentration (1-5 gr/li), pH (3.5-6) ...
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In this study, response surface methodology was used to determine the optimum raw sugar beet juice purification process conditions using bentonite to produce inverted liquid sugar. For this purpose, impact of factors on the purification process such as bentonite concentration (1-5 gr/li), pH (3.5-6) and temperature (35-95 ˚C) was investigated. For each response, a second-order polynomial model was developed using multiple linear regression analysis. Correlation coefficients of fitted regression models of color, turbidity, ash, adjusted purity and invert sugar for juice purification process were determined as 0.95, 0.89, 0.90, 0.91 and 0.96 respectively. Results showed that while increasing the bentonite concentration increased the turbidity content but the adjusted purity decreased, and had no significant effect on other parameters. At lower pH levels, separation of color and turbidity causes by bentonite, but was in creased it decreased separation of ash and also increased invert sugar levels. With increasing temperature from 35˚C, to 95˚C, Separation of color and turbidity causes and invert sugar and adjusted purity content as well as increased, while this variable has no significant effect on syrup ash content. The optimum conditions of raw sugar beet juice purification process using bentonite was determined to obtain minimum color, turbidity and ash with maximum invert sugar and adjusted purity which were verified experimentals were found to be bentonite concentration of 1.70 gr/li, pH of 4.47 and temperature of 75˚C. At this optimum point, color, turbidity, ash, adjusted purity and invert sugar content were found to be 1664 ICU420, 6.3 NTU, 0.55 %, 93.9 % and 1.60 %, respectively.
