Seyed Mahdi Ojagh; Bahareh Shabanpour; Aniseh Jamshidi; Azam Siyamiyan
Abstract
Introduction: Value added products are defined as a set of products that are made up of the primary food with the help of different types of human or mechanical processing, and vary in appearance, texture, flavor and odor with their primary substance. One examples of value added products is battered ...
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Introduction: Value added products are defined as a set of products that are made up of the primary food with the help of different types of human or mechanical processing, and vary in appearance, texture, flavor and odor with their primary substance. One examples of value added products is battered and breaded products. Nuggets are products which are made of mixing mince or surimi with flavored and additive ingredients. The mixture is prepared after battering and being coated with toasted flour. It is then primary fried in oil and after freezing, packaged and stored. Therefore, the consumer only uses the final baking step, which usually involves frying in oil, consuming the product after thawing. Deep fat frying is a common cooking method in which fat is used as a heat transfer medium, during which foods with unique characteristics are produced in terms of taste, texture and appearance. During the frying process, along with shifting and moving the temperature, transferring and moving the material happens. Usually, with increasing frying time, the amount of oil absorption increases, but there is no linear relationship between. The amount of oil absorption depends on several factors such as oil quality, frying time, oil and food temperature, food form, porosity and chemical composition, especially the initial moisture content of the product.In general, fried foods at temperatures between 175 and 190°C have good brittle properties. Temperatures above 175°C may be associated with acrylamide formation, which is a carcinogenic substance. Therefore, the purpose of this study was to investigate the effect of frying medium (different vegetable oils) and temperature on the variations in the approximate composition and physical parameters of the fried silver carp nugget.
Materials and methods: In order to produce fish nuggets, 87% of minis were mixed with additive and flavoring ingredients, 5% breadcrumbs, 5% onions, 1% garlic, 1.5% salt and 0.5% spices. The mixture was shaped into round shapes and immersed in the glaze with a specific formulation and after dripping the extra glaze was covered with toasted flour. Then, nuggets were prepared using sunflower, olive, canola and sesame oil for 30 seconds at temperatures of 150, 170 and 190 degrees of celsius preheated by frying deep frying and after cooling to room temperature was packed in zipper bags and was frozen at -20°C. After a day, the nuggets were removed from the freezer and after de-damping at ambient temperature, chemical (including approximate analysis, pH measurements, water holding capacity) and physical tests (including viscosity, yield of product, shrinkage, Colorimetric and sensory analysis) were performed on fish nuggets. For physical tests and sensory analysis, nuggets were deep fried in sunflower oil for 3 minutes at 180°C.
Results & Discussion: The findings showed that fried nugget in sunflower oil and sesame oil contained moisture content, yield and high red color index, and oil absorption and yellowness index were less than fried nugget in olive oil and canola. From the temperatures of 150, 170 and 190°C in the primary frying, the temperature of 170°C had the highest moisture content and yield, and the average value of the brightness and redness index was 150 and 190°C. The temperature of 150°C showed lower oil absorption than 170°C and 190°C. According to the sensory evaluation, the sensory indexes of color, taste, smell, fat sensation in the mouth, texture, juiciness and general acceptance of the treatments in different oils and different temperatures of the initial frying were the same and did not show any significant difference. The priority was to select the panel of fried nugget panels in olive oil and prefer the initial frying temperature of 170 and 190°C. According to the results of this study, in terms of physical factors and the rate of absorption, fried nuggets in sunflower and sesame oil were more effective. Between the different temperatures of the initial frying, temperatures of 170°C for all of the measured indexes yielded better results than temperatures of 150 and 190°C.
Seyed Mahdi Ojagh; Akbar Vejdan Taleshmikaeil; Mehdi Abdollahi
Abstract
Introduction: Natural polymers have gained increasing attention for the development of packaging to reduce ecologically-related problems caused by plastic packaging (environmental pollution). Among these natural polymers, proteins such as gelatin is considered a good candidate for food packaging. However, ...
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Introduction: Natural polymers have gained increasing attention for the development of packaging to reduce ecologically-related problems caused by plastic packaging (environmental pollution). Among these natural polymers, proteins such as gelatin is considered a good candidate for food packaging. However, several studies have shown that gelatin films are brittle, and their hydrophilic nature connotes high water vapor permeability and water solubility. Different solutions have been suggested to overcome these weaknesses, including adding crosslinking agents and chemical modification, adding nanoparticles and developing bio-film blends and bilayers with polysaccharides. Agar is a polysaccharide extracted from marine red algae, which is biocompatible, has good mechanical properties and possesses good film-forming properties. Preventing food spoilage from light and oxygen-induced oxidation is one of the greatest concerns in the food industry. Despite having good mechanical and relatively good water vapor permeability properties, protein- or polysaccharide-based films don't have sufficient barrier properties against oxygen and UV light that can't properly prevent the oxidation of food products. Among nanoparticles, metal oxides like TiO2 (such as antiradiation and antimicrobial activities) and Montmorillonite (such as improved mechanical and barrier properties against moisture, WVP and gases) have evidenced good potential to improve functional properties of bio-films. Thus, the present study aimed to develop a new biodegradable bilayer agar/gelatin film incorporating nanoclay and TiO2 for food packaging, with maximum water sensitivity and maximum UV light and oxygen barrier properties.
Materials and Methods: Agar/gelatin bilayer films were prepared by a two-step casting technique. First, the agar layer was produced by solubilization of 1.5 g of agar powder (agar-agar analytical grade were obtained from Merck Co., Germany) in 100 mL of distilled water. Then, glycerol (obtained from Merck Co., Germany) was added as plasticizer. The agar film-forming solution was casted onto petri-dish. In the next step, the gelatin (obtained from cold water fish skin was purchased from Sigma-Aldrich, St. Louis, MO, USA) solutions were prepared by dissolving 4 g of the fish gelatin in 100 mL of distilled water. Glycerol was also added as plasticizer. The TiO2 dispersions (in ratios of 0 and 2% of the gelatin) and MMT (Na+–montmorillonite (in ratios of 0, 3, 5 and 10% of the gelatin)) were added to the gelatin solution and stirred and sonnicated. Finally, produced solutions were then casted. The agar/gelatin films, with or without TiO2 and MMT, were characterized using SEM analysis. Film transparency, water vapor permeability, water solubility, swelling, surface color and mechanical properties of the bilayer films were also examined.
Results and Discussion: In this study, bilayer films based on agar and gelatin incorporated with TiO2-MMT nanoparticles have been successfully developed. Results demonstrated that some properties of the bilayer films were greatly influenced by TiO2 and MMT nanoparticle content. So that, the addition of TiO2 decreased water vapor permeability of the bilayers more than 15%, upon increasing TiO2 content to 2%. However, swelling ratio and moisture content increased with the increase in the nano-TiO2 content, probably due to the hydrophilic nature of the TiO2 nanoparticles. Also, whiteness index (WI) increased by adding 2% of TiO2 nanoparticles. As shown in the surface photograph of the bilayer films, TiO2 generated more opaque and whiter films, which might be related to the white color of TiO2 nanoparticles in solution form. Also, the addition of MMT (0, 3, 5, and 10%) to bilayer-2% TiO2 significantly decreased water vapor permeability and transmission of UV light of the bilayer films. However, tensile strength (TS) decreased with further increase of the nanoparticle concentration. Increasing the concentration of nanoparticles' MMT to 5%, the tensile TS of the agar/gelatin films increased from 12.86 to 20.54 MPa; it might also be related to the interactions between sulphydryl and carboxylic groups from certain amino acids in the gelatin structure with MMT and TiO2 nanoparticles. However, the TS decreased again with further increase of the filler content up to 10% MMT. Also, the addition of MMT from 3%-10% concentration significantly reduced the elongation at break value (EB) of the bilayer films from 41.77 to 28.90% for the bilayer films (p
Zeinab Noori Hashemabad; Bahareh Shabanpour; Hamed Azizi; Seyed Mahdi Ojagh; Alireza Alishahi
Abstract
Introduction: The importance of maintenance and supply fresh fish instead of frozen due to the consumers interested in fresh fish is highly regarded. Titanium dioxide is a non-toxic nanoparticle that the American Food and Drug Administration approve its using at levels that are in contact with food. ...
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Introduction: The importance of maintenance and supply fresh fish instead of frozen due to the consumers interested in fresh fish is highly regarded. Titanium dioxide is a non-toxic nanoparticle that the American Food and Drug Administration approve its using at levels that are in contact with food. The antimicrobial and anti-fungal effects of this nanoparticle have been proven in a wide range of microorganisms (Saito et al, 1999).The use of titanium dioxide nanoparticles in polyethylene and polypropylene coatings has been investigated. The results showed that this nanoparticle, in addition to reducing the oxidation content of the package, could be effective in reducing silicone recovery of polyethylene and polypropylene in nature (Manangan et al, 2010). Rainbow trout is one of the most widely consumed breeding fish in Iran. Due to the high production and consumption of this fish, it is vital to take the necessary measures to maintain quality and increase its shelf-life. Therefore, this research was conducted to investigate the effect of titanium dioxide nanoparticle polyethylene packaging on quality and shelf-life of rainbow trout fillets during storage in a refrigerator.
Material and methods: Chemical (Peroxide value (PV) )Pearson,1997(., Tiobarbioritic acid (TBA) (Egan et al., 1997(, total volatile basic-nitrogen (TVB-N) (Pearson, 1997), pH), microbial (Total viable, Total viable counts, psychrophilic counts, lactic acid bacteria and Enterobacteriaceae) and Sensory analysis of samples was calculated and determined. The results of ANOVA using SPSS 16 software analysis and comparison of data using Duncan's multiple range test was 0.05 Sensory evaluation and analysis of non-parametric Mann-Whitney U test was used to test.
Result and Discussion: The process of microbial changes in the rainbow trout fillet was increased, except for the psychrophilic bacteria that were in the packaged nanocomposite treatment until the 4th day of the growing trend and then until the end of the period was reduced. Nanocomposites containing titanium dioxide containing nanoparticles prevent the growth of pseudomonas. (Bodaghi et al, 2013).The total amount of all chemical factors during the storage period showed an increasing trend in both treatments except for the factor observed in the packed sample. The results showed that in the control sample, the sensitivity rating on the day 8 was kept to a limit of less than 4, while in the sample packed with the nanocomposite until the 16th day, the points were less than the limit and the color score on day 12 Limiting receipts. Fat oxidation and microbial decomposition, and the production of esophagus combustion agents and fish tissue were changed. The antioxidant and antimicrobial effects of the packaged sample resulted in prolonging the shelf life and maintaining the quality of the fillets until the 16th day. Sensory, chemical and microbiological analysis results showed that the rainbow trout shelf life in nanocomposite packaging is suitable for 16-18 days.
