Food Technology
Bahareh Shabanpour; Parastoo Pourashouri; Aniseh Jamshidi; Kaveh Rahmani farah; Akbar Vejdan Taleshmikaeil
Abstract
Introduction
Consumption of ready-to-eat products especially seafood, has become very popular based on the lifestyle during these years. Battered and breaded products are highly acceptable due to their attractive appearance and unique taste. Shrimp and shrimp products are one of the most popular ...
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Introduction
Consumption of ready-to-eat products especially seafood, has become very popular based on the lifestyle during these years. Battered and breaded products are highly acceptable due to their attractive appearance and unique taste. Shrimp and shrimp products are one of the most popular seafood products in many countries because of their unique flavor, nutritional value and texture. The interactions of proteins with other ingredients can play a critical role in the structure of processed foods. Protein-polysaccharide interactions provide functional properties in foods especially when proteins are the main ingredients, such as processed shrimp products without affecting the original flavor of the food. The use of gelling properties of carbohydrates in the formulation of food products is increasingly growing. The wide variety of hydrocolloids have been examined to modify the mechanical, textural and functional properties of shrimp products. In this regard, application of carrageenan, xanthan, and alginate have been reported to improve the physicochemical and sensory attributes of shrimp products. In the present study, surimi was produced and used in combination with different percentages of carrageenan, alginate and xanthan gums in order to simulate breaded shrimp and produce shrimp nuggets with a texture similar to battered and breaded shrimp.
Materials and Methods
In the first step, surimi was prepared from silver carp fillets. In the next step, shrimp nuggets were produced from obtained surimi in combination with additives (including starch, salt, garlic, and spices) and different percentages (0.5, 1, 1.5 and 2% ) of carrageenan, alginate and xanthan gums. The prepared mixture was kept at 35 °C for 1 hour and then battered and breaded after molding. Physical (expressible water, product yield, and shrinkage), chemical (moisture, fat, and pH), color, texture, and sensory analysis were performed on several samples of shrimp nuggets (containing different percentages of carrageenan, alginate, and xanthan gums) in comparison with the control sample (battered and breaded shrimp immersed in salt and polyphosphate).
Results and Discussion
Based on the results, the amount of shrinkage decreased in all samples containing gums in comparison with the control (p < 0.05). Shrimp nuggets containing xanthan and alginate showed a lower amount of fat in comparison with the control and the samples containing carrageenan (p < 0.05). The highest amount of pH value observed in the control sample, and the sample containing 1.5 and 2 % alginate showed the lowest amounts of pH. The shrimp nuggets containing 2 % alginate demonstrated the highest amounts of water holding capacity.However, the other samples did not show significant differences with the control (p > 0.05). There were no significant differences between the control and shrimp nuggets containing gums in terms of product yield (p > 0.05). Shrimp nuggets containing 2 % xanthan and the control showed the highest and lowest amounts of brightness, respectively. The highest value of adhesion observed in shrimp nuggets containing 2 % alginate and the control.The lowest amounts of adhesion were observed in shrimp nuggets containing 2 % xanthan, 0.5 % alginate, 1 and 2 % carrageenan (p < 0.05). Samples containing 1% carrageenan showed the highest scores of the sensory attributes of taste, smell, texture and overall acceptance, as same as the control (p ˃ 0.05).
Conclusion
Hydrocolloid additions were found to be significantly affecting the quality parameters including fat content, pH value, shrinkage and texture of produced shrimp nuggets. Therefore, it seems that producing shrimp nuggets containing 1 % carrageenan showed the nearest physical, chemical, and sensory characteristics to the control (battered and breaded shrimp), and this sample can be used as alternative of battered and breaded shrimp.
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
