Feather, as a by-product of the poultry industry, has long been treated as a solid waste, which causes environ- mental and economic problems. In this work, the hydrolyzed feather keratin （HFK） was extracted from the...Feather, as a by-product of the poultry industry, has long been treated as a solid waste, which causes environ- mental and economic problems. In this work, the hydrolyzed feather keratin （HFK） was extracted from the chicken feather using a cost-effective method of alkali-extraction and acid-precipitation by applying urea and sodium sulfide. The aim was development and characterization of the eco-friendly films based on the HFK with variable glycerol contents by a thermoplastic process. The thermal analysis showed that high temperature and high pres- sure improved the compatibility between the glycerol and the HFI（ molecules. Also it was shown that the addi- tion of water is necessary in the hot-pressing process of films, The FT-IR analysis indicated that the formation of the new hydrogen bonds between HFK and glycerol. By increasing the glycerol content, the film tensile strength （orb ） decreases from 10,5 MPa to 5.7 MPa and the solubility increases from 15.3% to 20.9%, while the elongation at break （εb） achieves the maximum value of 63,8% for the film with 35% glycerol. The swelling was just below 16.9% at 25 ℃ for 24 h, suggesting a good stability of the films in water. The water vapor permeability （WVP） varied between 3.02 x 10 ^10g. m 2. s-1 . pa-1 and 4.11 x 10-10g · m-2 · s-1 · Pa-1 for the films with 20%and 40% glycerol, respectively. The HFK film was uniform, translucent and tough, which could be used in packaging and agricultural field.展开更多
In the present study, films and coatings for food applications based on a gum exudate from Brea tree （Cercidium praecox） were formulated and the influence of plasticizer content on their functional properties was ev...In the present study, films and coatings for food applications based on a gum exudate from Brea tree （Cercidium praecox） were formulated and the influence of plasticizer content on their functional properties was evaluated. Brea gum is a renewable resource available in semi-desert areas, extracted by native people. Films were produced by casting method and characterized through water vapour permeability, mechanical （tensile strength and elongation at break）, morphological and optical properties. Glycerol was used as plasticizer. Brea gum films presented good visual aspect, transparency and amber colour. Microscopic observation showed a dense and homogeneous structure. Film wettability increased with glycerol content due to hydrophilic nature of the plasticizer. Solubility of films in water increased with temperature. Water sorption isotherms of films at 25 ~C showed that at high aw （above 0.50）, the film matrix swells altering its structure and properties. Water vapour permeability remained practically constant up to 20% of glycerol content and then increases linearly with the plasticizer. The addition of glycerol decreased the opacity and tensile strength. The best film properties were obtained at 20% of glycerol concentration.展开更多
基金Supported by the National Natural Science Foundation of China(21176269,31371880,31401526)Higher School Science and Technology Innovation Project of Guangdong Province(2013KJCX0102)Science and Technology Plan Project of Guangdong Province(2013B010403029)
文摘Feather, as a by-product of the poultry industry, has long been treated as a solid waste, which causes environ- mental and economic problems. In this work, the hydrolyzed feather keratin （HFK） was extracted from the chicken feather using a cost-effective method of alkali-extraction and acid-precipitation by applying urea and sodium sulfide. The aim was development and characterization of the eco-friendly films based on the HFK with variable glycerol contents by a thermoplastic process. The thermal analysis showed that high temperature and high pres- sure improved the compatibility between the glycerol and the HFI（ molecules. Also it was shown that the addi- tion of water is necessary in the hot-pressing process of films, The FT-IR analysis indicated that the formation of the new hydrogen bonds between HFK and glycerol. By increasing the glycerol content, the film tensile strength （orb ） decreases from 10,5 MPa to 5.7 MPa and the solubility increases from 15.3% to 20.9%, while the elongation at break （εb） achieves the maximum value of 63,8% for the film with 35% glycerol. The swelling was just below 16.9% at 25 ℃ for 24 h, suggesting a good stability of the films in water. The water vapor permeability （WVP） varied between 3.02 x 10 ^10g. m 2. s-1 . pa-1 and 4.11 x 10-10g · m-2 · s-1 · Pa-1 for the films with 20%and 40% glycerol, respectively. The HFK film was uniform, translucent and tough, which could be used in packaging and agricultural field.
文摘In the present study, films and coatings for food applications based on a gum exudate from Brea tree （Cercidium praecox） were formulated and the influence of plasticizer content on their functional properties was evaluated. Brea gum is a renewable resource available in semi-desert areas, extracted by native people. Films were produced by casting method and characterized through water vapour permeability, mechanical （tensile strength and elongation at break）, morphological and optical properties. Glycerol was used as plasticizer. Brea gum films presented good visual aspect, transparency and amber colour. Microscopic observation showed a dense and homogeneous structure. Film wettability increased with glycerol content due to hydrophilic nature of the plasticizer. Solubility of films in water increased with temperature. Water sorption isotherms of films at 25 ~C showed that at high aw （above 0.50）, the film matrix swells altering its structure and properties. Water vapour permeability remained practically constant up to 20% of glycerol content and then increases linearly with the plasticizer. The addition of glycerol decreased the opacity and tensile strength. The best film properties were obtained at 20% of glycerol concentration.
