Dept of Food Science and Technology, Seoul Women's Univ, 621 Hwarangro, Nowon-gu Seoul 139-774, Republic of Korea.
J Food Sci. 2012 Sep;77(9):E240-6. doi: 10.1111/j.1750-3841.2012.02880.x. Epub 2012 Aug 21.
Edible biopolymer films were developed from gelatin extracted from trout skin (TSG) using thermal protein denaturation conditions and plasticizer (glycerol) concentration as variables. The amino acid composition of the TSG, elastic modulus, viscous modulus, and the viscosity of film-forming solutions, and tensile properties, water vapor permeability, solubility in water, and color of TSG-based films were determined. A 6.8% (w/w, wet basis) trout skin-extracted gelatin solution containing 9, 17, or 23% (w/w, dry basis) glycerol was heated at 80, 90, or 100 °C for 30, 45, or 60 min to prepare a film-forming solution. TSG can be characterized as a gelatin containing high contents of methionine and aspartic acid. The gelation temperature of the film-forming solution was 7 °C and the solution was subjected to heating to form a stable matrix for a film. Increased heating time of the film-forming solution reduced the film solubility (P < 0.05). Heating at 90 °C for 30 min was suggested as the requirement for film formation. As the concentration of glycerol in the film increased, film strength and moisture barrier properties decreased, while film stretchability increased (P < 0.05). Trout skin by-products can be used as a natural protein source for fabricating biopolymer films stable at ambient conditions with certain physical and moisture barrier properties by controlling thermal treatment conditions and glycerol concentrations.
The fishing industry produces a significant amount of waste, including fish skin, due to fish processing. Trout skin waste has potential value as a protein source that can be used to form biopolymer edible films for packaging low and intermediate water activity food products, and thus may have practical applications in the food industry, which could be one way to cut waste disposal in the trout processing industry.
本研究以从鳟鱼皮中提取的明胶为原料，通过热变性条件和增塑剂（甘油）浓度这两个变量，制备出可食用的生物聚合物薄膜。我们测定了鳟鱼皮明胶的氨基酸组成、弹性模量、粘性模量、薄膜形成溶液的黏度以及鳜鱼皮基薄膜的拉伸性能、水蒸气透过率、在水中的溶解度和颜色。将 6.8%（w/w，湿基）的鳜鱼皮提取明胶溶液与 9%、17%或 23%（w/w，干基）甘油混合，加热至 80、90 或 100°C 并保持 30、45 或 60min，以制备成膜溶液。鳜鱼皮明胶可以被认为是一种含有高含量蛋氨酸和天冬氨酸的明胶。成膜溶液的胶凝温度为 7°C，该溶液受热后可形成稳定的薄膜基质。增加成膜溶液的加热时间会降低薄膜的溶解度（P<0.05）。建议将 90°C 加热 30min 作为成膜的要求。随着薄膜中甘油浓度的增加，薄膜的强度和水分阻隔性能降低，而拉伸性能增加（P<0.05）。通过控制热处理条件和甘油浓度，可以利用鱼皮等水产加工副产物作为天然蛋白质源，制备在环境条件下稳定、具有一定物理和水分阻隔性能的生物聚合物薄膜，这在食品工业中具有实际应用价值，也是减少鳜鱼加工行业废物处理的一种方法。
由于鱼类加工，渔业会产生大量的废物，包括鱼皮。鳜鱼皮废弃物具有作为蛋白质来源的潜在价值，可用于形成可食用的生物聚合物薄膜，用于包装低水分活度和中等水分活度的食品，因此在食品工业中有实际应用价值，这可能是减少鳜鱼加工行业废物处理的一种方法。
