加工工程での食品タンパク質の品質改良並びにその機能改変

抄録

When surimi containing nitro blue tetrazolium was heated with vitamin C (AsA), the color intensified. This coloration faded upon the addition of tiron, a scavenger of the superoxide anion radical (), indicating that was generated from AsA in the surimi. In myosin prepared from carp, the generation of thiyl radicals (S•) by was detected using electron spin resonance spectroscopy. These results illustrate the quality improvement mechanism of AsA in gelatinous protein foods as follows: (1) AsA added to surimi reduces the transition metal, which becomes oxidized, (2) O₂ is reduced to via one-electron reduction, (3) pulls hydrogen radicals (H•) from the SH group on myosin to form S•, and (4) disulfide (SS) bonds are formed between myosins by radical oxidation, which leads to a denser structure and a quality improvement effect. When cream chicken was prepared using the vacuum cooking method, separation was observed in the sauce. This phenomenon was caused by the dissolution of soluble proteins in the meat during heating. The soluble protein was examined by scanning electron microscopy and was found to consist of spherical particles in a random structure at 75°C heating; upon heating to 90°C, the SS bonds formed a strong structure, resulting in a more uniform material and forming a gel with a wide space and a large surface area. Thus, heating to 90°C is speculated to be the reason for the separation of the source, as the structure at 90°C firmly held the casein micelles and oil droplets. In the functional alteration of chicken myofibrillar proteins (Mfs) through glycation, using the Maillard reaction, the solubility of protein in low-ionic-strength solutions and the antioxidant capacity were determined. The glucose-modified chicken Mfs showed antioxidant capacity in the heated gel. In contrast, the glucose-modified soybean 11S globulin showed high emulsification stability, indicating the possibility of developing an emulsifier that suppresses oil autoxidation. As an antioxidant, soybean 11S globulin was also found to be sufficient to suppress oil oxidation.