Nonprotein Nitrogenous Compounds and Gelling Property of Whitecheek Shark (C archarhinus Dussumieri ) Mince as Affected by Washing and Microbial Transglutaminase

Abstract

Changes in nonprotein nitrogenous compounds and gelling properties of whitecheek shark (Carcharhinus dussumieri) meat during iced storage for 12 days were monitored. Total volatile base (TVB), trimethylamine (TMA) and ammonia contents increased, whereas urea content decreased during the storage (P < 0.05). TVB, TMA, urea and ammonia contents were lower in washed mince, indicating the removal of those compounds by washing. The addition of microbial transglutaminase (MTGase, 0.6 unit/g sample) was able to increase breaking force, deformation and water-holding capacity of both gels from mince and washed mince. Nevertheless, gel strengthening effect of MTGase was lowered when mince or washed mince were obtained from shark stored for an extended time. Polymerization of myosin heavy chain was enhanced when MTGase was incorporated but took place at a lower degree for mince and washed mince produced from unfresh shark. Washing process in combination with MTGase addition could therefore improve gel quality of shark meat. Practical Applications Shark meat is a good source of protein, which could be a suitable source for surimi production. However, the meat is considered to have a low market value because of undesirable odor, which is mainly from the decomposition of urea to ammonia during extended storage. Appropriate washing to remove those compounds, along with the use of microbial transglutaminase (MTGase), can be a promising means to improve the textural properties of gels from shark mince. Thus, shark meat can be better exploited, especially for the surimi industry.