Optimization Processing Technique Of Cured Fish And Studies On Factors Effect On Flavor Development Of Cured Fish

Effect of processing technique on quality of cured fish made of silver carp was studied, the model of evaluation of cured fish's quality was established. Two novel processing techniques, named as low-temperature, low-salt pickle technique and low-temperature drying technique were put forward. The pickle dynamics model was set up to describe the diffusion process of brine. The volatiles in cured fish were extracted and identified through solid phase micro-extraction (SPME) and GC-MS. Results were summrised as follows:The quality of cured fish could be valued by content of solids, rough protein, sodium chloride, water-soluble protein, amino nitrogen, total acidity and value of 2-thiobarbituric acid, and the sensory quality of cured fish could be divided into five types, such as salt taste, delicate, daintiness, aroma and texture. Texture property of cured fish is comprised of toughness, extension, shear and elasticity. Cured fish with high sensory and texture quality could be achieved, if solids content in cured fish ranged from 54.0% to 64.0%, sodium chloride from 4.0% to 8.0%, rough protein from 66.0% to 70.0%, amino nitrogen from 0.34% to 0.39%, value of 2-thiobarbituric acid from 2.3 ×10^-6 to 3.8 ×10^-6, water-soluble protein > 8.0%, and total acidity ≤ 0.10 mol/kg.The processing technique and parameters significantly affected quality of cured fish, and the best condition was pickleing fish at low temperature and low salte constant in brine. Cured fish with high quality could be obtained while fish was pickled in 10% sodium chloride solution for 3 hours at 10℃, then dried at 10～20℃ for 66～96 hours. Content of sodium chloride in fish-muscle, water-soluble protein and amino nitrogen in brine could be well described by dynamics models with time, temperature and sodium chloride concentration during pickle processing.With SPME collecting volatile compounds in cured fish, the optimum technique was: cured fish powder in 5 milliliter extraction bottle, adsorbed with the SPME fiber with 5μrn polyacrylate (PA) for 30 minutes at 35℃, then the fiber directly thermal desorpted for 8 minutes in the injector of GC. Pickle significantly affected types and content of volatile compounds of cured fish. The volatile compounds in cured fish varied with concentration of brine, and many kinds of ester compounds exsited in cured fish pickled in different brine.There were more kinds of volatile compounds in cured fish dried at lower temperature than at higher temperature, so pickled fish should be dried at lower temperature to obtain cured fish with high quality.