Abstract: During the hydrolysis ofsmall yellow fish meat the concentration changes of protein nucleic acid αamino nitrogen,total nitrogen and clarity level were measured by 280nm uv,260nm uv,biuret reaction formaldehyde method.MicroKjeldahl method and 640nm visible spectrometer.The experiment results showed that instead of Micro-Kjeldahl method,280nm uv measure could be used tbr analysis total nitrogen amount change during the specially designated hydrolysis.The absorbency at 280nm was regularly increased in a steady rate.The relation betWeen total nitrogen and absorbency at 280nm could be written as Y=2.O16X-0.04.The absorbency increase at 260nm illustrated that the procedure of fish meat hydrolysis accompanied the release of nucleic acid .The absorbency at 540nm for biuret reaction decreased during the procedure.The results showed that the soluble protein in the clear liquid was digested.The amount of α amino nitrogen produced was in proportion to the delicious tase.

Key words: Fish protein Enzyme Hydrolysis Ultrviolet absorption Biuret reaction Amino nitrogen