بررسي علل فساد زود رس كوسه ماهي منجمد

A surv ey of the reasons for early corruption of frozen sharks

Significa nt biochmical differ en ces exi st be tween sharks and verteb ra ted fishes . Th e level of nonpro teinous nitr og en ous mater ial in sha rks is 8 times more than other marine crea tures .The sys tem ofabso rbing and exc reting urea in sharks is outsta nd ing among fishes. High content o f blood urea and TMAO he lp th is anima l keep the os mo tic pressure ba lance d .So they are able to live in bot h salt-water & fresh water . To prevent spo ilage, blood extract ion have to be per form ed a fte r hunti ng. Thi s s tep can not perform ed comple te ly in large sharks becau se the blo od gus hes out not jets out. . The idea of thi s resarch was based on the reports o f unpleasant sme ll of fishes present ed in the market whic b are so ld as Acipeneer Stellatu s and som e cases ofallergy &hyp ersens itivity . Tnthi s survey which was carr ied out during auto mn & winter from sma ll re frcgcra ting rooms in the region o f Sarchcshrnch, 34 cases (74%) o f sha rks and 38 (53%) of other fishes were selected. These fishes that were transported to preserv ing room sirnoultanous ly, were sampled by ex pe rts and tran sfer ed to the laboratory qui ckly. Th e result of examination was reported according to TVN test to di stin guish fish spoilage . From 34 cases o f shark , 29 (85/29%) we re not suitab le for consuming because of hav ing high index o f TVN test. Th e remaining cases (14/7 %) were about to spoil and so werenot appropria te for present ing in th e market. From the se cond group (38 ca ses) am ong whi ch 10 fishes were cut into pieces, ju st 8 ea scs(2 1°1.1) were not suitab le for coo kin g .10 ca5c5(26.4%) were at the border o f bein g spoilage and the re st(52.6%) we re suitable to be cons umed by cos tumers . .The majority of unsuitable or low qu ali ty cases were those whi ch were cut into pieces